Santander Uk 20-F 7 Mar 22 2021 FY Annual report (foreign) Financial data

Cover Page

Cover Page	12 Months Ended
	Dec. 31, 2021shares
Document And Entity Information [Line Items]
Document Type	20-F
Document Registration Statement	false
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Document Shell Company Report	false
Entity File Number	001-37595
Entity Registrant Name	Santander UK Group Holdings plc
Entity Incorporation, State or Country Code	X0
Entity Address, Address Line One	2 Triton Square
Entity Address, Address Line Two	Regent’s Place
Entity Address, City or Town	London
Entity Address, Postal Zip Code	NW1 3AN
Entity Address, Country	GB
Entity Common Stock, Shares Outstanding	7,060,000,000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Document Accounting Standard	International Financial Reporting Standards
Entity Shell Company	false
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Entity Central Index Key	0001649373
Business Contact
Document And Entity Information [Line Items]
Entity Address, Address Line One	2 Triton Square
Entity Address, Address Line Two	Regent’s Place
Entity Address, City or Town	London
Entity Address, Postal Zip Code	NW1 3AN
Entity Address, Country	GB
Contact Personnel Name	Julian Curtis
City Area Code	+44
Local Phone Number	800 085 1491
Contact Personnel Email Address	julian.curtis@santander.co.uk
3.571% Notes due 2023
Document And Entity Information [Line Items]
Title of 12(b) Security	3.571% Notes due 2023
Trading Symbol	SAN/23
Security Exchange Name	NYSE
3.373% Fixed Rate/Floating Rate Notes due 2024
Document And Entity Information [Line Items]
Title of 12(b) Security	3.373% Fixed Rate/Floating Rate Notes due 2024
Trading Symbol	SAN/24A
Security Exchange Name	NYSE
4.796% Fixed Rate/Floating Rate Notes due 2024
Document And Entity Information [Line Items]
Title of 12(b) Security	4.796% Fixed Rate/Floating Rate Notes due 2024
Trading Symbol	SAN/24B
Security Exchange Name	NYSE
1.089% Fixed Rate/Floating Rate Notes due 2025
Document And Entity Information [Line Items]
Title of 12(b) Security	1.089% Fixed Rate/Floating Rate Notes due 2025
Trading Symbol	SAN/25C
Security Exchange Name	NYSE
1.532% Fixed Rate Resetting Notes due 2026
Document And Entity Information [Line Items]
Title of 12(b) Security	1.532% Fixed Rate Resetting Notes due 2026
Trading Symbol	SAN/26
Security Exchange Name	NYSE
1.673% Fixed Rate/Floating Rate Notes due 2027
Document And Entity Information [Line Items]
Title of 12(b) Security	1.673% Fixed Rate/Floating Rate Notes due 2027
Trading Symbol	SAN/27A
Security Exchange Name	NYSE
3.823% Fixed Rate/Floating Rate Notes due 2028
Document And Entity Information [Line Items]
Title of 12(b) Security	3.823% Fixed Rate/Floating Rate Notes due 2028
Trading Symbol	SAN/28
Security Exchange Name	NYSE
2.896% Fixed Rate/Floating Rate Notes due 2032
Document And Entity Information [Line Items]
Title of 12(b) Security	2.896% Fixed Rate/Floating Rate Notes due 2032
Trading Symbol	SAN/32
Security Exchange Name	NYSE

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Audit Information [Abstract]
Auditor Firm ID	876
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	London, UK

Consolidated Income Statement

Consolidated Income Statement - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	[1]	Dec. 31, 2019	[1]
Profit (loss) [abstract]
Interest and similar income	£ 4,830	£ 5,071		£ 5,872
Interest expense and similar charges	(833)	(1,690)		(2,645)
Net interest income	3,997	3,381		3,227
Fee and commission income	694	681		1,043
Fee and commission expense	(414)	(363)		(416)
Net fee and commission income	280	318		627
Other operating income	267	136		178
Total operating income	4,544	3,835		4,032
Operating expenses before credit impairment write-backs/losses, provisions and charges	(2,540)	(2,425)		(2,466)
Credit impairment write-backs/ (losses)	233	(639)		(198)
Provisions for other liabilities and charges	(379)	(263)		(428)
Total operating credit impairment write-backs/losses, provisions and charges	(146)	(902)		(626)
Profit from continuing operations before tax	1,858	508		940
Tax on profit from continuing operations	(485)	(101)		(261)
Profit from continuing operations after tax	1,373	407		679
Profit/(loss) from discontinued operations after tax	32	31		30
Profit after tax	1,405	438		709
Attributable to:
Equity holders of the parent	1,369	402		672
Non-controlling interests	36	36		37
Profit after tax	£ 1,405	£ 438		£ 709
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Statement of comprehensive income [abstract]
Profit after tax	£ 1,405	£ 438	[1]	£ 709	[1]
Movement in fair value reserve (debt instruments):
Change in fair value	(111)	114		147
Income statement transfers	110	(107)		(147)
Taxation	(2)	(2)		0
Other comprehensive income, fair value reserve (debt instruments)	(3)	5		0
Cash flow hedges:
Effective portion of changes in fair value	(875)	974		(864)
Income statement transfers	357	(803)		1,021
Taxation	142	(53)		(40)
Other comprehensive income, cash flow hedges, total	(376)	118		117
Currency translation on foreign operations	0	0		(3)
Net other comprehensive (expense)/income that may be reclassified to profit or loss subsequently	(379)	123		114
Pension remeasurement:
Change in fair value	1,263	(505)		(523)
Taxation	(419)	133		131
Pension remeasurement, total	844	(372)		(392)
Own credit adjustment:
Change in fair value	0	(3)		(77)
Taxation	0	0		19
Own credit adjustment, total	0	(3)		(58)
Net other comprehensive income/(expense) that will not be reclassified to profit or loss subsequently	844	(375)		(450)
Total other comprehensive income/(expense) net of tax	465	(252)		(336)
Total comprehensive income	1,870	186		373
Attributable to:
Equity holders of the parent	1,834	152		334
Non-controlling interests	36	34		39
Total comprehensive income	£ 1,870	£ 186		£ 373
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Consolidated Balance Sheet

Consolidated Balance Sheet - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Assets
Cash and balances at central banks	£ 50,494	£ 43,537
Financial assets at fair value through profit or loss:
Derivative financial instruments	1,720	3,451
Other financial assets at fair value through profit or loss	676	834
Financial assets at amortised cost:
Loans and advances to customers	213,525	212,178
Loans and advances to banks	1,420	2,004
Reverse repurchase agreements – non trading	12,683	19,599
Other financial assets at amortised cost	506	1,163
Financial assets at fair value through other comprehensive income	5,851	8,950
Interests in other entities	201	172
Intangible assets	1,545	1,649
Property, plant and equipment	1,555	1,740
Current tax assets	351	271
Retirement benefit assets	1,573	496
Other assets	1,576	3,020
Total assets	293,676	299,064
Financial liabilities at fair value through profit or loss:
Derivative financial instruments	1,019	1,920
Other financial liabilities at fair value through profit or loss	803	1,434
Financial liabilities at amortised cost:
Deposits by customers	192,914	193,088
Deposits by banks	33,862	20,973
Repurchase agreements – non trading	11,718	15,848
Debt securities in issue	31,580	43,679
Subordinated liabilities	2,228	2,556
Other liabilities	2,198	2,343
Provisions	366	468
Deferred tax liabilities	573	107
Retirement benefit obligations	37	403
Total liabilities	277,298	282,819
Equity
Share capital	7,060	7,060
Other equity instruments	2,191	2,241
Retained earnings	6,754	6,030
Other reserves	138	517
Total shareholders’ equity	16,143	15,848
Non-controlling interests	235	397
Total equity	16,378	16,245
Total liabilities and equity	£ 293,676	£ 299,064

Consolidated Cash Flow Statemen

Consolidated Cash Flow Statement - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Cash flows from operating activities
Profit after tax	£ 1,405	£ 438	[1]	£ 709	[1]
Non-cash items included in profit:
– Depreciation and amortisation	506	570		545
– Provisions for other liabilities and charges	383	274		443
– Impairment losses	(228)	672		238
– Corporation tax charge	497	114		272
– Other non-cash items	(244)	93		(345)
– Pension charge/(credit) for defined benefit pension schemes	38	38		35
Non-cash items included in profit	952	1,761		1,188
Net change in operating assets and liabilities:
– Cash and balances at central banks	(64)	(152)		(84)
– Derivative assets	1,731	(88)		1,959
– Other financial assets at fair value through profit or loss	1,143	1,561		1,637
– Loans and advances to banks and customers	(960)	(5,421)		(605)
– Reverse repurchase agreements - non trading	7,024	3,924		(5,044)
– Other assets	327	(343)		240
– Deposits by banks and customers	12,747	20,812		2,225
– Repurchase agreements - non trading	(7,550)	(2,959)		5,943
– Derivative liabilities	(902)	211		115
– Other financial liabilities at fair value through profit or loss	(1,109)	(1,618)		(959)
– Debt securities in issue	(330)	(202)		(548)
– Other liabilities	(608)	(937)		(545)
Net change in operating assets and liabilities	11,449	14,788		4,334
Corporation taxes paid	(418)	(161)		(309)
Effects of exchange rate differences	(640)	366		(1,445)
Net cash flows from operating activities	12,748	17,192		4,477
Cash flows from investing activities
Purchase of property, plant and equipment and intangible assets	(615)	(378)		(510)
Proceeds from sale of property, plant and equipment and intangible assets	437	166		108
Purchase of financial assets at amortised cost and financial assets at FVOCI	(1,256)	(3,015)		(5,013)
Proceeds from sale and redemption of financial assets at amortised cost and financial assets at FVOCI	4,509	9,858		8,300
Net cash flows from investing activities	3,075	6,631		2,885
Cash flows from financing activities
Issue of other equity instruments	450	0		500
Issuance costs of other equity instruments	0	0		0
Issue of debt securities and subordinated notes	2,853	5,599		4,145
Issuance costs of debt securities and subordinated notes	(6)	(13)		(15)
Repayment of debt securities and subordinated notes	(13,728)	(13,287)		(7,969)
Disposal of non-controlling interests	(181)	0		(14)
Repurchase of other equity instruments	(500)	0		(304)
Dividends paid on ordinary shares	(1,346)	(103)		(262)
Dividends paid on other equity instruments	(143)	(147)		(142)
Dividends paid on non-controlling interests	(17)	(32)		(30)
Principal elements of lease payments	(25)	(46)		(55)
Net cash flows from financing activities	(12,643)	(8,029)		(4,146)
Change in cash and cash equivalents	3,180	15,794		3,216
Cash and cash equivalents at beginning of the year	50,206	34,367		31,204
Effects of exchange rate changes on cash and cash equivalents	(19)	45		(53)
Cash and cash equivalents at end of the year	53,367	50,206		34,367
Cash and cash equivalents consist of:
Cash and balances at central banks	50,494	43,537		26,395
Less: regulatory minimum cash balances	(935)	(871)		(720)
Cash and bank balances at central banks less regulatory minimum cash balances	49,559	42,666		25,675
Other cash equivalents: Loans and advances to banks - Non trading	1,270	1,690		2,209
Other cash equivalents: Reverse repurchase agreements	2,538	5,850		6,483
Cash and cash equivalents at the end of the year	£ 53,367	£ 50,206		£ 34,367
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Consolidated Statement of Chang

Consolidated Statement of Changes in Equity - GBP (£) £ in Millions	Total		Total	Share capital	Other equity instruments	Fair value	Cash flow hedging	Currency translation	Retained earnings	Non-controlling interests
Beginning balance at Dec. 31, 2018	£ 16,220		£ 15,820	£ 7,060	£ 2,041	£ 24	£ 251	£ 5	£ 6,439	£ 400
Profit after tax	709	[1]	672						672	37
Other comprehensive (expense)/income, net of tax:
– Fair value reserve (debt instruments)	0
– Cash flow hedges	117		117				117
– Pension remeasurement	(392)		(394)						(394)	2
– Own credit adjustment	(58)		(58)						(58)
– Currency translation on foreign operations	(3)		(3)					(3)
Total comprehensive income	373		334			0	117	(3)	220	39
Issue of other equity instruments	500		500		500
Repurchase of other equity instruments	(304)		(304)		(300)				(4)
Dividends on ordinary shares	(262)		(262)						(262)
Dividends on other equity instruments	(142)		(142)						(142)
Dividends on non-controlling interests	(30)									(30)
Repurchase of non-controlling interests	(14)									(14)
Ending balance at Dec. 31, 2019	16,341		15,946	7,060	2,241	24	368	2	6,251	395
Profit after tax	438	[1]	402						402	36
Other comprehensive (expense)/income, net of tax:
– Fair value reserve (debt instruments)	5		5			5
– Cash flow hedges	118		118				118
– Pension remeasurement	(372)		(370)						(370)	(2)
– Own credit adjustment	(3)		(3)						(3)
Total comprehensive income	186		152			5	118	0	29	34
Dividends on ordinary shares	(103)		(103)						(103)
Dividends on other equity instruments	(147)		(147)						(147)
Dividends on non-controlling interests	(32)									(32)
Ending balance at Dec. 31, 2020	16,245		15,848	7,060	2,241	29	486	2	6,030	397
Profit after tax	1,405		1,369						1,369	36
Other comprehensive (expense)/income, net of tax:
– Fair value reserve (debt instruments)	(3)		(3)			(3)
– Cash flow hedges	(376)		(376)				(376)
– Pension remeasurement	844		844						844
– Own credit adjustment	0
Total comprehensive income	1,870		1,834			(3)	(376)	0	2,213	36
Issue of other equity instruments	450		450		450
Disposal of non-controlling interests	(181)									(181)
Repurchase of other equity instruments	(500)		(500)		(500)
Other	0
Dividends on ordinary shares	(1,346)		(1,346)						(1,346)
Dividends on other equity instruments	(143)		(143)						(143)
Dividends on non-controlling interests	(17)									(17)
Ending balance at Dec. 31, 2021	£ 16,378		£ 16,143	£ 7,060	£ 2,191	£ 26	£ 110	£ 2	£ 6,754	£ 235
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Company Balance Sheet

Company Balance Sheet - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Financial assets at fair value through profit or loss:
Other financial assets at fair value through profit or loss	£ 676	£ 834
Financial assets at amortised cost:
Loans and advances to banks	1,420	2,004
Other financial assets at amortised cost	506	1,163
Interests in other entities	201	172
Current tax assets	351	271
Other assets	1,576	3,020
Total assets	293,676	299,064
Financial liabilities at fair value through profit or loss:
Other financial liabilities at fair value through profit or loss	803	1,434
Financial liabilities at amortised cost:
Deposits by banks	33,862	20,973
Debt securities in issue	31,580	43,679
Subordinated liabilities	2,228	2,556
Other liabilities	2,198	2,343
Total liabilities	277,298	282,819
Equity
Share capital	7,060	7,060
Other equity instruments	2,191	2,241
Retained earnings	6,754	6,030
Total equity	16,378	16,245
Total liabilities and equity	293,676	299,064
Santander UK Group Holdings plc
Financial assets at fair value through profit or loss:
Other financial assets at fair value through profit or loss	4,190	1,425
Financial assets at amortised cost:
Loans and advances to banks	5,926	7,934
Other financial assets at amortised cost	838	830
Interests in other entities	13,590	13,585
Current tax assets	15	11
Other assets	2	1
Total assets	24,561	23,786
Financial liabilities at fair value through profit or loss:
Other financial liabilities at fair value through profit or loss	4,190	1,425
Financial liabilities at amortised cost:
Deposits by banks	7	7
Debt securities in issue	6,013	7,970
Subordinated liabilities	838	830
Other liabilities	0	1
Total liabilities	11,048	10,233
Equity
Share capital	7,060	7,060
Other equity instruments	2,191	2,241
Retained earnings	4,262	4,252
Total equity	13,513	13,553
Total liabilities and equity	£ 24,561	£ 23,786

Company Cash Flow Statement

Company Cash Flow Statement - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Cash flows from operating activities
Profit after tax	£ 1,405	£ 438	[1]	£ 709	[1]
Adjustments for:
Non-cash items included in profit	952	1,761		1,188
Net change in operating assets and liabilities	11,449	14,788		4,334
Corporation taxes paid	(418)	(161)		(309)
Effects of exchange rate differences	(640)	366		(1,445)
Net cash flows from operating activities	12,748	17,192		4,477
Cash flows from investing activities
Purchase of financial assets at amortised cost and financial assets at fair value	(1,256)	(3,015)		(5,013)
Proceeds from sale and redemption of financial assets at amortised cost and financial assets at FVOCI	4,509	9,858		8,300
Net cash flows from investing activities	3,075	6,631		2,885
Cash flows from financing activities
Issue of other equity instruments	450	0		500
Issuance costs of other equity instruments	0	0		0
Issue of debt securities and subordinated notes	2,853	5,599		4,145
Repayment of debt securities and subordinated notes	(13,728)	(13,287)		(7,969)
Repurchase of other equity instruments	(500)	0		(304)
Issuance costs of debt securities and subordinated notes	(6)	(13)		(15)
Dividends paid on ordinary shares	(1,346)	(103)		(262)
Dividends paid on other equity instruments	(143)	(147)		(142)
Principal elements of lease payments	(25)	(46)		(55)
Net cash flows from financing activities	(12,643)	(8,029)		(4,146)
Change in cash and cash equivalents	3,180	15,794		3,216
Cash and cash equivalents at beginning of the year	50,206	34,367		31,204
Cash and cash equivalents at end of the year	53,367	50,206		34,367
Santander UK Group Holdings plc
Cash flows from operating activities
Profit after tax	1,499	240		449
Adjustments for:
Non-cash items included in profit	(3)	15
Net change in operating assets and liabilities	1,937	975
Corporation taxes paid	0	0
Effects of exchange rate differences	(94)	(51)
Net cash flows from operating activities	3,339	1,179
Cash flows from investing activities
Purchase of financial assets at amortised cost and financial assets at fair value	(2,774)	(1,424)		0
Proceeds from sale and redemption of financial assets at amortised cost and financial assets at FVOCI	0	336
Investments in other entities	0	0
Net cash flows from investing activities	(2,774)	(1,088)
Cash flows from financing activities
Issue of other equity instruments	450	0
Issuance costs of other equity instruments	0	0
Issue of debt securities and subordinated notes	2,797	1,410
Repayment of debt securities and subordinated notes	(8)	(1,250)
Repurchase of other equity instruments	(1,814)	0
Issuance costs of debt securities and subordinated notes	(500)	(1)
Dividends paid on ordinary shares	(1,346)	(103)
Dividends paid on other equity instruments	(143)	(147)
Principal elements of lease payments	0	0
Net cash flows from financing activities	(564)	(91)
Change in cash and cash equivalents	1	0
Cash and cash equivalents at beginning of the year	51	51
Cash and cash equivalents at end of the year	£ 52	£ 51		£ 51
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Company Statement of Changes in

Company Statement of Changes in Equity - GBP (£) £ in Millions	Total		Share capital	Other equity instruments	Retained earnings	Santander UK Group Holdings plc	Santander UK Group Holdings plcShare capital	Santander UK Group Holdings plcOther equity instruments	Santander UK Group Holdings plcRetained earnings
Beginning balance at Dec. 31, 2018	£ 16,220		£ 7,060	£ 2,041	£ 6,439
Profit after tax	709	[1]			672	£ 449
Issue of other equity instruments	500			500
Repurchase of other equity instruments	(304)			(300)	(4)
Dividends on ordinary shares	(262)				(262)
Dividends on other equity instruments	(142)				(142)
Ending balance at Dec. 31, 2019	16,341		7,060	2,241	6,251	13,563	£ 7,060	£ 2,241	£ 4,262
Profit after tax	438	[1]			402	240			240
Dividends on ordinary shares	(103)				(103)	(103)			(103)
Dividends on other equity instruments	(147)				(147)	(147)			(147)
Ending balance at Dec. 31, 2020	16,245		7,060	2,241	6,030	13,553	7,060	2,241	4,252
Profit after tax	1,405				1,369	1,499			1,499
Issue of other equity instruments	450			450		450		450
Repurchase of other equity instruments	(500)			(500)		(500)		(500)
Dividends on ordinary shares	(1,346)				(1,346)	(1,346)			(1,346)
Dividends on other equity instruments	(143)				(143)	(143)			(143)
Ending balance at Dec. 31, 2021	£ 16,378		£ 7,060	£ 2,191	£ 6,754	£ 13,513	£ 7,060	£ 2,191	£ 4,262
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Company Income Statement

Company Income Statement - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Statement [Line Items]
Interest and similar income	£ 4,830	£ 5,071	[1]	£ 5,872	[1]
Interest expense and similar charges	(833)	(1,690)	[1]	(2,645)	[1]
Net interest income	3,997	3,381	[1]	3,227	[1]
Other operating income	267	136	[1]	178	[1]
Total operating income	4,544	3,835	[1]	4,032	[1]
Operating expenses before credit impairment losses, provisions and charges	(2,540)	(2,425)	[1]	(2,466)	[1]
Tax on profit	(485)	(101)	[1]	(261)	[1]
Profit after tax	1,405	438	[1]	709	[1]
Santander UK Group Holdings plc
Statement [Line Items]
Interest and similar income	221	309		317
Interest expense and similar charges	(225)	(312)		(320)
Net interest income	(4)	(3)		(3)
Dividend income	1,497	260		450
Other operating income	8	(15)		4
Total operating income	1,501	242		451
Operating expenses before credit impairment losses, provisions and charges	(6)	(7)		(7)
Profit before tax	1,495	235		444
Tax on profit	4	5		5
Profit after tax	£ 1,499	£ 240		£ 449
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Risk Framework

Risk Framework	12 Months Ended
	Dec. 31, 2021
Risk Framework [Abstract]
Risk Framework	Our risk governance structure We are committed to the highest standards of corporate governance in every part of our business, including risk management. For details of our governance, including the Board and its Committees, see the ‘Governance’ section of this Annual Report. The Board delegates certain responsibilities to Board Level Committees as needed and where appropriate. Our risk governance structure strengthens our ability to identify, assess, manage and report risks, as follows: – Committees: A number of Board and Executive committees are responsible for specific parts of our Risk Framework – Key senior management roles: A number of senior roles have specific responsibilities for risk management – Risk organisational structure: We have the ‘three lines of defence’ model built into the way we run our business. Committees The Board and Board Level Committee responsibilities for risk are: Board Level Committee Main risk responsibilities The Board (including the Santander UK plc Board) – Has overall responsibility for business execution and for managing risk – Reviews and approves the Risk Framework and Risk Appetite Board Risk Committee (BRC) – Assesses the Risk Framework and recommends it to the Board for approval – Advises the Board on our overall Risk Appetite, tolerance and strategy – Oversees our exposure to risk and our strategy and advises the Board on both – Reviews the effectiveness of our risk management systems and internal controls – Receives regular updates on financial crime compliance measures and risks including money laundering, bribery and corruption and sanctions compliance and monitors KPIs to measure progress to return to approved Board risk appetite and sustain returns to Board risk appetite Board Responsible Banking Committee – Responsible for culture and operational risk from conduct, compliance, competition & legal matters – Reviews reports from the CLRO on the adequacy and effectiveness of the compliance function – Ensures that adequate and effective control processes are in place to identify and manage reputational risks – Oversees our Corporate Social Responsibility programme and how it impacts on employees, communities, the environment including sustainability and climate change, reputation, brand and market positioning Board Audit Committee – Monitors and reviews the financial statements integrity, and any formal announcements on financial performance – Reviews the adequacy and effectiveness of the internal financial controls and whistleblowing arrangements – Monitors and reviews the effectiveness of the internal audit function – Oversees the independence and performance of our auditors Board Remuneration Committee – Oversees implementation of remuneration policies, ensuring they promote sound and effective risk management The Executive Level Committee responsibilities for risk are: Executive Level Committee Main risk responsibilities Executive Committee – Reviews business plans in line with our Risk Framework and Risk Appetite before they are sent to the Board to approve – Receives updates on key risk issues managed by CEO-level committees and monitors the actions taken Senior Management Committee – Focuses on the responsibilities of the Executive Committee Senior Management Function holders and how they are discharged – Reviews updates on key risk issues, customer, reputational and conduct matters Executive Risk Control Committee (ERCC) – Reviews Risk Appetite proposals before they are sent to the Board Risk Committee and the Board to approve – Ensures that we comply with our Risk Framework, Risk Appetite and risk policies – Reviews and monitors our risk exposures and approves any corrective steps we need to take Asset and Liability Committee (ALCO) – Reviews liquidity risk appetite (LRA) proposals – Ensures we measure and control structural balance sheet risks, including capital, funding and liquidity, in line with the policies, strategies and plans set by the Board – Reviews and monitors key asset and liability management activities to ensure we keep our exposures within our Risk Appetite Pensions Committee – Reviews pension risk appetite proposals – Approves actuarial valuations and reviews the impact they may have on our contributions, capital and funding – Consults with the pension scheme trustees on the scheme’s investment strategy Capital Committee – Puts in place reporting systems and risk control processes to make sure capital risks are managed within our Risk Framework – Reviews capital adequacy and capital plans, including the ICAAP, before they are sent to the Board to approve Incident Accountability Committee – Considers, calibrates, challenges and agrees any appropriate individual remuneration adjustments – Presents recommendations to the Board Remuneration Committee Credit Approval Committee – Approves corporate and wholesale credit transactions which exceed levels delegated to lower level forums or individuals Investment Approval Committee – Approves equity type investment transactions which exceed levels delegated to lower level approval forums or individuals Financial Crime Committee – Ensures due reporting, consideration, oversight and informed decision making regarding compliance by the Company and its subsidiaries with financial crime laws and regulations, and best industry practice aligned to the Company’s stated risk appetite Key senior management roles Senior roles with specific responsibilities for risk management are: Role Main risk responsibilities Chief Executive Officer The Board delegates responsibility for our business activities and managing risk on a day-to-day basis to the CEO. The CEO proposes our strategy and business plan, puts them into practice and manages the risks involved. The CEO must also ensure we have a suitable system of controls to manage risks and report to the Board on it. Chief Risk Officer (CRO) Oversees and challenges risk activities, and ensures lending decisions are made within our Risk Appetite. Accountable for control and oversight of credit, market, liquidity, capital, pension, strategic & business, operational, model risk and risks associated with climate change. Chief Legal and Regulatory Officer (CLRO) Accountable for the control and oversight of legal, conduct and regulatory, reputational and financial crime risk, and is responsible for reporting on these risks to the CRO, to provide the CRO with a holistic enterprise wide view of all risks. Chief Financial Officer Responsible for developing strategy, leadership and management of the CFO Division. In supporting our corporate goals within our risk appetite, the CFO is responsible for managing interest rate, liquidity, pension and capital risks. The CFO aims to maximise the return on Regulatory and Economic Capital, ensuring transactions create value with the right risk-based profile. Chief Internal Auditor (CIA) Designs and uses an audit system that identifies key risks and evaluates controls. The CIA also develops an audit plan to assess existing risks that involve producing audit, assurance and monitoring reports. Money Laundering Reporting Officer (MLRO) Responsible to the CLRO for control and oversight of financial crime risk but has regulatory responsibility to report on this risk type to Executive and Board Committees and the FCA.

Credit Risk

Credit Risk	12 Months Ended
	Dec. 31, 2021
Disclosure of credit risk exposure [abstract]
Credit Risk	Credit risk Overview Credit risk is the risk of financial loss due to the default or credit quality deterioration of a customer or counterparty to which we provided credit, or for whom we have assumed a financial obligation. We set out how our exposures arise and our approach to credit risk across the credit risk lifecycle. We discuss our ECL approach and the key inputs to our ECL model. We also summarise various Covid-19 support measures provided to our customers and their impact on ECL. We then analyse our key metrics, credit performance and forbearance, and highlight how Covid-19 affected them where relevant. Key metrics Stage 3 ratio remained stable at 1.43% (2020: 1.42%). Loss allowances decreased to £866m (2020: £1,377m). Average LTV of 64% (2020: 64%) on new mortgage lending. CREDIT RISK MANAGEMENT Exposures ( audited ) Exposures to credit risk arise in our business segments from: Retail Banking Consumer Finance Corporate & Commercial Banking Corporate Centre In Homes, – We provide residential mortgages for customers with good credit quality (prime lending). – We provide these mostly for owner-occupied homes, with some buy-to-let mortgages provided to non-professional landlords. In Everyday Banking, – We provide unsecured lending to individuals, including personal loans, credit cards and account overdrafts. – We provide banking services to businesses with a turnover of up to £6.5m per annum and relatively simple borrowing needs. We offer overdrafts, credit cards and business loans. – We provide financing for cars, vans, motorbikes and caravans through Santander Consumer (UK) plc (SCUK). – Through our joint ventures, Hyundai Capital UK Ltd and Volvo Car Financial Services UK Limited, we provide retail point of sale customer finance and wholesale finance facilities (stock finance). – Loans, bank accounts, treasury services, invoice discounting, cash transmission, trade finance and asset finance. – We provide these to SMEs and mid-sized corporates with an annual turnover of up to £500m, Commercial Real Estate and Social Housing associations. – Asset and liability management of our balance sheet, as well as our non-core and legacy portfolios being run down. – Exposures include financial institutions, sovereign and other international organisation assets, and structured products, chosen for diversification and liquidity. – Crown Dependencies - mainly residential mortgages to individuals in Jersey and the Isle of Man. The segmental basis of presentation in this Annual Report has changed following a management review of our structure, and comparative amounts have been restated to be consistent with the new presentation. Previously, Consumer Finance was managed as part of Retail Banking. See Note 2 for more information. Santander UK transferred a significant part of the CIB business to the London branch of Banco Santander SA under a Part VII banking business transfer scheme which completed on 11 October 2021. For more information, see Note 43. Prior to the transfer, CIB provided loans, bank accounts, treasury services and markets activities, trade finance, receivables discounting and cash transmission to large corporates and financial institutions, under approved ring-fenced bank exceptions policy. In 2021, our product teams expanded their focus to develop new ways to help customers transition to a low carbon economy. We launched a market first bespoke home energy report, ‘EnergyFact’, in partnership with Countrywide, with a goal to start meaningful engagement with mortgage customers and to begin to raise awareness on home improvements targeting energy efficiency and reduced carbon emissions. More than 3,500 mortgage customers have completed EnergyFact assessments and created a tailored guidance plan for their home since the start of the programme in March 2021. EnergyFact will be prominent in the end-to-end customer journey we are building to support our customers on their net-zero journey. We will help customers become more informed, understand available grants and funding, provide green financing options, and benefit from partnerships with suppliers. We are looking to rapidly expand the distribution to customers throughout the UK. EnergyFact report for mortgage customers Our approach to credit risk We manage our portfolios across the credit risk lifecycle, from drawing up our risk strategy, plans, budgets and limits to make sure the actual risk profile of our exposures stays in line with our business plans and within our Risk Appetite. We further tailor the way we manage risk across the lifecycle to the type of product and regularly review our approach and refine it when we need to. 1. Risk strategy and planning (audited) All relevant areas of the business work together to create our business plans. We aim to balance our strategy, goals, and financial and technical resources with our Risk Appetite. To do this, we focus on economic and market conditions and forecasts, regulations, conduct matters, profitability, returns and market share. 2. Assessment and origination (audited) Managing credit risk begins with lending responsibly. That means only lending to customers who are committed to paying us back and can afford to, even if their circumstances change. We undertake a thorough risk assessment to make sure a customer can meet their obligations before we approve a loan. We take proportionate steps to assess whether a customer will be able to repay the money borrowed. We do this by a series of initial affordability and credit risk assessments. We access each customer’s credit profile and signs of how reliable they are at repaying credit. When a customer applies, we assess the data they provide, plus data from credit reference agencies (for Retail Banking and Consumer Finance) and performance on their other Santander accounts (if they have any) against our Credit Policy. Retail Banking In Homes, for secured loans, we assess affordability by reviewing the customer’s income and spending, their other credit commitments, and what would happen if interest rates went up. Many of our decisions are automated as we use data available to us. We tailor the process and how we assess the application based on the product. More complex transactions often need greater manual assessment. This means we have to rely more on our credit underwriters’ skill and experience in making the decision. In Everyday Banking, similar to Homes, many of our decisions are automated as we use data available to us. We tailor the process and how we assess the application based on the product. For unsecured personal loans and credit cards, we assess affordability by reviewing the customer’s income and spending, their other credit commitments and stress accommodation costs on a proportionate basis. For business banking services, we use a combination of internal, credit reference agency and application data in our credit assessments. Credit scoring combined with policy rules give us confidence that businesses are creditworthy and can afford their repayments. Credit risk mitigation The types of credit risk mitigation, including collateral, across each of our portfolios is: Portfolio Description Residential mortgages Collateral is in the form of a first legal charge over the property. Before we grant a mortgage, the property is valued either by a surveyor or using automated valuation methodologies where our confidence in the accuracy of this method is high. Unsecured lending There is no collateral or security tied to the loan that can be used to mitigate any potential loss if the customer does not pay us back. Business banking services Business banking lending is unsecured. When lending to incorporated businesses, we typically obtain personal guarantees from each director but we do not treat these as collateral. Consumer Finance In Consumer Finance, similar to Retail Banking, many of our decisions are automated as we use data available to us. We tailor the process and how we assess the application based on the product. Residual value risk is one of our top risks. We use leading independent vehicle valuation companies to assess the future value of the asset before the start of the agreement. Credit risk mitigation The type of credit risk mitigation, including collateral, is: Portfolio Description Consumer (auto) finance Collateral is in the form of legal ownership of the vehicle for most consumer (auto) finance loans, with the customer being the registered keeper. Only a very small proportion of the business is underwritten as a personal loan. In these cases, there is no collateral or security tied to the loan. We use a leading vehicle valuation company to assess the LTV at the proposal stage to ensure that the value of the vehicle being lent against is appropriate. Corporate & Commercial Banking Our risk assessment assigns each customer a credit rating according to the internal rating threshold, using our internal rating scale (see ‘Credit quality’ in ‘Santander UK group level – credit risk review’ section). To do this, we look at the customer’s financial history and trends in the economy, backed up by the expert judgement of a risk analyst. We review our internal ratings on a dynamic basis and at least once a year for those clients that are rated. We also assess the underlying risk of the transaction, taking account of any mitigating factors (see the tables below) and how it fits with our risk policies, limits and Risk Appetite. Responsible lending, including climate change and the transition to a low carbon economy We lend to a wide range of sectors and industries, including those that are intrinsic or of strategic importance to the economy of the UK. As part of lending responsibly, we observe the Equator Principles as a way to factor social, ethical and environmental impacts into our risk analysis and decision making for financial transactions. Our Reputational Risk and Environmental, Social and Climate Change (ESCC) Risk policies define how we create long-term value while managing those risks. Our policies cover Oil & Gas, Power Generation & Transmission, Mining & Metals and Soft Commodities. For example, financing is prohibited for project-related financing for Coal Fired Power Plants (CFPPs) projects worldwide and we will only work with new clients with CFPPs to provide specific financing for renewable energy projects. In line with the Banco Santander commitment, we will eliminate all exposure to thermal coal mining and stop providing financial services to power generation clients with over 10% revenue from thermal coal by 2030. We pay special attention to the ESCC risks of various activities and projects, including liquid natural gas facilities; deep-sea and ultra-deep-sea oilfields; nuclear power generation; solid and gaseous biomass; precious minerals and metals mining; and native tropical timber extraction. We review all relationships and transactions with identified ESCC risks or reputational risks including human rights, to ensure they are within our risk appetite. Key decisions can be escalated to the Reputational Risk Forum and, if required, the Board. Credit risk mitigation The types of credit risk mitigation, including collateral, across each of our portfolios are as follows. In addition, from time to time at a portfolio level we execute significant risk transfer transactions, which typically reduce RWAs. Portfolio Description SME and mid corporate Includes secured and unsecured lending. We can take mortgage debentures or a first charge on commercial property as collateral. Before agreeing the loan, we get an independent professional valuation which assesses the property. Loan agreements typically allow us to obtain revaluations during the term of the loan. We can also take guarantees, but we do not treat them as collateral unless they are supported by a tangible asset which is charged to us. We also lend against assets (like vehicles and equipment) and invoices for some customers. We value assets before we lend. For invoices, we review the customers' ledgers regularly and lend against debtors who meet agreed criteria. We consider the UK Government guarantee supporting losses on amounts lent under its Coronavirus Loan Schemes as collateral (80% for CBILS, CLBILS and RLS, and 100% for BBLS). Commercial Real Estate We take a first legal charge on commercial property as collateral. The loan is subject to strict criteria, including the property condition, age and location, tenant quality, lease terms and length, and the sponsor’s experience and creditworthiness. Before agreeing the loan, we visit the property and get an independent professional valuation which assesses the property, the tenant and future demand. Loan agreements typically allow us to obtain revaluations during the term of the loan. Social Housing We take a first legal charge on portfolios of residential real estate owned and let by UK Housing Associations as collateral, in most cases. We revalue this every three to five years (in line with industry practice), using the standard methods for property used for Social Housing. Corporate Centre We follow the same assessment and origination process in Corporate Centre as that in Corporate & Commercial Banking. Credit risk mitigation The types of credit risk mitigation, including collateral, across each of our portfolios are as follows. In addition, from time to time at a portfolio level we execute significant risk transfer transactions, which typically reduce RWAs. Portfolio Description Sovereign and Supranational In line with market practice, there is no collateral against these assets. Structured Products These are our High Quality Liquid Assets (HQLA) and Legacy Treasury asset portfolios. These assets are primarily ABS and covered bonds, which benefit from senior positions in the creditor hierarchy. Their credit rating reflects the over-collateralisation in the structure, and the assets that underpin their cash flows and repayment schedules. Social Housing We manage the risk on this portfolio in the same way as for the Social Housing portfolio in Corporate & Commercial Banking. Financial Institutions We use standard legal agreements to reduce credit risk via netting and collateralisation on derivatives, repos and reverse repos, and stock borrowing/lending. We also reduce risk by clearing trades through central counterparties (CCPs) where possible. Legacy Portfolios in run off We often hold collateral through a first legal charge over the underlying asset or cash. We get independent third-party valuations on fixed charge security in line with industry guidelines. Crown Dependencies We manage the risk on this portfolio in the same way as for mortgages in Retail Banking. Corporate & Investment Banking Prior to the transfer in Q4 2021, we followed the same assessment and origination process in Corporate & Investment Banking as that in Corporate & Commercial Banking and Corporate Centre. In addition, in Corporate & Investment Banking, a specialist analyst usually reviewed a transaction at the start and over its life. Credit risk mitigation The types of credit risk mitigation, including collateral, across each of our portfolios were as follows. Portfolio Description Large Corporates Most of these corporate loans and products were unsecured. We also had a structured finance portfolio, where we typically held legal charges over assets we financed. We monitored borrowers in line with expected performance and applicable covenants, so we detected any financial distress early. Financial Institutions Financial Institutions exposures were minimal and were managed in the same way as Large Corporates. 3. Monitoring (audited) We measure and monitor changes in our credit risk profile on a regular and systematic basis against our budgets, limits and benchmarks. Credit concentrations A core part of our monitoring and management is a focus on credit concentrations, such as the proportion of our lending that goes to specific borrowers, groups or industries. We set and monitor concentration limits in line with our Risk Appetite and review them on a regular basis. – Geographical concentrations: We set exposure limits to countries and geographies, with reference to the country limits set by Banco Santander and our own Risk Appetite. For more geographical information, see ‘Country risk exposures’. – Industry concentrations : We also set exposure limits by industry sector. We set these limits based on the industry outlook, our strategic aims and desired level of concentration, and relevant limits set by Banco Santander. We analyse committed exposures in the ‘Credit risk review’ section that follows. Retail Banking In Homes, we use IT systems and data available to us to monitor accounts. The main parts are: – Behavioural scoring: we use statistical models that help predict whether a customer will have problems repaying, based on how they use their accounts – Credit reference agencies: we often use data from agencies on how the borrower is handling credit from other lenders in our behaviour scoring models – Other Santander accounts: each month, we also look at how the customer uses their other accounts with us, so we can identify problems early. Our day-to-day retail credit risk monitoring relies on a mix of product, customer and portfolio performance measures as described above. However, changes in the wider UK macro-economy also impact our Homes portfolio. To reflect this, since 2017 we have used a Retail Risk Playbook tolerance framework to enhance our day-to-day risk monitoring. This is a formal, structured framework that sets out the macroeconomic variables that are most relevant to retail portfolio performance. We monitor these variables against the related forecasts in our business plans. If the economy deviates materially from our forecasts, we formally review and reconsider our retail risk management policy and strategy. This framework will stay in place for as long as we consider it necessary. Covid-19 has and will continue to affect the macro-economic environment and we have responded to this using the Retail Risk Playbook tolerance framework and management judgements to ensure that portfolio quality remains within Risk Appetite. Our monitoring can also mean we change our minds about whether a product is still right for a customer. If we find evidence that a customer is in financial difficulties, we contact them about arrears management including forbearance, which we explain in more detail below. For secured lending, our monitoring also takes account of changes in property prices. We estimate the property’s value every three months. In most cases, we use statistical models based on recent sales prices and valuations in that local area. Use of this model is subject to Model Risk Governance. Where a lack of data means the model’s valuation is not available, we use the original surveyor valuation with a House Price Index (HPI) adjustment as appropriate. In Everyday Banking, similar to Homes, we use IT systems and data available to us to monitor accounts, and we use the Retail Risk Playbook tolerance framework (except for business banking services) and management judgements to ensure that portfolio quality remains within Risk Appetite. For unsecured personal lending like credit cards and overdrafts, monitoring might lead us to raise or lower credit limits. For business banking services, we review revolving credit facilities each year to ensure the facilities remain appropriate for the customer's financial circumstances. Consumer Finance In Consumer Finance, similar to Retail Banking, we use IT systems and data available to us to monitor accounts, and we use the Retail Risk Playbook tolerance framework and management judgements to ensure that portfolio quality remains within Risk Appetite. We also check the Residual Value of our portfolio each month, using triggers set to identify any material change in trends. Corporate & Commercial Banking and Corporate Centre We regularly monitor and report our credit risk by portfolio, segment, industry, location and customer. We monitor detailed analyses of our credit exposures and risk trends each month. We also report our larger exposures and risks to the Board Risk Committee each month. Our Watchlist We also use a Watchlist for exposures subject to annual reviews to help identify potential problem debt early. Just because a customer is on our Watchlist does not mean they have defaulted. It just means that something has happened that has increased the probability of default, such as they breach a covenant or lose a major contract. We classify Watchlist cases as: – Enhanced monitoring: for less urgent cases. If they are significant, we monitor them more often and where appropriate may consider more collateral. – Proactive management: for more urgent or serious cases. We may take steps to restructure debt including extending the term, taking more collateral, agreeing a lower credit limit, or seeking repayment of the loan through refinancing or other means. We assess cases on the Watchlist for impairment as explained in the ‘Significant Increase in Credit Risk (SICR)’ section. When a customer is included in enhanced monitoring, we do not consider that it has suffered a SICR for ECL purposes, so it remains in Stage 1 for purposes of our loss allowance calculations. When a customer is included in proactive management, we consider that it has suffered a SICR. This means we transfer it to Stage 2 and subject it to a lifetime ECL assessment to calculate the new loss allowance. We take into account any forbearance we offer. This includes whether any extra security or guarantees are available, the likelihood of more equity and the potential to enhance value through asset management. In Corporate & Commercial Banking, as part of our client review process, for loans approaching maturity, we look at the prospects of refinancing the loan on current market terms and applicable credit policy. Where this seems unlikely, we put the case on our Watchlist. In Corporate & Commercial Banking, there are also exposures that are not subject to annual reviews, which are primarily high volume and low value cases. They are managed using early warning indicators, which are supported by teams of expert analysts. Early warning indicators include the use of data from credit reference agencies. In Corporate Centre, we typically monitor the credit quality of our exposures daily. We use both internal and third-party data to detect any potential credit deterioration. In addition, we manage the credit quality of our Crown Dependencies mortgages in the same way as for mortgages in Retail Banking. Corporate & Investment Banking Prior to the transfer in Q4 2021, we followed the same monitoring process in Corporate & Investment Banking as that in Corporate & Commercial Banking and Corporate Centre. In addition, we also monitored the credit quality of our exposures daily. We used both internal and third-party data to detect any potential credit deterioration. 4. Arrears management (audited) Retail Banking and Consumer Finance We have several strategies to manage arrears that we can use as early as the day after a missed payment. We assess the problems a customer is having, so we can offer them the right help to bring their account up to date as soon as possible. The strategy we use depends on the risk and the customer’s circumstances. Corporate & Commercial Banking and Corporate Centre We identify problem debt by close monitoring, supported by our Watchlist process for all exposures subject to annual reviews. When there is a problem, our Relationship Directors are the first to act, supported by the relevant credit risk expert. We aim to identify warning signs early by monitoring customers’ financial and trading data, checking to make sure they are not breaching any covenants, and by having regular dialogue with them. Our Restructuring & Recoveries team are engaged as needed on Watchlist cases and we may hand over more serious cases to them. For the exposures not subject to annual review, we have several strategies for managing arrears that can be used as early as the day of the missed payment. We assess the problems a customer is having, so we can offer them the right help to bring their account up to date as soon as possible. If a case becomes more urgent or needs specialist attention, and if it transfers to Stage 3, we transfer it to our Restructuring & Recoveries team. We aim to act before a customer defaults, to prevent it, if possible. The strategy we use depends on the type of customer, their circumstances and the level of risk. We use restructuring and rehabilitation tools to try to help our customers find their own way out of financial difficulty and agree on a plan that works for both of us. Corporate & Investment Banking Prior to the transfer in Q4 2021, we managed arrears in Corporate & Investment Banking in the same way as that in Corporate & Commercial Banking and Corporate Centre. For more, see the Forbearance section. 5. Debt recovery (audited) Sometimes, even when we have taken all reasonable and responsible steps to manage arrears, they are not effective. If this happens, we have to end our agreement with the customer and try to recover the whole debt, or as much of it as we can. Retail Banking In Homes, to recover what we are owed, we may use a debt collection agency, sell the debt, or take the customer to court. For retail mortgage loans we may consider legal action including repossession of the property as a last resort or, if necessary, to protect the property from damage or third-party claims. We make sure our estimated losses from repossessed properties are realistic by getting two independent valuations on each property, as well as the estimated cost of selling it. These form the basis of our loss allowances calculations. Where we do enforce the possession of a property we do not take ownership. We make use of external agents to realise the value and settle the debt. Any surplus funds are returned to the borrower or are otherwise dealt with in line with insolvency regulations. In Everyday Banking, to recover what we are owed, we may use a debt collection agency, sell the debt, or take the customer to court, similar to our approach in Homes. Consumer Finance To recover what we are owed, we may use a debt collection agency, sell the debt, or take the customer to court, similar to our approach in Retail Banking. We may consider taking steps to re-possess of the vehicles we have financed. Corporate & Commercial Banking and Corporate Centre Where we look for an exit, we aim to do this, if we can, by agreeing with the borrower that they will sell some or all their assets on a voluntary basis or agreeing to give them time to refinance their debt with another lender. Where we cannot find a way forward or reach a consensual arrangement, we consider recovery options. This can be through an insolvency proceeding, enforcing over any collateral or selling debt on the secondary market. We may also consider other legal action available to recover what we are owed from debtors and guarantors. If there is a shortfall, we write it off against loss allowances we hold. In certain very rare instances, we may act as mortgagee in possession of assets held as collateral against non-performing commercial lending. In such cases, we carry the assets on our balance sheet and classify them in line with our accounting policies. Corporate & Investment Banking Prior to the transfer in Q4 2021, we followed the same debt recovery process in Corporate & Investment Banking as that in Corporate & Commercial Banking and Corporate Centre. Loan modifications (audited) We sometimes change the terms of a loan when a customer gets into financial difficulty (this is known as forbearance), or for other commercial reasons. Forbearance When a customer gets into financial difficulties, we can change the terms of their loan, either temporarily or permanently. We do this to help customers through temporary periods of difficulty so they can get back on to sustainable terms and fully pay off the loan over its lifetime, with support if needed. We try to do this before the customer defaults. Whatever we offer, we assess it to make sure the customer can afford the repayments. Forbearance improves our customer relationships and our credit risk profile. We review our approach regularly to make sure it is still effective. In a few cases, we can help a customer in this way more than once. This can happen if the plan to repay their debt doesn’t work and we have to draw up another one. When this happens more than once in a year, or more than three times in five years, we call it multiple forbearance. We only use foreclosure or repossession as a last resort. We may offer the following types of forbearance, but only if our assessments show the customer can meet the revised payments: Action Description Term extension We can extend the term of the loan, making each monthly payment smaller. For retail customers, where applicable they must also meet our policies for maximum loan term and age when they finish repaying. Customers with interest-only mortgages have to make arrangements to repay the principal at the end of the mortgage. For corporate customers, we expect the customer to be able to pay the interest in the short-term and have a realistic chance of repaying the full balance in the long-term at a minimum. We may offer term extensions if the customer is up to date with their payments but showing signs of financial difficulties. We may also offer this option if the loan is about to mature and near-term refinancing is not possible on market terms. Interest-only For retail customers, interest-only is only offered as a short-term standard collections arrangement since March 2015. We now record any related shortfall in monthly payments as arrears and report them to the credit reference agencies. As a result, we do not classify interest-only arrangements agreed since March 2015 as forbearance. We continue to manage and report all interest-only arrangements offered before then as forbearance. For corporate customers, we can agree to let a customer pay only the interest on the loan for a short time – usually less than a year. We only agree to this if we believe their financial problems are temporary and they are going to recover. After the interest-only period, we expect the customer to go back to making full payments of interest and capital once they are in a stronger financial position. Other payment rescheduling, including capitalisation For retail customers, we offer two main types, which are often combined with term extensions and, in the past, interest-only concessions: – If the customer cannot afford to increase their monthly payment enough to pay off their arrears in a reasonable time but has been making their monthly payments (usually for at least six months), then we can add the arrears to the mortgage balance. – We can also add to the mortgage balance at the time of forbearance, unpaid property charges which are due to a landlord and which we pay on behalf of the customer to avoid the lease being forfeited. For corporate customers, we may agree to lower or stop their payments until they have had time to recover. We may: – Reschedule payments to better match the customer’s cash flow – for example if the business is seasonal – Provide a temporary increase in facilities to cover peak demand ahead of the customer’s trading improving. We might do this by adding their arrears to their loan balance (we call this arrears capitalisation) or drawing from an overdraft. We may also offer other types of forbearance, including providing new facilities, interest rate concessions, seasonal profiling and interest roll-up. In rare cases, we agree to forgive or reduce part of the debt. When we agree to forbearance, we consider that the account has suffered a Significant Increase in Credit Risk (SICR), as we explain later on. We review our loss allowance for it and report the account as forborne. For retail accounts, if an account is in Stage 1 (a 12-month ECL) when we agree forbearance, we transfer it to Stage 2 (a lifetime ECL). For all accounts, if an account is already in Stage 2 when we agree forbearance, we keep it in Stage 2 unless the forbearance arrangement involves an account that is deemed unlikely to pay (defined through a number of events listed in our Classification Policy), the forgiveness of fees and interest or debt, or is being granted multiple forbearances which would put the case into Stage 3 (a lifetime ECL). If an account is already in Stage 3 when we agree forbearance, we keep it in Stage 3. We monit

Market Risk

Market Risk	12 Months Ended
	Dec. 31, 2021
Disclosure Of Market Risk Exposure [Abstract]
Market Risk	Market risk Overview Market risk comprises non-traded market risk and traded market risk. Non-traded market risk is the risk of loss of income, economic or market value due to changes to interest rates in the non-trading book or to changes in other market risk factors (e.g. credit spread and inflation risk), where such changes would affect our net worth through an adjustment to revenues, assets, liabilities and off-balance sheet exposures in the non-trading book. Traded market risk is the risk of changes in market factors that affect the value of the positions in the trading book. In this section, we set out which of our assets and liabilities are exposed to non-traded and traded market risk. Then we explain how we manage these risks and discuss our key market risk metrics. We also provide an update on the process of replacing LIBOR and other Interbank Offered Rates. Key metrics Santander UK plc group Net Interest Margin (NIM) sensitivity to +25bps was £89m and to ‑25bps was £(94)m (2020: £116m and £(23)m) SFS NIM sensitivity to +25bps was £4m and to ‑25bps was £(4)m (2020: £3m and £(1)m) Santander UK plc group Economic Value of Equity (EVE) sensitivity to +25bps was £89m and to ‑25bps was £(125)m (2020: £190m and £(369)m) SFS EVE sensitivity to +25bps was £1m and to ‑25bps was £(2)m (2020: £(2)m and £(3)m) BALANCE SHEET ALLOCATION BY MARKET RISK CLASSIFICATION (AUDITED) We manage our assets and liabilities exposed to market risk as either non-traded or traded market risk. We classify all our assets and liabilities exposed to market risk as non-traded market risk, except for certain derivatives that we manage on a trading intent basis. For accounting purposes, we classify all derivatives as held for trading unless they are designated as being in a hedging relationship. The derivatives that we manage on a trading intent basis are a small proportion of the derivatives that we classify as held for trading for accounting purposes. For more, see Note 11 to the Consolidated Financial Statements. NON-TRADED MARKET RISK OUR KEY NON-TRADED MARKET RISKS (AUDITED) Non-traded market risk mainly comes from providing banking products and services to our customers, as well as our structural balance sheet exposures. It arises in all our business segments. In Retail Banking, Consumer Finance and Corporate & Commercial Banking, it is a by-product of us writing customer business and we transfer most of these risks to Corporate Centre to manage. The only types of non-traded market risk that we keep in Retail Banking, Consumer Finance and Corporate & Commercial Banking are short-term mismatches due to forecasting variances in prepayment and launch risk. This is where customers repay their loans earlier than their expected maturity date or do not take the expected volume of new products. Before the transfer in Q4 2021, in Corporate & Investment Banking, it arose from lending to corporates, which we also transferred to Corporate Centre to manage. Corporate Centre also manages our structural balance sheet exposures, such as foreign exchange and Income Statement volatility risk. Our key non-traded market risks are: Key risks Description Interest rate risk Yield curve risk: comes from timing mismatches in repricing fixed and variable rate assets, liabilities and off-balance sheet instruments. It also comes from investing non-rate sensitive liabilities in interest-earning assets. We mainly measure yield curve risk with NIM and EVE sensitivities, which are measures commonly used in the financial services industry. We also use other risk measures, such as Value at Risk (VaR) which is a statistical measure based on a historical simulation of events, and stress testing. Our NIM and EVE sensitivities cover all the material yield curve risk in our banking book balance sheet. Basis risk: comes from pricing assets using a different rate index to the liabilities that fund them. We are exposed to basis risks associated with Bank of England bank rate, reserve rate linked assets we deposit with central banks, the Sterling Overnight Index Average (SONIA) rate, and LIBOR rates of different terms. LIBOR for Sterling, Swiss Francs and Japanese Yen were replaced with Risk Free Rates at the end of 2021. We will have some legacy positions using synthetic LIBOR in 2022, but there should be no basis risk incurred on re-hedging these positions. We are also very advanced with the transition of our loan and derivative portfolios. As the transition progresses, we continue to monitor our basis risk positions. Spread risk Spread risk arises when the value of assets or liabilities which are accounted for at fair value (either through Other Comprehensive Income or through Profit and Loss) are affected by changes in the spread. We measure these spreads as the difference between the discount rate we use to value the asset or liability, and an underlying interest rate curve. Foreign exchange risk Our banking businesses operate mainly in sterling markets, so we do not create significant foreign exchange exposures. The only exception to this is money we raise in foreign currencies. For more on this, see ‘Wholesale funding’ in the ‘Liquidity risk’ section. Income statement We measure most of the assets and liabilities in our banking book balance sheet at amortised cost. We sometimes manage their risk profile by using derivatives. As all derivatives are accounted for at fair value, the mismatch in their accounting treatment can lead to volatility in our Income Statement. This happens even if the derivative is an economic hedge of the asset or liability. NON-TRADED MARKET RISK MANAGEMENT Risk appetite Our framework for dealing with market risk is part of our overall Risk Framework. Our Structural and Market Risk framework sets out our high-level arrangements and standards to manage, control and oversee non-traded market risk. Our Risk Appetite sets the controls, risk limits and key risk metrics for non-traded market risk. We articulate risk appetite by the income and value sensitivity limits we set in our Risk Appetite, at both Santander UK and Banco Santander group levels. Risk measurement For non-traded market risk, we mainly measure our exposures with NIM and EVE sensitivity analysis. We support this with VaR risk measures and stress testing. We also monitor our interest rate repricing gap. NIM and EVE sensitivities The calculations for NIM and EVE sensitivities involve many assumptions, including expected customer behaviour (such as early repayment of loans) and how interest rates may move. These assumptions are a key part of our overall control framework, so we update and review them regularly. Our NIM and EVE sensitivities include the interest rate risk from all our banking book positions. Our banking book positions generate almost all our reported net interest income. NIM sensitivity – NIM sensitivity is an income-based measure we use to forecast the changes to interest income and interest expense in different scenarios. It gives us a combined impact on net interest income over a given period – usually 12 or 36 months. – We calculate NIM sensitivity by simulating the NIM using two yield curves. The difference between the two NIM totals is the NIM sensitivity. – Our main model assumptions are that: – The balance sheet is dynamic. This means that it includes the run-off of current assets and liabilities as well as retained and new business – We use a behavioural balance sheet rather than a contractual one. This means that we adjust balances for their behavioural or assumed profile. We do this with most retail products whose behavioural maturity is different to the contractual maturity. This is usually because customers are exercising the option to withdraw or prepay early, or there is no contractual maturity. EVE sensitivity – We calculate EVE sensitivity as the change in the net present value of all the interest rate sensitive items in the banking book balance sheet for a defined set of instantaneous parallel and non-parallel shifts in the yield curve. – We use a static balance sheet. This means that all balance sheet items run-off according to their contractual, behavioural or assumed run-off behaviour (whichever is appropriate), and there is no retained or new business. The limitations of sensitivities We use sensitivities to measure the impact of standard, instantaneous, parallel shifts in relevant yield curves. The advantage of using standard parallel shifts is they generally give us a constant measure of the size of our market risk exposure, with a simple and consistent stress. This compares to specific scenarios like ‘flat rates’. The magnitude of flat rates depends on the shape of the current curve and the shift required to reach the flat rate scenario. We also run non-parallel stress tests, to calculate the impact of some plausible non-parallel scenarios, and over various time periods for income stresses, usually one or three years. VaR (audited) VaR – VaR indicates the losses that we might suffer because of unfavourable changes in the markets under normal (non-stressed) market conditions. – We run a historical simulation using historical daily price moves, at a 99% confidence level for example, to find how much we might lose – the VaR. – For any given day’s position, we expect to suffer losses greater than the VaR estimate 1% of the time – once every 100 trading days, or two to three times a year. – This gives us a consistent way of assessing risk for all relevant market risk factors in our portfolios. The limitations of VaR VaR is a useful and important market standard measure of risk, but it does have some limitations. These include: – VaR assumes what happened in the past is a reliable way to predict what will happen in the future. This may not always be the case – VaR is based on positions at the end of the business day so it doesn’t include intra-day positions – VaR does not predict how big the loss could be on the 1% of trading days that it is greater than the VaR – Using a time horizon of one day means VaR does not tell us everything about exposures that we cannot liquidate or hedge within a day, or products with infrequent pricing. Back-testing – comparing VaR estimates with reality To check that the way we estimate VaR is reasonable, we back-test our VaR by comparing it against both actual and hypothetical profits and losses, using a one-day time horizon. Back-testing allows us to identify exceptions – times when the predictions were out of line with what happened. We can then look for trends in these exceptions, which can help us decide whether we need to recalibrate our VaR model. Other ways of measuring risk As well as using sensitivities and stress tests, we can measure non-traded market risk using net notional positions. This can give us a simple view of our exposure, although we generally need to combine it with other risk measures to cover all aspects of a risk profile, such as projected changes over time. Other metrics we can use include Earnings at Risk (EaR). Although VaR can be useful as it captures changes in economic values, as we describe above, VaR will not reflect the actual Income Statement impact of most of our banking book positions. This is because we account for them at amortised cost rather than fair value. EaR is like VaR but captures changes in income rather than value. We use this approach for example to generate a one-year EaR measure to assess Basis risk. Stress testing Stress testing is an essential part of our risk management. It helps us to measure and evaluate the potential impact on portfolio values of more extreme, although plausible, events or market moves. We express limits as on how much we could lose in a stress event, and this restricts how much risk we take. Stress testing scenarios Simple stress tests (like parallel shifts in relevant curves) give us clear measures of risk control and a consistent starting point for setting limits. More complex, multi-factor and multi-time period stress tests can give us information about specific potential events. They can also test outcomes that we might not capture through parallel stresses or VaR-type measures because of data or model limitations. We can also use stress tests to estimate losses in extreme market events beyond the confidence level used in VaR models. We can adapt our stress tests to reflect current concerns such as climate change risk, the Covid-19 pandemic and other macroeconomic events or changing market conditions quicker than we can with other risk measures, like VaR. We can include both individual business area stresses and Santander UK-wide scenarios. We can produce stress tests using either income or value measures. They cover one or more categories of exposures on an accruals basis or at fair value. We use expert judgement to define appropriate hypothetical stress tests and any adjusting assumptions based on the balance sheet, management actions and customer behaviour. How we use stress testing We discuss stress testing results at senior management committees. They affect Corporate Centre’s decisions by highlighting possible risks in the banking book and the effectiveness of remedial actions we could take. We compare stress test results with stress limits and triggers set by our internal committees, or against metrics set by the PRA. If the results are over our limits or triggers, we take remedial actions and follow an escalation process. Risk mitigation (audited) We mitigate Income Statement volatility mainly through hedge accounting. We monitor any hedge accounting ineffectiveness that might lead to Income Statement volatility with a VaR measure and trigger, reported monthly. For our accounting policies for derivatives and hedge accounting, see Note 1 to the Consolidated Financial Statements. We typically hedge the interest rate risk of the securities we hold for liquidity and investment purposes with interest rate swaps, retaining spread exposures. These retained exposures are the key drivers of the VaR and stress tests we use to assess the risk of the portfolio. We hedge our foreign currency funding positions back to sterling, so our foreign exchange positions tend to be residual exposures that remain after hedging. These positions could be, for example, to ‘spot’ foreign exchange rates or to cross currency basis. We monitor foreign exchange risk against absolute net exposures and VaR-based limits and triggers. For more on this, see ‘Funding strategy‘ and ‘Term issuance’ in the ‘Liquidity risk’ section. Risk monitoring and reporting (audited) We monitor the non-traded market risks of the securities we hold for liquidity and investment purposes using sensitivities, VaR and stress tests. We report them against limits and triggers to senior management daily and to ALCO and ERCC each month. The VaR we report captures all key sources of volatility (including interest rate and spread risks) to fully reflect the potential volatility. In 2021, we continued to make good progress in the IBOR transition as substantial parts of the process began to come to an end. New reference rate products have been deployed to support the transition off IBOR rates and, in 2021, the majority of affected legacy contracts were transitioned from the LIBOR rates ceasing at the end of the year. We continue to work with our customers to agree the transition of the relatively small number of agreements that remain to be transitioned at the end of 2021. For more information, including the notional amounts of assets, liabilities and off-balance sheet commitments at 31 December 2021 and 31 December 2020 affected by IBOR reform that have yet to transition to an alternative benchmark interest rate, see Note 42 to the Consolidated Financial Statements. Managing IBOR transition NON-TRADED MARKET RISK REVIEW Interest rate risk Yield curve risk The table below shows how our base case income and valuation would be affected by a 25 basis points (bps) and a 50 bps parallel shift (both up and down) applied instantaneously to the yield curve at 31 December 2021 and 31 December 2020 for the Santander UK plc group and SFS . Sensitivity to parallel shifts represents the amount of risk in a way that we think is both simple and scalable. From 2021, we have typically focused on a 25bps stress for non-traded market risk controls that reflects a more plausible yield curve stress in the current low rate environment. We continue to monitor sensitivities to other parallel and non-parallel shifts as well as scenarios. Sensitivities to a 50bps shift are also provided this year as a bridge to previous year's disclosures. Santander UK plc group 2021 2020 +25bps -25bps +50bps -50bps +25bps -25bps +50bps -50bps £m £m £m £m £m £m £m £m NIM sensitivity (audited) 89 (94) 167 (205) 116 (23) 225 (15) EVE sensitivity 89 (125) 148 (301) 190 (369) 367 (585) SFS NIM sensitivity (audited) 4 (4) 8 (8) 3 (1) 6 (1) EVE sensitivity 1 (2) 2 (5) (2) (3) (4) (7) Basis risk We report basis risk using the EaR approach. 2021 2020 £m £m Basis risk EaR 2 8 Interest rate repricing gap The table below shows the interest rate repricing gap of our balance sheet by repricing buckets. 3 months 1 year 3 years 5 years >5years Not sensitive Total 2021 £m £m £m £m £m £m £m Assets 111,211 45,979 77,726 44,418 7,191 16,930 303,455 Liabilities 190,649 17,328 25,735 16,108 28,733 25,551 304,104 Off-balance sheet 27,369 (18,508) (19,842) 3,447 8,183 — 649 Net gap (52,069) 10,143 32,149 31,757 (13,359) (8,621) — 2020 Assets 121,812 47,975 71,729 37,114 7,944 16,513 303,087 Liabilities 191,178 22,836 21,013 16,322 27,385 25,551 304,285 Off-balance sheet 25,788 (11,081) (17,322) (1,794) 5,607 — 1,198 Net gap (43,578) 14,058 33,394 18,998 (13,834) (9,038) — Spread risk The table below shows the risk metrics covering the portfolios of securities we hold for liquidity and investment purposes. 2021 2020 £m £m VaR 4 7 Worst three month stressed loss 56 93 2021 compared to 2020 We regularly review our risk models and metrics including underlying modelling assumptions to ensure they continue to reflect the risks inherent in the prevailing rate environment and incorporate regulatory expectations. The adverse movement in Santander UK plc group NIM sensitivities in 2021 was largely driven by changes in modelling assumptions used for risk measurement purposes. These were partially offset by less margin compression risk following a steepening in the yield curve. These assumption changes also contributed to the movement in Santander UK plc group sensitivities in 2021 and this was offset to a larger extent by the higher curve and lower margin compression risk over the longer time horizon considered under the EVE metric. The basis risk EaR decreased in 2021 due to reduced underlying net basis position, following the move to risk-free rates as part of our IBOR transition programme. TRADED MARKET RISK OUR KEY TRADED MARKET RISKS (AUDITED) Our traded market risks come from providing financial services to our customers. Our exposures are affected by market movements in interest rates, credit spreads, and foreign exchange rates. Traded market risk can reduce our net income. We only have a very small amount of traded market risk in our principal ring fenced bank, Santander UK plc. This is from permitted products sold to permitted customers. We hedge risks from client trades. Our books are as close to back-to-back as possible. Market risk is hedged with Banco Santander SA or CCPs. This is required by Banking Reform legislation. Our principal ring-fenced bank Santander UK plc has two trading desks. The Link Desk transacts derivatives with our corporate clients that are permitted under the ring-fencing regime. The Retail Structured Products desk (RSP) sells investments to retail investors, through our UK branches and other channels. The Link Desk is exposed to the credit quality of our clients. We adjust valuations for this with the Credit Valuation Adjustment (CVA), which feeds our valuations and hence income and expenses. The low market risk in our trading business means that CVA is the main driver of income movements, along with similar factors – Debt Valuation Adjustment (DVA) driven by our own credit, and Liquidity Valuation Adjustment (LVA) driven by the market price of liquidity. These valuation adjustments are collectively referred to as XVAs. We calculate market risk capital using standard rules. TRADED MARKET RISK MANAGEMENT Risk appetite Market risk is managed within our overall Risk Framework. Our market risk framework sets our high level arrangements and standards for managing and controlling traded market risk. Our Risk Appetite for traded market risk is low. We only need to report a qualitative measure to the Board. Risk measurement We have a range of ways of measuring traded market risk, including stress testing (explained in the Non-traded market risk management section above) and detailed sensitivity measures. Stress testing This is an essential part of our risk management. It helps us measure and evaluate the possible results of extreme, although plausible, events and market moves. We set limits on what we could lose in a stress event. This restricts how much risk we take. Stress testing scenarios We calculate the impact of 100 scenarios on our trading books every month. The scenarios we create may be inspired by past events, like the global financial crisis and the Covid-19 pandemic. They may include ways that unusual market conditions could happen. They include interest rates, equity prices and exchange rates. Most are reported against limits, and so could lead to our front office being asked to reduce risk. Our scenarios are not all calibrated to the same severity; some may be for a much longer holding period or a completely artificial and unrealistic scenario. We therefore do not limit all of them in the same way. How we use stress testing We use limits to manage how much we can lose in a crisis. This limits the risk we take. We make sure that plausible losses are below the Risk Appetite set by the Board. We report to senior management regularly at the Market & Structural Risk Control Forum. Risk mitigation (audited) We manage and control traded market risk within clear limits. There are specific levels that need escalation or action. This means we limit the impact of negative market movements. We keep the areas that create traded market risk separate from areas which control and oversee risk. Risk monitoring and reporting (audited) We maintain a complete set of written policies, procedures, and processes. These make sure we identify, assess, manage, and report traded market risk. TRADED MARKET RISK REVIEW 2021 compared to 2020 In 2021, there were no significant changes to our traded market risk exposures in the Santander UK plc group. Our exposure to traded market risk is small, and arises from permitted transactions under the ring-fencing regime, offset by permitted market risk hedges. The Internal VaR for exposure to traded market risk in 2021 was less than £1m (2020: less than £1m).

Liquidity Risk

Liquidity Risk	12 Months Ended
	Dec. 31, 2021
Disclosure Of Liquidity Risk Exposure [Abstract]
Liquidity Risk	Liquidity risk Overview Liquidity risk is the risk that we do not have sufficient liquid financial resources available to meet our obligations when they fall due, or we can only secure such resources at excessive cost. In this section, we describe our sources and uses of liquidity and how we manage liquidity risk. We also analyse our key liquidity metrics, including our LCRs and our eligible liquidity pools. We then explain our funding strategy and structure and we analyse our wholesale funding. Finally, we analyse how we have encumbered some of our assets to support our funding activities. Key metrics RFB DoLSub LCR of 166% (2020: 150%) SFS LCR of 206% (2020: 165%) Wholesale funding with maturity <1 year £10.2bn (2020: £21.1bn) RFB DoLSub LCR eligible liquidity pool of £51.4bn (2020: £51.5bn) SFS LCR eligible liquidity pool of £2.8bn (2020: £2.8bn) OUR KEY LIQUIDITY RISKS (AUDITED) Through our LRA framework, we manage our funding or structural contingent and market liquidity risks wherever they arise. This can be in retail and corporate deposit outflows, wholesale secured and unsecured liquidity outflows and off-balance sheet activities. Other risks our framework covers include funding concentrations, intra-day cash flows, intra-group commitments and support, franchise retention and cross currency risk. Our main sources of liquidity Customer deposits finance most of our customer lending. Although these funds are mostly callable, in practice they give us a stable and predictable core of funding. This is due to the nature of retail accounts and the breadth of our retail customer relationships. We have a strong wholesale funding investor base, diversified across product types and geographies. Through the wholesale markets, we have active relationships in many sectors including banks, other financial institutions, corporates and investment funds. We access the wholesale funding markets through the issuance of capital, senior unsecured debt, covered bonds, structured notes and short-term funding. We also access these markets through securitisations of certain assets of Santander UK plc and our operating subsidiaries. For more on our programmes, see Notes 14, 22 and 26 in the Consolidated Financial Statements. We generate funding on the strength of our own balance sheet, our own profitability and our own network of investors. In addition, we have access to UK Government funding schemes. We comply with rules set by the PRA, other regulators, and Banco Santander standards. While we manage, consolidate and monitor liquidity risk centrally, we also manage and monitor it in the business area it comes from. Our main uses of liquidity Our main uses of liquidity are to fund our lending in Retail Banking, Consumer Finance and Corporate & Commercial Banking, to pay interest and dividends, and to repay debt. Our ability to pay dividends depends on various factors. These include our regulatory capital needs, the level of our distributable reserves, and our financial performance. We also use liquidity to pay for business combinations. LIQUIDITY RISK MANAGEMENT Introduction We manage liquidity risk on a consolidated basis in our CFO division, which is our centralised function for managing funding, liquidity and capital. We created our governance, oversight and control frameworks, and our LRA, on the same consolidated basis. We monitor and manage liquidity risk for the Santander UK plc group and SFS separately. Under this model, and the PRA’s liquidity rules, Santander UK plc and its subsidiary Cater Allen Limited form the RFB Domestic Liquidity Sub-group (the RFB DoLSub), which allows the entities to collectively meet regulatory requirements for the purpose of managing liquidity risk. Each member of the RFB DoLSub will support the other by transferring surplus liquidity in times of stress. We continue to transfer liquidity risks from the securities Santander UK Group Holdings plc issues, or the contracts it executes, into our subsidiaries largely through back-to-back transactions. We fund any mismatches, if needed, by ordinary share dividends from subsidiaries. Risk appetite Separate LRAs are in place for Santander UK plc group and SFS. These are appropriate to their individual business models and consistent with the strategy of Santander UK Group Holdings plc. Our LRA statement is based on the principles of liquidity management we use to manage our balance sheet. It also supports our need to meet or exceed the rules of our regulators. In line with our liquidity management principles, we avoid an over-reliance on funding from a single product, customer or counterparty. We also maintain enough unencumbered customer assets to support current and future funding and collateral requirements and maintain enough capacity to monetise liquid assets and other counterbalancing capacity within an appropriate timeframe. Our LRA is proposed to the Risk division and the Board, which is then approved under advice from the Board Risk Committee. Our LRA, in the context of our overall Risk Appetite, is reviewed and approved by the Board each year, or more often if needed. Risk measurement We use a number of metrics to manage liquidity risk. These include metrics that show the difference between cash and collateral inflows and outflows in different periods. They also include structural metrics, such as our level of encumbered assets. Ongoing business management Within our framework of prudent funding and liquidity management, we manage our activities to our liquidity risk appetite. We have clear responsibilities for short-term funding, medium-term funding, encumbrance, collateral and liquid asset management. This ensures we manage liquidity risks as part of our daily operations, strategy and planning. Our liquidity management framework is split between short-term and strategic activities. Our short-term activities focus on intra-day collateral; management and maintaining liquid assets to cover unexpected demands on cash in a stress scenario, such as large and unexpected deposit withdrawals by customers and loss of wholesale funding. Our strategic activities focus on ensuring we are not over reliant on any one source for funding and that we avoid excessive concentrations in the maturity of our funding. We regularly test the liquidity of our eligible liquidity pool, in line with PRA and Basel rules. We do this by realising some of the assets through repurchase or outright sale to the market. We make sure that over any 12-month period we realise a significant part of our eligible liquidity pool. As well as our eligible liquidity pool, we always hold a portfolio of unencumbered liquid assets. Our LRA and PRA requirements determine the size and composition of this portfolio. These assets give us a source of contingent liquidity, as we can realise some of them in a time of stress to create liquidity through repurchase or outright sale to the market. Stress testing We have a liquidity stress testing framework in place which is central to our LRA measurement and monitoring. It includes three severe but plausible stress test scenarios. To fit with our risk appetite, the liquidity outflows that come from these stress tests must be fully covered with high-quality liquid assets, other liquid assets and management actions sanctioned at the right level of governance. A funding plan disruption stress scenario also forms part of our LRA monitoring. Our Risk division runs a range of stress tests. Our LRA stress test is a combination of three tests that cover idiosyncratic, market-wide and combined scenarios. Our other tests consider scenarios such as a global economic slowdown that results in reduced confidence in the banking industry, a slowdown in one of the major economies or a deterioration in the availability of liquidity. These are considered on both an acute and protracted basis. We also run severe combined stress tests which look at both a deep and prolonged UK recession that results in a reduction in wholesale funding availability and a simultaneous idiosyncratic shock that would lead to retail and commercial outflows. We run a Covid-19 pandemic stress, in which no UK government support is assumed and like the combined stress includes a reduction in wholesale funding and retail and corporate outflows. We also conduct sensitivity analysis and reverse stress testing for instant liquidity shocks by each key liquidity risk. We do this to understand the impacts they would have on our LRA and our regulatory liquidity metrics. We monitor our LCR to ensure we continue to meet the requirements. We also monitor the Net Stable Funding Ratio (NSFR), which was implemented on 1 January 2022. We exceed the requirements for both LCR and NSFR. Risk mitigation (audited) The Board aims to make our balance sheet resilient at all times and for it to be perceived as such by stakeholders. This preserves our short and long-term viability. The Board recognises that as we are involved in maturity transformation, we cannot hold enough liquidity to cover all possible stress scenarios. The Board requires us to hold enough liquidity to make sure we will survive three plausible but severe stress scenarios (our LRA stress). We do this by maintaining a prudent balance sheet structure and approved liquid resources. Recovery & Resolution framework The CFO is the accountable SMF for recovery and resolution and the related work is managed by the CFO division. They are overseen by the Board Audit Committee and the Board. We review and refresh our recovery plan each year. It sets out the risks, the indicators we use to monitor these risks, and the actions that are available to mitigate a capital, liquidity or combined stress event. We are confident that we have sufficient credible and executable options to respond to a wide variety of stresses, be they market-wide or idiosyncratic, in a timely and effective manner. Recovery indicators are both qualitative and quantitative and are embedded into risk frameworks. We monitor recovery capacity, headroom to recovery triggers and recovery indicators regularly. If necessary, we would invoke recovery early to mitigate the effects of a stress and restore our financial position and balance sheet strength. Santander UK’s first self-assessment of its resolvability was submitted to the PRA in October 2021. More details will be set out in the public disclosure due in June 2022. Risk monitoring and reporting (audited) We monitor liquidity risk daily, weekly and monthly. We do this through different committees and levels of management, including ALCO and the Board Risk Committee. LIQUIDITY RISK REVIEW Liquidity Coverage Ratio This table shows our LCR and LRA at 31 December 2021 and 31 December 2020. We also show the SFS LCR and LRA separately, as we monitor and manage liquidity risk for SFS separately. The LRA data reflect the stress testing methodology in place at that time. RFB DoLSub LCR (1) RFB LRA (2) 2021 2020 2021 2020 £bn £bn £bn £bn Eligible liquidity pool (liquidity value) (3) 51.3 51.2 52.5 47.2 Net stress outflows (30.9) (34.1) (30.4) (34.4) Surplus 20.4 17.1 22.1 12.8 Eligible liquidity pool as a percentage of anticipated net cash flows 166 % 150 % 173 % 137 % SFS LCR SFS LRA Eligible liquidity pool (liquidity value) 2.8 2.8 2.8 2.8 Net stress outflows (1.4) (1.7) (1.5) (1.7) Surplus 1.4 1.1 1.3 1.1 Eligible liquidity pool as a percentage of anticipated net cash flows 206 % 165 % 184 % 168 % (1) The RFB LCR was 168% (2020:152%). (2) The LRA is calculated for the Santander UK plc group (the RFB Group) and is a three-month Santander UK specific requirement. (3) The liquidity value is calculated as applying an applicable haircut to the carrying value. LCR eligible liquidity pool This table shows the carrying value of our eligible liquidity pool assets at 31 December 2021 and 31 December 2020. It also shows the weighted average carrying value in the year. We also show SFS at 31 December 2021 and 31 December 2020, as we monitor and manage liquidity risk for SFS separately. RFB DoLSub Carrying value Weighted average carrying 2021 2020 2021 2020 Level 1 Level 2 Total Level 1 Level 2 Total Total Total £bn £bn £bn £bn £bn £bn £bn £bn Cash and balances at central banks 45.9 — 45.9 39.4 — 39.4 40.6 26.8 Government bonds 4.2 — 4.2 8.9 0.1 9.0 7.0 15.5 Supranational bonds and multilateral development banks 0.2 — 0.2 1.5 — 1.5 0.3 2.9 Covered bonds 0.8 — 0.8 1.0 — 1.0 1.1 1.2 Asset-backed securities — 0.3 0.3 — 0.6 0.6 0.4 0.6 Equities — — — — — — — — 51.1 0.3 51.4 50.8 0.7 51.5 49.4 47.0 SFS Cash and balances at central banks 2.3 — 2.3 2.3 — 2.3 2.0 4.7 Government bonds 0.5 — 0.5 0.5 — 0.5 0.5 0.5 2.8 — 2.8 2.8 — 2.8 2.5 5.2 Currency analysis This table shows the carrying value of our eligible liquidity pool by major currencies at 31 December 2021 and 31 December 2020. The composition of the pool is consistent with the currency profile of our net liquidity outflows. RFB DoLSub US Dollar Euro Sterling Other Total £bn £bn £bn £bn £bn 2021 0.8 0.4 50.2 — 51.4 2020 2.0 1.2 48.1 0.2 51.5 As we monitor and manage liquidity risk for SFS separately, their carrying values were in Sterling only at £2.8bn (2020: £2.8bn). 2021 compared to 2020 The RFB DoLSub LCR of 166% increased from 150% and remains significantly above regulatory requirements. We also monitor the Net Stable Funding Ratio (NSFR), which has been implemented on 1 January 2022 and we exceed the requirements. At 31 December 2021, the RFB DolSub NSFR was 136% and SFS NSFR was 137%. We remain in a strong liquidity position and the impacts of the Covid-19 pandemic did not trigger a liquidity stress. We hold sufficient liquid resources and have adequate governance and controls in place to manage the liquidity risks arising from its business and strategy. FUNDING RISK MANAGEMENT Funding strategy Our funding strategy continues to be based on maintaining a conservatively structured balance sheet and diverse sources of funding to meet the needs of our business strategy and plans. The CFO Division maintains a funding plan and ensures it is compliant with the LRA and regulatory liquidity and capital requirements. Most of our funding comes from customer deposits. We source the rest from a mix of secured and unsecured funding in the wholesale markets. Overall, this means that we do not rely too heavily on wholesale funds. We manage funding requirements by targeting a specific Liquidity Coverage Ratio, we ensure maturities are prefunded and capital/Minimum Requirements for Eligible Liabilities (MREl) requirements are prioritised. We also have checks and controls to limit our asset encumbrance from our secured funding operations. As part of maintaining a diverse funding base, we raise funding in a number of currencies, including EUR and USD, and convert it into sterling through currency swaps to fund our commercial assets which are largely sterling denominated. Our base of stable retail and corporate deposits is a key funding source for us. We leverage our large and diverse customer base to offer products that give us a long-term sustainable source of funding. We do this by focusing on building long-term relationships. Over 85% of our total core retail customer liabilities are covered by the Financial Services Compensation Scheme (the FSCS). Behavioural maturities The contractual maturity of our balance sheet assets and liabilities highlights the maturity transformation that underpins the role of banks to lend long term, but to fund themselves mainly with shorter-term liabilities, like customer deposits. We do this by diversifying our funding operations across a wide customer base, both in numbers and by type of depositor. In practice, the behavioural profiles of many liabilities show more stability and longer maturity than their contractual maturity. This is especially true of many types of retail and corporate deposits that, while they may be repayable on demand or at short notice, have shown good stability even in times of stress. We model behaviour profiles using our experience of customer behaviour. We use this data to determine the funds transfer pricing interest rates at which we reward and charge our business units for sources and uses of funds. We apply this rate until a customer changes to a different product or service offered by us or by one of our competitors. We continue to maintain the quality of our retail, commercial and wholesale deposits. We aim to deepen our customer relationships across all customer segments. We do this to lengthen the contractual and behavioural profile of our liability base. Deposit funding We mainly fund our Retail Banking, Consumer Finance and Corporate & Commercial Banking activities by customer deposits. We fund the rest through wholesale markets. Wholesale funding Composition of wholesale funding We are active in the wholesale markets and we have direct access to both money market and long-term investors through our funding programmes. This makes our wholesale funding well diversified by product, maturity, geography and currency. This includes currencies available across a range of channels from money markets, repo markets, senior unsecured, secured, medium-term and capital. Santander UK plc is our main operating company issuer of senior unsecured debt, structured notes, short-term funding and covered bonds. Santander UK Group Holdings plc is the issuer of capital and MREL/Total Loss Absorbing Capacity (TLAC) eligible senior unsecured debt. Under CRR II, G-SIBs have been subject to the MREL standard. As part of this, UK resolution entities that are G-SIBs or are part of a G-SIB, including Santander UK Group Holdings plc, are required to meet the MREL minimum requirements, implemented through the Bank of England Statement of Policy on MREL in the UK. From 1 January 2020, the MREL requirement is the higher of (i) two times the Pillar 1 capital requirements and one times their Pillar 2A add-ons; (ii) 6% of CRR leverage exposures or (iii) two times the minimum leverage ratio requirement. The MREL requirements has been fully implemented from 1 January 2022 and G-SIBs is required to meet the higher of (i) two times the sum of Pillar 1 capital requirements and their Pillar 2A add-ons; (ii) 6.75% of CRR leverage exposures or (iii) two times the minimum leverage ratio requirement. Our main operating company Santander UK plc is subject to internal MREL as it meets the requirements of a material subsidiary of our ultimate parent Banco Santander SA. We also access the wholesale markets through securitisations of certain assets of our operating subsidiaries. In addition, we have access to UK Government funding schemes. Eligible collateral for these schemes includes all collateral that is eligible in the Bank of England’s Discount Window Facility. We ensure that enough collateral is placed and available at the Discount Window. Issuance model and resolution Banco Santander is a multiple point of entry resolution group. This means that should it fail, it would be split up into parts. Healthy parts might be sold or be kept as a residual group without their distressed sister companies. The resolution or recapitalisation of the distressed parts might be effected via ‘bail in’ of bonds that had been issued to the market by a regional intermediate holding company. Santander UK is a single point of entry resolution group. This means that resolution would work downwards from the group’s holding company i.e. Santander UK Group Holdings plc. Losses in subsidiaries would first be transferred up to Santander UK Group Holdings plc. If the holding company is bankrupt as a result, the group is deemed to be failing or likely to fail, it will be put into resolution. The ‘bail in’ tool is applied to the holding company, with the equity being written off and bonds written off or converted into equity as needed to recapitalise the group. Those bondholders would become the new owners, and the group would stay together. Santander UK Group Holdings plc is the immediate holding company of Santander UK plc but does not guarantee its debts or other obligations. This structure is a Bank of England recommended configuration which aims to ensure the activities of the operating company are not disrupted as the Santander UK group goes through resolution, thereby maintaining continuity of services for customers. FUNDING RISK REVIEW Our funding strategy continues to be based on maintaining a conservatively structured balance sheet and diverse sources of funding to meet the needs of our business strategy and plans. The CFO Division maintains a funding plan and ensures it is compliant with the LRA and regulatory liquidity and capital requirements. 2021 compared to 2020 – Our overall funding strategy remains to develop and sustain a diversified funding base. We also need to fulfil regulatory requirements as well as support our credit ratings. – In 2021, we utilised central bank liquidity schemes to provide core funding to Santander UK plc. Wholesale markets were open and utilised by our peers but our large capacity and relative cost of the TFSME meant this was the cornerstone of 2021 funding for Santander. We have spoken to over 220 investors across all asset classes since the start of the Covid-19 pandemic, ensuring we retain relationships and can easily resume wholesale funding as required going forward. – We drew further on TFSME in Q421, with £31.9bn outstanding at year end. We repaid all TFS outstanding. We issued £2.8bn of MREL eligible senior unsecured securities. Wholesale funding costs improved in 2021 with buy backs and maturities being refinanced at lower cost. – Our structural hedge position remained broadly stable at c£103bn, with an average duration of c2.6 years. – Maturities in 2021 were £19.2bn (2020: £16.5bn). At 31 December 2021, 85% (2020: 68%) of wholesale funding had a maturity of greater than one year, with an overall residual duration of 47 months (2020: 38 months). – Our level of encumbrance from external and internal issuance of securitisations and covered bonds fell in 2021. Reconciliation of wholesale funding to the balance sheet (audited) This table reconciles our wholesale funding to our balance sheet at 31 December 2021 and 31 December 2020. Balance sheet line item Funding Deposits by banks (3) Deposits by customers (1) Repurchase agreements - non trading Financial Debt Subordinated Other equity instruments and non- controlling interests (2) 2021 £bn £bn £bn £bn £bn £bn £bn £bn Deposits by banks 0.2 0.2 — — — — — — Certificates of deposit and commercial paper 5.1 — — — — 5.1 — — Senior unsecured – public benchmark 12.4 — — — — 12.4 — — – privately placed 0.6 — — — 0.5 0.1 — — Covered bonds 12.5 — — — — 12.5 — — Securitisation and structured issuance 0.7 — — — — 0.7 — — Term Funding Scheme — — — — — — — — TFSME 31.9 31.9 — — — — — — Subordinated liabilities and equity 4.4 — — — — — 2.0 2.4 Total wholesale funding 67.8 32.1 — — 0.5 30.8 2.0 2.4 Repos 11.7 — — 11.7 — — — — Foreign exchange and hedge accounting 1.0 — — — — 0.8 0.2 — Other 2.1 1.8 — — 0.3 — — — Balance sheet total 82.6 33.9 — 11.7 0.8 31.6 2.2 2.4 2020 Deposits by banks — — — — — — — — Certificates of deposit and commercial paper 5.7 — — — — 5.7 — — Senior unsecured – public benchmark 15.5 — — — — 15.5 — — – privately placed 1.1 — — — 0.9 0.2 — — Covered bonds 17.9 — — — — 17.9 — — Securitisation and structured issuance 2.8 — — — 0.5 2.3 — — Term Funding Scheme 6.3 6.3 — — — — — — TFSME 11.7 11.7 — — — — — — Subordinated liabilities and equity 4.7 — — — — — 2.2 2.5 Total wholesale funding 65.7 18.0 — — 1.4 41.6 2.2 2.5 Repos 15.8 — — 15.8 — — — — Foreign exchange and hedge accounting 2.5 — — — — 2.1 0.4 — Other 3.0 3.0 — — — — — — Balance sheet total 87.0 21.0 — 15.8 1.4 43.7 2.6 2.5 (1) This is included in our balance sheet total of £192,914m (2020: £193,088m). (2) Consists of £nil (2020: £nil) fixed/floating rate non-cumulative callable preference shares, £235m (2020: £235m) Step-up Callable Perpetual Reserve Capital Instruments and £2,191m (2020: £2,241m) Perpetual Capital Securities (net of issuance costs). See Notes 33 and 34 to the Consolidated Financial Statements. (3) Other consists of items in the course of transmission and other deposits, excluding the TFS. See Note 24 to the Consolidated Financial Statements. Maturity profile of wholesale funding (audited) This table shows our main sources of wholesale funding. It does not include securities finance agreements. The table is based on exchange rates at issue and scheduled repayments and call dates. It does not reflect the final contractual maturity of the funding. ≤ 1 >1 and ≤ 3 months >3 and ≤ 6 months >6 and ≤ 9 months >9 and ≤ 12 months Sub-total >1 and >2 and >5 years Total 2021 £bn £bn £bn £bn £bn £bn £bn £bn £bn £bn Santander UK Group Holdings plc (1) Senior unsecured – public benchmark 0.8 — 0.4 — — 1.2 3.0 4.1 1.8 10.1 – privately placed — — — — — — — — 0.1 0.1 Subordinated liabilities and equity (incl. AT1) — — 0.8 — — 0.8 — 1.9 0.3 3.0 0.8 — 1.2 — — 2.0 3.0 6.0 2.2 13.2 Santander UK plc Deposits by banks 0.2 — — — — 0.2 — — — 0.2 Certificates of deposit and commercial paper 1.3 3.0 0.7 0.1 — 5.1 — — — 5.1 Senior unsecured – public benchmark 0.6 — — — — 0.6 0.3 1.1 0.3 2.3 – privately placed — — — — — — — 0.3 0.2 0.5 Covered bonds — — 0.8 — 0.9 1.7 1.9 5.6 3.3 12.5 Securitisation & structured issuance (2) 0.2 — 0.1 0.1 — 0.4 0.2 0.1 — 0.7 Term Funding Scheme (TFS) — — — — — — — — — — TFSME — — — — — — — 28.0 3.9 31.9 Subordinated liabilities — 0.2 — — — 0.2 0.5 — 0.7 1.4 2.3 3.2 1.6 0.2 0.9 8.2 2.9 35.1 8.4 54.6 Other group entities Securitisation & structured issuance (3) — — — — — — — — — — Total at 31 December 2021 3.1 3.2 2.8 0.2 0.9 10.2 5.9 41.1 10.6 67.8 Of which: – Secured 0.2 — 0.9 0.1 0.9 2.1 2.1 33.7 7.2 45.1 – Unsecured 2.9 3.2 1.9 0.1 — 8.1 3.8 7.4 3.4 22.7 3.1 3.2 2.8 0.2 0.9 10.2 5.9 41.1 10.6 67.8 2020 Total at 31 December 2020 2.2 5.6 8.0 4.1 1.2 21.1 7.9 28.3 8.4 65.7 Of which: – Secured 0.4 1.6 5.2 3.0 0.2 10.4 5.3 18.6 4.4 38.7 – Unsecured 1.8 4.0 2.8 1.1 1.0 10.7 2.6 9.7 4.0 27.0 (1) 95% of senior unsecured debt issued from Santander UK Group Holdings plc has been downstreamed to Santander UK plc as ‘secondary non-preferential debt’ in line with the guidelines from the Bank of England for Internal MREL. (2) Includes funding from mortgage-backed securitisation vehicles where Santander UK plc is the asset originator. (3) Includes funding from asset-backed securitisation vehicles where entities other than Santander UK plc are the asset originator. Currency composition of wholesale funds (audited) This table shows our wholesale funding by major currency at 31 December 2021 and 31 December 2020. 2021 2020 Sterling US Dollar Euro Other Sterling US Dollar Euro Other % % % % % % % % Santander UK Group Holdings plc Senior unsecured – public benchmark 10 59 31 — 11 61 28 — – privately placed — — — 100 — — — 100 Subordinated liabilities and equity (incl. AT1) 75 25 — — 75 25 — — 24 51 24 1 27 51 21 1 Santander UK plc Deposits by banks 32 68 — — — — — — Certificates of deposit and commercial paper 45 53 2 — 51 44 4 1 Senior unsecured – public benchmark 14 46 40 — 10 73 17 — – privately placed 92 — 6 2 41 37 10 12 Covered bonds 44 8 48 — 48 5 46 1 Securitisation & structured issuance 74 26 — — 77 23 — — Term Funding Scheme — — — — 100 — — — TFSME 100 — — — 100 — — — Subordinated liabilities 57 43 — — 63 37 — — 77 10 13 — 63 18 19 — Other group entities Securitisation & structured issuance — — — — 100 — — — Total 67 18 15 — 57 24 19 — Term issuance (audited) In 2021, our external term issuance (sterling equivalent) was: Sterling US Dollar Euro Other Total 2021 Total 2020 £bn £bn £bn £bn £bn £bn Santander UK Group Holdings plc Senior unsecured – public benchmark — 2.2 0.6 — 2.8 1.4 Subordinated debt and equity (inc. AT1) 0.5 — — — 0.5 — 0.5 2.2 0.6 — 3.3 1.4 Santander UK plc Securitisations and other secured funding — — — — — — Covered bonds — — — — — 3.0 Senior unsecured – public benchmark — — — — — 1.0 – privately placed 0.1 — — — 0.1 — TFSME 20.2 — — — 20.2 11.7 20.3 — — — 20.3 15.7 Other group entities Securitisations — — — — — — Total gross issuances 20.8 2.2 0.6 — 23.6 17.1 Encumbrance We have encumbered an asset if we have pledged or transferred it as collateral against an existing liability. This means it is no longer available to secure funding, meet our collateral needs or be sold to reduce future funding needs. Being able to pledge or transfer assets as collateral is an integral part of a financial institution’s operations. The main ways we encumber assets are that we: – Enter into securitisation, covered bonds, and repurchase agreements (including central bank programmes) to access medium and long-term funding – Enter into short-term funding transactions. These include repurchase agreements and stock borrowing transactions as part of our operational liquidity management – Pledge collateral as part of participating in payment and settlement systems – Post collateral as part of derivatives activity. We monitor our mix of secured and unsecured funding sources in our funding plan. We aim to use our available collateral efficiently to raise secured funding and to meet our other collateralised obligations. Our biggest source of encumbrance is where we use our mortgage portfolio to raise funds through Bank of England facilities, securitisation, covered bonds or other structured borrowing. We control our levels of encumbrance from these by setting a minimum level of unencumbered assets that must be available after we factor in our future funding plans, whether we can use our assets for our future collateral needs, the impact of a possible stress and our current level of encumbrance. Assets classified as readily available for encumbrance include cash and securities we hold in our eligible liquidity pool. They also include other unencumbered assets that give us a source of contingent liquidity. We do not rely on these extra unencumbered assets in our LRA, but we might use some of them in a time of stress. We can create liquidity by using them as collateral for secured funding or through outright sale. Loans and advances to customers are only classified as readily available for encumbrance if they are already in a form we can use to raise funding without any other actions on our part. This includes excess collateral that is already in a secured funding structure. It also includes collateral that is pre-positioned at central banks and is available for use in secured funding. All other loans and advances are classified as not readily available for encumbrance, however, they may still be suitable for use in secured funding structures. Encumbrance of customer loans and advances We have issued prime retail mortgage-backed and other asset-backed securitised products to a diverse investor base through our mortgage-backed and other asset-backed funding programmes. We have raised funding with mortgage-backed notes, both issued to third parties and retained – the latter being central bank eligible collateral for funding purposes in other Bank of England facilities. We also have a covered bond programme, under which we issue securities to investors secured by a pool of residential mortgages. For more on how we have issued notes from our secured programmes externally and also retained them, and what we have used them for, see Notes 14 and 26 to the Consolidated Financial Statements. On-balance sheet encumbered and unencumbered assets (audited) Encumbered with counterparties other than central banks Unencumbered assets not pre-positioned with central banks Covered Securitis- Other Total Assets positioned at central banks (3) Readily Other Cannot be Total Total 2021 £m £m £m £m £m £m £m £m £m £m Cash and balances at central banks (1)(2) — — 1,580 1,580 935 47,979 — — 48,914 50,494 Financial assets at FVTPL: – Derivative financial instruments — — — — — — — 1,720 1,720 1,720 – Other financial assets at FVTPL — — — — — — — 676 676 676 Financial assets at amortised cost: – Loans and advances to customers 15,713 3,720 84 19,517 80,623 74,890 18,893 19,602 194,008 213,525 – Loans and advances to banks — — 478 478 — — — 942 942 1,420 – Repurchase agreements – non trading — — — — — — — 12,683 12,683 12,683 – Other financial assets at amortised cost — — — — — 506 — — 506 506 Financial assets at FVOCI — — 4,434 4,434 — 1,417 — — 1,417 5,851 Interests in other entities — — — — — — — 201 201 201 Intangible assets — — — — — — — 1,545 1,545 1,545 Property, plant and equipment — — — — — — 1,555 — 1,555 1,555 Current tax assets — — — — — — — 351 351 351 Retirement benefit assets — — — — — — — 1,573 1,573 1,573

Capital Risk

Capital Risk	12 Months Ended
	Dec. 31, 2021
Disclosure Of Capital Risk Exposure [Abstract]
Capital Risk	Capital risk Overview Capital risk is the risk that we do not have an adequate amount or quality of capital to meet our internal business objectives, regulatory requirements and market expectations. In this section, we set out how we are regulated. We also give details of the results of the Bank of England’s 2019 stress testing exercise. We explain how we manage capital on a standalone basis as a subsidiary in the Banco Santander group. We then analyse our capital resources and key capital ratios including our leverage and RWAs. Key metrics CET1 capital ratio of 15.9% (2020: 15.2%) Total qualifying regulatory capital of £14.7bn (2020: £15.4bn) UK leverage ratio of 5.2% (2020: 5.1%) THE SCOPE OF OUR CAPITAL ADEQUACY Regulatory supervision For capital purposes, we are subject to prudential supervision by the PRA, as a UK banking group, and by the European Central Bank (ECB) as part of the Banco Santander group. The ECB supervises Banco Santander as part of the Single Supervisory Mechanism (SSM). Although we are part of the Banco Santander group, we do not have a guarantee from our immediate and ultimate parent Banco Santander SA and we operate as a standalone subsidiary. As we are part of the UK sub-group that is regulated by the PRA, we have to meet the PRA capital requirements on a standalone basis. We also have to show the PRA that we can withstand capital stress tests without the support of our parent. Reinforcing our corporate governance framework, the PRA exercises oversight through its rules and regulations on the Board and senior management appointments. Santander UK Group Holdings plc is the holding company of Santander UK plc and is the head of the Santander UK group for regulatory capital and leverage purposes. Santander UK plc is the head of the ring-fenced bank sub-group and is subject to regulatory capital and leverage rules in relation to that sub-group. Our basis of consolidation for our capital disclosures is substantially the same as for our Consolidated Financial Statements. CAPITAL RISK MANAGEMENT The Board is responsible for capital management strategy and policy and ensuring that we monitor and control our capital resources within regulatory and internal limits. We manage our funding and maintain capital adequacy on a standalone basis. We operate within the capital risk framework and appetite approved by our Board. This reflects the business environment we operate in, our strategy for each material risk and the potential impact of any adverse scenarios or stresses on our capital position. Management of capital requirements (audited) Our capital risk appetite aims to maintain capital levels appropriate to the level of stress applied, and the expected regulatory response. In: – An adverse economic stress, which we might expect to occur once in 20 years, the firm should remain profitable and exceed all regulatory capital minimums at all times. – A very severe economic stress, which we might expect to occur once in 100 years, and which has been designed to test any specific weaknesses of a firm’s business model, the firm should meet all regulatory capital minimums at all times. This is subject to the use of regulatory buffers designed to absorb losses in such a stress. Management of capital resources (audited) We use a mix of regulatory and EC ratios and limits, internal buffers and restrictions to manage our capital resources. We also take account of the costs of differing capital instruments and capital management techniques. We also use these to shape the best structure for our capital needs. We decide how to allocate our capital resources as part of our strategic planning process. We base this in part on the relative returns on capital using both EC and regulatory capital measures. We plan for severe stresses and we set out what action we would take if an extremely severe stress threatened our viability and solvency. This could include not paying dividends, selling assets, reducing our business and issuing more capital. Risk measurement We apply Banco Santander’s approach to capital measurement and risk management for CRD IV. Santander UK Group Holdings plc is classified as a significant subsidiary of Banco Santander SA. For more on the CRD IV risk measurement of our exposures, see Banco Santander’s Pillar 3 report. Key metrics The main metrics we use to measure capital risk are CET1 capital ratio, total capital ratio and UK leverage ratio.We continue to be in excess of overall capital requirements, minimum leverage requirements and minimum requirements for own funds and eligible liabilities (MREL). Stress testing Each year we create a capital plan, as part of our ICAAP. We share our ICAAP with the PRA. The PRA then tells us how much capital (Pillar 2A), and of what quality, it thinks we should hold on top of our Pillar 1 requirements and buffer levels. We also develop a series of economic scenarios to stress test our capital needs and confirm that we have enough regulatory capital to meet our projected and stressed capital needs and to meet our obligations as they fall due. We augment our regulatory minimum capital with internal buffers. We hold buffers to ensure we have enough time to take action against unexpected movements. Risk mitigation We have designed our capital risk framework, policies and procedures to ensure that we operate within our Risk Appetite. We manage capital transferability between our subsidiaries in line with our business strategy, our risk and capital management policies, and UK laws and regulations. There are no legal restrictions on us moving capital resources promptly, or repaying liabilities, between the Company and its subsidiaries except for distributions between Santander UK entities in the ring-fenced bank sub-group and Santander UK entities that are not members of the ring-fenced bank sub-group, where the PRA is required to assess the impact of proposed distribution prior to payment. For details on our Recovery framework in the event of a capital stress, see the risk mitigation section in the ‘Liquidity risk’ section. At 31 December 2021, Santander UK plc (RFB), Cater Allen Limited and certain other non-regulated subsidiaries within the RFB were party to the RFB Sub-Group Capital Support Deed dated 13 November 2018. These parties were permitted by the PRA to form a core UK group as defined in the PRA Rulebook. Exposures of each of the regulated entities to other members of the core UK group were exempt from large exposure limits that would otherwise apply and intra-group exposures risk-weighted at 0% on a solo as well as consolidated basis. The purpose of the 2018 Deed was to facilitate the prompt transfer of available capital resources from, or repayment of liabilities by, the non-regulated parties to any of the regulated parties in the RFB Sub-Group in the event that one of the regulated parties breached or was at risk of breaching its capital resources or risk concentrations requirements. A new RFB Sub-Group Capital Support Deed was entered into on 17 December 2021 and effective from 1 January 2022. This reflected the latest version of associated regulation and addition of two RFB subsidiaries including Santander ISA Managers Limited, an entity regulated by the FCA. The parties to the 2021 Deed were granted a new permission by the PRA to operate the RFB core UK group from 1 January 2022 to 31 December 2024, following expiry of the previous permission on 31 December 2021. Where applicable this also provides for intra-group exposures to be excluded from leverage exposure on a solo as well as consolidated basis. At 31 December 2021, Santander UK Group Holdings plc and Santander Financial Services plc, the regulated entities, and Santander Equity Investments Limited were party to the Non-RFB Sub-Group Capital Support Deed dated 13 November 2018. These parties were permitted by the PRA to form a core UK group as defined in the PRA Rulebook. Exposures of each of the regulated entities to other members of the core UK group were exempt from large exposure limits that would otherwise apply and intra-group exposures risk-weighted at 0% on a solo as well as consolidated basis. The purpose of the 2018 Deed was to facilitate the prompt transfer of available capital resources from, or repayment of liabilities by, the non-regulated parties to any of the regulated parties in the Non-RFB Sub-Group in the event that one of the regulated parties breached or was at risk of breaching its capital resources or risk concentrations requirements. Santander UK Group Holdings plc became a PRA-regulated firm from 12 December 2021. A new Non-RFB Sub-Group Capital Support Deed was entered into on 17 December 2021 and effective from 1 January 2022, reflecting the latest version of associated regulation. The parties to the Non-RFB Sub-Group Capital Support Deed 2021 remained unchanged with the PRA granting permission for a renewal of the Non-RFB core UK group from 1 January 2022 to 31 December 2024, following expiry of the previous permission on 31 December 2021. Risk monitoring and reporting We monitor and report regularly against our capital plan. We do this to identify any change in our business performance that might affect our capital. Each month, we also review the economic assumptions we use to create and stress test our capital plan. We do this to identify any potential reduction in our capital. Meeting evolving capital requirements We target a CET1 management buffer of sufficient size to absorb volatility in CET1 deductions, capital supply and capital demand whilst remaining above the regulatory CET1 requirement. Distribution restrictions would be expected to be applied if we were unable to meet both our minimum requirement, which consists of the Pillar 1 minimum plus Pillar 2A, the CRD IV buffers consisting of the Capital Conservation Buffer (CCB), the Countercyclical Capital Buffer (CCyB), and the Other Systemically Important Institutions Buffer (O-SII) at the level of the RFB Group. Impact of IFRS 9 on regulatory capital Our ECL methodology takes account of forward-looking data and covers a range of possible economic outcomes, and consequently provision movements may result in increased pro-cyclicality of risk-based capital and leverage ratios. However, the impact is currently mitigated by our surplus of IRB model regulatory expected losses over provisions for exposures using the IRB approach. For such exposures (which include residential mortgages) the adverse impact on CET1 capital of provision increases from reserve movements is offset by the related reduction of the negative CET1 capital adjustment for regulatory expected loss amounts. Furthermore, the UK CRR transitional rules for the capital impact of IFRS 9 mean that adverse CET1 effects from increases in ECL-based provisions from the level of such provisions at 1 January 2018 are partly reduced until the end of 2024. We reflect projections of ECL provisions in our capital position forecasting under base case and stress scenarios for ICAAP and capital management purposes. We also consider the dynamics of ECL in how we assess, monitor and manage capital risk. A period of economic instability, such as that seen in early 2020 due to the impacts of the Covid-19 pandemic, could significantly impact our results and our financial assets. It could also impact the amount of capital we have to hold. We take into account the volatility of ECL in our capital planning strategy. Bank of England stress testing The results of the latest round of Bank of England stress tests were released in December 2021. As a result of the exercise, the Bank of England did not require Santander UK to undertake any actions. Before management actions and on a non-transitional IFRS 9 basis, with a low-point CET1 capital ratio of 11.2% we were well above the reference rate of 8.2%. Additionally, with a low-point UK leverage ratio of 4.1%, we were above the reference rate of 3.5%. The Bank of England’s reference rates comprise the sum of minimum capital requirements (4.5% of RWA plus Pillar 2A for the CET1 ratio, and 3.25% of Leverage Exposure for the UK Leverage Ratio), applicable systemic buffers, and an adjustment to offset the pro-cyclical impacts of IFRS 9. Headroom of our CET1 capital ratio to our current MDA trigger level at 31 December 2021 At 31 December 2021, the headroom of our CET1 capital ratio of 15.9% to our 7% AT1 permanent write down (PWD) securities trigger was 8.9% of total RWAs or £6.1bn (2020 : 8.2% of total RWAs or £6.0bn). The headroom of our CET1 capital ratio to our current maximum distributable amount (MDA) trigger level at 31 December 2021 was: Current MDA % Pillar 1 4.5 Pillar 2A (1) 3.0 Capital conservation buffer 2.5 Current MDA trigger 10.0 Headroom to current MDA 5.9 Total CET1 capital ratio 15.9 (1) Santander UK's Pillar 2 requirement was 5.3% at 31 December 2021, Pillar 2A guidance is a point in time assessment. MREL recapitalisation To date, we have issued £10.2bn of MREL compliant senior unsecured bonds. Our forward-looking MREL recapitalisation plan assumes the Pillar 2A requirement remains at 5.3% and is calculated using RWA, leverage exposures and exchange rates at 31 December 2021. Based on this set of assumptions, our MREL requirements are driven by RWA. Santander UK’s indicative MREL requirements including combined buffer requirements is currently circa £20bn from 1 January 2022. In addition to meeting our minimum requirement, we intend to have an MREL recapitalisation management buffer in excess of the value of Santander UK Group Holdings plc senior unsecured securities that are due to become MREL ineligible over the following six months, plus a buffer for foreign exchange movements. Key capital ratios Santander UK Group Holdings plc Santander UK plc 2021 2020 2021 2020 % % % % CET1 capital ratio 15.9 15.2 16.1 15.4 AT1 3.2 3.1 2.9 2.7 Grandfathered Tier 1 0.2 0.3 0.2 0.4 Tier 2 2.3 2.5 2.7 2.7 Total capital ratio 21.6 21.1 21.9 21.2 The total subordination available to Santander UK plc bondholders was 21.9% (2020:21.2%) of RWAs. Return on assets - profit after tax divided by average total assets was 0.48% (2020: 0.15%). 2021 compared to 2020 CET1 capital ratio increased 70bps to 15.9%, 590bps above the MDA threshold, largely due to lower RWAs and retained profit. CET1 capital ratio includes a benefit of circa 20bps and UK leverage ratio circa 5bps from the change in treatment of software assets outlined in the EBA technical standard on the prudential treatment of software assets. The PRA have outlined in Policy Statement PS17/21 on the implementation of Basel Standards that this treatment will fall away at the start of 2022 and software assets will instead be fully deducted from CET1 capital from that date. Total capital ratio increased by 50bps to 21.6%, with lower RWA and retained profits offsetting the reduction in capital securities in issue and the increased effect from January 2021 of the CRD IV Grandfathering Cap rules that reduce the recognition of grandfathered capital instruments issued by Santander UK plc. Regulatory capital resources (audited) This table shows our qualifying regulatory capital: 2021 2020 £m £m CET1 capital instruments and reserves: – Capital instruments 7,060 7,060 – Retained earnings 6,754 6,030 – Accumulated other reserves and non-controlling interests 138 679 CET1 capital before regulatory adjustments 13,952 13,769 CET1 regulatory adjustments: – Additional value adjustments (25) (21) – Goodwill (net of tax) (1,130) (1,150) – Other intangibles (195) (199) – Fair value reserves related to gains or losses on cash flow hedges (110) (486) – Negative amounts resulting from the calculation of regulatory expected loss amounts (585) (368) – Gains or losses on liabilities valued at fair value resulting from changes in own credit standing — (6) – Deferred tax assets that rely on future profitability excluding timing differences (2) (9) – Defined benefit pension fund assets (1,061) (364) – Dividend accrual (17) (18) – IFRS 9 Transitional Adjustment 21 73 – Deductions for non-controlling interests — (162) CET1 capital 10,848 11,059 AT1 capital instruments: – Capital instruments 2,191 2,241 – Amount of qualifying items subject to phase out from AT1 163 324 – Regulatory deductions for instruments issued by subsidiary undertakings (48) (93) AT1 capital 2,306 2,472 Tier 1 capital 13,154 13,531 Tier 2 capital instruments: – Capital instruments 2,263 2,076 – Amount of qualifying items subject to phase out from Tier 2 35 352 – Regulatory deductions for instruments issued by subsidiary undertakings or subject to CRDIV amortisation and repurchases (725) (571) Tier 2 capital 1,573 1,857 Total regulatory capital 14,727 15,388 2021 compared to 2020 We remain strongly capitalised and the impacts of the Covid-19 pandemic did not trigger a capital stress. We paid £1,346m interim ordinary share dividends related to 2021 profit and an assessment of capital surpluses (2020: £103m). Dividends were paid in line with our dividend policy following review and approval by the Santander UK Board. Movements in regulatory capital: CET1 capital AT1 capital Tier 2 capital Total £m £m £m £m At 1 January 2021 11,059 2,472 1,857 15,388 – Retained earnings 724 — — 724 – Other reserves and non-controlling interests (541) — — (541) – Additional value adjustments (4) — — (4) – Goodwill (net of tax) 20 — — 20 – Other intangibles 4 — — 4 – Fair value reserves related to gains and losses on cash flow hedges 376 — — 376 – Negative amounts resulting from the calculation of regulatory expected loss amounts (217) — — (217) – Gains or losses on liabilities valued at fair value resulting from changes in own credit standing 6 — — 6 – Deferred tax assets that rely on future profitability excluding timing differences 7 — — 7 – Defined benefit pension fund assets (697) — — (697) – Dividend accrual 1 — — 1 – Deductions for non-controlling interests 162 — — 162 – Capital instruments — (50) 187 137 – IFRS 9 Transitional Adjustment (52) — — (52) – Amount of qualifying items subject to phase out from AT1 — (161) — (161) – Amount of qualifying items subject to phase out from Tier 2 — — (317) (317) - Deductions for instruments issued by subsidiary undertakings or subject to CRD IV amortisation — 45 (154) (109) At 31 December 2021 10,848 2,306 1,573 14,727 In line with the position of the Basel Committee views following the outbreak of the Covid-19 pandemic, the UK has now adopted revised IFRS 9 transitional adjustment rules which apply a higher level of transitional relief to capital following rises in IFRS 9 provisions. The original transitional adjustments consisted of a Static component, which was impacted on 1 January 2018 and a Dynamic component with changes in provisions for non-impaired assets made after 1 January 2018. A transitional factor was applied to the Dynamic component to determine the level of offset that was available over time (95% in 2018, 85% in 2019, 70% in 2020, 50% in 2021 and 25% in 2022). The revisions to the transitional adjustment are part of the ‘Quick fix' CRR amendments which have been in force from 27 June 2020. They have involved dividing the original Dynamic component into two parts – creating an ‘old’ component for provision changes from 1 January 2018 to 1 January 2020, and then a new Dynamic component for provision changes from 1 January 2020 and applying a revised higher transitional factor to this latter component, with an extended transitional period. CET1, AT1 and Tier 2 regulatory adjustments These are adjustments required by CRD IV. AT1 capital These are preference shares and innovative/hybrid Tier 1 securities. None of the instruments we issued before 1 January 2014 fully meet the CRD IV AT1 capital rules, which apply from that date. The instruments contribution to Tier 1 capital has been phased out by CRD IV rules as at the end of 2021. The £750m Fixed Rate Reset Perpetual AT1 Capital Securities (net of issuance costs), the £800m Perpetual Capital Securities and the £500m Perpetual Capital Securities we issued since then fully meet the CRD IV AT1 capital rules. Tier 2 capital These are fully CRD IV eligible Tier 2 instruments and grandfathered Tier 2 instruments whose recognition as capital has been phased out under CRD IV as at the end of 2021. Risk-weighted assets The tables below are consistent with our regulatory filings for 31 December 2021 and 31 December 2020. 2021 2020 RWAs by risk £bn £bn Credit risk 60.2 64.8 Counterparty risk 1.0 1.1 Market risk 0.2 0.2 Operational risk 6.7 6.8 68.1 72.9 2021 2020 RWAs by segment £bn £bn Retail Banking 42.9 41.0 – Homes 34.2 32.4 – Everyday Banking 8.7 8.6 Consumer Finance 6.4 8.5 Corporate & Commercial Banking 12.9 13.3 Corporate & Investment Banking — 3.8 Corporate Centre 5.9 6.3 68.1 72.9 Movements in RWAs by risk: Credit/counterparty Market risk Operational Total £bn £bn £bn £bn At 1 January 2021 65.9 0.2 6.8 72.9 Asset size 0.7 — — 0.7 Asset quality (0.6) — — (0.6) Model updates — — — — Methodology and policy — — — — Acquisitions and disposals (4.8) — — (4.8) Foreign exchange movements — — — — Other — — (0.1) (0.1) At 31 December 2021 61.2 0.2 6.7 68.1 2021 compared to 2020 RWA reduced c£6bn following a sale of our PSA shareholding to PSA Financial Services Spain, the transfer of CIB to SLB, sale of our London head office and the sale of a £0.6bn retail mortgage portfolio. These sales and transfers reduced customer loans by £6.0bn. Regulatory leverage 2021 2020 £m £m Regulatory exposure 246,304 259,044 End-point Tier 1 capital (1) 12,849 13,164 UK leverage ratio 5.2 % 5.1 % BBLS lending excluded from leverage exposure (3,622) (3,986) (1) Includes deductions and AT1 adjustment permitted under the recommendation from the Financial Policy Committee on 25 July 2016. Under the PRA rules, we adjust our total assets per the Consolidated Balance Sheet to calculate our regulatory exposure for leverage purposes. We do this as follows: 2021 2020 £m £m Total assets per the Consolidated Balance Sheet 293,676 299,064 Derivatives netting and potential future exposure (646) (1,521) Securities financing current exposure add-on 518 767 Removal of IFRS netting 1,052 1,144 Removal of qualifying central bank claims (54,116) (47,537) Commitments calculated in accordance with Basel Committee Leverage Framework 7,619 8,114 CET1 regulatory adjustments (1,799) (987) 246,304 259,044 The adjustments are: – Derivatives netting and potential future exposure: where a qualifying netting agreement is in place netting is allowed for leverage purposes. This is partially offset by including the Potential Future Exposure (PFE) we use to calculate EADs – Securities financing current exposure add-on: we include an add-on for securities financing transactions to show current exposure for leverage purposes – Removal of IFRS netting: where netting of assets and liabilities is allowed under IFRS, but not under the Basel rules, we remove it for leverage purposes – Removal of qualifying central banks claims: permitted under the recommendation of the Financial Policy Committee (FPC) on 25 July 2016, but under CRD IV rules the exposure measure does not allow the removal of qualifying central bank deposits or claims – Commitments calculated in accordance with Basel Committee Leverage Framework: we add the gross value of off-balance sheet commitments for leverage purposes after we apply regulatory credit conversion factors – CET1 regulatory adjustments: where we have deducted assets from CET1, they can be deducted for leverage purposes. 2021 compared to 2020 The UK leverage ratio improved by 10bps to 5.2%,160bps above the regulatory minimum, largely due to lower assets. Distributable items Distributable items are equivalent to distributable profits under the UK Companies Act 2006. The distributable items of Santander UK Group Holdings plc under CRD IV at 31 December 2021 and 31 December 2020, and movements in the period, were as follows: 2021 2020 £m £m At 1 January 4,252 4,262 Dividends approved: – AT1 Capital Securities (143) (147) – Tax on above item 27 28 – Ordinary shares (1,346) (103) Dividends receivable: – Investment in AT1 Capital Securities 131 131 – Tax on above item (25) (25) – Investment in ordinary shares of subsidiary 1,366 129 Other income statement items (Company) — (23) At period end 4,262 4,252

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2021
Disclosure Of Significant Accounting Policies [Abstract]
Accounting Policies	1. ACCOUNTING POLICIES These financial statements are prepared for Santander UK Group Holdings plc (the Company) and the Santander UK Group Holdings plc group (the Santander UK group) under the UK Companies Act 2006. The principal activity of the Santander UK group is the provision of a wide range of banking and financial services to personal, business and corporate customers. Santander UK Group Holdings plc is a public company, limited by shares and incorporated in England and Wales having a registered office at 2 Triton Square, Regent’s Place, London, NW1 3AN, phone number 0870-607-6000. It is a financial services holding company. Basis of preparation These financial statements incorporate the financial statements of the Company and entities it controls (its subsidiaries) made up to 31 December each year. The consolidated financial statements have been prepared on the going concern basis using the historical cost convention, except for financial assets and liabilities that have been measured at fair value. An assessment of the appropriateness of the adoption of the going concern basis of accounting is disclosed in the statement of going concern in the Directors’ report. On 31 December 2020, International Financial Reporting Standards (IFRSs) as adopted by the European Union at that date were brought into UK law and became UK-adopted International Accounting Standards (IAS), with future changes being subject to endorsement by the UK Endorsement Board. The Company and its subsidiaries transitioned to UK-adopted IAS in its consolidated financial statements on 1 January 2021. This change constitutes a change in accounting framework. Although there was a change in accounting framework, this change had no impact on recognition, measurement or disclosures in the periods reported in these financial statements. Compliance with International Financial Reporting Standards The consolidated financial statements of the Santander UK group and the separate financial statements of the Company comply with UK-adopted IAS. The financial statements are also prepared in accordance with IFRSs as issued by the International Accounting Standards Board (IASB), including interpretations issued by the IFRS Interpretations Committee, as there are no applicable differences from IFRSs as issued by the IASB for the periods presented. Disclosures required by IFRS 7 ‘Financial Instruments: Disclosure’ relating to the nature and extent of risks arising from financial instruments, and IAS 1 ‘Presentation of Financial Statements’ relating to objectives, policies and processes for managing capital, can be found in the risk governance, credit risk, market risk, liquidity risk and capital risk sections of the Risk review and are labelled as audited. Those disclosures form an integral part of these financial statements. Climate change Santander UK continues to develop its assessment of the potential impacts that climate change and the transition to a low carbon economy may have on the assets and liabilities recognised and presented in its financial statements. Santander UK is mindful of its responsibilities as a responsible lender and is focused on ways to meet the objectives of the Paris Agreement on climate change and to support the UK’s transition to a climate-resilient, net zero economy. Santander UK's current climate change strategy focuses on three main areas to achieve Banco Santander's ambition to reach net zero emissions by 2050: 1. Managing climate risks by integrating climate considerations into risk management frameworks, screening and stress testing our portfolio for climate related financial risks, and setting risk appetites to help steer our portfolio in line with the Paris Agreement, 2. Supporting our customers’ transition by developing products and services that promote a reduction in CO 2 emissions, and 3. Reducing emissions in our operations and supply chain by focusing on continuous improvement in our operations, and environmental and energy management systems in accordance with ISO14001 and 15001, promoting responsible procurement practices and employee engagement. Santander UK's current climate change strategy and its view of the risks associated with climate change and the transition to a low carbon economy are reflected in its critical judgements and accounting estimates, although climate change risk did not have a significant impact at 31 December 2021, consistent with management's assessment that climate change and the transition to a low carbon economy are not currently expected to have a meaningful impact on the viability of the Santander UK group in the medium term. At 31 December 2021, management specifically considered the potential impact of climate change and the transition to a low carbon economy on: – Loans and advances to customers (see Note 13 and the credit risk section of the Risk review). Some climate change risks arise due to the requirements of IFRS 9 and others relate to specific portfolios and sectors: – ECL calculations are based on multiple forward-looking economic scenarios developed by management covering a period of 5 years, during which timeframe climate change risks may crystallise. – For Mortgages in Retail Banking and Commercial Real Estate lending in Corporate & Commercial Banking, the value of property collateral might be affected by physical impacts related to the frequency and scale of extreme weather events, such as flood and subsidence risk, or changing environmental performance standards for property. – For automotive loans in Consumer Finance, the residual value of automotive vehicles might be impacted by diesel obsolescence and the transition to electric vehicles. – For corporate lending in Corporate & Commercial Banking, certain sectors give rise to fossil fuel exposures, such as Oil & Gas, Mining & Extraction and Power Generation. – Goodwill impairment assessment (see Note 20). Estimates underpinning the determination of whether or not goodwill balances are impaired are partly based on forecast business performance beyond the time horizon for management's detailed plans. Future changes to Santander UK's climate change strategy may impact Santander UK's critical judgements and accounting estimates and result in material changes to financial results and the carrying values of certain assets and liabilities in future reporting periods. Accounting developments Interest Rate Benchmark Reform In 2019, the IASB issued ‘Interest Rate Benchmark Reform: Amendments to IFRS 9, IAS 39 and IFRS 7’. The Santander UK group applies IAS 39 hedge accounting so the amendments to IFRS 9 do not apply. Although the IAS 39 and IFRS 7 amendments, which apply to all hedging relationships directly affected by uncertainties related to interbank offered rate (IBOR) reform, became effective from 1 January 2020, following their endorsement, the Santander UK group early adopted those amendments in the preparation of the financial statements for the year ended 31 December 2019. The exceptions given by the IAS 39 amendments meant that IBOR reform had no impact on hedge relationships for affected hedges. In 2020, the IASB issued ‘Interest Rate Benchmark Reform – Phase 2 - Amendments to IFRS 9, IAS 39, IFRS 7, IFRS 4 and IFRS 16’. These amendments apply only to changes required by IBOR reform to financial instruments and hedging relationships. Although the amendments became effective from 1 January 2021 and are applied retrospectively without restating comparative information, following their endorsement, the Santander UK group early adopted the amendments in the preparation of the financial statements for the year ended 31 December 2020. The amendments address the accounting issues for financial instruments when IBOR reform is implemented including providing a practical expedient for changes to contractual cash flows, giving relief from specific hedge accounting requirements, and specifying a number of additional disclosures to enable users of financial statements to understand the effect of IBOR reform on an entity’s financial instruments and risk management strategy. Further details of the impact of these amendments on the financial statements for the year ended 31 December 2021 and the additional disclosures required are provided in Note 43. Other changes The Santander UK group adopted IFRS 16 and amendments to IAS 12 in 2019, with the impact included in the statement of changes in equity for that year end. Future developments At 31 December 2021 , for the Santander UK group, there were no significant new or revised standards and interpretations, and amendments thereto, which have been issued but which are not yet effective, or which have otherwise not been early adopted where permitted. Comparative information As required by US public company reporting requirements, these financial statements include two years of comparative information for the consolidated income statement, consolidated statement of comprehensive income, consolidated statement of changes in equity, consolidated statement of cash flows and related notes. Consolidation a) Subsidiaries The consolidated financial statements incorporate the financial statements of the Company and entities (including structured entities) controlled by it and its subsidiaries. Control is achieved where the Company (i) has power over the investee; (ii) is exposed, or has rights, to variable returns from its involvement with the investee; and (iii) has the ability to use its power to affect its returns. The Company reassesses whether or not it controls an investee if facts and circumstances indicate that there are changes to one or more of the three elements of control listed above. When the Company has less than a majority of the voting rights of an investee, it has power over the investee when the voting rights are sufficient to give it the practical ability to direct the relevant activities of the investee unilaterally. The Company considers all relevant facts and circumstances in assessing whether or not the Company's voting rights in an investee are sufficient to give it power, including: – The size of the Company's holding of voting rights relative to the size and dispersion of holdings of the other vote holders – Potential voting rights held by the Company, other vote holders or other parties – Rights arising from other contractual arrangements – Any additional facts and circumstances that indicate that the Company has, or does not have, the current ability to direct the relevant activities at the time that decisions need to be made, including voting patterns at previous shareholders' meetings. Consolidation of a subsidiary begins when the Company obtains control over the subsidiary and ceases when the Company loses control of the subsidiary. Specifically, the results of a subsidiary acquired or disposed of during the year are included in the consolidated income statement and the consolidated statement of comprehensive income from the date the Company gains control until the date the Company loses control. Inter-company transactions, balances and unrealised gains on transactions between Santander UK group companies are eliminated; unrealised losses are also eliminated unless the cost cannot be recovered. The acquisition method of accounting is used to account for the acquisition of subsidiaries which meet the definition of a business. The cost of an acquisition is measured at the fair value of the assets given up, shares issued or liabilities undertaken at the date of acquisition. Acquisition-related costs are expensed as incurred. The excess of the cost of acquisition, as well as the fair value of any interest previously held, over the fair value of the Santander UK group’s share of the identifiable net assets of the subsidiary at the date of acquisition is recorded as goodwill. When the Santander UK group loses control of a subsidiary, the profit or loss on disposal is calculated as the difference between (i) the aggregate of the fair value of the consideration received and the fair value of any retained interest and (ii) the previous carrying amount of the assets (including goodwill), less liabilities of the subsidiary and any non-controlling interests. Amounts previously recognised in other comprehensive income in relation to the subsidiary are accounted for (i.e. reclassified to profit or loss or transferred directly to retained earnings) in the same manner as would be required if the relevant assets or liabilities are disposed of. The fair value of any investment retained in a former subsidiary at the date when control is lost is regarded as the fair value on initial recognition for subsequent accounting under IFRS 9 or, when applicable, the costs on initial recognition of an investment in an associate or joint venture. Business combinations between entities under common control (i.e. fellow subsidiaries of Banco Santander SA, the ultimate parent) are outside the scope of IFRS 3 – ‘Business Combinations’, and there is no other guidance for such transactions under IFRS. The Santander UK group elects to account for business combinations between entities under common control at their book values in the acquired entity by including the acquired entity’s results from the date of the business combination and not restating comparatives. Reorganisations of entities within the Santander UK group are also accounted for at their book values. Interests in subsidiaries are eliminated during the preparation of the consolidated financial statements. Interests in subsidiaries in the Company unconsolidated financial statements are held at cost subject to impairment. Credit protection entities established as part of significant risk transfer (SRT) transactions are not consolidated by the Santander UK group in cases where third party investors have the exposure, or rights, to all of the variability of returns from the performance of the entities. b) Joint ventures Joint ventures are joint arrangements whereby the parties that have joint control of the arrangement have rights to its net assets. Joint control is the contractually agreed sharing of control of an arrangement, which exists only when decisions about the relevant activities require unanimous consent of the parties sharing control. Accounting policies of joint ventures have been aligned to the extent there are differences from the Santander UK group’s policies. Investments in joint ventures are accounted for by the equity method of accounting and are initially recorded at cost and adjusted each year to reflect the Santander UK group’s share of their post-acquisition results. When the Santander UK group's share of losses of a joint venture exceeds its interest in that joint venture, the Santander UK group discontinues recognising its share of further losses. Further losses are recognised only to the extent that the Santander UK group has incurred legal or constructive obligations or made payments on behalf of the joint venture. Foreign currency translation Items included in the financial statements of each entity (including foreign branch operations) in the Santander UK group are measured using the currency that best reflects the economic substance of the underlying events and circumstances relevant to that entity (the functional currency). The consolidated financial statements are presented in sterling, which is the functional currency of the Company. Income statements and cash flows of foreign entities are translated into the Santander UK group’s presentation currency at average exchange rates for the year and their balance sheets are translated at the exchange rates ruling on 31 December. Exchange differences on the translation of the net investment in foreign entities are recognised in other comprehensive income. When a foreign entity is sold, such exchange differences are recognised in the income statement as part of the gain or loss on sale. Foreign currency transactions are translated into the functional currency of the entity involved at the exchange rates prevailing at the dates of the transactions. Foreign exchange gains and losses resulting from the settlement of such transactions and from the translation of monetary assets and liabilities denominated in foreign currencies are recognised in the income statement unless recognised in other comprehensive income in connection with a cash flow hedge. Non-monetary items denominated in a foreign currency measured at historical cost are not retranslated. Exchange rate differences arising on non-monetary items measured at fair value are recognised in the consolidated income statement except for differences arising on equity securities measured at fair value through other comprehensive income (FVOCI), which are recognised in other comprehensive income. Revenue recognition a) Interest income and expense Interest and similar income comprise interest income on financial assets measured at amortised cost, investments in debt instruments measured at FVOCI and interest income on hedging derivatives. Interest expense and similar charges comprises interest expense on financial liabilities measured at amortised cost, and interest expense on hedging derivatives. Interest income on financial assets measured at amortised cost, investments in debt instruments measured at FVOCI and interest expense on financial liabilities other than those at fair value through profit or loss (FVTPL) is determined using the effective interest rate method. The effective interest rate is the rate that discounts the estimated future cash payments or receipts over the expected life of the instrument or, when appropriate, a shorter period, to the gross carrying amount of the financial asset (i.e. its amortised cost before any impairment allowance) or to the amortised cost of a financial liability. When calculating the effective interest rate, the future cash flows are estimated after considering all the contractual terms of the instrument excluding expected credit losses. The calculation includes all amounts paid or received by the Santander UK group that are an integral part of the overall return, direct incremental transaction costs related to the acquisition, issue or disposal of the financial instrument and all other premiums or discounts. Interest income is calculated by applying the effective interest rate to the gross carrying amount of financial assets, except for financial assets that have subsequently become credit-impaired (i.e. Stage 3), for which interest revenue is calculated by applying the effective interest rate to their amortised cost (i.e. net of the ECL provision). For more information on stage allocations of credit risk exposures, see ‘Significant increase in credit risk’ in the ‘Santander UK group level – credit risk management’ section of the Risk review. b) Fee and commission income and expense Fees and commissions that are not an integral part of the effective interest rate are recognised when the service is performed. Most fee and commission income is recognised at a point in time. Certain commitment, upfront and management fees are recognised over time but are not material. For retail and corporate products, fee and commission income consists principally of collection services fees, commission on foreign currencies, commission and other fees received from retailers for processing credit card transactions, fees received from other credit card issuers for providing cash advances for their customers through the Santander UK group’s branch and ATM networks, annual fees payable by credit card holders and fees for non-banking financial products. For insurance products, fee and commission income consists principally of commissions and profit share arising from the sale of building and contents insurance and life protection insurance. Commissions arising from the sale of buildings and contents insurance are recognised over the period of insurance cover, adjusted to take account of cancelled policies. Profit share income from the sale of buildings and contents insurance which is not subject to any adjustment is recognised when the profit share income is earned. Commissions and profit share arising from the sale of life protection insurance is subject to adjustment for cancellations of policies within 3 years from inception. Fee and commission income which forms an integral part of the effective interest rate of a financial instrument (for example certain loan commitment fees) is recognised as an adjustment to the effective interest rate and recorded in ‘Interest income’. c) Dividend income Except for equity securities classified as trading assets or financial assets held at fair value through profit or loss, described below, dividend income is recognised when the right to receive payment is established. This is the ex-dividend date for equity securities. d) Other operating income Other operating income includes all gains and losses from changes in the fair value of financial assets and liabilities held at fair value through profit or loss (comprising financial assets and liabilities held for trading, trading derivatives and other financial assets and liabilities at fair value through profit or loss), together with related interest income, expense, dividends, and changes in fair value of any derivatives managed in conjunction with these assets and liabilities. Changes in fair value of derivatives in a fair value hedging relationship are also recognised in other operating income. Other operating income also includes income from operating lease assets, and profits and losses arising on the sales of property, plant and equipment and subsidiary undertakings. Borrowing costs Borrowing costs directly attributable to the acquisition, construction, or production of qualifying assets, including computer software, which are assets that necessarily take a substantial period of time to develop for their intended use, are added to the cost of those assets, until the assets are substantially ready for their intended use. All other borrowing costs are recognised in profit or loss in the period in which they occur. Pensions and other post-retirement benefits a) Defined benefit schemes A defined benefit scheme is a pension scheme that guarantees an amount of pension benefit to be provided, usually as a function of one or more factors such as age, years of service or compensation. Pension costs are charged to ‘Administration expenses’, within the line item ‘Operating expenses before impairment losses, provisions and charges’ with the net interest on the defined benefit asset or liability included within ‘Net interest income’ in the income statement. The asset or liability recognised in respect of defined benefit pension schemes is the present value of the defined benefit obligation at the balance sheet date, less the fair value of scheme assets. The defined benefit obligation is calculated annually by independent actuaries using the projected unit credit method. The assets of the schemes are measured at their fair values at the balance sheet date. The present value of the defined benefit obligation is estimated by projecting forward the growth in current accrued pension benefits to reflect inflation and salary growth to the date of pension payment, then discounted to present value using the yield applicable to high-quality AA rated corporate bonds of the same currency and which have terms to maturity closest to the terms of the scheme liabilities, adjusted where necessary to match those terms. In determining the value of scheme liabilities, demographic and financial assumptions are made by management about life expectancy, inflation, discount rates, pension increases and earnings growth, based on past experience and future expectations. Financial assumptions are based on market conditions at the balance sheet date and can generally be derived objectively. Demographic assumptions require a greater degree of estimation and judgement to be applied to externally derived data. Any surplus or deficit of scheme assets over liabilities is recognised in the balance sheet as an asset (surplus) or liability (deficit). An asset is only recognised to the extent that the surplus can be recovered through reduced contributions in the future or through refunds from the scheme. The income statement includes the net interest income/expense on the net defined benefit liability/asset, current service cost and any past service cost and gain or loss on settlement. Remeasurement of defined benefit pension schemes, including return on scheme assets (excludes amounts included in net interest), actuarial gains and losses (arising from changes in demographic assumptions, the impact of scheme experience and changes in financial assumptions) and the effect of the changes to the asset ceiling (if applicable), are recognised in other comprehensive income. Remeasurement recognised in other comprehensive income will not be reclassified to the income statement. Past service costs are recognised as an expense in the income statement at the earlier of when the scheme amendment or curtailment occurs and when the related restructuring costs or termination benefits are recognised. Curtailments include the impact of significant reductions in the number of employees covered by a scheme, or amendments to the terms of the scheme so that a significant element of future service will no longer qualify for benefits or will qualify only for reduced benefits. Curtailment gains and losses on businesses that meet the definition of discontinued operations are included in profit or loss for the year from discontinued operations. Gains and losses on settlements are recognised when the settlement occurs. b) Defined contribution plans A defined contribution plan is a pension scheme under which the Santander UK group pays fixed contributions as they fall due into a separate entity (a fund). The pension paid to the member at retirement is based on the amount in the separate fund for each member. The Santander UK group has no legal or constructive obligations to pay further contributions into the fund to ‘top up’ benefits to a certain guaranteed level. The regular contributions constitute net periodic costs for the year in which they are due and are included in staff costs within Operating expenses in the income statement. c) Post-retirement medical benefit plans Post-retirement medical benefit liabilities are determined using the projected unit credit method, with actuarial valuations updated at each year-end. The expected benefit costs are accrued over the period of employment using an accounting methodology similar to that for the defined benefit pension scheme. Share-based payments The Santander UK group engages in cash-settled and equity-settled share-based payment transactions in respect of services received from certain of its employees. Shares of the Santander UK group’s parent, Banco Santander SA are purchased in the open market by the Santander UK group (for the Employee Sharesave scheme) or are purchased by Banco Santander SA or another Banco Santander subsidiary (including awards granted under the Long-Term Incentive Plan and the Deferred Shares Bonus Plan) to satisfy share options or awards as they vest. Options granted under the Employee Sharesave scheme and awards granted under the Transformation Incentive Plan are accounted for as cash-settled share-based payment transactions. Awards granted under the Long-Term Incentive Plan and Deferred Shares Bonus Plan are accounted for as equity-settled share-based payment transactions. The fair value of the services received is measured by reference to the fair value of the shares or share options initially on the date of the grant for both the cash and equity settled share-based payments and then subsequently at each reporting date for the cash-settled share-based payments. The cost of the employee services received in respect of the shares or share options granted is recognised in the income statement in administration expenses over the period that the services are received i.e. the vesting period. A liability equal to the portion of the services received is recognised at the fair value determined at each balance sheet date for cash-settled share-based payments. A liability equal to the amount to be reimbursed to Banco Santander SA is recognised at the fair value determined at the grant date for equity-settled share-based payments. The fair value of the options granted under the Employee Sharesave scheme is determined using an option pricing model, which takes into account the exercise price of the option, the current share price, the risk-free interest rate, the expected volatility of the Banco Santander SA share price over the life of the option and the dividend growth rate. The fair value of the awards granted for the Long-Term Incentive Plan was determined at the grant date using an option pricing model, which takes into account the share price at grant date, the risk-free interest rate, the expected volatility of the Banco Santander SA share price over the life of the award and the dividend growth rate. Vesting conditions included in the terms of the grant are not taken into account in estimating fair value, except for those that include terms related to market conditions. Non-market vesting conditions are taken into account by adjusting the number of shares or share options included in the measurement of the cost of employee service so that, ultimately, the amount recognised in the income statement reflects the number of vested shares or share options. Where vesting conditions are related to market conditions, the charges for the services received are recognised regardless of whether or not the market–related vesting conditions are met, provided that the non-market vesting conditions are met. Where an award has been modified, as a minimum, the expense of the original award continues to be recognised as if it had not been modified. Where the effect of a modification is to increase the fair value of an award or increase the number of equity instruments, the incremental fair value of the award or incremental fair value of the modification of the award is recognised in addition to the expense of the original grant, measured at the date of modification, over the modified vesting period. Cancellations in the vesting period are treated as an acceleration of vesting and recognised immediately for the amount that would otherwise have been recognised for services over the vesting period. Goodwill and other intangible assets Goodwill represents the excess of the cost of an acquisition, as well as the fair value of any interest previously held, over the fair value of the share of the identifiable net assets of the acquired subsidiary, associate, or business at the date of acquisition. Goodwill on the acquisition of subsidiaries and businesses is included in intangible assets. Goodwill on acquisitions of associates is included as part of investment in associates. Goodwill is tested for impairment annually, or more frequently when events or changes in circumstances dictate, and carried at cost less accumulated impairment losses. Gains and losses on the disposal of an entity or business include the carrying amount of goodwill relating to the entity or business sold. Other intangible assets are recognised if they arise from contractual or other legal rights or if they are capable of being separated or divided from Santander UK and sold, transferred, licensed, rented or exchanged. The value of such intangible assets, where they are available for use, is amortised on a straight-line basis over their useful economic life of three to seven years and the assets are reviewed annually for impairment indicators and tested for impairment where indicators are present. Other intangible assets that are not yet available for use are tested for impairment annually or more frequently when events or changes in circumstances dictate. Software development costs are capitalised when they are direct costs associated with identifiable and unique software products that are expected to provide future economic benefits and the cost of those products can be measured reliably. These costs include payroll, materials, services and directly attributable overheads. Internally developed software meeting these criteria and externally purchased software are classified in intangible assets on the balance sheet and amortised on a straight-line basis over their useful life of three to seven years, unless the software is an integral part of the related computer hardware, in which case it is treated as property, plant and equipment as described below. Capitalisation of costs

Segments

Segments	12 Months Ended
	Dec. 31, 2021
Disclosure of operating segments [abstract]
Segments	2. SEGMENTS Santander UK’s principal activity is financial services, mainly in the UK. The business is managed and reported on the basis of the following segments, which are strategic business units that offer different products and services, have different customers and require different technology and marketing strategies. Retail Banking consists of two business units, Homes and Everyday Banking. Homes provides prime UK mortgage lending to owner occupiers and buy-to-let landlords with small portfolios. Everyday Banking provides banking services and unsecured lending to individuals and small businesses as well alongside wealth management for high-net-worth clients. – Consumer Finance provides prime auto consumer financing for individuals, businesses, and automotive distribution networks. – Corporate & Commercial Banking provides banking products and services to SMEs, mid-sized and larger corporates, typically with annual turnovers of between £2m and £500m as well as to Local Authorities and Housing Associations. – Corporate Centre provides treasury services for asset and liability management of our balance sheet, as well as management of non-core and legacy portfolios. – Corporate and Investment Banking provided services to corporate clients with an annual turnover of £500m and above. Santander UK transferred a significant part of the Corporate & Investment Banking business to the London branch of Banco Santander SA under a part VII banking business transfer scheme which completed on 11 October 2021. The residual parts of the business have been wound down or transferred to other segments. At 31 December 2021, the Corporate & Investment Banking business met the requirements for presentation as discontinued operations. For more details, see Note 43. Retail Banking delivers products through our omni-channel presence comprising branches, ATMs, telephony, digital and intermediary channels. Corporate and Commerical Banking expertise is provided by relationship managers, product specialists and through digital and telephony channels, and cover clients' needs both in the UK and overseas. The segmental basis of presentation in this Annual Report has changed following a management review of our structure. Previously, Consumer Finance was managed as part of Retail Banking. The segmental data below is presented in a manner consistent with the internal reporting to the committee which is responsible for allocating resources and assessing performance of the segments and has been identified as the chief operating decision maker. The segmental data is prepared on a statutory basis of accounting, in line with the accounting policies set out in Note 1. Transactions between segments are on normal commercial terms and conditions. Internal charges and internal UK transfer pricing adjustments are reflected in the results of each segment. Revenue sharing agreements are used to allocate external customer revenues to a segment on a reasonable basis. Funds are ordinarily reallocated between segments, resulting in funding cost transfers disclosed in operating income. Interest charged for these funds is based on Santander UK’s cost of wholesale funding. Interest income and interest expense have not been reported separately. The majority of segment revenues are interest income in nature and net interest income is relied on primarily to assess segment performance and to make decisions on the allocation of segment resources. Results by segment Retail Banking Consumer Finance Corporate & Commercial Banking Corporate & Investment Banking Corporate Centre Total 2021 £m £m £m £m £m £m Net interest income/(expense) 3,374 233 401 — (11) 3,997 Non-interest income 201 178 109 — 59 547 Total operating income 3,575 411 510 — 48 4,544 Operating expenses before credit impairment write-backs, provisions and charges (1,703) (163) (365) — (309) (2,540) Credit impairment write-backs 98 33 91 — 11 233 Provisions for other liabilities and charges (187) 4 (34) — (162) (379) Total operating credit impairment write-backs, provisions and charges (89) 37 57 — (151) (146) Profit/(loss) from continuing operations before tax 1,783 285 202 — (412) 1,858 Revenue from external customers 4,061 489 553 — (559) 4,544 Inter-segment revenue (486) (78) (43) — 607 — Total operating income 3,575 411 510 — 48 4,544 Revenue from external customers includes the following fee and commission income disaggregated by income type: (1) – Current account and debit card fees 428 — 50 — — 478 – Insurance, protection and investments 67 — — — — 67 – Credit cards 73 — — — — 73 – Non-banking and other fees (2) 2 10 62 — 2 76 Total fee and commission income 570 10 112 — 2 694 Fee and commission expense (384) — (22) — (8) (414) Net fee and commission income/(expense) 186 10 90 — (6) 280 Customer loans 185,608 4,984 16,997 — 3,027 210,616 Total assets (3) 193,214 8,873 16,997 — 74,592 293,676 Customer deposits 156,991 — 25,597 — 9,588 192,176 Total liabilities 157,622 1,173 25,613 — 92,890 277,298 Average number of full-time equivalent staff 16,149 670 2,281 528 216 19,844 (1) The disaggregation of fees and commission income as shown above is not included in reports provided to the chief operating decision maker but is provided to show the split by reportable segments. (2) Non-banking and other fees include mortgages (except mortgage account fees), consumer finance, commitment commission, asset finance, invoice finance and trade finance. (3) Includes customer loans, net of credit impairment loss allowances. Retail Banking (5) Consumer Finance (5) Corporate & Commercial Banking Corporate & Investment Banking (4) Corporate Centre Total 2020 £m £m £m £m £m £m Net interest income/(expense) 2,758 264 363 — (4) 3,381 Non-interest income 245 127 94 — (12) 454 Total operating income/(expense) 3,003 391 457 — (16) 3,835 Operating expenses before credit impairment losses, provisions and charges (1,792) (166) (324) — (143) (2,425) Credit impairment losses (264) (44) (294) — (37) (639) Provisions for other liabilities and charges (160) (8) (6) — (89) (263) Total operating credit impairment losses, provisions and charges (424) (52) (300) — (126) (902) Profit/(loss) from continuing operations before tax 787 173 (167) — (285) 508 Revenue from external customers 3,685 501 549 — (900) 3,835 Inter-segment revenue (682) (110) (92) — 884 — Total operating income/(expense) 3,003 391 457 — (16) 3,835 Revenue from external customers includes the following fee and commission income disaggregated by income type: (1) – Current account and debit card fees 442 — 42 — — 484 – Insurance, protection and investments 65 — — — — 65 – Credit cards 66 — — — — 66 – Non-banking and other fees (2) 3 10 50 — 3 66 Total fee and commission income 576 10 92 — 3 681 Fee and commission expense (337) — (22) — (4) (363) Net fee and commission income 239 10 70 — (1) 318 Customer loans 178,451 8,025 17,626 2,784 3,483 210,369 Total assets (3) 186,226 11,143 17,626 2,784 81,285 299,064 Customer deposits 152,167 — 24,985 6,506 8,074 191,732 Total liabilities 152,687 2,397 25,011 6,517 96,207 282,819 Average number of full-time equivalent staff 18,198 640 2,405 716 180 22,139 2019 Net interest income 2,581 246 422 — (22) 3,227 Non-interest income 531 155 109 — 10 805 Total operating income 3,112 401 531 — (12) 4,032 Operating expenses before credit impairment losses, provisions and charges (1,860) (179) (334) — (93) (2,466) Credit impairment (losses)/write-backs (129) (27) (45) — 3 (198) Provisions for other liabilities and charges (273) (8) (24) — (123) (428) Total operating credit impairment losses, provisions and (charges)/releases (402) (35) (69) — (120) (626) Profit/(loss) from continuing operations before tax 850 187 128 — (225) 940 Revenue from external customers 3,748 525 633 — (874) 4,032 Inter-segment revenue (636) (124) (102) — 862 — Total operating income 3,112 401 531 — (12) 4,032 Revenue from external customers includes the following fee and commission income disaggregated by income type: (1) – Current account and debit card fees 711 — 43 — — 754 – Insurance, protection and investments 69 — — — — 69 – Credit card fees 86 — — — — 86 – Non-banking and other fees (2) 33 13 65 — 23 134 Total fee and commission income 899 13 108 — 23 1,043 Fee and commission expense (372) — (24) — (20) (416) Net fee and commission income 527 13 84 — 3 627 Customer loans 171,078 7,684 18,391 4,041 4,104 205,298 Total assets (3) 178,665 10,748 18,391 4,046 76,638 288,488 Customer deposits 142,735 — 20,546 6,102 8,438 177,821 Total liabilities 143,570 2,748 20,572 6,233 99,024 272,147 Average number of full-time equivalent staff 19,669 612 2,464 804 157 23,706 (1) The disaggregation of fees and commission income as shown above is not included in reports provided to the chief operating decision maker but is provided to show the split by reportable segments. (2) Non-banking and other fees include mortgages (except mortgage account fees), consumer finance, commitment commission, asset finance, invoice finance and trade finance. (3) Includes cust omer loans, net of credit impairment loss allowances. (4) Restated to reflect the presentation of CIB as a discontinued operation, as set out in Note 43. (5) Restated to reflect the resegmentation of the Retail Banking segment into the Retail Banking and Consumer Finance segments described above. Geographical information is not provided, as substantially all of Santander UK’s activities are in the UK.

Net Interest Income

Net Interest Income	12 Months Ended
	Dec. 31, 2021
Analysis of income and expense [abstract]
Net Interest Income	3. NET INTEREST INCOME Group 2021 2020 (3) 2019 (3) £m £m £m Interest and similar income: Loans and advances to customers (3) 4,685 4,772 5,137 Loans and advances to banks 54 62 182 Reverse repurchase agreements – non trading 35 118 244 Other 56 119 309 Total interest and similar income (1) 4,830 5,071 5,872 Interest expense and similar charges: Deposits by customers (331) (884) (1,331) Deposits by banks (23) (28) (103) Repurchase agreements – non trading (3) (43) (126) Debt securities in issue (372) (614) (938) Subordinated liabilities (92) (111) (137) Other (12) (10) (10) Total interest expense and similar charges (2) (833) (1,690) (2,645) Net interest income 3,997 3,381 3,227 (1) This includes £22m (2020: £38m) of interest income on financial assets at FVOCI. (2) This includes £317m (2020: £451m) of interest expense on derivatives hedging debt issuances and £3m (2020: £3m ) of interest expense on lease liabilities.

Net Fee and Commission Income

Net Fee and Commission Income	12 Months Ended
	Dec. 31, 2021
Fee and commission income (expense) [abstract]
Net Fee and Commission Income	4. NET FEE AND COMMISSION INCOME Group 2021 2020 (2) 2019 (2) £m £m £m Fee and commission income: Current account and debit card fees 478 484 754 Insurance, protection and investments 67 65 69 Credit cards 73 66 86 Non-banking and other fees (1) 76 66 134 Total fee and commission income 694 681 1,043 Total fee and commission expense (414) (363) (416) Net fee and commission income 280 318 627 (1) Non-banking and other fees include mortgages (except mortgage account fees) , consumer finance, commitment commission, asset finance, invoice finance and trade finance.

Other Operating Income

Other Operating Income	12 Months Ended
	Dec. 31, 2021
Net Trading And Other Income [Abstract]
Other Operating Income	5. OTHER OPERATING INCOME Group 2021 2020 (1) 2019 (1) £m £m £m Net losses on financial instruments designated at fair value through profit or loss (68) (26) (102) Net gains on financial instruments mandatorily at fair value through profit or loss 50 64 95 Hedge ineffectiveness 8 19 8 Net profit on sale of financial assets at fair value through other comprehensive income 6 17 15 Income from operating lease assets 136 126 124 Other 135 (64) 38 267 136 178 (1) Restated to reflect the presentation of discontinued operations, as set out in Note 43. Assets and liabilities held at FVTPL, including derivatives, are predominantly used to provide customers with risk management solutions, and to manage and hedge the Santander UK group’s own risks, and do not give rise to significant overall net gains/(losses) in the income statement. 'Net gains on financial instruments mandatorily at FVTPL' includes fair value losses of £15m (2020: gains of £89m, 2019: losses of £42m) on embedded derivatives bifurcated from certain equity index-linked deposits, as described in the derivatives accounting policy in Note 1. The embedded derivatives are economically hedged, the results of which are also included in this line item and amounted to gains of £15m (2020: losses of £88m, 2019: gains of £43m). As a result, the net fair value movements recognised on the equity index-linked deposits and the related economic hedges were net gains of nil (2020: £1m, 2019: £1m). In 2019, ‘Net profit on sale of financial assets at FVOCI’ included additional consideration of £15m in connection with the 2017 Vocalink Holdings Limited shareholding sale. Exchange rate differences recognised in the Consolidated Income Statement on items not at fair value through profit or loss were £215m income (2020: £719m expense, 2019: £1,102m income) and are presented in the line ‘Other'. These are principally offset by related releases from the cash flow hedge reserve of £357m expense (2020: £803m income, 2019: £1,021m expense) as set out in the Consolidated Statement of Comprehensive Income, which are also presented in 'Other’. Exchange rate differences on items measured at FVTPL are included in the line items relating to changes in fair value. In 2021, the Santander UK group repurchased certain debt securities and subordinated liabilities as part of ongoing liability management exercises, resulting in a loss of £1m ( 2020 loss of £24m, 2019: nil). Other includes £73m of property gains from the sale of our London head office and branch properties.

Operating Expenses Before Credi

Operating Expenses Before Credit Impairment Losses, Provisions and Charges	12 Months Ended
	Dec. 31, 2021
Expenses by nature [abstract]
Operating Expenses Before Credit Impairment Losses, Provisions and Charges	6. OPERATING EXPENSES BEFORE CREDIT IMPAIRMENT LOSSES, PROVISIONS AND CHARGES Group 31 December 2021 2020 (1) 2019 (1) £m £m £m Staff costs: Wages and salaries 759 802 815 Performance-related payments 184 99 160 Social security costs 113 102 112 Pensions costs: – defined contribution plans 65 67 67 – defined benefit plans (2) 38 38 35 Other share-based payments 1 4 7 Other personnel costs 42 34 41 1,202 1,146 1,237 Other administration expenses 831 710 684 Depreciation, amortisation and impairment 507 569 545 2,540 2,425 2,466 (1) Adjusted to reflect the presentation of discontinued operations as set out in Note 43. (2) Pension costs for defined benefit plans include £5m for curtailment as set out in Note 30. Staff costs ’Performance-related payments’ include bonuses paid in cash and share awards granted under the arrangements described in Note 37. Included in this are equity-settled share-based payments, none of which related to option-based schemes. These are disclosed in the table below as ‘Share awards’. Performance-related payments above include amounts related to deferred performance awards as follows: Costs recognised in 2021 Costs expected to be recognised in 2022 or later Arising from awards in current year Arising from awards in prior year Total Arising from awards in current year Arising from awards in prior year Total £m £m £m £m £m £m Cash 3 5 8 9 6 15 Shares 3 5 8 8 6 14 6 10 16 17 12 29 The following table shows the amount of bonus awarded to employees for the performance year 2021. In the case of deferred cash and share awards, the final amount paid to an employee is influenced by forfeiture provisions and any performance conditions to which these awards are subject. The deferred share award amount is based on the fair value of these awards at the date of grant. Expenses charged in the year Expenses deferred to future periods Total 2021 2020 2021 2020 2021 2020 £m £m £m £m £m £m Cash award – not deferred 156 79 — — 156 79 – deferred 8 9 15 11 23 20 Shares award – not deferred 12 3 — — 12 3 – deferred 8 8 14 11 22 19 Total discretionary bonus 184 99 29 22 213 121 On 26 October 2018, the High Court handed down a judgement concluding that defined benefit schemes should equalise pension benefits for men and women in relation to GMP and concluded on the methods that were appropriate. The estimated increase in liabilities at the date of the judgement was £40m and was based on a number of assumptions and the actual impact may be different. This was reflected in the income statement and in the closing net accounting surplus of the Scheme in 2018. The allowance included in the Scheme liabilities at 31 December 2021 decreased by £5m (2020: £5m, 2019: £5m ) to £45m (2020: £50m, 2019 : £45m) to reflect the latest assumptions. This change was recognised in other comprehensive income. Work is being undertaken by the Trustee to implement GMP equalisation. ‘Other share-based payments’ consist of options granted under the Employee Sharesave scheme which comprise the Santander UK group’s cash-settled share-based payments. For more, see Note 37. The average number of full-time equivalent staff was 19,844 (2020: 22,139, 2019: 23,706). Depreciation, amortisation and impairment In 2021, depreciation, amortisation and impairment included depreciation of £81m (2020: £92m, 2019: £103m) on operating lease assets (where the Santander UK group is the lessor) with a net book value of £595m at 31 December 2021 (2020: £542m, 2019: £574m). It also included depreciation of £20m (2020: £59m, 2019: £61m) on right-of-use assets with a net book value of £119m at 31 December 2021 (2020: £103m, 2019: £153m). 'Other administration expenses' includes £23m (2020: £10m , 2019 : £13m ) expenses related to short-term leases. In 2021, 'Depreciation, amortisation and impairment' included an impairment charge of £88m ( 2020 : £nil) associated with branch and head office site closures as part of the transformation programme. For more, see Note 21.

Audit and Other Services

Audit and Other Services	12 Months Ended
	Dec. 31, 2021
Audit And Other Services [Abstract]
Audit and Other Services	7. AUDIT AND OTHER SERVICES Group 2021 2020 2019 £m £m £m Audit fees: Fees payable to the Company's auditor and its associates for the audit of the Santander UK group's annual accounts 12.1 10.5 8.5 Fees payable to the Company’s auditor and its associates for other services to the Santander UK group: – Audit of the Santander UK group’s subsidiaries 1.2 1.8 1.9 Total audit fees (1) 13.3 12.3 10.4 Non-audit fees: Audit-related assurance services 1.7 1.7 1.7 Other assurance services 0.5 0.5 0.4 Other non-audit services 0.2 0.0 0.2 Total non-audit fees 2.4 2.2 2.3 (1) 2021 audit fees included £1.2m (2020: £0.8m, 2019: £0.3m) which related to the prior year. Audit fees payable for the statutory audit of Santander UK Group Holdings plc were £0.5m (2020: £0.5m , 2019: £0.5m ). Audit-related assurance services mainly comprises services performed in connection with review of the financial information of the Company and reporting to the Company's UK regulators. Of the total non-audit fees, £1.2m (2020: £1.2m, 2019: £1.6m) accords with the definition of 'Audit Fees' per US Securities and Exchange Commission (SEC) guidance, £1.2m (2020: £1.0m, 2019: £0.5m) accords with the definition of 'Audit related fees' per that guidance and £nil (2020: £nil, 2019: £0.2m) accords with the definition of 'All other fees' per that guidance. In 2021, the Company’s auditors earned £27,000 fees (2020: £24,000, 2019: no fees) payable by entities outside the Santander UK group for the review of the financial position of corporate and other borrowers. In 2021, the Company's auditors earned £1.4m (2020: £1.5m, 2019: £1.5m), in relation to incremental work undertaken in support of the audit of Banco Santander SA.

Credit Impairment Losses and Pr

Credit Impairment Losses and Provisions	12 Months Ended
	Dec. 31, 2021
Disclosure Of Credit Impairment Loss And Provisions [Abstract]
Credit Impairment Losses and Provisions	8. CREDIT IMPAIRMENT LOSSES AND PROVISIONS Group 31 December 2021 2020 (1) 2019 (1) £m £m £m Credit impairment (write-backs)/losses: Loans and advances to customers (186) 666 216 Recoveries of loans and advances, net of collection costs (17) (24) (40) Off-balance sheet exposures (See Note 29) (30) (3) 22 (233) 639 198 Provisions for other liabilities and charges (excluding off-balance sheet credit exposures) (See Note 29) 388 257 422 Provisions for residual value and voluntary termination (9) 6 6 379 263 428 146 902 626 (1) Adjusted to reflect the presentation of discontinued operations as set out in Note 43. In 2021 and 2020 there were no material credit impairment losses on loans and advances to banks, non-trading reverse repurchase agreements, other financial assets at amortised cost and financial assets at FVOCI.

Taxation

Taxation	12 Months Ended
	Dec. 31, 2021
Major components of tax expense (income) [abstract]
Taxation	9. TAXATION Group 2021 2020 (1) 2019 (1) £m £m £m Current tax: UK corporation tax on profit for the year 400 92 244 Adjustments in respect of prior years (30) (27) (30) Total current tax 370 65 214 Deferred tax: Charge for the year 101 35 51 Adjustments in respect of prior years 14 1 (4) Total deferred tax 115 36 47 Tax on profit from continuing operations 485 101 261 (1) Adjusted to reflect the presentation of discontinued operations as set out in Note 43. The standard rate of UK corporation tax was 27% for banking entities and 19% for non-banking entities (2020: 27% for banking entities and 19% for non-banking entities; 2019: 27% for banking entities and 19% for non-banking entities) following the introduction of an 8% surcharge to be applied to banking companies from 1 January 2016. Taxation for other jurisdictions is calculated at the rates prevailing in the relevant jurisdictions. The Santander UK group’s effective tax rate for 2021 was 26.1% (2020: 19.9%, 2019(1): 27.8%). The tax on profit before tax differs from the theoretical amount that would arise using the basic corporation tax rate as follows: Group 31 December 2021 2020 (1) 2019 (1) £m £m £m Profit from continuing operations before tax 1,858 508 940 Tax calculated at a tax rate of 19% (2020: 19%, 2019: 19%) 353 97 179 Bank surcharge on profits 106 23 60 Non-deductible preference dividends paid 9 8 8 Non-deductible UK Bank Levy 14 20 24 Non-deductible conduct remediation, fines and penalties 6 (4) 44 Other non-deductible costs and non-taxable income 33 23 29 Effect of change in tax rate on deferred tax provision 8 6 (10) Tax relief on dividends in respect of other equity instruments (40) (40) (39) Adjustment to prior year provisions (4) (32) (34) Tax on profit from continuing operations 485 101 261 (1) Adjusted to reflect the presentation of discontinued operations as set out in Note 43. The UK government announced in its budget on 3 March 2021 that it would increase the main rate of corporation tax by 6% to 25% with effect from 1 April 2023. This change was substantively enacted on 24 May 2021 and, as a result, the effect has been reflected in the closing deferred tax position included in these financial statements. The comparative 2020 results reflected an increase in tax rates by 2% following an announcement in the 2020 budget to reverse a previously planned rate reduction from April 2020. A reduction in the Bank Surcharge rate from 8% to 3% was announced in October 2021 to be effective from 1 April 2023. This change in rate was substantively enacted on 2 February 2022 and as a result, the effects of this change have not been reflected in the closing balance sheet position for deferred tax. The effect of the change, had it been substantively enacted by the balance sheet date, would be expected to reduce the tax expense for the period by £22m and reduce the deferred tax liability by £89m . Current tax assets and liabilities Movements in current tax assets and liabilities during the year were as follows: Group 2021 2020 £m £m Assets 271 186 Liabilities — — At 1 January 271 186 Income statement charge (including discontinued operations) (382) (78) Other comprehensive income credit 33 1 Corporate income tax paid 418 161 Other movements 11 1 351 271 Assets 351 271 Liabilities — — At 31 December 351 271 The amount of corporation income tax paid differs from the tax charge for the period as a result of the timing of payments due to the tax authorities, the effects of movements in deferred tax, adjustments to prior period current tax provisions and current tax recognised directly in other comprehensive income. Santander UK proactively engages with HM Revenue & Customs to resolve tax matters relating to prior years. The accounting policy for recognising provisions for such matters are described in Note 1. It is not expected that there will be any material movement in such provisions within the next 12 months. Deferred tax The table below shows the deferred tax assets and liabilities including the movement in the deferred tax account during the year. Deferred tax balances are presented in the balance sheet after offsetting assets and liabilities where the Santander UK group has the legal right to offset and intends to settle on a net basis. Group Fair value of financial instruments Pension remeasurement Cash flow hedges Fair value reserve Tax losses carried forward Accelerated tax depreciation Other temporary differences Total £m £m £m £m £m £m £m £m At 1 January 2021 (65) (27) (100) (10) 15 39 41 (107) Income statement (charge)/credit (58) (67) — (1) (7) 39 (21) (115) Transfers/reclassifications — 5 (16) 1 — (10) (19) (39) Credited/(charged) to other comprehensive income — (419) 109 (2) — — — (312) At 31 December 2021 (123) (508) (7) (12) 8 68 1 (573) At 1 January 2020 (52) (98) (58) (8) 13 18 40 (145) Income statement (charge)/credit (13) (62) — — 2 21 16 (36) Transfers/reclassifications — — 12 — — — (15) (3) Credited/(charged) to other comprehensive income — 133 (54) (2) — — — 77 At 31 December 2020 (65) (27) (100) (10) 15 39 41 (107)

Dividends on Ordinary Shares

Dividends on Ordinary Shares	12 Months Ended
	Dec. 31, 2021
Dividends On Ordinary Shares [Abstract]
Dividends on Ordinary Shares	10. DIVIDENDS ON ORDINARY SHARES Dividends on ordinary shares declared and paid in the year were as follows: Group Group 2021 2020 2019 2021 2020 2019 Pence per share Pence per share Pence per share £m £m £m In respect of current year – first interim 4.05 1.46 1.95 286 103 138 – second interim 15.01 — 1.76 1,060 — 124 19.06 1.46 3.71 1,346 103 262 In 2021, an interim dividend of £1,346m (2020: £103m

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2021
Disclosure of nature and extent of risks arising from financial instruments [abstract]
Derivative Financial Instruments	11. DERIVATIVE FINANCIAL INSTRUMENTS a) Use of derivatives The Santander UK group undertakes derivative activities primarily to provide customers with risk management solutions and to manage and hedge the Santander UK group’s own risks. The Santander UK group’s derivative activities do not give rise to significant open positions in portfolios of derivatives. Any residual position is managed to ensure that it remains within acceptable risk levels, with matching transactions used to achieve this where necessary. When entering into derivatives, the Santander UK group employs the same credit risk management procedures to assess and approve potential credit exposures that are used for traditional lending. For information on how the Santander UK group is managing the transition to alternative benchmark interest rates, see ‘Managing IBOR transition’ in the Banking market risk section of the Risk review and Note 42. b) Analysis of derivatives The table below includes the notional amounts of transactions outstanding at the balance sheet date; they do not represent actual exposures. Group 2021 2020 Fair value Fair value Notional amount Assets Liabilities Notional amount Assets Liabilities £m £m £m £m £m £m Derivatives held for trading: Exchange rate contracts 11,750 159 183 15,465 395 431 Interest rate contracts 25,617 489 708 40,630 926 837 Equity and credit contracts 1,138 166 57 1,319 124 83 Total derivatives held for trading 38,505 814 948 57,414 1,445 1,351 Derivatives held for hedging Designated as fair value hedges: Exchange rate contracts 590 39 — 789 84 6 Interest rate contracts 80,651 908 737 93,748 1,225 1,885 Equity derivative contracts — — — 81,241 947 737 94,537 1,309 1,891 Designated as cash flow hedges: Exchange rate contracts 22,239 996 338 27,020 1,978 409 Interest rate contracts 21,329 177 216 19,407 467 23 Equity derivative contracts 47 7 1 13 6 — 43,615 1,180 555 46,440 2,451 432 Total derivatives held for hedging 124,856 2,127 1,292 140,977 3,760 2,323 Derivative netting (1) — (1,221) (1,221) — (1,754) (1,754) Total derivatives 163,361 1,720 1,019 198,391 3,451 1,920 (1) Derivative netting excludes the effect of cash collateral, which is offset against the gross derivative position. The amount of cash collateral received that had been offset against the gross derivative assets was £189m (2020: £330m) and the amount of cash collateral paid that had been offset against the gross derivative liabilities was £202m (2020: £651m). For information about the impact of netting arrangements on derivative assets and liabilities in the table above, see Note 41. The reduction in the notional value of interest rate derivatives held for trading in 2021 reflected the completion of a series of derivative trade compressions to reduce our gross LIBOR exposure. The table below analyses the notional and fair values of derivatives by trading and settlement method. Notional Traded over the counter Asset Liability Traded on recognised exchanges Settled by central counterparties Not settled by central counterparties Total Traded on recognised exchanges Traded over the counter Traded on recognised exchanges Traded over the counter 2021 £m £m £m £m £m £m £m £m Exchange rate contracts — — 34,579 34,579 — 1,193 — 522 Interest rate contracts — 117,560 10,037 127,597 — 353 — 441 Equity and credit contracts — — 1,185 1,185 — 174 — 56 — 117,560 45,801 163,361 — 1,720 — 1,019 2020 Exchange rate contracts — — 43,274 43,274 — 2,457 — 846 Interest rate contracts — 144,343 9,442 153,785 — 864 — 991 Equity and credit contracts — — 1,332 1,332 — 130 — 83 — 144,343 54,048 198,391 — 3,451 — 1,920 c) Analysis of derivatives designated as hedges The Santander UK group applies hedge accounting on both a fair value and cash flow basis depending on the nature of the underlying exposure. We establish the hedge ratio by matching the notional of the derivative with the underlying position being hedged. Only the designated risk is hedged and therefore other risks, such as credit risk are managed but not hedged. For interest rate hedges, the designated hedged risk is determined with reference to the underlying benchmark rate. Fair value hedges Portfolio hedges of interest rate risk Santander UK holds various portfolios of fixed rate assets and liabilities which expose it to changes in fair value due to movements in market interest rates. We manage these exposures by entering into interest rate swaps. Each portfolio contains assets or liabilities that are similar in nature and share the risk exposure that is designated as being hedged. The interest rate risk component is the change in fair value of fixed rate instruments for changes in the designated benchmark rate. Such changes are usually the largest component of the overall change in fair value. Separate hedges are maintained for each underlying currency. Effectiveness is assessed by comparing changes in fair value of the hedged item attributable to changes in the designated benchmark interest rate, with changes in the fair value of the interest rate swaps. Micro hedges of interest rate risk and foreign currency risk Santander UK accesses international markets to obtain funding, issuing fixed rate debt in its functional currency and other currencies. We are therefore exposed to changes in fair value due to changes in market interest rates and/or foreign exchange rates, principally in USD and EUR, which we mitigate through the use of receive fixed/pay floating rate interest rate swaps and/or receive fixed/pay floating rate cross currency swaps. The interest rate risk component is the change in fair value of the fixed rate debt due to changes in the benchmark rate. The foreign exchange component is the change in the fair value of the fixed rate debt issuance due to changes in foreign exchange rates prevailing from the time of execution. Effectiveness is assessed by using linear regression techniques to compare changes in the fair value of the debt caused by changes in the benchmark interest rate and foreign exchange rates, with changes in the fair value of the interest rate swaps and/or cross currency swaps. Cashflow hedges Hedges of interest rate risk Santander UK manages its exposure to the variability in cash flows of floating rate assets and liabilities attributable to movements in market interest rates by entering into interest rate swaps. The interest rate risk component is determined with reference to the underlying benchmark rate attributable to the floating rates asset or liability. Designated benchmark rates referenced are currently SONIA or USD LIBOR. Effectiveness is assessed by comparing changes in the fair value of the interest rate swap with changes in the fair value of the hedged item attributable to the hedged risk, applying a hypothetical derivative method using linear regression techniques. Hedges of foreign currency risk As Santander UK obtains funding in international markets, we assume significant foreign currency risk exposure, mainly in USD and EUR. In addition, the Santander UK group also holds debt securities for liquidity purposes which assumes foreign currency exposure, principally in JPY. Santander UK manages the exposures to the variability in cash flows of foreign currency denominated assets and liabilities to movements in foreign exchange rates by entering into either foreign exchange contracts (spot, forward and swaps) or cross currency swaps. These instruments are entered into to match the cash flow profile and maturity of the estimated interest and principal repayments of the hedged item. The foreign currency risk component is the change in cash flows of the foreign currency debt arising from changes in the relevant foreign currency forward exchange rate. Such changes constitute a significant component of the overall changes in cash flows of the instrument. Effectiveness is assessed by comparing changes in the fair value of the cross currency or foreign exchange swaps with changes in the fair value of the hedged debt attributable to the hedged risk applying a hypothetical derivative method using linear regression techniques. Equity risk on cash settled share-based transactions Santander Equity Investments Limited (SEIL) offers employees the chance to buy shares in Banco Santander SA at a discount under Sharesave, or other incentive schemes. This exposes Santander UK to equity price risk. The equity risk is managed by purchasing share options which allow Santander UK to buy shares at a fixed price. These instruments are entered into to match the amount of employee share options expected to be exercised. .The equity price risk is the change in cash flows arising from the change in share price over time. Santander UK established the hedge ratio by matching the notional of the derivative with the notional of the employee share options being hedged. Effectiveness is assessed by comparing the changes in fair value of the share options with changes in the fair value of the employee share options by using a hypothetical derivative method. IBOR Reform Note 42 includes details of the notional value of hedging instruments by benchmark interest rate impacted by IBOR reform and the notional amounts of assets, liabilities and off-balance sheet commitments affected by IBOR reform that have yet to transition to an alternative benchmark interest rate. Hedge effectiveness measurement Hedge effectiveness is assessed by using either dollar offset or linear regression techniques to compare changes in the fair value of the hedged item attributable to changes in the designated hedged risk and the hedging instrument. For cash flow hedges, a hypothetical derivative method is used to model the cash flows of the hedged item. Possible sources of hedge ineffectiveness For both fair value and cash flow hedges, hedge ineffectiveness can arise from hedging derivatives with a non-zero fair value at the date of initial designation. In addition, for: Fair value hedges Hedge ineffectiveness can also arise due to differences in discounting between the hedged item and the hedging instrument as cash collateralised swaps discount using Overnight Indexed Swaps discount curves not applied to the hedged item; and where counterparty credit risk impacts the fair value of the derivative but not the hedged item. For portfolio hedges of interest rate risk, it can also arise due to differences in the expected and actual volume of prepayments. Cash flow hedges Hedge ineffectiveness can also arise due to differences in the timing of cash flows between the hedged item and the hedging instrument. For micro hedges of interest rate risk, it can also arise due to differences in the basis of cash flows between the hedged item and the hedging instrument. For hedges of equity risk on cash settled share-based transactions, it can also arise due to changes in the expected number of Sharesave options to be exercised. Maturity profile and average price/rate of hedging instruments The following table sets out the maturity profile and average price/rate of the hedging instruments used in the Santander UK group’s hedging strategies: Group 2021 Hedging Instruments ≤1 month >1 and ≤3 months >3 and ≤12 months >1 and ≤5 years >5 years Total Fair value hedges: Interest rate risk Interest rate contracts- Nominal amount (£m) 3,121 6,223 21,442 44,644 4,991 80,421 Average fixed interest rate - GBP 0.59 % 0.42 % 0.09 % 0.88 % 3.13 % Average fixed interest rate - EUR 0.51 % 1.74 % 1.08 % 0.81 % 2.61 % Average fixed interest rate - USD 1.91 % 0.96 % 1.44 % 2.76 % 4.05 % Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) — — 107 381 102 590 Interest rate contracts - Nominal amount (£m) — — — 193 37 230 Average GBP - EUR exchange rate — — 1.21 1.16 1.17 Average fixed interest rate - EUR — — 3.29 % 2.03 % 2.62 % Cash flow hedges: Interest rate risk Interest rate contracts - Nominal amount (£m) 1,010 481 871 7,532 5,137 15,031 Average fixed interest rate - GBP 1.97 0.44 % 0.08 % 1.39 % 0.97 % FX risk Exchange rate contracts- Nominal amount (£m) 2,703 936 2,057 6,715 2,124 14,535 Interest rate contracts- Nominal amount (£m) — — — 2,438 887 3,325 Average GBP - JPY exchange rate — 142.91 148.86 — — Average GBP - EUR exchange rate 1.17 — 1.18 1.16 1.17 Average GBP - USD exchange rate 1.34 1.34 1.33 1.34 1.39 Equity risk Equity derivative contracts - Nominal amount (£m) — — 2 41 4 47 Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) 620 — 840 4,765 1,479 7,704 Interest rate contracts - Nominal amount (£m) — — — 2,049 924 2,973 Average GBP - EUR exchange rate 1.28 — 1.39 1.20 1.20 — Average GBP - USD exchange rate — — — 1.61 1.38 Average fixed interest rate - GBP 2.26 % — 1.17 % 2.72 % 3.41 % 2020 Fair value hedges: Interest rate risk Interest rate contracts- Nominal amount (£m) 2,429 7,617 27,791 47,749 7,889 93,475 Average fixed interest rate - GBP 0.69 % 0.65 % 0.82 % 0.73 % 3.61 % Average fixed interest rate - EUR 1.18 % 0.23 % 3.02 % 0.98 % 2.34 % Average fixed interest rate - USD 1.87 % 1.72 % 2.89 % 2.49 % 4.16 % Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) — 0 132 461 196 789 Interest rate contracts - Nominal amount (£m) — — — 236 37 273 Average GBP - EUR exchange rate — — 1.14 1.17 1.17 Average fixed interest rate - EUR — — 4.64 % 1.78 % 3.56 % Cash flow hedges: Interest rate risk Interest rate contracts - Nominal amount (£m) — 897 2,528 7,964 1,061 12,450 Average fixed interest rate - GBP — 0.46 % 0.57 % 1.45 % 1.33 % FX risk Exchange rate contracts- Nominal amount (£m) 1,439 2,015 3,877 7,113 1,119 15,563 Interest rate contracts- Nominal amount (£m) — — — 366 — 366 Average GBP - JPY exchange rate — 137.98 135.61 132.27 — Average GBP - EUR exchange rate — — 0.00 1.16 1.18 Average GBP - USD exchange rate 1.29 1.32 1.32 1.30 — Equity risk Equity derivative contracts - Nominal amount (£m) — — 0 12 1 13 Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) 732 — 2,583 6,550 1,592 11,457 Interest rate contracts - Nominal amount (£m) 732 — 882 4,062 915 6,591 Average GBP - EUR exchange rate — — 1.35 1.25 1.20 Average GBP - USD exchange rate 1.46 — 0.00 1.61 1.38 Average fixed interest rate - GBP 2.01 % — 3.18 % 2.48 % 3.39 % Net gains or losses arising from fair value and cash flow hedges included in other operating income Group 2021 2020 2019 £m £m £m Fair value hedging: Gains/(losses) on hedging instruments 846 (299) (360) (Losses)/gains on hedged items attributable to hedged risks (804) 364 414 Fair value hedging ineffectiveness 42 65 54 Cash flow hedging ineffectiveness (34) (46) (46) 8 19 8 Hedge ineffectiveness can be analysed by risk category as follows: Group 2021 2020 Change in FV of hedging instruments Change in FV of hedged items Recognised in income statement Change in FV of hedging instruments Change in FV of hedged items Recognised in income statement £m £m £m £m £m £m Fair value hedges: Interest rate risk 868 (838) 30 (358) 384 26 Interest rate/FX risk (22) 34 12 59 (20) 39 846 (804) 42 (299) 364 65 Group 2021 2020 Hedging Instruments Hedging Instruments Income statement line item affected by reclassification Change in FV Recognised in OCI Recognised in income statement Reclassified from reserves to income Change in FV Recognised in OCI Recognised in income statement Reclassified from reserves to income £m £m £m £m £m £m £m £m Cash flow hedges: Interest rate risk Net interest income (312) 306 (6) 70 185 (179) 6 33 FX risk Net interest income/other operating income (54) 54 — (158) (42) 38 (4) 2 Equity risk Operating expenses (1) 1 — 2 2 (2) — (5) Interest rate/FX risk Net interest income/other operating income (542) 514 (28) (273) 782 (830) (48) 773 (909) 875 (34) (359) 927 (973) (46) 803 In 2021, cash flow hedge accounting of £14m (2020: £57m) had to cease due to the hedged cash flows no longer being expected to occur. The following table provides a reconciliation by risk category of components of equity and analysis of OCI items (before tax) resulting from hedge accounting. Group 2021 2020 £m £m Balance at 1 January 649 479 Effective portion of changes in fair value: – Interest rate risk (306) 179 – Foreign currency risk (54) (38) – Equity risk (1) 2 – Interest rate/foreign currency risk (514) 830 (875) 973 Income statement transfers: – Interest rate risk (70) (33) – Foreign currency risk 158 (2) – Equity risk (2) 5 – Interest rate/foreign currency risk 273 (773) 359 (803) Balances at 31 December 133 649 Hedged exposures Santander UK hedges its exposures to various risks, including interest rate risk and foreign currency risk, as set out in the following table. Group 2021 2020 Accumulated amount of FV hedge adjustments Change in value to calculate hedge ineffectiveness Accumulated amount of FV hedge adjustments Change in value to calculate hedge ineffectiveness Carrying value Hedged item Portfolio hedge of interest rate risks Of which Discontinued hedges Carrying value Hedged item Portfolio hedge of interest rate risks Of which Discontinued hedges £m £m £m £m £m £m £m £m £m £m Fair value hedges Interest rate risk: Loans and advances to customers 58,455 — 88 500 (1,096) 54,118 — 1,202 904 332 Other financial assets at amortised cost 160 — 2 3 (12) 772 — 36 13 121 Reverse repurchase agreements – non trading 9,570 — (5) — (6) 12,149 — 1 — 3 Other financial assets at FVOCI 3,728 23 — 47 (112) 5,129 155 — 74 88 Deposits by customers — — — — 14 (4,305) (15) (10) (10) (13) Debt securities in issue (4,373) (188) (115) (230) 325 (8,889) (518) (137) (305) (120) Subordinated liabilities (293) (75) (8) (70) 49 (636) (185) (41) (166) (27) Interest rate/FX risk: Other financial assets at FVOCI 227 — — 1 (20) 299 5 — — 15 Debt securities in issue (423) (55) — (47) 55 (621) (94) — (76) (34) Subordinated liabilities 2 2 — 2 (1) 3 3 — 3 (1) 67,053 (293) (38) 206 (804) 58,019 (649) 1,051 437 364 Group 2021 2020 Change in value to calculate hedge ineffectiveness Cash flow Balances on cash flow hedge reserve for discontinued hedges Change in value to calculate hedge ineffectiveness Cash flow Balances on cash flow hedge reserve for discontinued hedges Hedged item balance sheet line item £m £m £m £m £m £m Cash flow hedges: Interest rate risk: Loans and advances to customers 236 (135) (2) (183) 165 1 Cash and balances at central banks 71 (80) — (2) 1 — Reverse repurchase agreements – non trading — — — (2) 1 — Deposits by banks (1) 1 — 7 (2) — Repurchase agreements – non trading — — — 1 (1) — FX risk: Other financial assets at FVOCI (194) (1) — 40 6 — Not applicable – highly probable forecast transactions 148 1 — 33 3 — Deposits by customers 4 — — (7) — — Debt securities in issue 90 67 6 (13) (46) — Repurchase agreements – non trading 6 — — (15) — — Equity risk: Other liabilities 1 3 — (2) 6 — Interest rate/FX risk: Debt securities in issue/loans and advances to customers 503 144 (4) (701) 322 (2) Subordinated liabilities/loans and advances to customers 11 133 80 (130) 194 — 875 133 80 (974) 649 (1)

Other Financial Assets at Fair

Other Financial Assets at Fair Value Through Profit or Loss	12 Months Ended
	Dec. 31, 2021
Financial assets at fair value through profit or loss [abstract]
Other Financial Assets at Fair Value Through Profit or Loss	12. OTHER FINANCIAL ASSETS AT FAIR VALUE THROUGH PROFIT OR LOSS Group 2021 2020 £m £m Loans and advances to customers: Loans to housing associations 12 13 Other loans 502 579 514 592 Debt securities 112 112 Equity securities 50 130 676 834 For the Santander UK group, other financial assets at FVTPL comprised £454m (2020: £508m) of financial assets designated at FVTPL and £222m (2020:£325m) of financial assets mandatorily held at FVTPL. Loans and advances to customers principally represented other loans, being a portfolio of roll-up mortgages and deferred consideration following the partial sale of the portfolio . These are managed, and have their performance evaluated, on a fair value basis in accordance with a documented investment strategy, and information about them is provided on that basis to management. Since 2009, the Santander UK group’s policy has been not to designate similar new loans at FVTPL. The net (loss)/gain in the year attributable to changes in credit risk for loans and advances at FVTPL was £nil (2020: £nil, 2019: £nil). The cumulative net loss attributable to changes in credit risk for loans and advances at FVTPL at 31 December 2021 was £2m (2020: £2m).

Loans and Advances to Customers

Loans and Advances to Customers	12 Months Ended
	Dec. 31, 2021
Net Loans And Advances To Customers [Abstract]
Loans and Advances to Customers	13. LOANS AND ADVANCES TO CUSTOMERS Group 2021 2020 £m £m Loans secured on residential properties 178,039 170,089 Corporate loans 19,282 23,613 Finance leases 3,916 6,554 Secured advances — — Other unsecured loans 9,405 10,169 Accrued interest and other adjustments 656 861 Amounts due from fellow Banco Santander subsidiaries and joint ventures 3,080 2,249 Loans and advances to customers 214,378 213,535 Credit impairment loss allowances on loans and advances to customers (828) (1,303) RV and voluntary termination provisions on finance leases (25) (54) Net loans and advances to customers 213,525 212,178 For movements in expected credit losses, see the 'Movement in total exposures and the corresponding ECL' table in the Santander UK group level - Credit risk review section of the Risk review. Finance lease and hire purchase contract receivables may be analysed as follows: Group 2021 2020 Gross investment Unearned finance income Net investment Gross investment Unearned finance income Net investment £m £m £m £m £m £m No later than one year 1,906 (5) 1,901 3,468 (297) 3,171 Later than one year and not later than two years 1,324 (201) 1,123 1,829 (173) 1,656 Later than two years and not later than three years 772 (141) 631 1,099 (106) 993 Later than three years and not later than four years 343 (82) 261 575 (55) 520 Later than four years and not later than five years 38 (38) — 231 (25) 206 Later than five years — — — 8 — 8 4,383 (467) 3,916 7,210 (656) 6,554 The Santander UK group enters into finance leasing arrangements primarily for the financing of motor vehicles and a range of assets for its corporate customers. Included in the carrying value of net investment in finance leases and hire purchase contracts is £1,510m (2020: £3,552m) of unguaranteed RV at the end of the current lease terms, which is expected to be recovered through re-payment, re-financing or sale. Contingent rent income of £nil (2020: £nil, 2019: £nil) was earned in the year, which was classified in ‘Interest and similar income’. Finance income on the net investment in finance leases was £243m (2020: £308m , 2019: £299m ). Finance lease receivable balances are secured over the asset leased. The Santander UK group is not permitted to sell or repledge the asset in the absence of default by the lessee. The Directors consider that the carrying amount of the finance lease receivables approximates to their fair value. Included within loans and advances to customers are advances assigned to bankruptcy remote structured entities and Abbey Covered Bonds LLP. These loans provide security to issues of covered bonds and mortgage-backed or other asset-backed securities issued by the Santander UK group. For more, see Note 14. At 31 December 2021 and 2020 , the Santander UK group had contracted with lessees for the following future undiscounted minimum lease payments receivable under operating leases. Group 2021 2020 £m No later than one year 31 17 Later than one year and not later than two years 27 17 Later than two years and not later than three years 22 16 Later than three years and not later than four years 15 11 Later than four years and not later than five years 11 10 Later than five years 28 30 134 101

Securitisations and Covered Bon

Securitisations and Covered Bonds	12 Months Ended
	Dec. 31, 2021
Disclosure Of Securitisations And Covered Bonds [Abstract]
Securitisations and Covered Bonds	14. SECURITISATIONS AND COVERED BONDS The information in this Note relates to securitisations and covered bonds for consolidated structured entities, used to obtain funding or collateral. It excludes structured entities relating to credit protection transactions. The Santander UK group uses structured entities to securitise some of the mortgage and other loans to customers that it originates. The Santander UK group also issues covered bonds, which are guaranteed by, and secured against, a pool of the Santander UK group’s mortgage loans transferred to Abbey Covered Bonds LLP. The Santander UK group issues mortgage-backed securities, other asset-backed securities and covered bonds mainly in order to obtain diverse, low-cost funding, but also to use as collateral for raising funds via third party bilateral secured funding transactions or for liquidity purposes in the future. The Santander UK group has successfully used bilateral secured transactions as an additional form of medium-term funding; this has allowed the Santander UK group to further diversify its medium-term funding investor base. Loans and advances to customers include portfolios of residential mortgage loans, and receivables derived from credit agreements with retail customers for the purchases of financed vehicles, which are subject to non-recourse finance arrangements. These loans and receivables have been purchased by, or assigned to, structured entities or Abbey Covered Bonds LLP, and have been funded primarily through the issue of mortgage-backed securities, other asset-backed securities or covered bonds. No gain or loss has been recognised as a result of these sales. The structured entities and Abbey Covered Bonds LLP are consolidated as subsidiary undertakings. The Company and its subsidiaries do not own directly, or indirectly, any of the share capital of any of the structured entities. a) Securitisations i) Master trust structures The Santander UK group makes use of master trust structures, whereby a pool of residential mortgage loans is assigned to a trust company by the asset originator. A funding entity acquires a beneficial interest in the pool of assets held by the trust company with funds borrowed from qualifying structured entities, which at the same time issue asset-backed securities to third-party investors or the Santander UK group. Santander UK plc and its subsidiaries receive payments from the securitisation companies in respect of fees for administering the loans, and payment of deferred consideration for the sale of the loans. Santander UK plc and its subsidiaries have no right or obligation to repurchase any securitised loan, except if certain representations and warranties given by Santander UK plc or its subsidiaries at the time of transfer are breached and, in certain cases, if there is a product switch or further advance, if a securitised loan is in arrears for over two months or if a securitised loan does not comply with regulatory requirements. In April 2020, Santander UK plc followed FCA guidance on how they expect mortgage lenders and administrators to treat customers fairly during the Covid-19 pandemic and restructured all its securitisations to accommodate its obligations as servicer under the principles set out in the FCA Handbook and Mortgage Conduct of Business rules. The granting of payment holidays to any securitised loans results in a corresponding decrease in revenue receipts available to the trust company to distribute to the funding entity on each distribution date. To mitigate the potential impact to the securitisations, the qualifying structured entities were amended to direct a cash payment to the funding entity in an amount equal to the funding entity's share of the aggregate amount of the interest that would have been due on any loans which are the subject of a payment holiday. To effect such cash payment, Santander UK plc’s share of revenue receipts is reduced by such amount and the funding entity's share of revenue receipts increased accordingly, making the impact neutral to the securitisation. ii) Other securitisation structures The Santander UK group also makes use of auto loan securitisations, whereby a pool of auto loans originated by a member of the Santander UK group is sold to a special purpose vehicle by the asset originator. The special purpose vehicle funds the purchase of the auto loans by issuing asset-backed securities to third-party investors. A proportion of the securities are also retained by members of the Santander UK group. Members of the Santander UK group also receive payments from the special purpose vehicle in respect of fees for administering the auto loans, and payment of deferred consideration for the sale of the auto loans. The seller has no right or obligation to repurchase any securitised loan, except if certain representations and warranties given by the Seller at the time of transfer are breached and, in certain cases, if there has been a subsequent variation in the terms of the underlying auto loan not permitted under the sale agreement. b) Covered bonds Santander UK plc also issues covered bonds, which are its direct, unsecured and unconditional obligation. The covered bonds benefit from a guarantee from Abbey Covered Bonds LLP. Santander UK plc makes a term advance to Abbey Covered Bonds LLP equal to the sterling proceeds of each issue of covered bonds. Abbey Covered Bonds LLP uses the proceeds of the term advance to purchase portfolios of residential mortgage loans and their security from Santander UK plc. Under the terms of the guarantee, Abbey Covered Bonds LLP has agreed to pay an amount equal to the guaranteed amounts when the same shall become due for payment, but which would otherwise be unpaid by Santander UK plc. c) Analysis of securitisations and covered bonds The Santander UK group’s principal securitisation programmes and covered bond programme, together with the balances of the advances subject to securitisation (or for the covered bond programme assigned) and the carrying value of the notes in issue at 31 December 2021 and 2020 are listed below. Gross assets External notes in issue Notes issued to Santander UK plc/subsidiaries as collateral 2021 2020 2021 2020 2021 2020 £m £m £m £m £m £m Mortgage-backed master trust structures: – Holmes 2,294 3,073 430 829 183 334 – Fosse 2,154 2,258 288 290 1,402 1,402 – Langton — 2,782 — — — 2,355 4,448 8,113 718 1,119 1,585 4,091 Other asset-backed securitisation structures: – Motor 38 189 41 104 — 97 – Auto ABS UK Loans — 1,460 — 1,107 — 361 38 1,649 41 1,211 — 458 Total securitisation programmes 4,486 9,762 759 2,330 1,585 4,549 Covered bond programmes – Euro 35bn Global Covered Bond Programme 15,713 23,670 12,760 19,285 — — Total securitisation and covered bond programmes (See Note 26) 20,199 33,432 13,519 21,615 1,585 4,549 Auto ABS UK Loans was held in PSA Finance UK Limited (PSA), which was a subsidiary of the Santander UK group. On 30 July 2021, the Santander UK group through Santander Consumer (UK) plc sold its entire 50% shareholding in PSA Finance UK Limited to PSA Financial Services Spain EFC SA, a joint venture between Santander Consumer Finance SA, a fellow subsidiary of Banco Santander SA, and Banque PSA Finance SA, the auto finance arm of Group PSA Peugeot Citroën. For more on PSA, see Note 19. The following table sets out the internal and external issuances and redemptions in 2021 and 2020 for each securitisation and covered bond programme. Internal issuances External issuances Internal redemptions External redemptions 2021 2020 2021 2020 2021 2020 2021 2020 £bn £bn £bn £bn £bn £bn £bn £bn Mortgage-backed master trust structures: – Holmes — — — — 0.2 0.3 0.4 0.9 – Langton — — — — 2.4 — — — Other asset-backed securitisation structures: – Motor — — — — 0.1 0.1 0.1 0.2 – Auto ABS UK Loans — — — 0.3 0.1 — 0.1 0.1 Covered bond programme — — — 3.0 — — 6.5 2.7 — — — 3.3 2.8 0.4 7.1 3.9 In 2021, all the remaining Langton bonds were redeemed and all the remaining associated mortgages were repurchased by Santander UK plc. There was no gain or loss on redemption. Issuances and redemptions for Auto ABS UK Loans are included until 30 July 2021, the date on which the Santander UK Group sold its entire shareholding in PSA Finance UK Limited. Holmes Funding Ltd has a beneficial interest of £0.5bn (2020: £1.0bn) in the residential mortgage loans held by Holmes Trustees Ltd. The remaining share of the beneficial interest in residential mortgage loans held by Holmes Trustees Ltd belongs to Santander UK plc. Fosse Funding (No.1) Ltd has a beneficial interest of £1.6bn (2020: £1.7bn) in the residential mortgage loans held by Fosse Trustee (UK) Ltd. The remaining share of the beneficial interest in residential mortgage loans held by Fosse Trustee (UK) Ltd belongs to Santander UK plc. Langton Funding (No.1) Ltd has a beneficial interest of £nil (2020: £2.4bn) in the residential mortgage loans held by Langton Mortgage Trustee (UK) Ltd, following the redemption of the remaining Langton bonds and repurchase of the associated mortgages by Santander UK plc. At 31 December 2021, Langton Mortgage Trustee (UK) Ltd was in the process of being liquidated, and all residential mortgage loans previously held by Langton Mortgage Trustee (UK) Ltd had been repurchased by Santander UK plc. At 31 December 2020, the remaining share of the beneficial interest in residential mortgage loans held by Langton Mortgage Trustee (UK) Ltd belonged to Santander UK plc.

Transfers of Financial Assets N

Transfers of Financial Assets Not Qualifying for Derecognition	12 Months Ended
	Dec. 31, 2021
Disclosure of transferred financial assets that are not derecognised in their entirety [abstract]
Transfers of Financial Assets Not Qualifying for Derecognition	15. TRANSFERS OF FINANCIAL ASSETS NOT QUALIFYING FOR DERECOGNITION The Santander UK group enters into transactions in the normal course of business by which it transfers recognised financial assets directly to third parties or to structured entities. These transfers may give rise to the full or partial derecognition of those financial assets. Transferred financial assets that do not qualify for derecognition consist of (i) securities held by counterparties as collateral under repurchase agreements, (ii) securities lent under securities lending agreements, and (iii) loans that have been securitised under arrangements by which the Santander UK group retains a continuing involvement in such transferred assets. . As the substance of the sale and repurchase and securities lending transactions is secured borrowings, the asset collateral continues to be recognised in full and the related liability reflecting the Santander UK group’s obligation to repurchase the transferred assets for a fixed price at a future date is recognised in deposits from banks or customers, as appropriate. As a result of these transactions, the Santander UK group is unable to use, sell or pledge the transferred assets for the duration of the transaction. The Santander UK group remains exposed to interest rate risk and credit risk on these pledged instruments. The counterparty’s recourse is not limited to the transferred assets. The Santander UK group securitisation transfers do not qualify for derecognition. The Santander UK group remains exposed to credit risks arising from the mortgage loans or credit agreements and has retained control of the transferred assets. Circumstances in which the Santander UK group has continuing involvement in the transferred assets may include retention of servicing rights over the transferred assets (the servicing fee in respect of which is dependent on the amount or timing of the cash flows collected from, or the non-performance of, the transferred assets), entering into a derivative transaction with the securitisation vehicle, retaining an interest in the securitisation vehicle or providing a cash reserve fund. Where the Santander UK group has continuing involvement, it continues to recognise the transferred assets to the extent of its continuing involvement and recognises an associated liability. The net carrying amount of the transferred assets and associated liabilities reflects the rights and obligations that the Santander UK group has retained. The following table analyses the carrying amount of financial assets that did not qualify for derecognition and their associated financial liabilities: Group 2021 2020 Assets Liabilities Assets Liabilities Nature of transaction £m £m £m £m Sale and repurchase agreements 171 (172) 1,597 (1,340) Securities lending agreements 1,892 (1,742) 918 (752) Securitisations (See Notes 14 and 26) 4,486 (759) 6,980 (2,330) 6,549 (2,673) 9,495 (4,422)

Reverse Repurchase Agreements -

Reverse Repurchase Agreements - Non Trading	12 Months Ended
	Dec. 31, 2021
Disclosure Of Reserve Repurchase Agreements Non-Trading [Abstract]
Reverse Repurchase Agreements - Non Trading	16. REVERSE REPURCHASE AGREEMENTS – NON TRADING Group 2021 2020 £m £m Agreements with banks 447 1,258 Agreements with customers 12,236 18,341 12,683 19,599

Other Financial Assets at Amort

Other Financial Assets at Amortised Cost	12 Months Ended
	Dec. 31, 2021
Financial assets at fair value through profit or loss [abstract]
Other Financial Assets at Amortised Cost	17. OTHER FINANCIAL ASSETS AT AMORTISED COST Group 2021 2020 £m £m Asset backed securities 443 491 Debt securities 63 672 506 1,163

Financial Assets at Fair Value

Financial Assets at Fair Value Through Other Comprehensive Income	12 Months Ended
	Dec. 31, 2021
Financial assets at fair value through other comprehensive income [abstract]
Financial Assets at Fair Value Through Other Comprehensive Income	18. FINANCIAL ASSETS AT FAIR VALUE THROUGH OTHER COMPREHENSIVE INCOME Group 2021 2020 £m £m Debt securities 5,833 8,929 Loans and advances to customers 18 21 5,851 8,950

Interests in Other Entities

Interests in Other Entities	12 Months Ended
	Dec. 31, 2021
Investments accounted for using equity method [abstract]
Interests in Other Entities	19. INTERESTS IN OTHER ENTITIES Group 2021 2020 £m £m Joint Ventures 201 172 201 172 The Santander UK group consists of a parent company, Santander UK Group Holdings plc, incorporated and domiciled in the UK and a number of subsidiaries and joint ventures held directly and indirectly by it. a) Interests in subsidiaries The Company holds directly or indirectly 100% of the issued ordinary share capital of its principal subsidiaries. All companies operate principally in their country of incorporation or registration. SFS has branch offices in Jersey and the Isle of Man. Subsidiaries with significant non-controlling interests The only subsidiary with significant non-controlling interests was PSA Finance UK Limited (PSA), which operates in the UK.On 30 July 2021, Santander UK through Santander Consumer (UK) plc sold its entire 50% shareholding in PSA to PSA Financial Services Spain EFC SA, a joint venture between Santander Consumer Finance SA, a fellow subsidiary of Banco Santander SA, and Banque PSA Finance SA, the auto finance arm of Group PSA Peugeot Citroën. The impact of the sale was to derecognise total assets of £3.2bn, total liabilities of £2.9bn and a non-controlling interest of £0.15bn. No material gain or loss arose on sale. In 2021, until the date of sale, and 2020, the proportion of ownership interests and voting rights held by non-controlling interests was 50%. 2021 2020 £m £m Profit attributable to non-controlling interests — 19 Accumulated non-controlling interests of the subsidiary — 162 Dividends paid to non-controlling interests — 15 Summarised financial information: Total assets — 3,451 Total liabilities — 3,127 Profit for the year — 38 Total comprehensive income for the year — 33 Interests in consolidated structured entities Structured entities are formed by Santander UK to accomplish specific and well-defined objectives. Santander UK consolidates these structured entities when the substance of the relationship indicates control, as described in Note 1. In addition to the structured entities disclosed in Note 14 which are used for securitisation and covered bond programmes, the only other structured entities consolidated by Santander UK are described below. All the external assets and liabilities in these entities are included in the financial statements and in relevant Notes. Other than as set out below, no significant judgements were required with respect to control or significant influence. Motor Securities 2018-1 Designated Activity Company (Motor 2018) Motor 2018 is a credit protection entity, and a Designated Activity Company limited by shares, incorporated in Ireland. It has issued a series of credit linked notes varying in seniority which reference portfolios of Santander UK group loans. Concurrently, these entity sells credit protection to Santander UK in respect of the referenced loans and, in return for a fee, is liable to make protection payments to Santander UK upon the occurrence of a credit event in relation to any of the referenced loans. Motor 2018 is consolidated as Santander UK holds a variable interest by retaining the junior tranche of notes issued by the entity. b) Interests in joint ventures Santander UK does not have any individually material interests in joint ventures. As set out in the accounting policies in Note 1, interests in joint ventures are accounted for using the equity method. In 2021, Santander UK’s share in the profit after tax of its joint ventures was £22m (2020: £20m) before elimination of transactions between Santander UK and the joint ventures. At 31 December 2021, the carrying amount of Santander UK’s interest was £201m (2020: £172m). At 31 December 2021 and 2020, the joint ventures had no commitments and contingent liabilities. c) Interests in unconsolidated structured entities Structured entities sponsored by the Santander UK group Santander UK has interests in structured entities which it sponsors but does not control. Santander UK considers itself a sponsor of a structured entity when it facilitates the establishment of the structured entity. Other than as set out below, no significant judgements were required with respect to control or significant influence. The structured entities sponsored but not consolidated by Santander UK are as follows. i) Santander (UK) Common Investment Fund The Santander (UK) Common Investment Fund (the Fund) is a common investment fund that was established to hold the assets of the Santander (UK) Group Pension Scheme. The Fund is not consolidated by Santander UK, but its assets of £14,100m (2020: £13,553m) are accounted for as part of the defined benefit assets and obligations recognised on Santander UK’s balance sheet. For more on the Fund, see Note 30. As the Fund holds the assets of the pension scheme, it is outside the scope of IFRS 10. Santander UK’s maximum exposure to loss is the carrying amount of the assets held. ii) Credit protection entities Santander UK has established three (2020: three) unconsolidated credit protection entities, which are Designated Activity Companies limited by shares, incorporated in Ireland. Each entity has issued a series of credit linked notes varying in seniority which reference portfolios of Santander UK group loans. Concurrently, these entities sell credit protection to Santander UK in respect of the referenced loans and, in return for a fee, are liable to make protection payments to Santander UK upon the occurrence of a credit event in relation to any of the referenced loans. Senior credit linked notes, which amounted to £1,184m (2020: £2,160m), are issued to, and held by, Santander UK. Junior credit linked notes, which amounted to £619m (2020: £678m), are all held by third party investors and suffer the first losses incurred in the referenced portfolios. Funds raised by the sale of the credit linked notes are deposited with Santander UK as collateral for the credit protection. The senior credit linked notes, along with the deposits and associated guarantees, are presented on a net basis, to reflect a legal right of set-off between the principal amounts of senior notes and the cash deposits. Deposits and associated guarantees in respect of the junior credit linked notes are included in ‘Deposits by customers’ (see Note 23). The entities are not consolidated by Santander UK because the third-party investors have the exposure, or rights, to all of the variability of returns from the performance of the entities. No assets are transferred to, or income received from, these entities. Since the credit linked notes (including those held by Santander UK) are fully cash collateralised, Santander UK’s maximum exposure to loss is equal to any unamortised fees paid to the entities in connection with the credit protection outlined above. Structured entities not sponsored by the Santander UK group Santander UK also has interests in structured entities which it does not sponsor or control. These consist of holdings of mortgage and other asset backed securities issued by entities that were established and/or sponsored by other unrelated financial institutions. These securities comprise the asset backed securities included in Note 17. Management has concluded that the Santander UK group has no control or significant influence over these entities and that the carrying value of the interests held in these entities represents the maximum exposure to loss.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2021
Disclosure of detailed information about intangible assets [abstract]
Intangible Assets	20. INTANGIBLE ASSETS a) Goodwill Group Cost Accumulated impairment Net book value £m £m £m At 31 December 2020, 1 January 2021 and 31 December 2021 1,285 (82) 1,203 Impairment of goodwill In 2021 and 2020, no impairment of goodwill was recognised. Goodwill is tested for impairment annually at 30 November, with a review for impairment indicators at 30 June and 31 December. Goodwill is tested for impairment if reviews identify an impairment indicator or when events or changes in circumstances dictate. Impairment is required where the book value of goodwill exceeds its recoverable amount. The annual review identified the continuing uncertainty due to the Covid-19 pandemic and its potential impact on the carrying value of goodwill as impairment indicators for all cash-generating units (CGUs). As a result, management updated the impairment test at 31 December 2021 for all CGUs. Basis of the recoverable amount The recoverable amount of all CGUs was determined based on its value in use (VIU) methodology at each testing date. For each CGU, the VIU is calculated by discounting management’s cash flow projections for the CGU. The cash flow projections also take account of increased internal capital allocations needed to achieve internal and regulatory capital targets including the leverage ratio. The key assumptions used in the VIU calculation for each CGU are set out below. The Retail Banking segment consists of the Private Banking CGU and the rest of Retail Banking, known as the Personal Financial Services CGU. Key assumptions in the Value in use calculation Goodwill Discount rate Growth rate beyond initial cash flow projections 2021 2020 2021 2020 2021 2020 CGU £m £m % % % % Personal Financial Services 1,169 1,169 13.6 13.6 1.6 1.6 Private Banking 30 30 16.3 8.9 1.6 1.6 Other 4 4 13.6 13.6 1.6 1.6 1,203 1,203 The CGUs do not carry on their balance sheets any other intangible assets with indefinite useful lives. Management’s judgement in estimating the cash flows of a CGU The cash flow projections for the purpose of impairment testing for each CGU are derived from the latest 3-year plan presented to the Board. The Board challenges and endorses management’s planning assumptions in light of internal capital allocations needed to support Santander UK’s strategy, current market conditions and the macro-economic outlook. For the goodwill impairment tests conducted at 31 December 2021, the determination of the carrying value of the Personal Financial Services CGU was based on an allocation of regulatory capital and management’s cash flow projections until the end of 2023. The assumptions included in the cash flow projections reflect an allocation to the cost of capital to support future growth, as well as the expected impact of Covid-19 on the UK economic environment and the financial outlook within which the CGUs operate. The cash flow projections are supported by Santander UK’s base case economic scenario. For more on the base case economic scenario, including our forecasting approach and the assumptions in place at 31 December 2021, see the Credit risk – Santander UK group level section of the Risk review. The cash flow projections take into account the likely impact of future climate change. Cash flow projections for the purpose of impairment testing do not take account of any adverse outcomes arising from contingent liabilities (see Note 31), whose existence will be confirmed by uncertain future events or where any obligation is not probable or otherwise cannot be measured reliably, nor do they take account of the benefits arising from Santander UK’s transformation plans that had not yet been implemented or committed at 31 December 2021. Discount rate The rate used to discount the cash flows is based on the cost of equity assigned to each CGU, which is derived using a capital asset pricing model (CAPM). The CAPM depends on a number of inputs reflecting financial and economic variables, including the risk-free rate and a premium to reflect the inherent risk of the business being evaluated. These variables are based on the market’s assessment of the economic variables and management’s judgement. In determining the discount rate, management have identified the cost of equity associated with market participants that closely resemble our CGUs and adjusted them for tax to arrive at the pre-tax equivalent rate. As the discount rate is derived from market data, it takes into account the likely impact of future climate change. Growth rate beyond initial cash flow projections The growth rate for periods beyond the initial cash flow projections is used to extrapolate the cash flows in perpetuity because of the long-term perspective of CGUs. In line with the accounting requirements, management uses the UK Government’s official estimate of UK long-term average GDP growth rate, as this is lower than management's estimate of the long-term average growth rate of the business. The estimated UK long-term average GDP growth rate has regard to the long-term impact of inherent uncertainties, such as Brexit, climate change and Covid-19. Goodwill arising on the acquisition of Personal Financial Services and Private Banking The VIU of each CGU remains higher than the carrying value of the related goodwill. The VIU review at 31 December 2021 did not indicate the need for an impairment in the Company’s goodwill balances. Management considered the level of headroom and the uncertainty relating to the respective estimates of the VIU for those CGUs but determined that there was a sufficient basis to conclude that no impairment was required. Sensitivities of key assumptions in calculating the At 31 December 2021 and 31 December 2020, the VIU of the Personal Financial Services CGU was sensitive to reasonably possible changes in the key assumptions supporting the recoverable amount. The table below presents a summary of the key assumptions underlying the most sensitive inputs to the model for the Personal Financial Services CGU, the key risks associated with each and details of a reasonably possible change in assumptions. The sensitivity analysis presented below has been prepared on the basis that a change in each key assumption would not have a consequential impact on other assumptions used in the impairment review. However, due to the interrelationships between some of the assumptions, a change in one of the assumptions might impact one or more of the other assumptions and could result in a larger or smaller overall impact. The VIU calculation is not sensitive overall to the UK long-term average GDP growth rate assumption given the amount of headroom as the increased profit after tax generated by growth of the business is mostly offset by the need to retain more profit to meet increased regulatory capital requirements driven by the growth in assets. No reasonably possible change in the growth rate assumption would have resulted in an impairment. Reasonably possible changes in key assumptions CGU Input Key assumptions Associated risks Reasonably possible change Personal Financial Services Cash flow projections – BoE Bank Rate – UK house price growth – UK mortgage loan market growth – UK unemployment rate – Position in the market – Regulatory capital levels. – Uncertain market outlook – Persistent low interest rate environment – Customer remediation and regulatory action outcomes – Uncertain regulatory capital requirements. – Cash flow projections decrease by 5% (2020: 5%). Discount rate – Discount rate used is a reasonable estimate of a suitable market rate for the profile of the business. – Market rates of interest rise. – Discount rate increases by 100 basis points (2020: 100 basis points). At 31 December 2021 and 31 December 2020, a reasonably possible change in the key assumptions in relation to the VIU calculation for the goodwill balance in the Personal Financial Services CGU would have resulted in an impairment as follows. Impairment 2021 2020 CGU Reasonably possible change £m £m Personal Financial Services Cash flow projections decrease by 5% (2020: 5%) — — Discount rate increases by 100 basis points (2020: 100 basis points) 276 — Sensitivity of Value in use changes to current assumptions to achieve nil headroom Although there was no impairment of goodwill at 31 December 2021, the test for the Personal Financial Services CGU remains sensitive to some of the assumptions used, as described above. In addition, the changes in assumptions detailed below for the discount rate and cash flow projections would eliminate the current headroom. As a result, there is a risk of impairment in the future should business performance or economic factors diverge from forecasts. In 2021, there was a decrease in headroom arising from a higher capital allocation to our Retail Banking business which was partially offset by higher profitability. The sensitivity analysis presented below has been prepared on the basis that a change in each key assumption would not have a consequential impact on other assumptions used in the impairment review. However, due to the interrelationships between some of the assumptions, a change in one of the assumptions might impact one or more of the other assumptions and could result in a larger or smaller overall impact. 2021 Carrying value Value in use Headroom Increase in post tax discount rate Decrease in cash flows CGU £m £m £m bps % Personal Financial Services 8,433 9,100 667 68 7 2020 Personal Financial Services 6,758 8,602 1,844 239 22 b) Other intangibles Group Cost Accumulated amortisation / impairment Net book value £m £m £m At 1 January 2021 1,317 (871) 446 Additions 83 — 83 Disposals (54) 53 (1) Charge — (159) (159) Impairment — (27) (27) At 31 December 2021 1,346 (1,004) 342 At 1 January 2020 1,263 (690) 573 Additions 101 — 101 Disposals (47) 47 — Charge — (198) (198) Impairment — (30) (30) At 31 December 2020 1,317 (871) 446 Other intangibles which consist of computer software, include computer software under development of £83m ( 2020 : £99m ), of which £31m is internally generated ( 2020 : £68m ). The impairment charge of £27m (2020: £30m) relates to computer software no longer expected to yield future economic benefits as it has become obsolete.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2021
Property, plant and equipment [abstract]
Property, Plant and Equipment	21. PROPERTY, PLANT AND EQUIPMENT Group Property Office fixtures and equipment Computer software Operating lease assets Right-of-use assets Total (2) £m £m £m £m £m £m Cost: At 1 January 2021 1,275 1,362 436 720 222 4,015 Additions 126 28 1 284 65 504 Disposals (420) (334) — (249) (29) (1,032) At 31 December 2021 981 1,056 437 755 258 3,487 Accumulated depreciation: At 1 January 2021 491 1,053 434 178 119 2,275 Charge for the year (1) 32 87 1 81 20 221 Impairment during the year 46 28 — — 23 97 Disposals (234) (305) — (99) (23) (661) At 31 December 2021 335 863 435 160 139 1,932 Net book value 646 193 2 595 119 1,555 Cost: At 1 January 2020 1,275 1,442 439 738 214 4,108 Additions 61 24 2 185 10 282 Disposals (61) (104) (5) (203) (2) (375) At 31 December 2020 1,275 1,362 436 720 222 4,015 Accumulated depreciation: At 1 January 2020 457 1,022 434 164 60 2,137 Charge for the year (1) 56 111 — 92 59 318 Impairment during the year 24 — — — — 24 Disposals (46) (80) — (78) — (204) At 31 December 2020 491 1,053 434 178 119 2,275 Net book value 784 309 2 542 103 1,740 (1) Following a review of the estimated useful lives of property as part of Santander UK's transformation program, the charge for the period includes accelerated property depreciation of £9m (2020: £9m). (2) Property, plant and equipment includes assets under construction of £106m (2020: £55m). In Q2 2021, we sold our current head office site in Triton Square, London to a wholly owned subsidiary of Banco Santander SA. Property, office fixtures and equipment and right-of-use assets were impaired in the period as a result of our multi-year transformation project. The impairment relates to leasehold properties within the scope of our branch network restructuring programme and head office sites which are either closing or consolidating. As part of our plan to be the best bank to work for in the UK, we are building a new head office in Milton Keynes to meet the flexible needs of a modern workforce. It represents a planned investment of more than £200m, funded from existing resources. Site works began in Q1 2020 with practical completion expected in March 2023. Expenditure at 31 December 2021 was approximately £57m .

Other Financial Liabilities at

Other Financial Liabilities at Fair Value Through Profit or Loss	12 Months Ended
	Dec. 31, 2021
Disclosure of financial liabilities [abstract]
Other Financial Liabilities at Fair Value Through Profit or Loss	22. OTHER FINANCIAL LIABILITIES AT FAIR VALUE THROUGH PROFIT OR LOSS Group 2021 2020 £m £m US$30bn Euro Medium Term Note Programme 5 102 Structured Notes Programmes 413 805 Eurobonds 142 150 Structured deposits 223 375 Collateral and associated financial guarantees 20 2 803 1,434 For the Santander UK group all (2020: all) of the other financial liabilities at FVTPL were designated as such. Collateral and associated financial guarantees in the table above represent collateral received, together with associated credit protection guarantees, in respect of the proceeds of the retained senior tranches of credit linked notes described in Note 12. The financial guarantees are valued using the same parameters as the related credit linked notes, such that changes in the respective valuations are offset exactly, and there is no charge or credit to the income statement. Gains and losses arising from changes in the credit spread of securities issued by the Santander UK group reverse over the contractual life of the debt, provided that the debt is not repaid at a premium or a discount. The net loss during the year attributable to changes in the Santander UK group’s own credit risk on the above securities was £12m (2020: £3m loss, 2019: £77m loss). The cumulative net loss attributable to changes in the Santander UK group’s own credit risk on the above securities at 31 December 2021 was £10m (2020: £3m). At 31 December 2021, the amount that would be required to be contractually paid at maturity of the securities above was £nil higher (

Deposits by Customers

Deposits by Customers	12 Months Ended
	Dec. 31, 2021
Deposits from customers [abstract]
Deposits by Customers	23. DEPOSITS BY CUSTOMERS Group 2021 2020 £m £m Demand and time deposits (1) 191,764 191,774 Amounts due to fellow Banco Santander subsidiaries and joint ventures 1,150 1,314 192,914 193,088 (1) Includes equity index-linked deposits of £549m (2020: £577m). The capital amount guaranteed/protected and the amount of return guaranteed in respect of the equity index-linked deposits were £549m and £2m (2020: £577m and £2m) respectively.

Deposits by Banks

Deposits by Banks	12 Months Ended
	Dec. 31, 2021
Disclosure Of Deposits From Banks [Abstract]
Deposits by Banks	24. DEPOSITS BY BANKS Group 2021 2020 £m £m Items in the course of transmission 414 375 Deposits held as collateral 941 2,071 Other deposits (1) 32,507 18,527 33,862 20,973 (1) Includes drawdown from the TFS of £0.0bn (2020: £6.3bn) and drawdown from the TFSME of £31.9bn (2020: £11.7bn).

Repurchase Agreements - Non Tra

Repurchase Agreements - Non Trading	12 Months Ended
	Dec. 31, 2021
Disclosure Of Repurchase Agreements [Abstract]
Repurchase Agreements - Non Trading	25. REPURCHASE AGREEMENTS – NON TRADING Group 2021 2020 £m £m Agreements with banks 4,145 6,358 Agreements with customers 7,573 9,490 11,718 15,848

Debt Securities in Issue

Debt Securities in Issue	12 Months Ended
	Dec. 31, 2021
Debt Securities In Issue [Abstract]
Debt Securities in Issue	26. DEBT SECURITIES IN ISSUE Group 2021 2020 £m £m Medium-term notes: – US$30bn Euro Medium Term Note Programme 1,405 1,694 – Euro 30bn Euro Medium Term Note Programme (1) 4,304 4,292 – US SEC-registered Debt Programme – Santander UK Group Holdings plc (2) 5,978 5,616 – US SEC-registered Debt Programme – Santander UK plc 1,224 4,723 12,911 16,325 Euro 35bn Global Covered Bond Programme (See Note 14) 12,760 19,285 US$20bn Commercial Paper Programmes 2,704 2,824 Certificates of deposit 2,387 2,858 Credit linked notes 59 57 Securitisation programmes (See Note 14) 759 2,330 31,580 43,679 (1) Restated for 2020 to reclassify £673m previously disclosed as Euro 750m Senior Unsecured Notes to Euro 30bn Euro Medium Term Note Programme due to an administrative error.

Subordinated Liabilities

Subordinated Liabilities	12 Months Ended
	Dec. 31, 2021
Subordinated liabilities [abstract]
Subordinated Liabilities	27. SUBORDINATED LIABILITIES Group 2021 2020 £m £m £325m Sterling preference shares 344 344 Undated subordinated liabilities 240 557 Dated subordinated liabilities 1,644 1,655 2,228 2,556 In 2021, the Santander UK group repurchased certain debt securities and subordinated liabilities as part of ongoing liability management exercises, resulting in a loss of £1m. In 2020, the Santander UK group repurchased certain debt securities and subordinated liabilities as part of ongoing liability management exercises, resulting in a loss of £24m . The above securities will, in the event of the winding up of the issuer, be subordinated to the claims of depositors and all other creditors of the issuer, other than creditors whose claims rank equally with, or are junior to, the claims of the holders of the subordinated liabilities. The subordination amongst each of the subordinated liabilities upon a winding up of the issuer is specified in their respective terms and conditions. In 2021 and 2020, the Santander UK group had no defaults of principal, interest or other breaches with respect to its subordinated liabilities. No repayment or purchase by the issuer of the subordinated liabilities may be made prior to their stated maturity without the consent of the PRA. Undated subordinated liabilities Group 2021 2020 First call date £m £m 10.0625% Exchangeable capital securities n/a 205 205 7.125% 30 Year Step-up perpetual callable subordinated notes 2030 35 352 240 557 In common with other debt securities issued by Santander UK group companies and notwithstanding the issuer’s first call dates in the table above, in the event of certain tax changes affecting the treatment of payments of interest on subordinated liabilities in the UK, the 7.125% 30 Year Step-up perpetual callable subordinated notes are redeemable at any time, and the 10.0625% Exchangeable capital securities are redeemable on any interest payment date – each in whole at the option of Santander UK plc, at their principal amount together with any accrued interest. The 10.0625% Exchangeable capital securities are exchangeable into fully paid 10.375% non-cumulative non-redeemable sterling preference shares of £1 each, at the option of Santander UK plc, on the business day immediately following any interest payment date. Dated subordinated liabilities Group 2021 2020 Maturity £m £m 5% Subordinated notes (US$1,500m) 2023 548 542 4.75% Subordinated notes (US$1,000m) 2025 541 536 7.95% Subordinated notes (US$1,000m) 2029 221 242 6.50% Subordinated notes 2030 28 31 5.875% Subordinated notes 2031 9 10 5.625% Subordinated notes (US$500m) 2045 297 294 1,644 1,655 The dated subordinated liabilities are redeemable in whole at the option of Santander UK plc in the event of certain tax changes affecting the treatment of payments of interest on the subordinated liabilities in the UK, at their principal amount together with any accrued interest. Each of the subordinated liabilities issued by Santander UK Group Holdings plc has been downstreamed to Santander UK plc by means of Santander UK plc issuing equivalent subordinated liabilities to Santander UK Group Holdings plc.

Other Liabilities

Other Liabilities	12 Months Ended
	Dec. 31, 2021
Subclassifications of assets, liabilities and equities [abstract]
Other Liabilities	28. OTHER LIABILITIES Group 2021 2020 £m £m Lease liabilities 134 100 Other 2,064 2,243 2,198 2,343

Provisions

Provisions	12 Months Ended
	Dec. 31, 2021
Disclosure of other provisions [abstract]
Provisions	29. PROVISIONS Group Customer remediation (2) Litigation and other regulatory (2) Bank Levy Property ECL on undrawn facilities and guarantees Restructuring Other (2) Total £m £m £m £m £m £m £m £m At 1 January 2021 69 198 38 45 75 39 4 468 Additional provisions (See Note 8) 25 72 53 52 — 81 109 392 Provisions released (See Note 8) — — — (2) (30) — (2) (34) Utilisation and other (50) (104) (103) (21) (7) (91) (97) (473) Recharge (1) — — 13 — — — — 13 At 31 December 2021 44 166 1 74 38 29 14 366 (1) Recharge in respect of the UK Bank Levy paid on behalf of other UK entities in the Banco Santander group (2) For 2021, operational loss provisions as they relate to customer accounts are included in 'Customer remediation', and 'Restructuring' provisions are now shown separately. As a result, provisions of £61m, £121m and £39m at 1 January 2021 have been reclassified from 'Regulatory and other' to 'Customer remediation', 'Litigation and other regulatory' and 'Restructuring' provisions, respectively, and £8m and £76m of 'Conduct remediation' provisions at 1 January 2021 have been reclassified to 'Customer remediation' and 'Litigation and other regulatory' provisions, respectively. Provisions expected to be settled within no more than 12 months after 31 December 2021 were £182m (2020: £340m). In 2021, the analysis of the provisions balance in the table above was enhanced to reflect its changing composition. PPI and Other products were combined with operational loss provisions relating to customer accounts which were previously included in 'Regulatory and Other' to give a clearer view of the overall 'Customer remediation' provision. Restructuring provisions relating to redundancy costs associated with transformation and organisational changes previously included in 'Regulatory and Other' are now shown separately to provide better insight. a) Customer remediation Customer remediation provisions included the estimated cost of making redress payments with respect to the past sales of products and systems issues, as well as operational loss provisions relating to customers' accounts. At 31 December 2021, there was no provision remaining for PPI redress and related costs (2020: £59m). An additional provision of £16m was recognised in December 2021 for interest and fees charged on discount plans. The remaining customer remediation provisions relate to sales of other products, primarily in regard to mortgage endowments, and other system issues around interest and fee charging, including an amount of £6m ( 2020: £47m ) that arose from a systems-related historical issue identified by Santander UK, relating to compliance with certain requirements of the Consumer Credit Act (CCA). As detailed in Note 31, there are aspects of the issue which remain under review. b) Litigation and other regulatory Litigation and other regulatory provisions principally comprised amounts in respect of litigation and other regulatory charges, operational loss and operational risk provisions, and related expenses. A number of uncertainties exist with respect to these provisions given the uncertainties inherent in litigation and other regulatory matters, that affect the amount and timing of any potential outflows with respect to which provisions have been established. These provisions are reviewed at least quarterly. Although the deadline for bringing PPI complaints has passed, customers can still commence Plevin related litigation. An increase in provision of £21m has been made for the best estimate of any obligation to pay compensation in respect of current stock and estimated future claims. There are ongoing factual issues to be resolved regarding such litigation which may have legal consequences including the volume and quality of future litigation claims. As a result, the extent of the potential liability and amount of any compensation to be paid remains uncertain. The balance also included an amount in respect of our best estimate of liability relating to a legal dispute regarding allocation of responsibility for a specific PPI portfolio of complaints, further described in Note 31. No further information on the best estimate is provided on the basis that it would be seriously prejudicial. In 2021 there were charges of £29m for legal provisions and £22m for other regulatory issues. c) Bank Levy A rate of 0.10% applies for 2021 (2020: 0.14%). Property provisions included £52m of transformation charges in 2021. These relate to a multi-year project to deliver on our strategic priorities and enhance efficiency in order for us to better serve our customers and meet our medium-term targets. These charges consist of costs relating to leasehold properties within the scope of our branch network restructuring programme and head office closures. They also include decommissioning costs relating to freehold head office sites which are either closing or consolidating. e) ECL on undrawn facilities and guarantees Provisions include expected credit losses relating to guarantees given to third parties and undrawn loan commitments. Off balance sheet ECL of £7m was included in the transfer of the CIB business of Santander UK SLB. f) Restructuring Restructuring provisions relate to severance costs associated with transformation and organisational changes. The provision includes a charge of £76m as part of our multi-year transformation programme to improve future returns, focused on simplifying, digitising and automating the bank. g) Other Other provisions include provisions that do not fit into any of the other categories, such as fraud losses and some categories of operational losses. In 2021 there were charges for operational risk provisions of £94m , including Authorised Push Payment fraud losses.

Retirement Benefit Plans

Retirement Benefit Plans	12 Months Ended
	Dec. 31, 2021
Disclosure of net defined benefit liability (asset) [abstract]
Retirement Benefit Plans	30. RETIREMENT BENEFIT PLANS The amounts recognised in the balance sheet were as follows: Group 2021 2020 £m £m Assets/(liabilities) Funded defined benefit pension scheme - surplus 1,573 496 Funded defined benefit pension scheme - deficit — (361) Unfunded pension and post-retirement medical benefits (37) (42) Total net assets 1,536 93 Remeasurement losses/(gains) recognised in other comprehensive income during the year were as follows: Group 2021 2020 2019 £m £m £m Pension remeasurement (1,263) 505 523 An expense of £65m (2020: £67m) was recognised for defined contribution plans in the period and is included in staff costs within operating expenses (see Note 6). b) Defined benefit pension schemes The Santander UK group operates a number of defined benefit pension schemes. The main scheme is the Santander (UK) Group Pension Scheme (the Scheme). It comprises seven legally segregated sections. The Scheme covers 11% (2020: 11%) of the Santander UK group’s current employees and is a funded defined benefit scheme which is closed to new members. The corporate trustee of the Scheme is Santander (UK) Group Pension Scheme Trustees Limited (the Trustee), a private limited company incorporated in 1996 and a wholly-owned subsidiary of Santander UK Group Holdings plc. The principal duty of the Trustee is to act in the best interests of the members of the Scheme. The Trustee board comprises five (2020: five) Directors selected by Santander UK Group Holdings plc, plus five (2020: five) member-nominated Directors selected from eligible members who apply for the role. The assets of the funded schemes including the Scheme are held independently of the Santander UK group’s assets in separate trustee administered funds. Investment strategy across the sections of the Scheme remains under regular review. Investment decisions are delegated by the Trustee to a common investment fund, managed by Santander (CF Trustee) Limited, a private limited company owned by five Trustee directors, three appointed by Santander UK plc and two by the Trustee. The Santander (CF Trustee) Limited directors’ principal duty, within the investment powers delegated to them, is to act in the best interest of the members of the Scheme. Ultimate responsibility for investment policy and strategy rests with the Trustee of the Scheme who is required under the Pensions Act 2004 to prepare a statement of investment principles. The defined benefit pension schemes expose the Santander UK group to risks such as investment risk, interest rate risk, longevity risk and inflation risk. The Santander UK group does not hold any insurance policies over the defined benefit pension schemes and has not entered into any significant transactions with them. Formal actuarial valuations of the assets and liabilities of the defined benefit schemes are carried out on at least a triennial basis by independent professionally qualified actuaries and valued for accounting purposes at each balance sheet date. The Scheme Trustee is responsible for the actuarial valuations and in doing so considers, or relies in part on, a report of a third-party expert. The latest formal actuarial valuation for the Scheme at 31 March 2019 was finalised in August 2019, with a deficit to be funded of £1,136m. The next scheduled triennial funding valuation will be at 31 March 2022. Any funding surpluses can be recovered by Santander UK plc from the Scheme through refunds as the Scheme is run off over time or could be used to pay for the cost of benefits which are accruing. The total amount charged to the income statement was as follows: Group 2021 2020 2019 £m £m £m Net interest income (5) (10) (24) Current service cost 38 36 34 Past service and GMP costs — 1 1 Past service curtailment costs 5 — — Administration costs 8 8 8 46 35 19 On 26 October 2018, the High Court handed down a judgement concluding that defined benefit schemes should equalise pension benefits for men and women in relation to GMP and concluded on the methods that were appropriate. The estimated increase in liabilities at the date of the judgement was £40m and was based on a number of assumptions and the actual impact may be different. This was reflected in the income statement and in the closing net accounting surplus of the Scheme in 2018. The allowance included in the Scheme liabilities at 31 December 2021 decreased by £5m (2020: £5m, 2019: £5m ) to £45m (2020: £50m, 2019 : £45m) to reflect the latest assumptions. This change was recognised in other comprehensive income. Work is being undertaken by the Trustee to implement GMP equalisation. On 20 November 2020, a further court ruling on the GMP equalisation case took place on the issue of whether or not there is an obligation to equalise transfers that occurred prior to October 2018. It was concluded that historic transfers should be equalised. The potential additional liability was estimated and was not material. As a result, no additional liability has been recognised. Past service curtailment costs of £5m were recognised in 2021 in connection with redundancies arising from branch closures and rationalisation of office sites. The amounts recognised in other comprehensive income were as follows: Group 2021 2020 2019 £m £m £m Return on plan assets (excluding amounts included in net interest expense) (452) (1,328) (873) Actuarial (gains)/losses arising from changes in demographic assumptions (17) 34 42 Actuarial gains arising from experience adjustments (19) (141) (40) Actuarial (gains)/losses arising from changes in financial assumptions (775) 1,940 1,394 Pension remeasurement (1,263) 505 523 Movements in the present value of defined benefit scheme obligations were as follows: Group 2021 2020 £m £m At 1 January (13,894) (12,165) Current service cost paid by Santander UK plc (29) (24) Current service cost paid by other subsidiaries (9) (12) Interest cost (188) (253) Employer salary sacrifice contributions (9) (2) Past service cost — (1) Past service curtailment costs (5) — Remeasurement due to actuarial movements arising from: – Changes in demographic assumptions 17 (34) – Experience adjustments 19 141 – Changes in financial assumptions 775 (1,940) Benefits paid 398 396 Derecognition of pension scheme liabilities arising from the sale of PSA 41 — At 31 December (12,884) (13,894) Movements in the fair value of the schemes’ assets were as follows: Group 2021 2020 £m £m At 1 January 13,987 12,555 Interest income 193 263 Contributions paid by employer and scheme members 247 245 Administration costs paid (8) (8) Return on plan assets (excluding amounts included in net interest expense) 452 1,328 Benefits paid (398) (396) Derecognition of pension scheme assets arising from the sale of PSA (53) — At 31 December 14,420 13,987 The composition and fair value of the schemes’ assets by category was: Group Quoted prices in active markets Prices not quoted in active markets Total Valuation 2021 £m % £m % £m % Technique UK equities 38 — — — 38 — A Overseas equities 1,401 10 1,065 7 2,466 17 A,C Corporate bonds 1,607 11 312 2 1,919 13 A,C Government fixed interest bonds 2,788 19 — — 2,788 19 A Government index-linked bonds 9,159 64 — — 9,159 64 A Property — — 1,409 10 1,409 10 B Derivatives — — (83) (1) (83) (1) A Cash — — 2,290 16 2,290 16 A Repurchase agreements (1) — — (6,582) (45) (6,582) (45) A Infrastructure — — 390 3 390 3 B,C Annuities — — 298 2 298 2 D Longevity swap — — (8) — (8) — D Other — — 336 2 336 2 C 14,993 104 (573) (4) 14,420 100 2020 UK equities 40 — — — 40 — A Overseas equities 1,271 9 1,004 7 2,275 16 A,C Corporate bonds 1,121 8 457 3 1,578 11 A,C Government fixed interest bonds 1,618 12 — — 1,618 12 A Government index-linked bonds 6,695 48 — — 6,695 48 A Property — — 1,454 10 1,454 10 B Derivatives — — 312 2 312 2 A Cash — — 1,161 8 1,161 8 A Repurchase agreements (1) — — (2,198) (15) (2,198) (15) A Infrastructure — — 406 3 406 3 B,C Annuities — — 317 2 317 2 D Longevity swap — — — — — — D Other — — 329 3 329 3 C 10,745 77 3,242 23 13,987 100 (1) Sale and repurchase agreements net of purchase and resale agreements. Valuation techniques At a high level, the main methods for measuring the fair value of the Scheme’s assets at 31 December 2021 and 2020 are set out below. A. The asset valuation is provided by the asset manager. The valuation is based on observable market data, and where relevant is typically based on bid price values, or the single price if only one price is available. B. The underlying asset valuations are prepared by an independent expert, adjusted for any cash movements where necessary since the latest valuation. C. Assets are valued by reference to the latest manager statements provided by the managers, adjusted for any cash movements since the latest valuation. D. Assets relating to insured liabilities are valued by the actuaries based on our year-end accounting assumptions. The ‘Other’ category includes hedge fund investments. At 31 December 2021, the value of the insured annuities included the value of a pensioner buy-in that was entered into on 27 May 2020 by the Trustee with an insurance company. This transaction insured 100% of the SMA section pensioner liabilities and 50% of the SPI section pensioner liabilities based on membership in the Scheme at 31 December 2018. In March 2021, the Trustee entered into a longevity swap. Approximately 85% of pensioner liabilities were covered by the longevity swap at inception. The value of the swap at 31 December 2021 was a liability of £8m. At 31 December 2021, as highlighted above the Scheme was invested in certain assets who values are not based on market observable data, such as the investments in unquoted equities and bonds, as well as property, infrastructure and hedge funds. The valuation of these assets relies on unobservable data as these assets do not have a readily available quoted price in an active market. A large proportion of the property is directly held and valued using a bespoke valuation method taking both the nature of the properties and the tenancy schedules as inputs to derive the fair value. Where there is a time lag between the net asset value and the balance sheet date, management adjusts the value of the assets for any cash movements. Due diligence has been conducted to ensure the values obtained in respect of these assets are appropriate and represent fair value. Given the nature of these investments, we are unable to prepare sensitivities on how their values could vary as market conditions or other variables change. A strategy is in place to manage interest rate and inflation risk relating to the liabilities. In H1 2021, the level of interest rate and inflation rate hedging was increased. The Scheme also has in place an equity collar to manage equity risk and hedges a proportion of its foreign exchange exposure to manage currency risk. At 31 December 2021 the equity collar had a notional value of £1,259m (2020: £1,076m) and the currency forwards had a notional value of £2,296m (2020: £2,378m). Some asset de-risking took place in 2021, with disinvestments made from listed equities. Significant investments were made in quoted corporate bonds over the year, funded from the government bond portfolio and listed equities. The Trustee has established the Sustainability Committee which is responsible for overseeing the Scheme’s policies, regulatory obligations and priorities in respect of climate change and wider Environmental, Social and Governance (ESG) related matters. This includes the monitoring of climate change related risks and opportunities, scenario analysis and monitoring of investments from an ESG perspective. The Santander UK group’s pension schemes did not directly hold any equity securities of the Company or any of its related parties at 31 December 2021 and 2020. The Santander UK group’s pension scheme assets do not include any property or other assets that are occupied or used by the Santander UK group. The Santander UK group's employee pension funds recognise the magnitude of the challenges that climate and energy transition pose to governments, companies and civil society. They are also aware of their impact on the ability to comply with their fiduciary duty providing long-term risk-adjusted returns to their members. They have therefore initiated the necessary actions to consider employee pension plans targets of net zero, showing their full support for the Santander UK group's vision, commitment to sustainability and climate change. Funding In August 2019, in compliance with the Pensions Act 2004, the Trustee and the Santander UK group agreed to a new recovery plan in respect of the Scheme and schedule of contributions following the finalisation of the 31 March 2019 actuarial valuation. The funding target for this actuarial valuation is for the Scheme to have sufficient assets to make payments to members in respect of the accrued benefits as and when they fall due. In accordance with the terms of the Trustee agreement in place at the time, the Santander UK group contributed £241m in 2021 (2020: £236m) to the Scheme, of which £194m (2020: £187m) was in respect of agreed deficit repair contributions. The agreed schedule of the Santander UK group’s remaining contributions to the Scheme broadly comprises contributions of £187m each year from 30 September 2019 to 31 March 2026. In addition, the Santander UK group has agreed to pay further contingent contributions should the funding position have fallen behind plan, and to date these have been paid into the Group section from 1 July 2021 onwards at a level of £1m per month. The Santander UK group also meets Scheme administration expenses. The funding valuation is used to judge the amount of cash contributions the Santander UK group needs to put into the pension scheme. It will always be different to the IAS 19 accounting deficit, which is an accounting rule concerning employee benefits and shown on the balance sheet of our financial statements. Actuarial assumptions The principal actuarial assumptions used for the defined benefit schemes were: Group 2021 2020 2019 % % % To determine benefit obligations (1) : – Discount rate for scheme liabilities 1.9 1.3 2.1 – General price inflation 3.4 3.0 3.0 – General salary increase 1.0 1.0 1.0 – Expected rate of pension increase 3.2 2.9 2.9 Years Years Years Longevity at 60 for current pensioners, on the valuation date: – Males 27.5 27.5 27.3 – Females 30.1 30.0 29.8 Longevity at 60 for future pensioners currently aged 40, on the valuation date: – Males 29.0 29.0 28.9 – Females 31.6 31.5 31.3 (1) The discount rate and inflation related assumptions set out in the table at 31 December 2021 reflect the assumptions calculated based on the Scheme’s duration and cash flow profile as a whole. The actual assumptions used were determined for each section independently based on each section’s duration and cash flow profile. At 30 September 2021, changes were made to the assumptions to reflect management’s current views. This included refinements to the inflation assumptions, and a move to section specific financial assumptions to better reflect each individual section’s duration and cash flow profile. The mortality assumption was also refined to reflect the latest 2020 projections model from the Continuous Mortality Investigation (CMI). The overall impact of these changes was small with the majority of the liability movement being due to changes in market conditions. Discount rate for scheme liabilities The rate used to discount the retirement benefit obligation for accounting purposes is based on the annual yield at the balance sheet date of high-quality corporate bonds on that date. There are only a limited number of higher quality Sterling-denominated corporate bonds, particularly those that are longer-dated. Therefore, in order to set a suitable discount rate, we need to construct a corporate bond yield curve. The model which we use for constructing the curve uses corporate bond data but excludes most convertible and asset-backed bonds. The curve is then constructed from this data by extrapolating the horizontal forward curve from 30 years , with the level of this forward rate being the average of the fitted forward rates over the 15 to 30 years year range. When considering an appropriate assumption, we project forward the expected cash flows of the Scheme and adopt a single equivalent cash flow weighted discount rate, subject to management judgement. In 2021, a review of the assumptions was carried out. We moved to using section specific discount rates, derived using the same methodology as before when calculating the discount rate for the Scheme, but based on the cash flows for each section. General price inflation Consistent with our discount rate methodology, we set the inflation assumption using the expected cash flows of the Scheme, fitting them to an inflation curve to give a weighted average inflation assumption. We then deduct an inflation risk premium to reflect the compensation holders of fixed rate instruments expect to receive for taking on the inflation risk. This premium is subject to a cap, to better reflect management’s view of inflation expectations. In 2020, management amended the general price inflation assumptions to reflect the expectation that the Retail Price Index would be brought in line with the Consumer Price Index from 2030. At 31 December 2020, this change increased the liabilities of the Scheme by £64m . In 2021, a review of the assumptions was carried out, and similar to the discount rate we moved to using section specific inflation rates, derived using the same methodology as before, but based on the cash flows for each section. General salary increase From 1 March 2015, a cap on pensionable pay increases of 1% each year was applied to staff in the Scheme. Expected rate of pension increase The pension increase assumption methodology uses a stochastic model, which is calibrated to consider both the observed historical volatility term structure and derivative pricing. The model allows for the likelihood that high or low inflation in one-year feeds into inflation remaining high or low in the next year. Mortality assumptions The mortality assumptions are based on an independent analysis of the Scheme’s actual mortality experience, carried out as part of the triennial actuarial valuation, together with recent evidence from the Continuous Mortality Investigation. An allowance is then made for expected future improvements to life expectancy based on the Continuous Mortality Investigation Tables. Following this review the S3 Medium all pensioner mortality table was adopted with appropriate adjustments to reflect the actual mortality experience. For future improvements, at 31 December 2021 the CMI 2020 projection model was adopted, with model parameters selected having had regard to the Scheme’s membership profile with an initial addition to improvements of 0.15% per annum, together with a long-term rate of future improvements to life expectancy of 1.25% for male and female members. No weight was placed on the 2020 data in the model, reflecting the uncertainty regarding whether, and how much, 2020 mortality data reflects likely future experience. Both the mortality table and the projection model are published by the Continuous Mortality Investigation. In 2019, the methodology for setting the demographic assumptions was changed to better represent current expectations, following a review carried out by the Trustee as part of the 2019 triennial valuation and a separate review conducted on early retirement experience. These reviews resulted in changes in the assumptions for commutation, family statistics and early retirement, which were retained at 31 December 2021. Actuarial assumption sensitivities The sensitivity analyses below have been determined based on reasonably possible changes of the respective assumptions occurring at the end of the reporting period, while holding all other assumptions constant. (Decrease)/increase Change in pension obligation at period end from 2021 2020 Assumption £m £m Discount rate 25 bps increase (571) (662) General price inflation (1) 25 bps increase 392 480 Mortality Each additional year of longevity assumed 478 515 (1) The general price inflation sensitivity of £365m at 31 December 2020 has been restated to correct an administrative error. The correction does not impact the actual reported values. The 25 bps sensitivity to the inflation assumption includes the corresponding impact of changes in future pension increase assumptions before and after retirement. The sensitivity analysis presented above may not be representative of the actual change in the defined benefit obligation as it is unlikely that the changes in assumptions would occur in isolation of one another as some of the assumptions may be correlated. Furthermore, in presenting the sensitivity analysis, the present value of the defined benefit obligation has been calculated using the projected unit credit method at the end of the reporting period, which is the same method used to calculate the defined benefit obligation recognised in the balance sheet. There were no changes in the methods and assumptions used in preparing the sensitivity analyses from prior years. The benefits expected to be paid in each of the next five years, and in the aggregate for the five years thereafter are: Year ending 31 December £m 2022 387 2023 335 2024 356 2025 381 2026 401 Five years ending 2031 2,240 The average duration of the defined benefit obligation at 31 December 2021 was 18.3 years (2020: 19.4 years). Covid-19 While Covid-19 resulted in some volatility in the IAS 19 position, there was recovery over 2021. Actions taken in 2021 to increase hedging and reduce asset risk, in line with the agreements already in place with the Trustee, served to improve the Scheme’s resilience to market volatility. The Santander UK group has collaborated with the Trustee to ensure the delivery of key functions and services could be maintained throughout the Covid-19 pandemic, to include most vitally the payment of pensions to members. At the start of the Covid-19 pandemic, an enhanced risk monitoring framework was also established to identify and monitor such risks and ensure they were adequately managed.

Contingent Liabilities and Comm

Contingent Liabilities and Commitments	12 Months Ended
	Dec. 31, 2021
Disclosure of contingent liabilities [abstract]
Contingent Liabilities and Commitments	31. CONTINGENT LIABILITIES AND COMMITMENTS Group 2021 2020 £m £m Guarantees given to third parties 363 939 Formal standby facilities, credit lines and other commitments 37,385 42,231 37,748 43,170 Capital support arrangements At 31 December 2021 Santander UK plc, Cater Allen Limited and certain other non-regulated subsidiaries of Santander UK plc were party to a capital support deed dated 13 November 2018 (the RFB Sub-Group Capital Support Deed). These parties were permitted by the PRA to form a core UK group as defined in the PRA Rulebook, a permission which expired on 31st December 2021. Exposures of each of the regulated entities to other members of the core UK group were exempt from large exposure limits that would otherwise apply and these exposures were risk-weighted at 0%. The purpose of the RFB Sub-Group Capital Support Deed was to facilitate the prompt transfer of available capital resources from, or repayment of liabilities by, the non-regulated parties to any of the regulated parties in the event that one of the regulated parties breached or was at risk of breaching its capital resources or risk concentrations requirements. A new RFB Sub-Group Capital Support Deed was entered into on 17 December 2021 and effective from 1 January 2022. This reflected the latest version of associated regulation and the addition of two further Santander UK plc subsidiaries including Santander ISA Managers Limited, an entity regulated by the FCA. The parties to the new RFB Sub-Group Capital Support Deed were granted a new permission by the PRA to form a core UK group from 1 January 2022 to 31 December 2024, following expiry of the previous core UK group permission on 31 December 2021. Where applicable this new permission also provides for intra-group exposures to be excluded from the leverage exposure measure. At 31 December 2021 Santander UK Group Holdings plc and Santander Financial Services plc, the regulated entities, and Santander Equity Investments Limited were party to a capital support deed dated 13 November 2018 (the Non-RFB Capital Support Deed). These parties were permitted by the PRA to form a core UK group as defined in the PRA Rulebook, a permission which expired on 31 December 2021. Exposures of each of the regulated entities to other members of the core UK group were exempt from large exposure limits that would otherwise apply and these exposures were risk-weighted at 0%. The purpose of the NRFB Capital Support Deed was to facilitate the prompt transfer of available capital resources from, or repayment of liabilities by, the non-regulated parties to any of the regulated parties in the event that one of the regulated parties breached or was at risk of breaching its capital resources or risk concentrations requirements. Santander UK Group Holdings plc became a PRA-regulated firm from 12 December 2021. A new NRFB Capital Support Deed was entered into on 17 December 2021 and effective from 1 January 2022, reflecting the latest version of associated regulation. The parties to the new NRFB Capital Support Deed remained unchanged and were granted a new permission by the PRA to form a core UK group from 1 January 2022 to 31 December 2024, following expiry of the previous core UK group permission on 31 December 2021. Liquidity support arrangements We monitor and manage liquidity risk for the Santander UK plc group and Santander Financial Services plc separately. Under this model, and the PRA’s liquidity rules, Santander UK plc and its subsidiary Cater Allen Limited form the RFB Domestic Liquidity Sub-group (the RFB DoLSub), which allows the entities to collectively meet regulatory requirements for the purpose of managing liquidity risk. Each member of the RFB DoLSub will support the other by transferring surplus liquidity in times of stress. Guarantees given to third parties Guarantees given to third parties consist primarily of letters of credit, bonds and guarantees granted as part of normal product facilities which are offered to customers. Formal standby facilities, credit lines and other commitments Standby facilities, credit lines and other commitments are also granted as part of normal product facilities which are offered to customers. Retail facilities comprise undrawn facilities granted on flexible mortgages, bank overdrafts and credit cards. On flexible mortgages, the credit limit is set at the point of granting the loan through property value and affordability assessments. Ongoing assessments are made to ensure that credit limits remain appropriate considering any change in the security value or the customer’s financial circumstances. For unsecured overdraft facilities and credit cards, the facilities are granted based on new business risk assessment and are reviewed more frequently based on internal, as well as external data. The delinquency status of the account would result in the withdrawal of the facility. Corporate facilities can comprise standby and revolving facilities which are subject to ongoing compliance with covenants and may require the provision of agreed security. Failure to comply with these terms can result in the withdrawal of the unutilised facility headroom. FSCS The FSCS is the UK’s independent statutory compensation fund for customers of authorised financial services firms and pays compensation if a firm is unable to pay certain claims against it. The FSCS is funded by levies on the industry (and recoveries and borrowings where appropriate). Loan representations and warranties In connection with the securitisations and covered bond transactions described in Note 14, the Santander UK group entities selling the relevant loans into the applicable securitisation or covered bond portfolios make representations and warranties with respect to such loans, in each case as of the date of the sale of the loans into the applicable portfolio. These representations and warranties cover, among other things, the ownership of the loan by the relevant Santander UK group entity, absence of a material breach or default by the relevant borrower under the loan, the loan’s compliance with applicable laws and absence of material disputes with respect to the relevant borrower, asset and loan. The specific representations and warranties made by Santander UK group companies which act as sellers of loans in these securitisations and covered bond transactions depend in each case on the nature of the transaction and the requirements of the transaction structure. In addition, market conditions and credit rating agency requirements may affect the representations and warranties required of the relevant Santander UK group companies in these transactions. In the event that there is a material breach of the representations and warranties given by Santander UK plc as seller of loans under the residential mortgage-backed securitisations or the covered bond programmes included in Note 14, or if such representations and warranties prove to be materially untrue at the date when they were given (being the sale date of the relevant mortgage loans), Santander UK plc may be required to repurchase the affected mortgage loans (generally at their outstanding principal balance plus accrued interest). These securitisations and covered bond programmes are collateralised by prime residential mortgage loans. Santander UK plc is principally a retail prime lender and has no appetite or product offering for any type of sub-prime business. In addition, Santander UK plc’s credit policy explicitly prohibits such lending. Similarly, under the auto loan securitisations in Note 14, in the event that there is a breach or inaccuracy in respect of a representation or warranty relating to the loans, the relevant Santander UK group entity who sold the auto loans into the securitisation portfolio will be required to repurchase such loans from the structure (also at their outstanding principal balance plus accrued interest). In addition to breaches of representation and warranties, under the auto loan securitisations, the seller may also have a repurchase obligation if certain portfolio limits are breached (which include, amongst other things, limits as to the size of a loan given to an individual customer, LTV ratio, average term to maturity and average seasoning). In the case of a repurchase of a loan from the relevant securitisation or covered bond programmes, the Santander UK group may bear any subsequent credit loss on such loan. The Santander UK group manages and monitors its securitisation and covered bond activities closely to minimise potential claims. Other legal actions and regulatory matters Santander UK engages in discussion, and co-operates, with the FCA, PRA, CMA and other regulators and government agencies in various jurisdictions in their supervision and review of Santander UK including reviews exercised under statutory powers, regarding its interaction with past and present customers, both as part of general thematic work and in relation to specific products, services and activities. During the ordinary course of business, Santander UK is also subject to complaints and threatened legal proceedings brought by or on behalf of current or former employees, customers, investors or other third parties, in addition to legal and regulatory reviews, challenges and tax or enforcement investigations or proceedings in various jurisdictions. All such matters are assessed periodically to determine the likelihood of Santander UK incurring a liability. In those instances where it is concluded that it is not yet probable that a quantifiable payment will be made, for example because the facts are unclear or further time is required to fully assess the merits of the case or to reasonably quantify the expected payment, no provision is made. In addition, where it is not currently practicable to estimate the possible financial effect of these matters, no provision is made. Payment Protection Insurance In relation to a specific PPI portfolio of complaints, a legal dispute regarding allocation of liability remains in its early stages. The dispute relates to the liability for PPI mis-selling complaints relating to pre-2005 PPI policies underwritten by AXA France IARD and AXA France Vie (together, AXA France - previously Financial Insurance Company Ltd and Financial Assurance Company Ltd respectively) and involves Santander Cards UK Limited (a former GE Capital Corporation entity and distributor of pre-2005 PPI known as GE Capital Bank Limited which was acquired by Banco Santander SA in 2008 and subsequently transferred to Santander UK plc) and a Banco Santander SA subsidiary Santander Insurance Services UK Limited (together the Santander Entities). During the relevant period, AXA France were owned by Genworth Financial International Holdings, Inc (Genworth). ###### In September 2015 AXA S.A. acquired AXA France from Genworth. In July 2017, the Santander Entities notified AXA France that they did not accept liability for losses on PPI policies relating to this period. Santander UK plc entered into a Complaints Handling Agreement (CHA) with AXA France pursuant to which it agreed to handle complaints on their behalf, and AXA France agreed to pay redress assessed to be due to relevant policyholders on a without prejudice basis. A standstill agreement was entered into between the Santander Entities and AXA France as a condition of the CHA. In July 2020, Genworth announced that it had agreed to pay AXA circa £624m in respect of PPI mis-selling losses in settlement of the related dispute concerning obligations under the sale and purchase agreement pursuant to which Genworth sold AXA France to AXA. The CHA between Santander UK plc and AXA France terminated on 26 December 2020. On 30 December 2020, AXA France provided written notice to the Santander Entities to terminate the standstill agreement. During 2021, AXA France commenced litigation against the Santander Entities seeking recovery of £636m and any further losses relating to pre-2005 PPI. The Santander Entities acknowledged service indicating their intention to defend the claim in full and have issued an application for AXA France’s claim to be struck out/summarily dismissed, which is being heard by the Commercial Court in February 2022. This dispute remains at an early stage and there are ongoing factual issues to be resolved which may have legal consequences including in relation to liability. These issues create uncertainties which mean that it is difficult to reliably predict the outcome or the timing of the resolution of the matter. The Litigation and other regulatory provision in Note 29 includes our best estimate of the Santander Entities’ liability to the specific portfolio. Further information has not been provided on the basis that it would be seriously prejudicial to the Santander Entities’ interests in connection with the dispute. In addition, and in relation to PPI more generally the Litigation and other regulatory provision includes an amount relating to litigation challenging the FCA’s industry guidance on the treatment of Plevin / recurring non-disclosure assessments. This provision is based on current stock levels, future projected claims, and average redress. There remains a risk that volumes received in future may be higher than forecast. The provision in Note 29 includes our best estimate of Santander UK’s liability for the specific issue. The actual cost of customer compensation could differ from the amount provided. German dividend tax arbitrage transactions In June 2018 the Cologne Criminal Prosecution Office and the German Federal Tax Office commenced an investigation in relation to the historical involvement of Santander UK plc, Santander Financial Services plc and Cater Allen International Limited (all subsidiaries of Santander UK Group Holdings plc) in German dividend tax arbitrage transactions (known as cum/ex transactions). These transactions allegedly exploited a loophole of a specific German settlement mechanism through short-selling and complex derivative structuring which resulted in the German government either refunding withholding tax where such tax had not been paid or refunding it more than once. The German authorities are investigating numerous institutions and individuals in connection with alleged transactions and practices which may be found to be illegal under German law. During 2021 we continued to cooperate with the German authorities and, with the assistance of external experts, to progress an internal investigation into the matters in question. From Santander UK plc’s perspective, the investigation is focused principally on the period 2009-2011 and remains on-going. There remain factual issues to be resolved which may have legal consequences including potentially material financial penalties. These issues create uncertainties which mean that it is difficult to predict the resolution of the matter including timing or the significance of the possible impact. Consumer credit The Santander UK group’s unsecured lending and other consumer credit business is governed by consumer credit law and related regulations, including the CCA. Claims brought by customers in relation to these requirements, including potential breaches, could result in costs to the Santander UK group where such potential breaches are not found to be de minimis. The CCA includes very detailed and prescriptive requirements for lenders, including in relation to post contractual data. Customer remediation provisions include an amount of £6m (2020: £47m ) arising from a systems-related historical issue identified by Santander UK, relating to compliance with certain requirements of the CCA. This provision has been based on detailed reviews of relevant systems related to consumer credit business operations, supported by external legal and regulatory advice. The Customer remediation provision in Note 29 includes our best estimate of Santander UK’s liability for the specific issue. The actual cost of customer compensation could differ from the amount provided. It is not practicable to provide an estimate of the risk and amount of any further financial impact. FCA civil regulatory investigation into Santander UK plc financial crime systems and controls, and compliance with the Money Laundering Regulations 2007 In 2021, Santander UK plc continued to cooperate with an FCA civil regulatory investigation which commenced in July 2017 into our compliance with the Money Laundering Regulations 2007 and potential breaches of FCA principles and rules relating to anti-money laundering and financial crime systems and controls. The FCA’s investigation focuses primarily on the period 2012 to 2017 and includes consideration of high-risk customers including Money Service Bureaus. It is not currently possible to make a reliable assessment of any liability resulting from the investigation including any financial penalty. Taxation The Santander UK group engages in discussion, and co-operates, with HM Revenue & Customs (HMRC) in their oversight of the Santander UK group’s tax matters. The Santander UK group adopted the UK’s Code of Practice on Taxation for Banks in 2010. Certain leases in which the Santander UK group is or was the lessor have been under review by HMRC in connection with claims for tax allowances. Under the terms of the lease agreements, the Santander UK group is fully indemnified in all material respects by the respective lessees for any liability arising from the disallowance of tax allowances plus accrued interest. During 2021, an outline agreement in principle in respect of a number of these lease arrangements was reached directly between the lessee and HMRC. It is anticipated that this agreement will be executed in H1 2022 which would result in a final payment by the lessee to HMRC in the region of £50m and conclude the review by HMRC. There is the possibility that the Santander UK Group would need to make the payment to HMRC and reclaim this from the lessee under the indemnity arrangements. Certain other lease arrangements, where the tax liabilities are considered immaterial, remain under review. Whilst legal opinions have been obtained to support the Santander UK group’s position, the matter remains uncertain pending formal resolution with HMRC and any subsequent litigation. These matters moved to formal litigation in 2017, as required under the terms of the leases, and it is currently anticipated that hearings will be held at the First Tier Tax Tribunal in 2022. Other On 2 November 2015, Visa Europe Ltd agreed to sell 100% of its share capital to Visa Inc. The deal closed on 21 June 2016. As a member and shareholder of Visa Europe Ltd, Santander UK received upfront consideration made up of cash and convertible preferred stock. Conversion of the preferred stock into Class A Common Stock of Visa Inc. depends on the outcome of litigation against Visa involving UK & Ireland (UK&I) multilateral interchange fees (MIFs). Following ring-fencing, all Visa stock is now held by Santander Equity Investments Limited (SEIL), outside the ring fenced bank. In valuing the preferred stock, SEIL makes adjustments for illiquidity and the potential for changes in conversion rate due to litigation costs. In June 2020, the Supreme Court issued a judgement finding that MIFs restricted competition. In 2020, this resulted in a change to the calculation of the fair value adjustments, which reduced the fair value of the convertible preferred stock by £10m. There has not been any further change to the calculation of the fair value adjustment in 2021. In September 2020, pursuant to the scheduled release assessment, Visa released half of the value of the convertible preferred stock. As a result of this release, SEIL was issued with 5,211 units of Series A Convertible Participating Preferred Stock (Series A Preferred Stock). In 2021, SEIL sold al l 5,211 units of Series A Preferred Stock for £82m . In addition, Santander UK and certain other UK&I banks have agreed to indemnify Visa Inc. in the event that the preferred stock is insufficient to meet the costs of this litigation. Visa Inc. has recourse to this indemnity once more than €1bn of losses relating to UK&I MIFs have arisen or once the total value of the preferred stock issued to UK&I banks on closing has been reduced to nil . Whilst Santander UK's liability under this indemnity is capped at €39.85m , Visa Inc. may have recourse to a general indemnity in place under Visa Europe Operating Regulations for damages not satisfied through the above mechanism. At this stage, it is unclear whether the litigation will give rise to more than €1bn of losses relating to UK&I MIFs which means it is difficult to predict the resolution of the matter including the timing or the significance of the possible impact. As part of the sale of subsidiaries, businesses and other entities, and as is normal in such circumstances, entities within the Santander UK group have given warranties and indemnities to the purchasers. Obligations under stock borrowing and lending agreements Obligations under stock borrowing and lending agreements represent contractual commitments to return stock borrowed. These obligations are offset by a contractual right to receive stock under other contractual agreements. See Note 36. Other off-balance sheet commitments The Santander UK group has commitments to lend at fixed interest rates which expose us to interest rate risk. For more, see the Risk review.

Share Capital

Share Capital	12 Months Ended
	Dec. 31, 2021
Disclosure of classes of share capital [abstract]
Share Capital	32. SHARE CAPITAL Group Ordinary shares Issued and fully paid share capital No. £m At 31 December 2020, 1 January 2021 and 31 December 2021 7,060,000,000 7,060

Other Equity Instruments

Other Equity Instruments	12 Months Ended
	Dec. 31, 2021
Disclosure of classes of share capital [abstract]
Other Equity Instruments	33. OTHER EQUITY INSTRUMENTS Group Interest rate 2021 2020 % Next call date £m £m AT1 securities: - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 6.75 June 2024 496 496 - £750m Fixed Rate Reset Perpetual AT1 Capital Securities 7.375 June 2022 745 745 - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 5.33 n/a — 500 - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 6.30 March 2025 500 500 - £450m Fixed Rate Reset Perpetual AT1 Capital Securities 4.25 March 2026 450 — 2,191 2,241 AT1 securities The AT1 securities are perpetual and pay a distribution on 24 March, June, September and December. At each distribution payment date, the Company can decide whether to pay the distribution, which is non-cumulative, in whole or in part. The distribution rate resets every five years. The securities will be automatically written down and the investors will lose their entire investment in the securities should the CET1 capital ratio of the Santander UK prudential consolidation group fall below 7%. They are redeemable at the option of the Company on their first call date or on any reset date thereafter in the cases of the 6.75% and 7.375% Fixed Rate Reset Perpetual AT1 Capital Securities, and on any distribution payment date thereafter in the case of the 6.30% Fixed Rate Reset Perpetual AT1 Capital Securities and on any day falling in the period commencing on (and including) 24 March 2026 and ending on (and including) the First Reset Date; or on any Distribution Payment Date subsequent to the First Reset Date, in the case of the 4.25% Fixed Rate Reset Perpetual AT1 Capital Securities . N o such redemption may be made without the consent of the PRA. The £450m 4.25% Fixed Rate Reset Perpetual AT1 Capital Securities and the £500m 6.30% Fixed Rate Reset Perpetual AT1 Capital Securities were fully subscribed by the Company’s immediate parent company, Banco Santander SA. £100m of the £750m 7.375% Fixed Rate Reset Perpetual AT1 Capital Securities were subscribed by Banco Santander SA. In March 2021, Santander UK Group Holdings plc purchased and redeemed the £500m 5.33% Fixed Rate Reset Perpetual AT1 Capital Securities and issued £450m 4.25% Fixed Rate Reset Perpetual AT1 Capital Securities, which were fully subscribed by the Company’s immediate parent company, Banco Santander SA.

Non-Controlling Interests

Non-Controlling Interests	12 Months Ended
	Dec. 31, 2021
Disclosure Of Noncontrolling Interests [Abstract]
Non-Controlling Interests	34. NON-CONTROLLING INTERESTS Initial interest rate 2021 2020 % First call date £m £m Santander UK plc issued: – £300m Step-up Callable Perpetual Reserve Capital Instruments 7.037 February 2026 235 235 PSA Finance UK Limited — 162 235 397 Step-up Callable Perpetual Reserve Capital Instruments These instruments are redeemable by Santander UK plc on 14 February 2026 or on any coupon payment date thereafter, subject to the prior approval of the PRA. They are perpetual and pay interest annually. The coupon rate resets every five years, based on the UK five-year benchmark gilt rate. Interest payments may be deferred by Santander UK plc. The instruments are not redeemable at the option of the holders and the holders do not have any rights against other Santander UK group companies. PSA Finance UK Limited PSA Finance UK Limited was the only subsidiary in the Santander UK group that gave rise to significant non-controlling interests. See Note 19 for summarised financial information of PSA Finance UK Limited. On 30 July 2021, Santander UK through Santander Consumer (UK) plc sold its entire 50%

Notes to Cash Flows

Notes to Cash Flows	12 Months Ended
	Dec. 31, 2021
Cash Flows Explanatory Notes [Abstract]
Notes to Cash Flows	35. NOTES TO CASH FLOWS Changes in liabilities arising from financing activities The table below shows the changes in liabilities arising from financing activities. The changes in equity arising from financing activities are set out in the Consolidated Statement of Changes in Equity. Group 2021 2020 Balance sheet line item Balance sheet line item Debt securities in issue Subordinated liabilities Other equity instruments Lease liabilities Dividends paid Total Debt securities in issue Subordinated liabilities Other equity instruments Lease liabilities Dividends paid Total (1) £m £m £m £m £m £m £m £m £m £m £m £m At 1 January 43,679 2,556 2,241 100 — 48,576 50,171 3,528 2,241 138 — 56,078 Proceeds from issue of debt securities 2,847 — — — — 2,847 5,586 — — — — 5,586 Repayment of debt securities (13,724) — — — — (13,724) (12,348) — — — — (12,348) Repayment of subordinated liabilities — (4) — — — (4) — (939) — — — (939) Issue of other equity instruments — — 450 — — 450 — — — — — — Repurchase of other equity instruments — — (500) — — (500) — — — — — — Payment of lease liability — — — (25) — (25) — — — (46) — (46) Dividends paid — — — — (1,506) (1,506) — — — — (282) (282) Liability-related other changes (473) (4) — 59 — (418) (243) (10) — 8 — (245) Non-cash changes: — — – Unrealised foreign exchange (930) 14 — — — (916) 359 (6) — — — 353 – Other changes 181 (334) — — 1,506 1,353 154 (17) — — 282 419 At 31 December 31,580 2,228 2,191 134 — 36,133 43,679 2,556 2,241 100 — 48,576 (1) Restated for 2020 to include changes in liabilities arising from financing activities relating to lease liabilities. In addition, in 2021, there was a disposal of non-controlling interests of £181m . Footnotes to the cash flow For 2021, Principal elements of lease payments are included as a separate line item in the Consolidated Cash Flow Statement. As a result, cash flows of £46m for 2020 (2019: £55m) have been reclassified from 'Other liabilities' within operating activities to 'Principal elements of lease payments' within financing activities. Total cash outflow for leases was £28m (2020: £49m). Net cash flows from operating activities includes interest received of £4,873m (2020: £5,176m, 2019: £5,856m), interest paid of £1,085m (2020: £1,900m, 2019: £2,587m) and dividends received of £nil (2020: £nil, 2019: £nil). Restatements in the cash flow

Assets Charged as Security for

Assets Charged as Security for Liabilities and Collateral Accepted as Security for Assets	12 Months Ended
	Dec. 31, 2021
Disclosure Of Assets Pledged As Security [Abstract]
Assets Charged as Security for Liabilities and Collateral Accepted as Security for Assets	36. ASSETS CHARGED AS SECURITY FOR LIABILITIES AND COLLATERAL ACCEPTED AS SECURITY FOR ASSETS The following transactions are conducted under terms that are usual and customary to collateralised transactions including, where relevant, standard securities lending and repurchase agreements. a) Assets charged as security for liabilities The financial assets below are analysed between those assets accounted for on-balance sheet and off-balance sheet. Group 2021 2020 £m £m On-balance sheet: Cash and balances at central banks 1,580 985 Loans and advances to banks 478 804 Loans and advances to customers – securitisations and covered bonds (See Note 14) 19,432 31,138 Loans and advances to customers – other 41,953 23,690 Other financial assets at amortised cost — 648 Financial assets at fair value through other comprehensive income 4,435 5,677 Total on-balance sheet 67,878 62,942 Total off-balance sheet 14,449 24,701 The Santander UK group provides assets as collateral in the following areas of the business. Sale and repurchase agreements The Santander UK group enters into sale and repurchase agreements and similar transactions of debt securities, which are accounted for as secured borrowings. Upon entering into such transactions, the Santander UK group provides collateral in excess of the borrowed amount. The carrying amount of assets that were so provided at 31 December 2021 was £15,368m (2020: £25,874m), of which £639m (2020: £1,392m) was classified within ‘Loans and advances to customers – securitisations and covered bonds’ in the table above. Securitisations and covered bonds As described in Note 14 to the Consolidated Financial Statements in the 2020 Annual Report, Santander UK plc and certain of its subsidiaries issue securitisations and covered bonds. At 31 December 2021, there were £20,199m (2020: £33,432m) of gross assets in these secured programmes, of which £767m (2020: £2,294m) related to internally retained issuances that were available for use as collateral for liquidity purposes in the future. At 31 December 2021, a total of £1,855m (2020: £4,530m) of notes issued under securitisation and covered bond programmes had been retained internally, a proportion of which had been used as collateral via third party bilateral secured funding transactions, which totalled £500m at 31 December 2021 (2020: £1,114m), or for use as collateral for liquidity purposes in the future. Stock borrowing and lending agreements Asset balances under stock borrowing and lending agreements represent stock lent by the Santander UK group. These balances amounted to £46,007m at 31 December 2021 (2020: £30,135m) and are offset by contractual commitments to return stock borrowed or cash received. Derivatives business In addition to the arrangements described, collateral is also provided in the normal course of derivative business to counterparties. At 31 December 2021 £2,159m (2020: £1,888m) of such collateral in the form of cash had been provided by the Santander UK group and is included in the table. b) Collateral accepted as security for assets The collateral held as security for assets, analysed between those liabilities accounted for on balance sheet and off-balance sheet, was: Group 2021 2020 £m £m On-balance sheet: Deposits by banks 941 2,071 Total on-balance sheet 941 2,071 Total off-balance sheet 18,240 31,043 Purchase and resale agreements The Santander UK group also enters into purchase and resale agreements and similar transactions of debt securities, which are accounted for as collateralised loans. Upon entering into such transactions, the Santander UK group receives collateral in excess of the loan amount. The level of collateral held is monitored daily and if required, further calls are made to ensure the market values of collateral remains at least equal to the loan balance. The subsidiaries are permitted to sell or repledge the collateral held in the absence of default. At 31 December 2021, the fair value of such collateral received was £14,562m (2020: £25,972m). Of the collateral received, almost all was sold or repledged. The subsidiaries have an obligation to return collateral that they have sold or pledged. Stock borrowing and lending agreements Obligations representing contractual commitments to return stock borrowed by the Santander UK group amounted to £3,678m at 31 December 2021 (2020: £5,071m) and are offset by a contractual right to receive stock lent. Derivatives business In addition to the arrangements described, collateral is also received from counterparties in the normal course of derivative business. At 31 December 2021, £941m (2020: £2,071m) of such collateral in the form of cash had been received by the Santander UK group and is included in the table. Lending activities In addition to the collateral held as security for assets, the Santander UK group may obtain a charge over a customer’s property in connection with its lending activities. Details of these arrangements are set out in the ‘Credit risk’ section of the Risk review.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2021
Disclosure of terms and conditions of share-based payment arrangement [abstract]
Share-Based Compensation	37. SHARE-BASED COMPENSATION The Santander UK group operates share schemes and arrangements for eligible employees. The main current schemes are the Sharesave Schemes, the Deferred Shares Bonus Plan, the Partnership Shares scheme and the Transformation Incentive Plan. All the share options and awards relate to shares in Banco Santander SA. The amount charged to the income statement in respect of share-based payment transactions is set out in Note 6. At 31 December 2021, the carrying amount of liabilities arising from share-based payment transactions, excluding any cash element was £3.7m (2020: £0.5m), of which £0.4m had vested at 31 December 2021 (2020: £nil). a) Sharesave Schemes The Santander UK group launched its fourteen HM Revenue & Customs approved Sharesave invitation under Banco Santander SA sponsorship in September 2021. Sharesave invitations have been offered since 2008 under broadly similar terms. Under the Sharesave Scheme’s HMRC-approved savings limits, eligible employees may enter into contracts to save between £5 and £500 per month. For all schemes, at the end of a fixed term of three or five years after the grant date, the employees can use these savings to buy shares in Banco Santander SA at a discount, calculated in accordance with the rules of the scheme. The option price is calculated as the average middle market quoted price of Banco Santander SA shares over the first three dealing days prior to invitation and discounted by up to 20%. This year a 10% discount was applied. The vesting of awards under the scheme depends on continued employment with the Banco Santander SA group. Participants in the scheme have six months from the date of vest to exercise the option. The table below summarises movements in the number of options, and changes in weighted average exercise price over the same period. 2021 2020 Number of options Weighted average exercise price Number of options Weighted average exercise price ‘000 £ ‘000 £ Outstanding at 1 January 21,162 2.32 23,373 3.03 Granted 9,414 2.43 11,642 1.65 Exercised (48) 1.86 (860) 2.75 Forfeited/expired (4,535) 2.95 (12,993) 2.96 Outstanding at 31 December 25,993 2.25 21,162 2.32 Exercisable at 31 December 1,321 2.75 1,805 3.59 The weighted average share price at the date the options were exercised was £2.65 (2020: £2.92). The following table summarises the range of exercise prices and weighted average remaining contractual life of the options at 31 December 2021 and 2020. 2021 2020 Weighted average remaining contractual life Weighted average exercise price Weighted average remaining contractual life Weighted average exercise price Range of exercise prices Years £ Years £ £1 to £2 3 1.65 4 1.65 £2 to £3 3 2.81 2 2.81 £3 to £4 1 3.38 1 3.38 £4 to £5 1 4.02 1 4.02 The fair value of each option at the date of grant is estimated using an analytical model that also reflects the correlation between EUR and GBP. This model uses assumptions on the share price, the EUR/GBP FX rate, the EUR/GBP risk-free interest rate, dividend yields, the expected volatilities of both the underlying shares and EUR/GBP for the expected lives of options granted. The weighted average grant-date fair value of options granted during the year was £0.20 (2020: £0.21). b) Deferred shares bonus plan Deferred bonus awards are designed to align employee performance with shareholder value and encourage increased retention of senior employees. Those employees who are designated as Material Risk Takers receive part of their annual bonus as a deferred award comprising 50% in conditional shares, and 50% in cash. Either 40% (for any variable pay award of less than £500,000) or 60% (for any variable pay award greater than £500,000) is deferred over a four, five or seven year period from the anniversary of the initial award. Deferred bonus awards in shares are subject to an additional one-year retention period from the point of delivery. Any deferred awards are dependent on continued employment and subject to Santander UK's discretion, and the vesting of deferred bonus awards are subject to risk and performance adjustment. c) Partnership Shares scheme A Partnership Shares scheme is operated for eligible employees under the Share Incentive Plan (SIP) umbrella. Participants can choose to invest up to £1,800 per tax year (or no more than 10% of an employee’s salary for the tax year) from pre-tax salary to buy Banco Santander SA shares. Shares are held in trust for the participants. There are no vesting conditions attached to these shares, and no restrictions as to when the shares can be removed from the trust. However, if a participant chooses to sell the shares before the end of five years, they will be liable for the taxable benefit received when the shares are taken out of the trust. The shares can be released from trust after five years free of income tax and national insurance contributions. 3,618,796 shares were outstanding at 31 December 2021 (2020: 3,254,900 shares). d) Transformation Incentive Plan This is a one-off long-term incentive plan which is designed to recognise the achievement of financial targets and an enhanced customer experience, whilst maintaining appropriate conduct controls and risk management, over the course of our transformation period.

Transactions with Directors and

Transactions with Directors and Other Key Management Personnel	12 Months Ended
	Dec. 31, 2021
Disclosure Of Remuneration Of Directors And Other Key Management Personnel [Abstract]
Transactions with Directors and Other Key Management Personnel	38. TRANSACTIONS WITH DIRECTORS AND OTHER KEY MANAGEMENT PERSONNEL The Directors of Santander UK Group Holdings plc did not receive any remuneration in respect of their services to the Company. The remuneration disclosures in these financial statements reflect their remuneration in respect of the Santander UK plc group. a) Remuneration of Directors and Other Key Management Personnel The remuneration of the Directors and Other Key Management Personnel of the Santander UK group is set out in aggregate below. 2021 2020 2019 Directors’ remuneration £ £ £ Salaries and fees 3,835,797 3,906,401 5,045,302 Performance-related payments (1) 5,195,722 748,495 3,896,382 Other fixed remuneration (pension and other allowances & non-cash benefits) 806,103 1,047,986 1,386,439 Expenses 3,705 2,579 42,526 Total remuneration 9,841,327 5,705,461 10,370,649 2021 2020 2019 Directors' and Other Key Management Personnel compensation £ £ £ Short-term employee benefits (2) 23,392,657 17,886,869 23,238,187 Post-employment benefits (3) 913,842 2,107,544 3,674,772 Total compensation 24,306,499 19,994,413 26,912,959 (1) In line with the Code, a proportion of the performance-related payment was deferred. Further details can be found in the Directors Remuneration Report. (2) In addition to the remuneration in the table above, grants of shares in Banco Santander SA were made as buy-outs of deferred performance-related payments of shares in connection with previous employment for one member of Key Management Personnel of £107,225 of which £25,413 vested in the year (2020: two individuals, one to a director of £1,293,678 of which £242,605 vested in the year and one to Key Management Personnel of £924,133 of which £60,500 vested in the year ). (3) No Termination payments were paid in 2021 to key management persons (2020: £nil ; 2019: £1,076,435 for one individual). In 2021, the remuneration, excluding pension contributions, of the highest paid Director, was £4,638,290 (2020: £2,200,138) of which £2,913,000 (2020: £748,495) was performance related. In 2021, the accrued defined benefit pension relating to the highest paid director was £22,119 per annum (2020: £21,309 per annum for the same individual). b) Retirement benefits Defined benefit pension schemes are provided to certain employees. See Note 30 for details of the schemes and the related costs and obligations. One director has a deferred pension benefit accruing under a defined benefit scheme. Ex gratia pensions paid to former Directors of Santander UK plc in 2021, which have been provided for previously, amounted to £370,668 (2020: £366,248; 2019: £335,202). In 1992, the Board decided not to award any new such ex gratia pensions. c) Transactions with Directors, Other Key Management Personnel and each of their connected persons Directors, Other Key Management Personnel (defined as the Executive Committee of Santander UK plc who served during the year) and their connected persons have undertaken the following transactions with the Santander UK group in the ordinary course of business. 2021 2020 No. £000 No. £000 Secured loans, unsecured loans and overdrafts At 1 January 9 1,825 18 4,920 Net movements (5) (1,798) (9) (3,095) At 31 December 4 27 9 1,825 Deposit, bank and instant access accounts and investments At 1 January 16 8,063 32 11,975 Net movements — (1,636) (16) (3,912) At 31 December 16 6,427 16 8,063 In 2021 and 2020, no Director held any interest in the shares of any company in the Santander UK group and no Director exercised or was granted any rights to subscribe for shares in any company in the Santander UK group. In addition, in 2021 and 2020, no Directors exercised share options over shares in Banco Santander SA, the ultimate parent company of the Company. Secured loans, unsecured loans and overdrafts are made to Directors, Other Key Management Personnel and their connected persons, in the ordinary course of business, with terms prevailing for comparable transactions and on the same terms and conditions as applicable to other employees in the Santander UK group. Such loans do not involve more than the normal risk of collectability or present any unfavourable features. Amounts deposited by Directors, Other Key Management Personnel and their connected persons earn interest at the same rates as those offered to the market or on the same terms and conditions applicable to other employees in the Santander UK group. Deposits, bank and instant access accounts and investments are entered into by Directors, Other Key Management Personnel and their connected persons on normal market terms and conditions, or on the same terms and conditions as applicable to other employees in Santander UK group. In 2021, loans were made to two Directors (2020: four Directors), with a principal amount of £15,430 outstanding at 31 December 2021 (2020: £13,994). In 2021, loans were made to two Other Key Management Personnel (2020: five), with a principal amount of £11,678 outstanding at 31 December 2021 (2020: £1,811,171). In 2021 and 2020, there were no other transactions, arrangements or agreements with Santander UK in which Directors, Other Key Management Personnel or their connected persons had a material interest. In addition, in 2021 and 2020, no Director had a material interest in any contract of significance with Santander UK other than a service contract.

Related Party Disclosures

Related Party Disclosures	12 Months Ended
	Dec. 31, 2021
Disclosure of transactions between related parties [abstract]
Related Party Disclosures	39. RELATED PARTY DISCLOSURES a) Parent undertaking and controlling party The Company’s immediate and ultimate parent and controlling party is Banco Santander SA, a company incorporated in Spain. The smallest and largest groups into which the Santander UK group’s results are included are the group accounts of Banco Santander SA , copies of which may be obtained from Shareholder Relations, 2 Triton Square, Regent’s Place, London NW1 3AN. b) Transactions with related parties Transactions with related parties during the year and balances outstanding at the year-end: Group Interest, fees and Interest, fees and Amounts owed by Amounts owed to 2021 2020 2019 2021 2020 2019 2021 2020 2021 2020 £m £m £m £m £m £m £m £m £m £m Ultimate parent (210) (120) (150) 34 158 334 1,049 1,857 (1,392) (2,463) Fellow subsidiaries (47) (54) (58) 151 148 158 20 37 (467) (498) Associates & joint ventures (34) (29) (29) 4 — — 3,075 2,234 (918) (1,034) (291) (203) (237) 189 306 492 4,144 4,128 (2,777) (3,995) For more on this, see ‘Balances with other Banco Santander companies’ in the Risk review. In addition, transactions with pension schemes operated by the Santander UK group are described in Note 30. The above transactions were made in the ordinary course of business, on substantially the same terms as for comparable transactions with third party counterparties, and within limits acceptable to the PRA. Such transactions do not involve more than the normal risk of collectability or present any unfavourable features. In 2020, Santander Consumer (UK) plc (SCUK) purchased a 50% share in a new joint venture, Volvo Car Financial Services UK Limited. In 2021, £390m of dealer lending was transferred from SCUK to the new entity. In 2021, SCUK sold its entire 50% shareholding in PSA Finance UK Limited to PSA Financial Services Spain EFC SA, a joint venture between Santander Consumer Finance SA, a fellow subsidiary of Banco Santander SA, and Banque PSA Finance SA. For more details, see Note 34. In 2021, a significant part of the Corporate & Investment Banking business of Santander UK was transferred to the London branch of Banco Santander SA by way of a Part VII banking business transfer scheme. For more details, see Note 43. In 2021, we sold our current head office site in Triton Square, London to a wholly owned subsidiary of our parent.

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2021
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Abstract]
Financial Instruments	40. FINANCIAL INSTRUMENTS a) Measurement basis of financial assets and liabilities Financial assets and financial liabilities are measured on an ongoing basis either at fair value or at amortised cost. Note 1 describes how the classes of financial instruments are measured, and how income and expenses, including fair value gains and losses, are recognised. b) Fair value measurement and hierarchy (i) Fair value measurement The fair value of financial instruments is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in the principal, or in its absence, the most advantageous market to which Santander UK has access at that date. The fair value of a liability reflects its non-performance risk. Financial instruments valued using observable market prices If a quoted market price in an active market is available for an instrument, the fair value is calculated as the current bid price multiplied by the number of units of the instrument held. Financial instruments valued using a valuation technique In the absence of a quoted market price in an active market, management uses internal models to make its best estimate of the price that the market would set for that financial instrument. In order to make these estimations, various techniques are employed, including extrapolation from observable market data and observation of similar financial instruments with similar characteristics. Wherever possible, valuation parameters for each product are based on prices directly observable in active markets or that can be derived from directly observable market prices. Chosen valuation techniques incorporate all the factors that market participants would take into account in pricing transactions. Santander UK manages certain groups of financial assets and liabilities on the basis of its net exposure to either market risks or credit risk. As a result, it has elected to use the exception under IFRS 13 which permits the fair value measurement of a group of financial assets and financial liabilities on the basis of the price that would be received to sell a net long position for a particular risk exposure or paid to transfer a net short position for a particular risk exposure in an orderly transaction between market participants at the measurement date under current market conditions. (ii) Fair value hierarchy Santander UK applies the following fair value hierarchy that prioritises the inputs to valuation techniques used in measuring fair value. The hierarchy establishes three categories for valuing financial instruments, giving the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. The three categories are: quoted prices in active markets (Level 1), internal models based on observable market data (Level 2) and internal models based on other than observable market data (Level 3). If the inputs used to measure an asset or a liability fall to different levels within the hierarchy, the classification of the entire asset or liability will be based on the lowest level input that is significant to the overall fair value measurement of the asset or liability. Santander UK categorises assets and liabilities measured at fair value within the fair value hierarchy based on the inputs to the valuation techniques as follows: Level 1 Unadjusted quoted prices for identical assets or liabilities in an active market that Santander UK can access at the measurement date. Active markets are assessed by reference to average daily trading volumes in absolute terms and, where applicable, by reference to market capitalisation for the instrument. Level 2 Quoted prices in inactive markets, quoted prices for similar assets or liabilities, recent market transactions, inputs other than quoted market prices for the asset or liability that are observable either directly or indirectly for substantially the full term, and inputs to valuation techniques that are derived principally from or corroborated by observable market data through correlation or other statistical means for substantially the full term of the asset or liability. Level 3 Significant inputs to the pricing or valuation techniques are unobservable. These unobservable inputs reflect the assumptions that market participants would use when pricing assets or liabilities and are considered significant to the overall valuation. Changes in the observability of significant valuation inputs during the reporting period may result in a transfer of assets and liabilities within the fair value hierarchy. The Santander UK group recognises transfers between levels of the fair value hierarchy when there is a significant change in either its principal market or the level of observability of the inputs to the valuation techniques at the end of the reporting period. c) Valuation techniques The main valuation techniques employed in internal models to measure the fair value of the financial instruments at 31 December 2021 and 2020 are set out below. In substantially all cases, the principal inputs into these models are derived from observable market data. Santander UK did not make any material changes to the valuation techniques and internal models it used in 2021, 2020 and 2019. During 2021, Santander UK updated the interest rate market data valuation inputs to reflect the cessation of LIBOR at the end of 2021, using risk-free rates in line with market practice. A In the valuation of financial instruments requiring static hedging (for example interest rate, currency derivatives and property derivatives) and in the valuation of loans and advances and deposits, the ‘present value’ method is used. Expected future cash flows are discounted using the interest rate curves of the applicable currencies or forward house price index levels, as well as credit spreads. The interest rate curves are generally observable market data and reference yield curves derived from quoted interest rates in appropriate time bandings, which match the timings of the cash flows and maturities of the instruments. B In the valuation of equity financial instruments requiring dynamic hedging (principally equity securities, options and other structured instruments), proprietary local volatility and stochastic volatility models are used. These types of models are widely accepted in the financial services industry. Observable market inputs used in these models include the bid-offer spread, foreign currency exchange rates, volatility and correlation between indices. In limited circumstances, other inputs may be used in these models that are based on unobservable market data, such as the Halifax’s UK HPI volatility, HPI forward growth, HPI spot rate, mortality, mean reversion and contingent litigation risk. C In the valuation of financial instruments exposed to interest rate risk that require either static or dynamic hedging (such as interest rate futures, caps and floors, and options), the present value method (futures), Black’s model (caps/floors) and the Hull/White and Markov functional models (Bermudan options) are used. These types of models are widely accepted in the financial services industry. The significant inputs used in these models are observable market data, including appropriate interest rate curves, volatilities, correlations and exchange rates. In limited circumstances, other inputs may be used in these models that are based on unobservable market data, such as HPI volatility, HPI forward growth, HPI spot rate and mortality. D In the valuation of linear instruments such as credit risk and fixed-income derivatives, credit risk is measured using dynamic models similar to those used in the measurement of interest rate risk. In the case of non-linear instruments, if the portfolio is exposed to credit risk such as credit derivatives, the probability of default is determined using the credit default spread market. The main inputs used to determine the underlying cost of credit of credit derivatives are quoted credit risk premiums and the correlation between the quoted credit derivatives of various issuers. The fair values of the financial instruments arising from Santander UK’s internal models take into account, among other things, contract terms and observable market data, which include such factors as bid-offer spread, interest rates, credit risk, exchange rates, the quoted market price of equity securities, volatility and prepayments. In all cases, when it is not possible to derive a valuation for a particular feature of an instrument, management uses judgement to determine the fair value of the particular feature. In exercising this judgement, a variety of tools are used including proxy observable data, historical data and extrapolation techniques. Extrapolation techniques take into account behavioural characteristics of equity markets that have been observed over time, and for which there is a strong case to support an expectation of a continuing trend in the future. Estimates are calibrated to observable market prices when they become available. Santander UK believes its valuation methods are appropriate and consistent with other market participants. Nevertheless, the use of different valuation methods or assumptions, including imprecision in estimating unobservable market inputs, to determine the fair value of certain financial instruments could result in different estimates of fair value at the reporting date and the amount of gain or loss recorded for a particular instrument. Most of the valuation models are not significantly subjective, because they can be tested and, if necessary, recalibrated by the internal calculation of and subsequent comparison to market prices of actively traded securities, where available. d) Control framework Fair values are subject to a control framework designed to ensure that they are either determined or validated by a function independent of the risk-taker. To this end, ultimate responsibility for the determination of fair values lies with the Risk Department. For all financial instruments where fair values are determined by reference to externally quoted prices or observable pricing inputs to models, independent price determination or verification is utilised. In inactive markets, direct observation of a traded price may not be possible. In these circumstances, Santander UK will source alternative market information to validate the financial instrument’s fair value, with greater weight given to information that is considered to be more relevant and reliable. The factors that are considered in this regard include: – The extent to which prices may be expected to represent genuine traded or tradeable prices – The degree of similarity between financial instruments – The degree of consistency between different sources – The process followed by the pricing provider to derive the data – The elapsed time between the date to which the market data relates and the balance sheet date – The manner in which the data was sourced. The source of pricing data is considered as part of the process that determines the classification of the level of a financial instrument. Consideration is given to the quality of the information available that provides the current mark-to-model valuation and estimates of how different these valuations could be on an actual trade, taking into consideration how active the market is. For spot assets that cannot be sold due to illiquidity, forward estimates are discounted to estimate a realisable value over time. Adjustments for illiquid positions are regularly reviewed to reflect changing market conditions. For fair values determined using a valuation model, the control framework may include, as applicable, independent development and / or validation of: (i) the logic within the models; (ii) the inputs to those models; and (iii) any adjustments required outside the models. Internal valuation models are validated independently within the Risk Department. A validation report is produced for each model-derived valuation that assesses the mathematical assumptions behind the model, the implementation of the model and its integration within the trading system. Group 2021 2020 Fair value Carrying Fair value Carrying Level 1 Level 2 Level 3 Total value Level 1 Level 2 Level 3 Total value £m £m £m £m £m £m £m £m £m £m Assets Loans and advances to customers — — 216,279 216,279 213,525 — — 214,730 214,730 212,178 Loans and advances to banks — 1,420 — 1,420 1,420 — 2,004 — 2,004 2,004 Reverse repurchase agreements - non trading — 12,453 226 12,679 12,683 — 19,382 226 19,608 19,599 Other financial assets at amortised cost 164 348 — 512 506 799 393 — 1,192 1,163 164 14,221 216,505 230,890 228,134 799 21,779 214,956 237,534 234,944 Liabilities Deposits by customers — 52 192,887 192,939 192,914 — 109 193,102 193,211 193,088 Deposits by banks — 33,780 82 33,862 33,862 — 20,966 16 20,982 20,973 Repurchase agreements - non trading — 11,718 — 11,718 11,718 — 15,847 — 15,847 15,848 Debt securities in issue 4,070 27,084 1,218 32,372 31,580 — 43,500 1,430 44,930 43,679 Subordinated liabilities 1,019 1,512 238 2,769 2,228 — 2,830 239 3,069 2,556 5,089 74,146 194,425 273,660 272,302 — 83,252 194,787 278,039 276,144 The carrying value above of any financial assets and liabilities that are designated as hedged items in a portfolio (or macro) fair value hedge relationship excludes gains and losses attributable to the hedged risk, as this is included in other assets on the balance sheet. Valuation methodology for financial instruments carried at amortised cost The valuation approach to specific categories of financial instruments is described below. Assets: Loans and advances to customers The approach to estimating the fair value of loans and advances to customers has been determined by discounting expected cash flows to reflect either current market rates or credit spreads relevant to the specific industry of the borrower. The determination of their fair values is an area of considerable estimation and uncertainty as there is no observable market and values are significantly affected by customer behaviour. i) Advances secured on residential property The fair value of the mortgage portfolio is calculated by discounting contractual cash flows by different spreads for each LTV Band, after taking account of expected customer prepayment rates. The spread is based on new business interest rates derived from publicly available competitor market information. ii) Corporate loans The determination of the fair values of performing loans is calculated by discounting the contractual cash flows and also deducting other costs relating to expected credit losses, cost of capital, credit risk capital, operational risk capital, cost of funding and operating costs. iii) Other loans These consist of unsecured personal loans, credit cards, overdrafts and consumer (auto) finance. The weighted average lives of these portfolios are short and relate to relatively new business. As a result, contractual interest rates approximate new business interest rates, and therefore no mark-to-market surplus or deficit has been recorded with respect to the performing book, with the exception of unsecured personal loans and consumer (auto) finance loans, where a small surplus or deficit has been recognised based on the differential between existing portfolio margins and the current contractual interest rates. Loans and advances to banks These comprise secured loans, short-term placements with banks including collateral and unsettled financial transactions. The secured loans have been valued based on a discounted spread for the term of the loans using valuation technique A as described above. The carrying amount of the other items is deemed a reasonable approximation of their fair value, as the transactions are very short-term in duration. Reverse repurchase agreements - non-trading The fair value of the reverse repurchase agreements - non trading has been estimated using valuation technique A as described above, using a spread appropriate to the underlying collateral. Other financial assets at amortised cost These consist of asset backed securities and debt securities. The asset backed securities can be complex products and in some instances are valued with the assistance of an independent, specialist valuation firm. These fair values are determined using industry-standard valuation techniques, including discounted cash flow models. The inputs to these models used in these valuation techniques include quotes from market makers, prices of similar assets, adjustments for differences in credit spreads, and additional quantitative and qualitative research. The debt security investments consist of a portfolio of government debt securities. The fair value of this portfolio has been determined using quoted market prices. Liabilities: Deposits by customers The majority of deposit liabilities are payable on demand and therefore can be deemed short-term in nature with the fair value equal to the carrying value. Certain of the deposit liabilities are at a fixed rate until maturity. The deficit/surplus of fair value over carrying value of these liabilities has been estimated by reference to the market rates available at the balance sheet date for similar deposit liabilities of similar maturities. The fair value of such deposit liabilities has been estimated using valuation technique A as described above. Deposits by banks The fair value of deposits by banks, including repos, has been estimated using valuation technique A as described above, discounted at the appropriate credit spread. Repurchase agreements - non trading The fair value of the repurchase agreements - non trading has been estimated using valuation technique A as described above, discounted at a spread appropriate to the underlying collateral. Debt securities in issue and subordinated liabilities Where reliable prices are available, the fair value of debt securities in issue and subordinated liabilities has been calculated using quoted market prices. f) Fair values of financial instruments measured at fair value The following tables summarise the fair values of the financial assets and liabilities accounted for at fair value at 31 December 2021 and 31 December 2020, analysed by their levels in the fair value hierarchy - Level 1, Level 2 and Level 3. Group 2021 2020 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Valuation £m £m £m £m £m £m £m £m technique Assets Derivative financial instruments Exchange rate contracts — 1,193 1 1,194 — 2,455 2 2,457 A Interest rate contracts — 1,574 — 1,574 — 2,604 14 2,618 A & C Equity and credit contracts — 118 55 173 — 71 59 130 B & D Netting — (1,221) — (1,221) — (1,754) — (1,754) — 1,664 56 1,720 — 3,376 75 3,451 Other financial assets at FVTPL Loans and advances to customers — 440 74 514 — 493 99 592 A Debt securities — 1 111 112 — 3 109 112 A, B & D Equity securities — — 50 50 83 — 47 130 B Reverse repurchase agreements – non trading — — — — — — — — A — 441 235 676 83 496 255 834 Financial assets at FVOCI Debt securities 5,833 — — 5,833 8,501 428 — 8,929 D Loans and advances to customers — — 18 18 — — 21 21 D 5,833 — 18 5,851 8,501 428 21 8,950 Total assets at fair value 5,833 2,105 309 8,247 8,584 4,300 351 13,235 Liabilities Derivative financial instruments Exchange rate contracts — 521 — 521 — 846 — 846 A Interest rate contracts — 1,659 2 1,661 — 2,742 3 2,745 A & C Equity and credit contracts — 28 30 58 — 54 29 83 B & D Netting — (1,221) — (1,221) — (1,754) — (1,754) — 987 32 1,019 — 1,888 32 1,920 Other financial liabilities at FVTPL Debt securities in issue — 555 5 560 — 1,051 6 1,057 A Structured deposits — 223 — 223 — 375 — 375 A Repurchase agreements – non trading — — — — — — — — A Collateral and associated financial guarantees — 19 1 20 — — 2 2 D — 797 6 803 — 1,426 8 1,434 Total liabilities at fair value — 1,784 38 1,822 — 3,314 40 3,354 Transfers between levels of the fair value hierarchy In 2021 there were no significant transfers of financial instruments between levels of the fair value hierarchy. In 2020, there was a £81m transfer of Visa shares from Level 3 to Level 1 due to the changes in litigation matters relating to these shares. A ruling was made whereby Type B Visa shares were converted into Type A Visa shares. Type B Visa shares are not liquid observable, but Type A Visa shares are. g) Fair value adjustments The internal models incorporate assumptions that Santander UK believes would be made by a market participant to establish fair value. Fair value adjustments are adopted when Santander UK considers that there are additional factors that would be considered by a market participant that are not incorporated in the valuation model. Santander UK classifies fair value adjustments as either ‘risk-related’ or ‘model-related’. The fair value adjustments form part of the portfolio fair value and are included in the balance sheet values of the product types to which they have been applied. The magnitude and types of fair value adjustment are listed in the following table: 2021 2020 £m £m Risk-related: - Bid-offer and trade specific adjustments (9) (8) - Uncertainty 40 45 - Credit risk adjustment 6 11 - Funding fair value adjustment 3 3 40 51 Model-related — — Day One profit — — 40 51 Risk-related adjustments Risk-related adjustments are driven, in part, by the magnitude of Santander UK’s market or credit risk exposure, and by external market factors, such as the size of market spreads. (i) Bid-offer and trade specific adjustments Portfolios are marked at bid or offer, as appropriate. Valuation models will typically generate mid-market values. The bid-offer adjustment reflects the cost that would be incurred if substantially all residual net portfolio market risks were closed using available hedging instruments or by disposing of or unwinding the position. For debt securities, the bid-offer spread is based on a market price at an individual security level. For other products, the major risk types are identified. For each risk type, the net portfolio risks are first classified into buckets, and then a bid-offer spread is applied to each risk bucket based upon the market bid-offer spread for the relevant hedging instrument. (ii) Uncertainty Certain model inputs may be less readily determinable from market data, and/or the choice of model itself may be more subjective. In these circumstances, a range of possible values exists that the financial instrument or market parameter may assume, and an adjustment may be needed to reflect the likelihood that in estimating the fair value of the financial instrument, market participants would adopt more conservative values for uncertain parameters and/or model assumptions than those used in the valuation model. (iii) Credit risk adjustment Credit risk adjustments comprise credit and debit valuation adjustments. The credit valuation adjustment (CVA) is an adjustment to the valuation of OTC derivative contracts to reflect within fair value the possibility that the counterparty may default, and Santander UK may not receive the full market value of the transactions. The debit valuation adjustment (DVA) is an adjustment to the valuation of the OTC derivative contracts to reflect within the fair value the possibility that Santander UK may default, and that Santander UK may not pay full market value of the transactions. Santander UK calculates a separate CVA and DVA for each Santander UK legal entity, and within each entity for each counterparty to which the entity has exposure. Santander UK calculates the CVA by applying the probability of default of the counterparty to the expected positive exposure to the counterparty, and multiplying the result by the loss expected in the event of default i.e. LGD. Conversely, Santander UK calculates the DVA by applying the PD of the Santander UK group, conditional on the non-default of the counterparty, to the expected positive exposure of the counterparty to Santander UK and multiplying the result by the LGD. Both calculations are performed over the life of the potential exposure. For most products Santander UK uses a simulation methodology to calculate the expected positive exposure to a counterparty. This incorporates a range of potential exposures across the portfolio of transactions with the counterparty over the life of the portfolio. The simulation methodology includes credit mitigants such as counterparty netting agreements and collateral agreements with the counterparty. The methodologies do not, in general, account for wrong-way risk. Wrong-way risk arises where the underlying value of the derivative prior to any credit risk adjustment is positively correlated to the probability of default of the counterparty. When there is significant wrong-way risk, a trade-specific approach is applied to reflect the wrong-way risk within the valuation. Exposure to wrong-way risk is limited via internal governance processes and deal pricing. Santander UK considers that an appropriate adjustment to reflect wrong-way risk is £nil (2020: £nil). (iv) Funding fair value adjustment (FFVA) The FFVA is an adjustment to the valuation of OTC derivative positions to include the net cost of funding uncollateralised derivative positions. This is calculated by applying a suitable funding cost to the expected future funding exposure of any uncollateralised component of the OTC derivative portfolio. Model-related adjustments Models used for portfolio valuation purposes may be based upon a simplifying set of assumptions that do not capture all material market characteristics. Additionally, markets evolve, and models that were adequate in the past may require development to capture all material market characteristics in current market conditions. In these circumstances, model limitation adjustments are adopted. As model development progresses, model limitations are addressed within the core revaluation models and a model limitation adjustment is no longer needed. The table below provides an analysis of financial instruments valued using internal models based on information other than market data together with further details on the valuation techniques used for each type of instrument. Each instrument is initially valued at transaction price: Balance sheet value Fair value movements recognised in profit/(loss) 2021 2020 2021 2020 2019 Balance sheet line item Category Financial instrument product type £m £m £m £m £m 1. Derivative assets Equity and credit contracts Reversionary property interests 45 51 — 3 2 2. FVTPL assets Loans and advances to customers Roll-up mortgage portfolio 48 56 (5) 6 — 3. FVTPL assets Loans and advances to customers Other loans 26 43 (2) 3 1 4. FVTPL assets Debt securities Reversionary property securities 91 107 5 6 (17) 5. FVTPL assets Equity securities Unlisted equity shares 50 47 1 12 42 6. FVTPL assets Debt securities Credit linked notes 20 2 (5) (16) 7 7. FVOCI assets Loans and advances to customers Other loans 18 21 (3) (4) (2) 8. Derivative liabilities Equity contracts Property options and forwards (30) (29) (1) (3) — 9. FVTPL liabilities Financial guarantees Credit protection guarantee (1) (2) 5 16 (7) 267 296 (5) 23 26 Other Level 3 assets 11 24 2 7 15 Other Level 3 liabilities (7) (9) 2 (3) (7) Total net assets 271 311 (1) 27 34 Total income/(expense) (1) 27 34 Valuation techniques 1. Derivative assets – Equity and credit contracts These are valued using a probability weighted set of HPI forward prices, which are assumed to be a reasonable representation of the increase in value of the Santander UK group’s reversionary interest portfolio underlying the derivatives. The probability used reflects the likelihood of the homeowner vacating the property and is calculated from mortality rates and acceleration rates which are a function of age and gender, obtained from the relevant mortality tables. Indexing is felt to be appropriate due to the size and geographical dispersion of the reversionary interest portfolio. These are determined using HPI Spot Rates adjusted to reflect estimated forward growth. Non-seasonally adjusted (NSA) national and regional HPI are used in the valuation model to avoid any subjective judgement in the adjustment process, which is made by Markit, which publishes the Halifax House Price Index. The inputs used to determine the value of the reversionary property derivatives are HPI spot, HPI forward growth and mortality rates. The principal pricing parameter is HPI forward growth. 2. FVTPL assets – Loans and advances to customers – roll-up mortgage portfolio These represent roll-up mortgages (sometimes referred to as lifetime mortgages), which are an equity release scheme under which a property owner takes out a loan secured against their home. The owner may not make any interest payments during their lifetime in which case the fixed interest payments are rolled up into the mortgage. The loan or mortgage (capital and rolled-up interest) is repaid upon the owner’s vacation of the property and the value of the loan is only repaid from the value of the property. This is known as a ‘no negative equity guarantee’. Santander UK suffers a loss if the sale proceeds from the property are insufficient to repay the loan, as it is unable to pursue the homeowner’s estate or beneficiaries for the shortfall. The value of the mortgage ‘rolls up’ or accretes until the owner vacates the property. In order to value the roll-up mortgages, Santander UK uses a probability-weighted set of European option prices (puts) determined using the Black-Scholes model, in which the ‘no negative equity guarantee’ are valued as short put options. The probability weighting applied is calculated from mortality rates and acceleration rates as a function of age and gender, taken from mortality tables. The inputs used to determine the value of these instruments are HPI spot, HPI forward growth, HPI volatility, mortality rates and repayment rates. The principal pricing parameter is HPI forward growth. The HPI forward growth rate used is unobservable and is the same as used in the valuation of Instrument 1 above. The other parameters do not have a significant effect on the value of the instruments. 3. FVTPL assets – Loans and advances to customers – other loans These relate to loans to transport and education companies. The fair value of these loans is estimated using the ‘present value’ model based on a credit curve derived from current market spreads. Loan specific credit data is unobservable, so a proxy population is applied based on industry sector and credit rating. 4. FVTPL assets – Debt securities These consist of reversionary property securities and are an equity release scheme, where the property owner receives an upfront lump sum in return for paying a fixed percentage of the sales proceeds of the property when the owner vacates the property. These reversionary property securities are valued using a probability-weighted set of HPI forward prices which are assumed to be a reasonable representation of the increase in value of Santander UK’s reversionary interest portfolio underlying the derivatives. The probability weighting used reflects the probability of the homeowner vacating the property through death or moving into care and is calculated from mortality rates and acceleration factors which are a function of age and gender, obtained from the relevant mortality table. The inputs used to determine the value of these instruments are HPI spot, HPI forward growth and mortality rates. The principal pricing parameter is HPI forward growth. Discussion of the HPI spot rate, HPI forward growth rate and mortality rates for this financial instrument is the same as Instrument 1 above. An adjustment is also made to reflect the specific property risk. Specific property risk is from the difference between the specific properties in the portfolio, and the average price as expressed in the regionally weighted house price index. 5. FVTPL assets – Equity securities These consist of unquoted equity investments in companies providing infrastructure services to the financial services industry. Observable market inputs to valuation models used include equity prices and foreign currency exchange rates. The significant unobservable input is contingent litigation costs and related expenses in respect of convertible preferred stock in Visa Inc, as described in Note 31. This is estimated by reference to best estimates received from third party legal counsel. 6 .FVTPL assets – Debt securities (Credit linked notes) These consist of the

Offsetting Financial Assets and

Offsetting Financial Assets and Liabilities	12 Months Ended
	Dec. 31, 2021
Disclosure of offsetting of financial liabilities [abstract]
Offsetting Financial Assets and Liabilities	41. OFFSETTING FINANCIAL ASSETS AND LIABILITIES Financial assets and financial liabilities are reported on a net basis on the balance sheet only if there is a legally enforceable right to set off the recognised amounts and there is an intention to settle on a net basis, or to realise the asset and settle the liability simultaneously. The following table shows the impact of netting arrangements on: – All financial assets and liabilities that are reported net on the balance sheet – All derivative financial instruments and repurchase agreements and other similar secured lending and borrowing agreements that are subject to enforceable master netting arrangements or similar agreements, but do not qualify for balance sheet netting. The table identifies the amounts that have been offset in the balance sheet and also those amounts that are covered by enforceable netting arrangements (offsetting arrangements and financial collateral) but do not qualify for netting under the requirements described above. For derivative contracts, the ‘Financial instruments’ column identifies financial assets and liabilities that are subject to set off under netting agreements, such as the ISDA Master Agreement or derivative exchange or clearing counterparty agreements, whereby all outstanding transactions with the same counterparty can be offset and close-out netting applied across all outstanding transactions covered by the agreements if an event of default or other predetermined events occur. Financial collateral refers to cash and non-cash collateral obtained, typically daily or weekly, to cover the net exposure between counterparties by enabling the collateral to be realised in an event of default or if other predetermined events occur. For repurchase and reverse repurchase agreements and other similar secured lending and borrowing, the ‘Financial instruments’ column identifies financial assets and liabilities that are subject to set off under netting agreements, such as global master repurchase agreements and global master securities lending agreements, whereby all outstanding transactions with the same counterparty can be offset and close-out netting applied across all outstanding transactions covered by the agreements if an event of default or other predetermined events occur. Financial collateral typically comprises highly liquid securities which are legally transferred and can be liquidated if a counterparty defaults. Santander UK engages in a variety of counterparty credit mitigation strategies in addition to netting and collateral arrangements. Therefore, the net amounts presented in the tables below do not purport to represent Santander UK’s actual credit exposure. Group Amounts subject to enforceable netting arrangements Effects of offsetting on balance sheet Related amounts not offset Assets not subject to enforceable netting arrangements (2) Gross Amounts Net amounts Financial Financial collateral (1) Net Balance sheet total (3) 2021 £m £m £m £m £m £m £m £m Assets Derivative financial assets 2,870 (1,221) 1,649 (582) (693) 374 72 1,721 Reverse repurchase, securities borrowing & similar agreements: - Amortised cost 14,882 (2,199) 12,683 (435) (12,248) — — 12,683 - Fair value — — — — — — — — Loans and advances to customers and banks (4) 4,316 (923) 3,393 — — 3,393 211,552 214,945 22,068 (4,343) 17,725 (1,017) (12,941) 3,767 211,624 229,349 Liabilities Derivative financial liabilities 2,197 (1,221) 976 (582) (351) 43 43 1,019 Repurchase, securities lending & similar agreements: - Amortised cost 13,917 (2,199) 11,718 (435) (11,283) — — 11,718 - Fair value — — — — — — — — Deposits by customers and banks (4) 2,683 (923) 1,760 — — 1,760 225,016 226,776 18,797 (4,343) 14,454 (1,017) (11,634) 1,803 225,059 239,513 2020 Assets Derivative financial assets 5,116 (1,754) 3,362 (820) (1,840) 702 89 3,451 Reverse repurchase, securities borrowing & similar agreements: - Amortised cost 26,084 (6,485) 19,599 (129) (19,470) — — 19,599 - Fair value — — — — — — — — Loans and advances to customers and banks (4) 7,524 (1,073) 6,451 — — 6,451 207,731 214,182 38,724 (9,312) 29,412 (949) (21,310) 7,153 207,820 237,232 Liabilities Derivative financial liabilities 3,597 (1,754) 1,843 (820) (839) 184 77 1,920 Repurchase, securities lending & similar agreements: - Amortised cost 22,333 (6,485) 15,848 (129) (15,719) — — 15,848 - Fair value — — — — — — — — Deposits by customers and banks (4) 3,222 (1,073) 2,149 — (502) 1,647 211,912 214,061 29,152 (9,312) 19,840 (949) (17,060) 1,831 211,989 231,829 (1) Financial collateral is reflected at its fair value but has been limited to the net balance sheet exposure so as not to include any over-collateralisation. (2) This column includes contractual rights of set-off that are subject to uncertainty under the laws of the relevant jurisdiction. (3) The balance sheet total is the sum of ‘Net amounts reported on the balance sheet’ that are subject to enforceable netting arrangements and ‘Amounts not subject to enforceable netting arrangements’.

Interest Rate Benchmark Reform

Interest Rate Benchmark Reform	12 Months Ended
	Dec. 31, 2021
Interest Rate Benchmark Reform [Abstract]
Interest Rate Benchmark Reform	42. INTEREST RATE BENCHMARK REFORM In September 2019, the IASB amended IFRS 9 'Financial Instruments', IAS 39 'Financial Instruments: Recognition and Measurement' and IFRS 7 'Financial Instruments: Disclosures' to address issues affecting financial reporting in the period before the reform of an interest rate benchmark, including the replacement of an interest rate benchmark with an alternative benchmark rate (the Phase 1 amendments). These Phase 1 amendments provided temporary exceptions to specific hedge accounting requirements because of the uncertainty arising from the reform. After issuing the Phase 1 amendments, in August 2020, the IASB issued further amendments to various IFRSs to address issues that might affect financial reporting during the reform of an interest rate benchmark, including the effects of changes to contractual cash flows or hedging relationships arising from the replacement of an interest rate benchmark with an alternative benchmark rate (the Phase 2 amendments). The Phase 2 amendments do not supersede the Phase 1 amendments. In March 2021, the FCA confirmed that all LIBOR settings will either cease to be provided by any administrator or no longer be representative: – immediately after 31 December 2021, in the case of all sterling, euro, Swiss franc and Japanese yen settings, and the 1-week and 2-month US dollar settings; and – immediately after 30 June 2023, in the case of the remaining US dollar settings (i.e. overnight, 1-month, 3-month, 6-month and 12-month). Under the UK Benchmarks Regulation (BMR), the FCA may designate LIBOR, or individual tenor/currency LIBOR rates, as Article 23A benchmarks if the benchmark has become, or is at risk of becoming, unrepresentative. In September 2021, the FCA designated 1-month, 3-month, and 6-month GBP and JPY LIBOR as Article 23A benchmarks, with effect from 00:01 on 1 January 2022. This enabled the FCA to reduce disruption to holders of legacy contracts through requiring the continued provision of LIBOR rates using a modified methodology. This modified methodology is commonly referred to as a 'synthetic' LIBOR. The synthetic rates will be calculated using the methodology proposed by the FCA in June 2021, being the sum of the forward-looking term rate for the relevant currency/tenor combination and the applicable ISDA spread adjustment. Furthermore, pursuant to the Critical Benchmarks (References and Administrators’ Liability) Act 2021, references to GBP and JPY LIBOR in contracts governed by a law of the United Kingdom are deemed to be references to the applicable synthetic LIBOR rate, subject to the operation of fallback provisions that are intended to transition the contract to an alternative reference rate on a particular date or, for example, on the applicable LIBOR rate becoming unrepresentative. The FCA has permitted legacy use of the 6 synthetic LIBOR settings in all contracts except cleared derivatives and does not propose to apply any limitations or conditionality to the above permissions, at least before the end of 2022. Consequently, the Phase 1 amendments continue to apply to Santander UK's GBP LIBOR cash flow hedges for these legacy contracts and for USD LIBOR cash flow hedges (but not any using 1-week or 2-month USD LIBOR settings). Phase 1 amendments The amendments provide temporary exceptions from applying specific hedge accounting requirements to hedging relationships that are directly affected by the IBOR reform. The exceptions have the effect that IBOR reform should not generally cause hedge accounting to terminate, however any hedge ineffectiveness continues to be recognised in the income statement. The exceptions end at the earlier of: – when the uncertainty regarding the timing and the amount of interest rate benchmark-based cash flows is no longer present, and – discontinuance of the hedge relationship (or reclassification of all amounts from the cash flow hedge reserve). The amendments apply to all hedging relationships directly affected by uncertainties related to IBOR reform and had no impact on hedge relationships for affected hedges. The main assumptions or judgements made by Santander UK in applying the amendments are outlined below. – For cash flow hedges where the hedged items are tough legacy contracts (as explained above), Santander UK management has assumed that the interest rate benchmark on which hedged cash flows are based is not altered as a result of IBOR reform when assessing whether the future cash flows are highly probable. For discontinued hedging relationships, the same assumption has been applied for determining whether the hedged future cash flows are expected to occur. – In making its prospective hedge effectiveness assessments, Santander UK assumes that the interest rate benchmark on which the hedged item and the hedging instrument are based is not altered as a result of IBOR reform. – Santander UK will not discontinue hedge accounting during the period of IBOR-related uncertainty solely because the retrospective effectiveness falls outside the required 80-125% range. – For hedges of a non-contractually specified benchmark portion of an interest rate, Santander UK only considers at inception of such a hedging relationship whether the separately identifiable requirement is met. Phase 2 amendments These amendments apply only to changes required by IBOR reform to financial instruments and hedging relationships. Changes are directly required by IBOR reform if, and only if, the change is necessary as a direct consequent of interest rate benchmark reform, and the new basis for determining the contractual cash flow is economically equivalent to the previous basis. The exceptions given by the amendments mean that IBOR reform did not result in the discontinuation of hedge accounting and any hedge ineffectiveness continued to be recognised in profit or loss for affected hedges at and for the year ended 31 December 2021. The amendments address the accounting issues for financial instruments when IBOR reform is implemented as described below. Practical expedient for changes to contractual cash flows For instruments to which the amortised cost measurement applies, the amendments require entities, as a practical expedient, to account for a change in the basis for determining the contractual cash flows by updating the effective interest rate using the guidance in IFRS 9 resulting in no immediate gain or loss being recognised, provided that, the change is directly required by IBOR reform and takes place on an economically equivalent basis. Whereas the majority of instruments referencing LIBOR or other IBORs transitioned to alternative benchmark interest rates during 2021, legacy contracts and USD LIBOR cash flow hedges remain. Santander UK has no lease contracts which are indexed to LIBOR or other IBORs. The practical expedient was applied to all instruments or contracts that transitioned to alternative benchmark interest rates during 2021 and had no material impact for the Santander UK group. Relief from specific hedge accounting requirements The table below sets out the hedge accounting amendments, and their impact for Santander UK, which provide additional temporary reliefs from applying specific IAS 39 hedge accounting requirements to hedging relationships directly affected by IBOR reform. For GBP LIBOR cash flow hedges of legacy contracts and for USD LIBOR cash flow hedges, the transition to alternative benchmark interest rates will take place during 2022 and, for USD LIBOR cash flow hedges, no later than June 2023. Hedge accounting amendment Impact for the Santander UK group Allow amendment of the designation of a hedging relationship to reflect changes that are required by the reform. The hedge designation must be amended by the end of the reporting period in which the changes are made. This amendment means any change to hedge documentation will not result in discontinuation of hedge accounting nor the designation of a new hedge relationship. It expects the majority of its hedge relationships will transition to alternative benchmark rates during 2021 and Santander UK group used this relief for those hedges that transitioned. When a hedged item in a cash flow hedge is amended to reflect the changes that are required by the reform, the amount accumulated in the cash flow hedge reserve will be deemed to be based on the alternative benchmark rate on which the hedged future cash flows are determined. This amendment would result in the release of the cash flow hedge reserve to profit or loss in the same period or periods in which the hedged cash flows that are now based on the alternative benchmark interest rate affect profit or loss. During the year, most of the Santander UK group’s GBP LIBOR cash flow hedges transitioned to alternative benchmark interest rates. An entity may, on an individual hedge basis, reset to zero the cumulative fair value changes of the hedged item and hedging instrument when ceasing to apply the retrospective effectiveness assessment relief provided by the Phase 1 amendments. The Santander UK group assessed on a hedge-by-hedge basis as the hedging instruments transitioned away from LIBORs or other IBORs during 2021. Resetting the cumulative fair value changes to zero had no effect on the amounts recorded in profit or loss. All hedge ineffectiveness including any outside the 80-125% range arising from IBOR reform has been recognised in profit or loss. When amending the hedge relationships for groups of items, hedged items are allocated to sub-groups based on the alternative benchmark interest rate being hedged, and the benchmark rate for each sub-group is designated as the hedged risk. All hedge relationships have transitioned to alternative benchmark interest rates and hedge documentation was amended accordingly. An alternative benchmark interest rate designated as a non-contractually specified risk component, that is not separately identifiable at the date when it is designated, is deemed to have met the requirements at that date if the entity reasonably expects that it will meet the requirements within a period of 24 months from the date of first designation. The 24-month period will apply to each alternative benchmark interest rate separately. The risk component will, however, be required to be reliably measurable. The amendment eases transition to alternative benchmark interest rates by allowing hedging relationships to be designated and to continue even before the new benchmark interest rates are fully established as market benchmarks. For the Santander UK group, the majority of hedge relationships, where an alternative benchmark interest rate is to be designated as a non-contractually specified risk component, were GBP fair value hedge relationships and most transitioned to SONIA during the year, and this rate was considered separately identifiable. For other changes that are not as a direct consequence of IBOR reform, Santander UK separately assesses those changes to determine if they result in derecognition or discontinuation of hedge accounting by applying the relevant accounting policies as set out in Note 1. Managing LIBOR transition Following the decision by global regulators to phase out IBORs and replace them with alternative reference rates, Santander UK set up a project to oversee the design of alternative reference rate products and the transition for any legacy contracts referencing affected IBOR rates. The CFO sponsored the project and it was driven by senior staff from across the business, including our client-facing business areas, Legal, Compliance, Risk, Operations and Technology, and Finance. It had a formal governance structure, including a Senior Management Forum that met monthly, and thematic and product working groups. ALCO, ERCC and the Board Risk Committee received regular reports. IBOR reform exposed banks to various risks, which were monitored and managed closely. These included: – Conduct risk arising from discussions with clients and market counterparties due to the changes to existing contracts needed to effect IBOR transition – Risk of financial losses to our clients and us if markets were disrupted due to IBOR transition – Pricing risk from potential lack of market data if liquidity in IBORs reduced before some RFRs became liquid – Operational risk arising from changes to IT systems and processes, and the risk of payments being disrupted if IBORs ceased to be available – Accounting risk if hedging relationships failed, and from unrepresentative income statement volatility as financial instruments transition to RFRs. While these risks were increased somewhat by diverging approaches to IBOR transition in different geographies, Santander UK’s main exposures were to GBP LIBOR corporate loans and derivatives, and the IBOR reform developments in different countries were closely monitored. Santander UK also recognised that IBOR transition presented potential challenges for customers. We communicated with customers and launched a website to provide more information and help outline options available. Santander UK also continued to participate actively in industry forums and consultations in 2021. New reference rate products were deployed to support the transition from IBORs and, in 2021, the majority of affected legacy contracts were transitioned from the LIBOR rates ceasing at the end of the year. Santander UK continues to work with its customers to agree the transition of the relatively small number of agreements that remained un-transitioned at the end of 2021. The following tables show the notional amounts of assets, liabilities and off-balance sheet commitments at 31 December 2021 and 31 December 2020 affected by IBOR reform that have yet to transition to an alternative benchmark interest rate. Group 2021 GBP (3) LIBOR USD (3) LIBOR Other (3) Total £m £m £m £m Assets Derivatives (1)(2) — 1,648 — 1,648 Other financial assets at fair value through profit and loss 8 — — 8 Financial assets at amortised cost 1,373 81 1 1,455 1,381 1,729 1 3,111 Liabilities Derivatives (1)(2) 338 1,975 — 2,313 Other financial liabilities at fair value through profit and loss — 5 — 5 Financial liabilities at amortised cost (4) 34 2,401 — 2,435 372 4,381 — 4,753 Off-balance sheet commitments given 338 59 — 397 2020 Assets Derivatives (1)(2) 33,857 4,844 2,149 40,850 Other financial assets at fair value through profit and loss 968 22 — 990 Financial assets at amortised cost 15,062 1,191 90 16,343 Financial assets at fair value through comprehensive income 428 — — 428 50,315 6,057 2,239 58,611 Liabilities Derivatives (1)(2) 35,312 5,381 88 40,781 Other financial liabilities at fair value through profit and loss 1,128 69 — 1,197 Financial liabilities at amortised cost 2,354 3,515 — 5,869 38,794 8,965 88 47,847 Off-balance sheet commitments given 11,405 2,126 573 14,104 (1) Many of the Santander UK group’s derivatives subject to IBOR reform are governed by ISDA definitions. In October 2020 ISDA issued an IBOR fallbacks supplement setting out how the amendments to new alternative benchmark rates will be accomplished, the effect of which is to create fallback provisions in derivatives that describe what floating rates will apply on the permanent discontinuation of certain key IBORs or upon ISDA declaring a non-representative determination of an IBOR. The Santander UK group has adhered to the protocol to implement the fallbacks to derivative contracts that were entered into before the effective date of the supplement (25 January 2021). If derivative counterparties also adhere to the pro tocol, new fallbacks will automatically be implemented in existing derivative contracts when the supplement becomes effective. Following the announcement by the FCA on 5 March 2021 that certain LIBOR settings will permanently cease immediately after 31 December 2021 (and for overnight, 1-month, 3-month, 6-month and 12-month US dollar LIBOR after 30 June 2023), the ISDA fallback spread adjustment is fixed as of the date of the FCA announcement. GBP & JPY LIBOR for certain legacy contracts has been extended until at least the end of 2022 but not for cleared derivative contracts. (2) Derivatives shown in the table above exclude contracts that automatically transitioned under ISDA fall back protocols at 00:01 on 1 January 2022. (3) Cessation dates are: GBP, JPY, NOK LIBOR & 1-week and 2-month USD LIBOR 31/12/2021 remaining USD LIBOR settings 30/06/23, EONIA 03/01/2022; GBP & JPY LIBOR for certain legacy contracts has been extended until at least 31/12/2022. (4) Financial liabilities at amortised cost is comprised of securitisation issuance which was called in January 2022. The following tables show the notional amount of derivatives in hedging relationships directly affected by uncertainties related to IBOR reform. 2021 2020 GBP USD Other Total GBP USD Other Total £m £m £m £m £m £m £m £m Total notional value of hedging instruments: – Cash flow hedges — 2,586 — 2,586 15,198 5,119 — 20,317 – Fair value hedges — 160 — 160 32,223 1,077 778 34,078 — 2,746 — 2,746 47,421 6,196 778 54,395 Maturing after cessation date (1) – Cash flow hedges — 2,586 — 2,586 10,553 2,562 — 13,115 – Fair value hedges — 160 — 160 12,477 162 720 13,359 — 2,746 — 2,746 23,030 2,724 720 26,474 (1) Cessation dates are: GBP, JPY, NOK LIBOR & 1-week and 2-month USD LIBOR 31/12/2021, for remaining USD LIBOR settings 30/06/23, EONIA 03/01/2022; GBP & JPY LIBOR for certain legacy contracts has been extended until at least 31/12/2022. The Santander UK group’s USD LIBOR cash flow hedges extend beyond the anticipated cessation dates for LIBOR. The Santander UK group expects that USD LIBOR will be replaced by SOFR but there remains uncertainty over the timing and amount of the replacement rate cash flows for USD LIBOR cash flow hedges. Hedging relationships impacted by uncertainty about IBOR reform may experience ineffectiveness due to market participants’ expectations of when the shift from the existing IBOR benchmark rate to an alternative benchmark interest rate will occur or because transition of the hedged item and the hedging instrument could occur at different times. The Santander UK group will cease to apply the assumptions that the hedged benchmark interest rate, the cash flows of the hedged item and/or hedging instrument will not be altered because of IBOR reform when the uncertainty arising from IBOR reform is no longer present. This will require amendment to hedge documentation by the end of the reporting period in which the changes occur. Cumulative changes in the hedged cash flows and the hedging instrument based on new alternative benchmark rates will also be remeasured when IBOR reform uncertainty is removed.

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2021
Discontinued Operations and Assets and Liabilities Held for Sale [Abstract]
Discontinued Operations	43. DISCONTINUED OPERATIONS Discontinued operations Transfer of the CIB business Santander UK plc transferred a significant part of its Corporate & Investment Banking business to the London branch of Banco Santander SA under a Part VII banking business transfer scheme, which completed on 11 October 2021. The residual parts of the Corporate & Investment Banking business have been wound down or transferred to other segments. At 31 December 2021, the Corporate & Investment Banking business met the requirements for presentation as discontinued operations. The financial performance and cash flow information relating to the discontinued operations were as follows: 2021 2020 2019 £m £m £m Net interest income 33 55 68 Net fee and commission income 34 65 62 Other operating income 2 2 8 Total operating income 69 122 138 Operating expenses before credit impairment losses, provisions and charges (32) (62) (60) Credit impairment losses 11 (6) (22) Provisions for other liabilities and charges (4) (10) (15) Total operating credit impairment losses, provisions and charges 7 (16) (37) Profit from discontinued operations before tax 44 44 41 Tax on profit from discontinued operations (12) (13) (11) Profit from discontinued operations after tax 32 31 30 Of the £2,784m of assets and £6,517m of liabilities relating to the Corporate & Investment Banking business at 31 December 2020 (see Note2): £1.9bn of assets and £2.1bn of liabilities were transferred to the London branch of Banco Santander SA under a Part VII banking business transfer scheme, which completed on 11 October 2021, in exchange for a net cash payment of £0.2bn; £1.0bn of liabilities were transferred elsewhere within Santander UK; and – The remaining business either matured or customers closed their accounts. There were no gains or losses recognised on the measurement to fair value less costs to sell or on the disposal of the asset groups constituting the discontinued operations. In 2021, the net cash flows attributable to the operating activities, investing activities and financing activities in respect of discontinued operations were £3,612m outflow (2020: £1,815m ou tflow, 2019: £1,033m inflow), £nil (2020: £nil, 2019: £nil ) and £nil (2020: £nil, 2019: £nil ), respectively.

Events After the Balance Sheet

Events After the Balance Sheet Date	12 Months Ended
	Dec. 31, 2021
Disclosure of non-adjusting events after reporting period [abstract]
Events After the Balance Sheet Date	44. EVENTS AFTER THE BALANCE SHEET DATE There have been no significant events between 31 December 2021 and the date of approval of these financial statements which would require a change to or additional disclosure in the financial statements.

Accounting Policies - Parent

Accounting Policies - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure Of Significant Accounting Policies [Line Items]
Accounting Policies	1. ACCOUNTING POLICIES These financial statements are prepared for Santander UK Group Holdings plc (the Company) and the Santander UK Group Holdings plc group (the Santander UK group) under the UK Companies Act 2006. The principal activity of the Santander UK group is the provision of a wide range of banking and financial services to personal, business and corporate customers. Santander UK Group Holdings plc is a public company, limited by shares and incorporated in England and Wales having a registered office at 2 Triton Square, Regent’s Place, London, NW1 3AN, phone number 0870-607-6000. It is a financial services holding company. Basis of preparation These financial statements incorporate the financial statements of the Company and entities it controls (its subsidiaries) made up to 31 December each year. The consolidated financial statements have been prepared on the going concern basis using the historical cost convention, except for financial assets and liabilities that have been measured at fair value. An assessment of the appropriateness of the adoption of the going concern basis of accounting is disclosed in the statement of going concern in the Directors’ report. On 31 December 2020, International Financial Reporting Standards (IFRSs) as adopted by the European Union at that date were brought into UK law and became UK-adopted International Accounting Standards (IAS), with future changes being subject to endorsement by the UK Endorsement Board. The Company and its subsidiaries transitioned to UK-adopted IAS in its consolidated financial statements on 1 January 2021. This change constitutes a change in accounting framework. Although there was a change in accounting framework, this change had no impact on recognition, measurement or disclosures in the periods reported in these financial statements. Compliance with International Financial Reporting Standards The consolidated financial statements of the Santander UK group and the separate financial statements of the Company comply with UK-adopted IAS. The financial statements are also prepared in accordance with IFRSs as issued by the International Accounting Standards Board (IASB), including interpretations issued by the IFRS Interpretations Committee, as there are no applicable differences from IFRSs as issued by the IASB for the periods presented. Disclosures required by IFRS 7 ‘Financial Instruments: Disclosure’ relating to the nature and extent of risks arising from financial instruments, and IAS 1 ‘Presentation of Financial Statements’ relating to objectives, policies and processes for managing capital, can be found in the risk governance, credit risk, market risk, liquidity risk and capital risk sections of the Risk review and are labelled as audited. Those disclosures form an integral part of these financial statements. Climate change Santander UK continues to develop its assessment of the potential impacts that climate change and the transition to a low carbon economy may have on the assets and liabilities recognised and presented in its financial statements. Santander UK is mindful of its responsibilities as a responsible lender and is focused on ways to meet the objectives of the Paris Agreement on climate change and to support the UK’s transition to a climate-resilient, net zero economy. Santander UK's current climate change strategy focuses on three main areas to achieve Banco Santander's ambition to reach net zero emissions by 2050: 1. Managing climate risks by integrating climate considerations into risk management frameworks, screening and stress testing our portfolio for climate related financial risks, and setting risk appetites to help steer our portfolio in line with the Paris Agreement, 2. Supporting our customers’ transition by developing products and services that promote a reduction in CO 2 emissions, and 3. Reducing emissions in our operations and supply chain by focusing on continuous improvement in our operations, and environmental and energy management systems in accordance with ISO14001 and 15001, promoting responsible procurement practices and employee engagement. Santander UK's current climate change strategy and its view of the risks associated with climate change and the transition to a low carbon economy are reflected in its critical judgements and accounting estimates, although climate change risk did not have a significant impact at 31 December 2021, consistent with management's assessment that climate change and the transition to a low carbon economy are not currently expected to have a meaningful impact on the viability of the Santander UK group in the medium term. At 31 December 2021, management specifically considered the potential impact of climate change and the transition to a low carbon economy on: – Loans and advances to customers (see Note 13 and the credit risk section of the Risk review). Some climate change risks arise due to the requirements of IFRS 9 and others relate to specific portfolios and sectors: – ECL calculations are based on multiple forward-looking economic scenarios developed by management covering a period of 5 years, during which timeframe climate change risks may crystallise. – For Mortgages in Retail Banking and Commercial Real Estate lending in Corporate & Commercial Banking, the value of property collateral might be affected by physical impacts related to the frequency and scale of extreme weather events, such as flood and subsidence risk, or changing environmental performance standards for property. – For automotive loans in Consumer Finance, the residual value of automotive vehicles might be impacted by diesel obsolescence and the transition to electric vehicles. – For corporate lending in Corporate & Commercial Banking, certain sectors give rise to fossil fuel exposures, such as Oil & Gas, Mining & Extraction and Power Generation. – Goodwill impairment assessment (see Note 20). Estimates underpinning the determination of whether or not goodwill balances are impaired are partly based on forecast business performance beyond the time horizon for management's detailed plans. Future changes to Santander UK's climate change strategy may impact Santander UK's critical judgements and accounting estimates and result in material changes to financial results and the carrying values of certain assets and liabilities in future reporting periods. Accounting developments Interest Rate Benchmark Reform In 2019, the IASB issued ‘Interest Rate Benchmark Reform: Amendments to IFRS 9, IAS 39 and IFRS 7’. The Santander UK group applies IAS 39 hedge accounting so the amendments to IFRS 9 do not apply. Although the IAS 39 and IFRS 7 amendments, which apply to all hedging relationships directly affected by uncertainties related to interbank offered rate (IBOR) reform, became effective from 1 January 2020, following their endorsement, the Santander UK group early adopted those amendments in the preparation of the financial statements for the year ended 31 December 2019. The exceptions given by the IAS 39 amendments meant that IBOR reform had no impact on hedge relationships for affected hedges. In 2020, the IASB issued ‘Interest Rate Benchmark Reform – Phase 2 - Amendments to IFRS 9, IAS 39, IFRS 7, IFRS 4 and IFRS 16’. These amendments apply only to changes required by IBOR reform to financial instruments and hedging relationships. Although the amendments became effective from 1 January 2021 and are applied retrospectively without restating comparative information, following their endorsement, the Santander UK group early adopted the amendments in the preparation of the financial statements for the year ended 31 December 2020. The amendments address the accounting issues for financial instruments when IBOR reform is implemented including providing a practical expedient for changes to contractual cash flows, giving relief from specific hedge accounting requirements, and specifying a number of additional disclosures to enable users of financial statements to understand the effect of IBOR reform on an entity’s financial instruments and risk management strategy. Further details of the impact of these amendments on the financial statements for the year ended 31 December 2021 and the additional disclosures required are provided in Note 43. Other changes The Santander UK group adopted IFRS 16 and amendments to IAS 12 in 2019, with the impact included in the statement of changes in equity for that year end. Future developments At 31 December 2021 , for the Santander UK group, there were no significant new or revised standards and interpretations, and amendments thereto, which have been issued but which are not yet effective, or which have otherwise not been early adopted where permitted. Comparative information As required by US public company reporting requirements, these financial statements include two years of comparative information for the consolidated income statement, consolidated statement of comprehensive income, consolidated statement of changes in equity, consolidated statement of cash flows and related notes. Consolidation a) Subsidiaries The consolidated financial statements incorporate the financial statements of the Company and entities (including structured entities) controlled by it and its subsidiaries. Control is achieved where the Company (i) has power over the investee; (ii) is exposed, or has rights, to variable returns from its involvement with the investee; and (iii) has the ability to use its power to affect its returns. The Company reassesses whether or not it controls an investee if facts and circumstances indicate that there are changes to one or more of the three elements of control listed above. When the Company has less than a majority of the voting rights of an investee, it has power over the investee when the voting rights are sufficient to give it the practical ability to direct the relevant activities of the investee unilaterally. The Company considers all relevant facts and circumstances in assessing whether or not the Company's voting rights in an investee are sufficient to give it power, including: – The size of the Company's holding of voting rights relative to the size and dispersion of holdings of the other vote holders – Potential voting rights held by the Company, other vote holders or other parties – Rights arising from other contractual arrangements – Any additional facts and circumstances that indicate that the Company has, or does not have, the current ability to direct the relevant activities at the time that decisions need to be made, including voting patterns at previous shareholders' meetings. Consolidation of a subsidiary begins when the Company obtains control over the subsidiary and ceases when the Company loses control of the subsidiary. Specifically, the results of a subsidiary acquired or disposed of during the year are included in the consolidated income statement and the consolidated statement of comprehensive income from the date the Company gains control until the date the Company loses control. Inter-company transactions, balances and unrealised gains on transactions between Santander UK group companies are eliminated; unrealised losses are also eliminated unless the cost cannot be recovered. The acquisition method of accounting is used to account for the acquisition of subsidiaries which meet the definition of a business. The cost of an acquisition is measured at the fair value of the assets given up, shares issued or liabilities undertaken at the date of acquisition. Acquisition-related costs are expensed as incurred. The excess of the cost of acquisition, as well as the fair value of any interest previously held, over the fair value of the Santander UK group’s share of the identifiable net assets of the subsidiary at the date of acquisition is recorded as goodwill. When the Santander UK group loses control of a subsidiary, the profit or loss on disposal is calculated as the difference between (i) the aggregate of the fair value of the consideration received and the fair value of any retained interest and (ii) the previous carrying amount of the assets (including goodwill), less liabilities of the subsidiary and any non-controlling interests. Amounts previously recognised in other comprehensive income in relation to the subsidiary are accounted for (i.e. reclassified to profit or loss or transferred directly to retained earnings) in the same manner as would be required if the relevant assets or liabilities are disposed of. The fair value of any investment retained in a former subsidiary at the date when control is lost is regarded as the fair value on initial recognition for subsequent accounting under IFRS 9 or, when applicable, the costs on initial recognition of an investment in an associate or joint venture. Business combinations between entities under common control (i.e. fellow subsidiaries of Banco Santander SA, the ultimate parent) are outside the scope of IFRS 3 – ‘Business Combinations’, and there is no other guidance for such transactions under IFRS. The Santander UK group elects to account for business combinations between entities under common control at their book values in the acquired entity by including the acquired entity’s results from the date of the business combination and not restating comparatives. Reorganisations of entities within the Santander UK group are also accounted for at their book values. Interests in subsidiaries are eliminated during the preparation of the consolidated financial statements. Interests in subsidiaries in the Company unconsolidated financial statements are held at cost subject to impairment. Credit protection entities established as part of significant risk transfer (SRT) transactions are not consolidated by the Santander UK group in cases where third party investors have the exposure, or rights, to all of the variability of returns from the performance of the entities. b) Joint ventures Joint ventures are joint arrangements whereby the parties that have joint control of the arrangement have rights to its net assets. Joint control is the contractually agreed sharing of control of an arrangement, which exists only when decisions about the relevant activities require unanimous consent of the parties sharing control. Accounting policies of joint ventures have been aligned to the extent there are differences from the Santander UK group’s policies. Investments in joint ventures are accounted for by the equity method of accounting and are initially recorded at cost and adjusted each year to reflect the Santander UK group’s share of their post-acquisition results. When the Santander UK group's share of losses of a joint venture exceeds its interest in that joint venture, the Santander UK group discontinues recognising its share of further losses. Further losses are recognised only to the extent that the Santander UK group has incurred legal or constructive obligations or made payments on behalf of the joint venture. Foreign currency translation Items included in the financial statements of each entity (including foreign branch operations) in the Santander UK group are measured using the currency that best reflects the economic substance of the underlying events and circumstances relevant to that entity (the functional currency). The consolidated financial statements are presented in sterling, which is the functional currency of the Company. Income statements and cash flows of foreign entities are translated into the Santander UK group’s presentation currency at average exchange rates for the year and their balance sheets are translated at the exchange rates ruling on 31 December. Exchange differences on the translation of the net investment in foreign entities are recognised in other comprehensive income. When a foreign entity is sold, such exchange differences are recognised in the income statement as part of the gain or loss on sale. Foreign currency transactions are translated into the functional currency of the entity involved at the exchange rates prevailing at the dates of the transactions. Foreign exchange gains and losses resulting from the settlement of such transactions and from the translation of monetary assets and liabilities denominated in foreign currencies are recognised in the income statement unless recognised in other comprehensive income in connection with a cash flow hedge. Non-monetary items denominated in a foreign currency measured at historical cost are not retranslated. Exchange rate differences arising on non-monetary items measured at fair value are recognised in the consolidated income statement except for differences arising on equity securities measured at fair value through other comprehensive income (FVOCI), which are recognised in other comprehensive income. Revenue recognition a) Interest income and expense Interest and similar income comprise interest income on financial assets measured at amortised cost, investments in debt instruments measured at FVOCI and interest income on hedging derivatives. Interest expense and similar charges comprises interest expense on financial liabilities measured at amortised cost, and interest expense on hedging derivatives. Interest income on financial assets measured at amortised cost, investments in debt instruments measured at FVOCI and interest expense on financial liabilities other than those at fair value through profit or loss (FVTPL) is determined using the effective interest rate method. The effective interest rate is the rate that discounts the estimated future cash payments or receipts over the expected life of the instrument or, when appropriate, a shorter period, to the gross carrying amount of the financial asset (i.e. its amortised cost before any impairment allowance) or to the amortised cost of a financial liability. When calculating the effective interest rate, the future cash flows are estimated after considering all the contractual terms of the instrument excluding expected credit losses. The calculation includes all amounts paid or received by the Santander UK group that are an integral part of the overall return, direct incremental transaction costs related to the acquisition, issue or disposal of the financial instrument and all other premiums or discounts. Interest income is calculated by applying the effective interest rate to the gross carrying amount of financial assets, except for financial assets that have subsequently become credit-impaired (i.e. Stage 3), for which interest revenue is calculated by applying the effective interest rate to their amortised cost (i.e. net of the ECL provision). For more information on stage allocations of credit risk exposures, see ‘Significant increase in credit risk’ in the ‘Santander UK group level – credit risk management’ section of the Risk review. b) Fee and commission income and expense Fees and commissions that are not an integral part of the effective interest rate are recognised when the service is performed. Most fee and commission income is recognised at a point in time. Certain commitment, upfront and management fees are recognised over time but are not material. For retail and corporate products, fee and commission income consists principally of collection services fees, commission on foreign currencies, commission and other fees received from retailers for processing credit card transactions, fees received from other credit card issuers for providing cash advances for their customers through the Santander UK group’s branch and ATM networks, annual fees payable by credit card holders and fees for non-banking financial products. For insurance products, fee and commission income consists principally of commissions and profit share arising from the sale of building and contents insurance and life protection insurance. Commissions arising from the sale of buildings and contents insurance are recognised over the period of insurance cover, adjusted to take account of cancelled policies. Profit share income from the sale of buildings and contents insurance which is not subject to any adjustment is recognised when the profit share income is earned. Commissions and profit share arising from the sale of life protection insurance is subject to adjustment for cancellations of policies within 3 years from inception. Fee and commission income which forms an integral part of the effective interest rate of a financial instrument (for example certain loan commitment fees) is recognised as an adjustment to the effective interest rate and recorded in ‘Interest income’. c) Dividend income Except for equity securities classified as trading assets or financial assets held at fair value through profit or loss, described below, dividend income is recognised when the right to receive payment is established. This is the ex-dividend date for equity securities. d) Other operating income Other operating income includes all gains and losses from changes in the fair value of financial assets and liabilities held at fair value through profit or loss (comprising financial assets and liabilities held for trading, trading derivatives and other financial assets and liabilities at fair value through profit or loss), together with related interest income, expense, dividends, and changes in fair value of any derivatives managed in conjunction with these assets and liabilities. Changes in fair value of derivatives in a fair value hedging relationship are also recognised in other operating income. Other operating income also includes income from operating lease assets, and profits and losses arising on the sales of property, plant and equipment and subsidiary undertakings. Borrowing costs Borrowing costs directly attributable to the acquisition, construction, or production of qualifying assets, including computer software, which are assets that necessarily take a substantial period of time to develop for their intended use, are added to the cost of those assets, until the assets are substantially ready for their intended use. All other borrowing costs are recognised in profit or loss in the period in which they occur. Pensions and other post-retirement benefits a) Defined benefit schemes A defined benefit scheme is a pension scheme that guarantees an amount of pension benefit to be provided, usually as a function of one or more factors such as age, years of service or compensation. Pension costs are charged to ‘Administration expenses’, within the line item ‘Operating expenses before impairment losses, provisions and charges’ with the net interest on the defined benefit asset or liability included within ‘Net interest income’ in the income statement. The asset or liability recognised in respect of defined benefit pension schemes is the present value of the defined benefit obligation at the balance sheet date, less the fair value of scheme assets. The defined benefit obligation is calculated annually by independent actuaries using the projected unit credit method. The assets of the schemes are measured at their fair values at the balance sheet date. The present value of the defined benefit obligation is estimated by projecting forward the growth in current accrued pension benefits to reflect inflation and salary growth to the date of pension payment, then discounted to present value using the yield applicable to high-quality AA rated corporate bonds of the same currency and which have terms to maturity closest to the terms of the scheme liabilities, adjusted where necessary to match those terms. In determining the value of scheme liabilities, demographic and financial assumptions are made by management about life expectancy, inflation, discount rates, pension increases and earnings growth, based on past experience and future expectations. Financial assumptions are based on market conditions at the balance sheet date and can generally be derived objectively. Demographic assumptions require a greater degree of estimation and judgement to be applied to externally derived data. Any surplus or deficit of scheme assets over liabilities is recognised in the balance sheet as an asset (surplus) or liability (deficit). An asset is only recognised to the extent that the surplus can be recovered through reduced contributions in the future or through refunds from the scheme. The income statement includes the net interest income/expense on the net defined benefit liability/asset, current service cost and any past service cost and gain or loss on settlement. Remeasurement of defined benefit pension schemes, including return on scheme assets (excludes amounts included in net interest), actuarial gains and losses (arising from changes in demographic assumptions, the impact of scheme experience and changes in financial assumptions) and the effect of the changes to the asset ceiling (if applicable), are recognised in other comprehensive income. Remeasurement recognised in other comprehensive income will not be reclassified to the income statement. Past service costs are recognised as an expense in the income statement at the earlier of when the scheme amendment or curtailment occurs and when the related restructuring costs or termination benefits are recognised. Curtailments include the impact of significant reductions in the number of employees covered by a scheme, or amendments to the terms of the scheme so that a significant element of future service will no longer qualify for benefits or will qualify only for reduced benefits. Curtailment gains and losses on businesses that meet the definition of discontinued operations are included in profit or loss for the year from discontinued operations. Gains and losses on settlements are recognised when the settlement occurs. b) Defined contribution plans A defined contribution plan is a pension scheme under which the Santander UK group pays fixed contributions as they fall due into a separate entity (a fund). The pension paid to the member at retirement is based on the amount in the separate fund for each member. The Santander UK group has no legal or constructive obligations to pay further contributions into the fund to ‘top up’ benefits to a certain guaranteed level. The regular contributions constitute net periodic costs for the year in which they are due and are included in staff costs within Operating expenses in the income statement. c) Post-retirement medical benefit plans Post-retirement medical benefit liabilities are determined using the projected unit credit method, with actuarial valuations updated at each year-end. The expected benefit costs are accrued over the period of employment using an accounting methodology similar to that for the defined benefit pension scheme. Share-based payments The Santander UK group engages in cash-settled and equity-settled share-based payment transactions in respect of services received from certain of its employees. Shares of the Santander UK group’s parent, Banco Santander SA are purchased in the open market by the Santander UK group (for the Employee Sharesave scheme) or are purchased by Banco Santander SA or another Banco Santander subsidiary (including awards granted under the Long-Term Incentive Plan and the Deferred Shares Bonus Plan) to satisfy share options or awards as they vest. Options granted under the Employee Sharesave scheme and awards granted under the Transformation Incentive Plan are accounted for as cash-settled share-based payment transactions. Awards granted under the Long-Term Incentive Plan and Deferred Shares Bonus Plan are accounted for as equity-settled share-based payment transactions. The fair value of the services received is measured by reference to the fair value of the shares or share options initially on the date of the grant for both the cash and equity settled share-based payments and then subsequently at each reporting date for the cash-settled share-based payments. The cost of the employee services received in respect of the shares or share options granted is recognised in the income statement in administration expenses over the period that the services are received i.e. the vesting period. A liability equal to the portion of the services received is recognised at the fair value determined at each balance sheet date for cash-settled share-based payments. A liability equal to the amount to be reimbursed to Banco Santander SA is recognised at the fair value determined at the grant date for equity-settled share-based payments. The fair value of the options granted under the Employee Sharesave scheme is determined using an option pricing model, which takes into account the exercise price of the option, the current share price, the risk-free interest rate, the expected volatility of the Banco Santander SA share price over the life of the option and the dividend growth rate. The fair value of the awards granted for the Long-Term Incentive Plan was determined at the grant date using an option pricing model, which takes into account the share price at grant date, the risk-free interest rate, the expected volatility of the Banco Santander SA share price over the life of the award and the dividend growth rate. Vesting conditions included in the terms of the grant are not taken into account in estimating fair value, except for those that include terms related to market conditions. Non-market vesting conditions are taken into account by adjusting the number of shares or share options included in the measurement of the cost of employee service so that, ultimately, the amount recognised in the income statement reflects the number of vested shares or share options. Where vesting conditions are related to market conditions, the charges for the services received are recognised regardless of whether or not the market–related vesting conditions are met, provided that the non-market vesting conditions are met. Where an award has been modified, as a minimum, the expense of the original award continues to be recognised as if it had not been modified. Where the effect of a modification is to increase the fair value of an award or increase the number of equity instruments, the incremental fair value of the award or incremental fair value of the modification of the award is recognised in addition to the expense of the original grant, measured at the date of modification, over the modified vesting period. Cancellations in the vesting period are treated as an acceleration of vesting and recognised immediately for the amount that would otherwise have been recognised for services over the vesting period. Goodwill and other intangible assets Goodwill represents the excess of the cost of an acquisition, as well as the fair value of any interest previously held, over the fair value of the share of the identifiable net assets of the acquired subsidiary, associate, or business at the date of acquisition. Goodwill on the acquisition of subsidiaries and businesses is included in intangible assets. Goodwill on acquisitions of associates is included as part of investment in associates. Goodwill is tested for impairment annually, or more frequently when events or changes in circumstances dictate, and carried at cost less accumulated impairment losses. Gains and losses on the disposal of an entity or business include the carrying amount of goodwill relating to the entity or business sold. Other intangible assets are recognised if they arise from contractual or other legal rights or if they are capable of being separated or divided from Santander UK and sold, transferred, licensed, rented or exchanged. The value of such intangible assets, where they are available for use, is amortised on a straight-line basis over their useful economic life of three to seven years and the assets are reviewed annually for impairment indicators and tested for impairment where indicators are present. Other intangible assets that are not yet available for use are tested for impairment annually or more frequently when events or changes in circumstances dictate. Software development costs are capitalised when they are direct costs associated with identifiable and unique software products that are expected to provide future economic benefits and the cost of those products can be measured reliably. These costs include payroll, materials, services and directly attributable overheads. Internally developed software meeting these criteria and externally purchased software are classified in intangible assets on the balance sheet and amortised on a straight-line basis over their useful life of three to seven years, unless the software is an integral part of the related computer hardware, in which case it is treated as property, plant and equipment as described below. Capitalisation of costs
Santander UK Group Holdings plc
Disclosure Of Significant Accounting Policies [Line Items]
Accounting Policies	ACCOUNTING POLICIES Basis of preparation The accounting policies of the Company are the same as those of the Santander UK Group Holdings plc group which are set out in Note 1 to the extent that the Company has similar transactions to the Santander UK Group Holdings plc group, except as set out below. CRITICAL JUDGEMENTS AND ACCOUNTING ESTIMATES The preparation of the financial statements requires management to make judgements and accounting estimates that affect the reported amount of assets and liabilities at the date of the financial statements and the reported amount of income and expenses during the reporting period. Management evaluates its judgements and accounting estimates, which are based on historical experience and on various other factors that are believed to be reasonable under the circumstances, on an ongoing basis. Actual results may differ from these accounting estimates under different assumptions or conditions. In preparing the financial statements, no significant judgements have been made in the process of applying the accounting policies, other than those involving estimations about interests in other entities. Interests in other entities - Investment in subsidiaries The carrying amount of investments in subsidiaries is based on the application of judgements including the basis of the cost of investment impairment calculation assumptions. Estimates include forecasts used for determining cash flows for the subsidiary's business and discount rates which factor in risk-free rates and applicable risk premiums, which are variables subject to fluctuations in external market rates and economic conditions beyond management’s control. Santander UK undertakes an annual assessment to evaluate whether the carrying value of investments in subsidiaries is impaired, carrying out this assessment more frequently if reviews identify indicators of impairment or when events or changes in circumstances dictate. The estimation of future cash flows and the level to which they are discounted is inherently uncertain and requires significant judgement and is subject to potential change over time. For more on these assumptions, including changes in the assumptions that would trigger an impairment, see Note 45.7.

Operating Expenses Before Cre_2

Operating Expenses Before Credit Impairment Losses, Provisions and Charges - Parent	12 Months Ended
	Dec. 31, 2021
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Operating Expenses Before Credit Impairment Losses, Provisions and Charges	6. OPERATING EXPENSES BEFORE CREDIT IMPAIRMENT LOSSES, PROVISIONS AND CHARGES Group 31 December 2021 2020 (1) 2019 (1) £m £m £m Staff costs: Wages and salaries 759 802 815 Performance-related payments 184 99 160 Social security costs 113 102 112 Pensions costs: – defined contribution plans 65 67 67 – defined benefit plans (2) 38 38 35 Other share-based payments 1 4 7 Other personnel costs 42 34 41 1,202 1,146 1,237 Other administration expenses 831 710 684 Depreciation, amortisation and impairment 507 569 545 2,540 2,425 2,466 (1) Adjusted to reflect the presentation of discontinued operations as set out in Note 43. (2) Pension costs for defined benefit plans include £5m for curtailment as set out in Note 30. Staff costs ’Performance-related payments’ include bonuses paid in cash and share awards granted under the arrangements described in Note 37. Included in this are equity-settled share-based payments, none of which related to option-based schemes. These are disclosed in the table below as ‘Share awards’. Performance-related payments above include amounts related to deferred performance awards as follows: Costs recognised in 2021 Costs expected to be recognised in 2022 or later Arising from awards in current year Arising from awards in prior year Total Arising from awards in current year Arising from awards in prior year Total £m £m £m £m £m £m Cash 3 5 8 9 6 15 Shares 3 5 8 8 6 14 6 10 16 17 12 29 The following table shows the amount of bonus awarded to employees for the performance year 2021. In the case of deferred cash and share awards, the final amount paid to an employee is influenced by forfeiture provisions and any performance conditions to which these awards are subject. The deferred share award amount is based on the fair value of these awards at the date of grant. Expenses charged in the year Expenses deferred to future periods Total 2021 2020 2021 2020 2021 2020 £m £m £m £m £m £m Cash award – not deferred 156 79 — — 156 79 – deferred 8 9 15 11 23 20 Shares award – not deferred 12 3 — — 12 3 – deferred 8 8 14 11 22 19 Total discretionary bonus 184 99 29 22 213 121 On 26 October 2018, the High Court handed down a judgement concluding that defined benefit schemes should equalise pension benefits for men and women in relation to GMP and concluded on the methods that were appropriate. The estimated increase in liabilities at the date of the judgement was £40m and was based on a number of assumptions and the actual impact may be different. This was reflected in the income statement and in the closing net accounting surplus of the Scheme in 2018. The allowance included in the Scheme liabilities at 31 December 2021 decreased by £5m (2020: £5m, 2019: £5m ) to £45m (2020: £50m, 2019 : £45m) to reflect the latest assumptions. This change was recognised in other comprehensive income. Work is being undertaken by the Trustee to implement GMP equalisation. ‘Other share-based payments’ consist of options granted under the Employee Sharesave scheme which comprise the Santander UK group’s cash-settled share-based payments. For more, see Note 37. The average number of full-time equivalent staff was 19,844 (2020: 22,139, 2019: 23,706). Depreciation, amortisation and impairment In 2021, depreciation, amortisation and impairment included depreciation of £81m (2020: £92m, 2019: £103m) on operating lease assets (where the Santander UK group is the lessor) with a net book value of £595m at 31 December 2021 (2020: £542m, 2019: £574m). It also included depreciation of £20m (2020: £59m, 2019: £61m) on right-of-use assets with a net book value of £119m at 31 December 2021 (2020: £103m, 2019: £153m). 'Other administration expenses' includes £23m (2020: £10m , 2019 : £13m ) expenses related to short-term leases. In 2021, 'Depreciation, amortisation and impairment' included an impairment charge of £88m ( 2020 : £nil) associated with branch and head office site closures as part of the transformation programme. For more, see Note 21.
Santander UK Group Holdings plc
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Operating Expenses Before Credit Impairment Losses, Provisions and Charges	OPERATING EXPENSES BEFORE CREDIT IMPAIRMENT LOSSES, PROVISIONS AND CHARGESThese comprise wages and salaries of £6m (2020: £7m) recharged by the operating company, Santander UK plc. In 2021 and 2020, the Company had no full-time staff as they are all employed by Santander UK plc.

Dividends on Ordinary Shares -

Dividends on Ordinary Shares - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividends on Ordinary Shares	10. DIVIDENDS ON ORDINARY SHARES Dividends on ordinary shares declared and paid in the year were as follows: Group Group 2021 2020 2019 2021 2020 2019 Pence per share Pence per share Pence per share £m £m £m In respect of current year – first interim 4.05 1.46 1.95 286 103 138 – second interim 15.01 — 1.76 1,060 — 124 19.06 1.46 3.71 1,346 103 262 In 2021, an interim dividend of £1,346m (2020: £103m
Santander UK Group Holdings plc
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividends on Ordinary Shares	DIVIDENDS ON ORDINARY SHARESDividends on ordinary shares declared and paid during the year are set out in Note 10 to the Consolidated Financial Statements.

Other Financial Assets at Fai_2

Other Financial Assets at Fair Value Through Profit or Loss - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure Of Financial Assets Designated As Measured At Fair Value Through Profit Or Loss [Line Items]
Other Financial Assets at Fair Value Through Profit or Loss	12. OTHER FINANCIAL ASSETS AT FAIR VALUE THROUGH PROFIT OR LOSS Group 2021 2020 £m £m Loans and advances to customers: Loans to housing associations 12 13 Other loans 502 579 514 592 Debt securities 112 112 Equity securities 50 130 676 834 For the Santander UK group, other financial assets at FVTPL comprised £454m (2020: £508m) of financial assets designated at FVTPL and £222m (2020:£325m) of financial assets mandatorily held at FVTPL. Loans and advances to customers principally represented other loans, being a portfolio of roll-up mortgages and deferred consideration following the partial sale of the portfolio . These are managed, and have their performance evaluated, on a fair value basis in accordance with a documented investment strategy, and information about them is provided on that basis to management. Since 2009, the Santander UK group’s policy has been not to designate similar new loans at FVTPL. The net (loss)/gain in the year attributable to changes in credit risk for loans and advances at FVTPL was £nil (2020: £nil, 2019: £nil). The cumulative net loss attributable to changes in credit risk for loans and advances at FVTPL at 31 December 2021 was £2m (2020: £2m).
Santander UK Group Holdings plc
Disclosure Of Financial Assets Designated As Measured At Fair Value Through Profit Or Loss [Line Items]
Other Financial Assets at Fair Value Through Profit or Loss	OTHER FINANCIAL ASSETS AT FAIR VALUE THROUGH PROFIT OR LOSS 2021 2020 £m £m Debt securities 4,190 1,425 4,190 1,425 Other financial assets at FVTPL comprised £4,190m (2020: £1,425m) of financial assets mandatorily held at FVTPL. In 2021, as part of MREL requirements, the Company issued £2,765m (2020: £1,425m ) debt securities, which were subsequently downstreamed to Santander UK plc.

Loans and Advances to Banks - P

Loans and Advances to Banks - Parent	12 Months Ended
	Dec. 31, 2021
Santander UK Group Holdings plc
Net Loans And Advances To Banks [Line Items]
Loans and Advances to Banks	LOANS AND ADVANCES TO BANKS Loans and advances to banks principally comprise amounts due from Santander UK group undertakings. The fair values of loans and advances to banks are equal to their carrying amounts. In 2021 and 2020, there were no material expected credit losses. All of our senior debt issued out of Santander UK Group Holdings plc is downstreamed to our principal operating company Santander UK plc.

Other Financial Assets at Amo_2

Other Financial Assets at Amortised Cost - Parent	12 Months Ended
	Dec. 31, 2021
Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Other Financial Assets at Amortised Cost	17. OTHER FINANCIAL ASSETS AT AMORTISED COST Group 2021 2020 £m £m Asset backed securities 443 491 Debt securities 63 672 506 1,163
Santander UK Group Holdings plc
Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Other Financial Assets at Amortised Cost	OTHER FINANCIAL ASSETS AT AMORTISED COSTThese consist of investments in subordinated notes and have a maturity greater than 10 years.

Interests in Other Entities - P

Interests in Other Entities - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure of subsidiaries [line items]
Interests in Other Entities	19. INTERESTS IN OTHER ENTITIES Group 2021 2020 £m £m Joint Ventures 201 172 201 172 The Santander UK group consists of a parent company, Santander UK Group Holdings plc, incorporated and domiciled in the UK and a number of subsidiaries and joint ventures held directly and indirectly by it. a) Interests in subsidiaries The Company holds directly or indirectly 100% of the issued ordinary share capital of its principal subsidiaries. All companies operate principally in their country of incorporation or registration. SFS has branch offices in Jersey and the Isle of Man. Subsidiaries with significant non-controlling interests The only subsidiary with significant non-controlling interests was PSA Finance UK Limited (PSA), which operates in the UK.On 30 July 2021, Santander UK through Santander Consumer (UK) plc sold its entire 50% shareholding in PSA to PSA Financial Services Spain EFC SA, a joint venture between Santander Consumer Finance SA, a fellow subsidiary of Banco Santander SA, and Banque PSA Finance SA, the auto finance arm of Group PSA Peugeot Citroën. The impact of the sale was to derecognise total assets of £3.2bn, total liabilities of £2.9bn and a non-controlling interest of £0.15bn. No material gain or loss arose on sale. In 2021, until the date of sale, and 2020, the proportion of ownership interests and voting rights held by non-controlling interests was 50%. 2021 2020 £m £m Profit attributable to non-controlling interests — 19 Accumulated non-controlling interests of the subsidiary — 162 Dividends paid to non-controlling interests — 15 Summarised financial information: Total assets — 3,451 Total liabilities — 3,127 Profit for the year — 38 Total comprehensive income for the year — 33 Interests in consolidated structured entities Structured entities are formed by Santander UK to accomplish specific and well-defined objectives. Santander UK consolidates these structured entities when the substance of the relationship indicates control, as described in Note 1. In addition to the structured entities disclosed in Note 14 which are used for securitisation and covered bond programmes, the only other structured entities consolidated by Santander UK are described below. All the external assets and liabilities in these entities are included in the financial statements and in relevant Notes. Other than as set out below, no significant judgements were required with respect to control or significant influence. Motor Securities 2018-1 Designated Activity Company (Motor 2018) Motor 2018 is a credit protection entity, and a Designated Activity Company limited by shares, incorporated in Ireland. It has issued a series of credit linked notes varying in seniority which reference portfolios of Santander UK group loans. Concurrently, these entity sells credit protection to Santander UK in respect of the referenced loans and, in return for a fee, is liable to make protection payments to Santander UK upon the occurrence of a credit event in relation to any of the referenced loans. Motor 2018 is consolidated as Santander UK holds a variable interest by retaining the junior tranche of notes issued by the entity. b) Interests in joint ventures Santander UK does not have any individually material interests in joint ventures. As set out in the accounting policies in Note 1, interests in joint ventures are accounted for using the equity method. In 2021, Santander UK’s share in the profit after tax of its joint ventures was £22m (2020: £20m) before elimination of transactions between Santander UK and the joint ventures. At 31 December 2021, the carrying amount of Santander UK’s interest was £201m (2020: £172m). At 31 December 2021 and 2020, the joint ventures had no commitments and contingent liabilities. c) Interests in unconsolidated structured entities Structured entities sponsored by the Santander UK group Santander UK has interests in structured entities which it sponsors but does not control. Santander UK considers itself a sponsor of a structured entity when it facilitates the establishment of the structured entity. Other than as set out below, no significant judgements were required with respect to control or significant influence. The structured entities sponsored but not consolidated by Santander UK are as follows. i) Santander (UK) Common Investment Fund The Santander (UK) Common Investment Fund (the Fund) is a common investment fund that was established to hold the assets of the Santander (UK) Group Pension Scheme. The Fund is not consolidated by Santander UK, but its assets of £14,100m (2020: £13,553m) are accounted for as part of the defined benefit assets and obligations recognised on Santander UK’s balance sheet. For more on the Fund, see Note 30. As the Fund holds the assets of the pension scheme, it is outside the scope of IFRS 10. Santander UK’s maximum exposure to loss is the carrying amount of the assets held. ii) Credit protection entities Santander UK has established three (2020: three) unconsolidated credit protection entities, which are Designated Activity Companies limited by shares, incorporated in Ireland. Each entity has issued a series of credit linked notes varying in seniority which reference portfolios of Santander UK group loans. Concurrently, these entities sell credit protection to Santander UK in respect of the referenced loans and, in return for a fee, are liable to make protection payments to Santander UK upon the occurrence of a credit event in relation to any of the referenced loans. Senior credit linked notes, which amounted to £1,184m (2020: £2,160m), are issued to, and held by, Santander UK. Junior credit linked notes, which amounted to £619m (2020: £678m), are all held by third party investors and suffer the first losses incurred in the referenced portfolios. Funds raised by the sale of the credit linked notes are deposited with Santander UK as collateral for the credit protection. The senior credit linked notes, along with the deposits and associated guarantees, are presented on a net basis, to reflect a legal right of set-off between the principal amounts of senior notes and the cash deposits. Deposits and associated guarantees in respect of the junior credit linked notes are included in ‘Deposits by customers’ (see Note 23). The entities are not consolidated by Santander UK because the third-party investors have the exposure, or rights, to all of the variability of returns from the performance of the entities. No assets are transferred to, or income received from, these entities. Since the credit linked notes (including those held by Santander UK) are fully cash collateralised, Santander UK’s maximum exposure to loss is equal to any unamortised fees paid to the entities in connection with the credit protection outlined above. Structured entities not sponsored by the Santander UK group Santander UK also has interests in structured entities which it does not sponsor or control. These consist of holdings of mortgage and other asset backed securities issued by entities that were established and/or sponsored by other unrelated financial institutions. These securities comprise the asset backed securities included in Note 17. Management has concluded that the Santander UK group has no control or significant influence over these entities and that the carrying value of the interests held in these entities represents the maximum exposure to loss.
Santander UK Group Holdings plc
Disclosure of subsidiaries [line items]
Interests in Other Entities	INTERESTS IN OTHER ENTITIES 2021 2020 £m £m Interests in ordinary shares of subsidiaries 11,635 11,630 £500m Fixed Rate Reset Perpetual AT1 Capital Securities 495 495 £750m Fixed Rate Reset Perpetual AT1 Capital Securities 750 750 £500m Fixed Rate Reset Perpetual AT1 Capital Securities 210 210 £500m Fixed Rate Reset Perpetual AT1 Capital Securities 500 500 13,590 13,585 Details of subsidiaries, joint ventures and associates are set out in the Shareholder information section. For information on AT1 Capital Securities, see Note 33. The Company has no interests in joint ventures or associates. Interests in other entities mainly relate to investments in 100% of the ordinary share capital of Santander UK plc, Santander Financial Services plc and Santander Equity Investments Limited, as well as holdings of AT1 Capital Securities issued by Santander UK plc. Interests in subsidiaries are held at cost subject to impairment. The Company’s interests in subsidiaries was as follows: Cost Impairment Net book value £m £m £m At 31 December 2021 11,645 (10) 11,635 At 31 December 2020 11,645 (15) 11,630 Impairment testing Interests in other entities are tested for impairment annually at 31 December. Interests in other entities are otherwise tested for impairment if reviews identify an indicator of impairment or when events or changes in circumstances dictate. Impairment is required where the carrying value of an investment exceeds its recoverable amount. Basis of the recoverable amount The recoverable amount of all interests in other entities was determined based on a value in use (VIU) methodology at each testing date. For each investment, the VIU is calculated by discounting management’s cash flow projections for the investment. The cash flow projections also take account of increased internal capital allocations needed to achieve internal and regulatory capital targets including the leverage ratio. The key assumptions used in the VIU calculation for each investment are set out below. Key assumptions in the VIU calculation Carrying value of investment Discount rate Growth rate beyond initial cash flow projections 2021 2020 2021 2020 2021 2020 Investment £m £m % % % % Santander UK plc 11,267 11,267 13.6 14.0 1.6 1.6 Santander Financial Services plc 337 337 15.6 13.7 1.6 1.6 Other 31 26 11,635 11,630 Management’s judgement in estimating the cash flows of a CGU The VIU calculation uses cash flow projections derived from the latest 3-year plan presented to the Board. For more details, see Note 20. Cash flow projections for the purpose of impairment testing do not take account of any adverse outcomes arising from contingent liabilities (see Note 31), whose existence will be confirmed by uncertain future events or where any obligation is not probable or otherwise cannot be measured reliably, nor do they take account of the benefits arising from Santander UK’s transformation plans that had not yet been implemented or committed at 31 December 2021. Discount rate The rate used to discount the cash flows is based on the cost of equity assigned to each investment, which is derived using a CAPM. The CAPM depends on a number of inputs reflecting financial and economic variables, including the risk-free rate and a premium to reflect the inherent risk of the investment being evaluated. These variables are based on the market’s assessment of the economic variables and management’s judgement. In determining the discount rate, management have identified the cost of equity associated with market participants that closely resemble our investments and adjusted them for tax to arrive at the pre-tax equivalent rate. Growth rate beyond initial cash flow projections The growth rate for periods beyond the initial cash flow projections is used to extrapolate the cash flows in perpetuity because of the long-term perspective of the business. In line with the accounting requirements, management uses the UK Government’s official estimate of the UK long-term average GDP growth rate, as this is lower than management's estimate of the long-term average growth rate of the business. Investments in Santander UK plc and Santander Financial Services plc The VIU of each investment remains higher than the carrying value of the investment. The VIU review at 31 December 2021 did not indicate the need for an impairment in the Company’s investments in Santander UK plc and Santander Financial Services plc. Management considered the reduction in headroom and the uncertainty relating to the respective estimates of the VIU for those investments, but determined that there was a sufficient basis to conclude that no impairment was required. Sensitivities of key assumptions in calculating the VIU of the investment in Santander UK plc At 31 December 2021 and 2020, the VIU was sensitive to reasonably possible changes in the key assumptions similar to those applied in determining the recoverable amount of goodwill recognised in the Santander UK plc group (see Note 20 to the Consolidated Financial Statements). In addition, given the lack of significant headroom, the VIU is sensitive to the UK long-term average GDP growth rate assumption. At 31 December 2021 and 2020, a reasonably possible change in the following key assumptions in relation to the VIU calculation for the Company’s investment in Santander UK plc would have resulted in an impairment, as shown in the table below. The sensitivity analysis presented below has been prepared on the basis that a change in each key assumption would not have a consequential impact on other assumptions used in the impairment review. However, due to the interrelationships between some of the assumptions, a change in one of the assumptions might impact one or more of the other assumptions and could result in a larger or smaller overall impact. Impairment 2021 2020 Subsidiary Reasonably possible change £m £m Santander UK plc Cash flow projections decrease by 5% (2020: 5%) — 109 Discount rate increases by 100 basis points (2020: 100 basis points) 381 637 GDP growth rate decreases by 10 basis points (2020: 10 basis points) — — The decrease in cash flow projections in the table above includes the impact of holding back the required capital to support the growth of the business. Under current regulatory capital regulations as they apply to Santander UK plc, the calculation is not sensitive overall to the UK long-term average GDP growth rate assumption as the increased profit after tax generated by growth of the business is mostly offset by the need to retain more profit to meet increased regulatory capital requirements driven by the growth in assets. Sensitivity of VIU changes to current assumptions to achieve nil headroom Although there was no impairment of the Company's investment in Santander UK plc at 31 December 2021 and 2020, the test remains sensitive to some of the assumptions used, as described above. In addition, the changes in assumptions detailed below for the discount rate and cash flow projections would eliminate the current headroom. As a result, there is a risk of impairment in the future should business performance or economic factors diverge from forecasts. The sensitivity analysis presented below has been prepared on the basis that a change in each key assumption would not have a consequential impact on other assumptions used in the impairment review. However, due to the interrelationships between some of the assumptions, a change in one of the assumptions might impact one or more of the other assumptions and could result in a larger or smaller overall impact. 2021 Carrying value Value in use Headroom Increase in post tax discount rate Decrease in cash flows Subsidiary £m £m £m bps % Santander UK plc 11,267 12,147 880 67 7 2020 Santander UK plc 11,267 11,745 478 40 4 Sensitivities of key assumptions in calculating the VIU of the investment in Santander Financial Services plc At 31 December 2021 and 2020, the VIU was sensitive to reasonably possible changes in the key assumptions for the discount rate and cash flows similar to those applied in determining the recoverable amount of goodwill recognised in the Santander UK plc group (see Note 20). In line with the position for Santander UK plc, the VIU is not sensitive to the UK long-term average GDP growth rate assumption overall as the increased profit after tax generated by growth of the business is mostly offset by the need to retain more profit to meet increased regulatory capital requirements driven by the growth in assets. At 31 December 2021 and 2020, a reasonably possible change in the following key assumptions in relation to the VIU calculation for the Company’s investment in Santander Financial Services plc would have resulted in an impairment, as shown in the table below. The sensitivity analysis presented below has been prepared on the basis that a change in each key assumption would not have a consequential impact on other assumptions used in the impairment review. However, due to the interrelationships between some of the assumptions, a change in one of the assumptions might impact one or more of the other assumptions and could result in a larger or smaller overall impact. Impairment 2021 2020 Subsidiary Reasonably possible change £m £m Santander Financial Services plc Cash flow projections decrease by 5% (2020: 5%) — — Discount rate increases by 100 basis points (2020: 100 basis points) — 5 The decrease in cash flow projections in the table above includes the impact of holding back the required capital to support the growth of the business. Sensitivity of VIU changes to current assumptions to achieve nil headroom Although there was no impairment of the Company's investment in Santander Financial Services plc at 31 December 2021 and 2020, the test remains sensitive to the some of the assumptions used, as described above. In addition, the changes in assumptions detailed below for the discount rate and cash flow projections would eliminate the current headroom. As a result, there is a risk of impairment in the future should business performance or economic factors diverge from forecasts. The sensitivity analysis presented below has been prepared on the basis that a change in each key assumption would not have a consequential impact on other assumptions used in the impairment review. However, due to the interrelationships between some of the assumptions, a change in one of the assumptions might impact one or more of the other assumptions and could result in a larger or smaller overall impact. 2021 Carrying value Value in use Headroom Increase in post tax discount rate Decrease in cash flows Subsidiary £m £m £m bps % Santander Financial Services plc 337 376 39 145 10 2020 Santander Financial Services plc 337 363 26 82 7

Other Financial Liabilities a_2

Other Financial Liabilities at Fair Value Through Profit or Loss - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Other Financial Liabilities at Fair Value Through Profit or Loss	22. OTHER FINANCIAL LIABILITIES AT FAIR VALUE THROUGH PROFIT OR LOSS Group 2021 2020 £m £m US$30bn Euro Medium Term Note Programme 5 102 Structured Notes Programmes 413 805 Eurobonds 142 150 Structured deposits 223 375 Collateral and associated financial guarantees 20 2 803 1,434 For the Santander UK group all (2020: all) of the other financial liabilities at FVTPL were designated as such. Collateral and associated financial guarantees in the table above represent collateral received, together with associated credit protection guarantees, in respect of the proceeds of the retained senior tranches of credit linked notes described in Note 12. The financial guarantees are valued using the same parameters as the related credit linked notes, such that changes in the respective valuations are offset exactly, and there is no charge or credit to the income statement. Gains and losses arising from changes in the credit spread of securities issued by the Santander UK group reverse over the contractual life of the debt, provided that the debt is not repaid at a premium or a discount. The net loss during the year attributable to changes in the Santander UK group’s own credit risk on the above securities was £12m (2020: £3m loss, 2019: £77m loss). The cumulative net loss attributable to changes in the Santander UK group’s own credit risk on the above securities at 31 December 2021 was £10m (2020: £3m). At 31 December 2021, the amount that would be required to be contractually paid at maturity of the securities above was £nil higher (
Santander UK Group Holdings plc
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Other Financial Liabilities at Fair Value Through Profit or Loss	OTHER FINANCIAL LIABILITIES AT FAIR VALUE THROUGH PROFIT OR LOSS 2021 2020 £m £m Medium-term notes 4,190 1,425 4,190 1,425 Other financial liabilities at FVTPL comprised £4,190m (2020: £1,425m ) of other financial liabilities designated at FVTPL. In 2021`, as part of MREL requirements, the Company issued £2,765m (2020:£1,425m ) of debt securities, which were then downstreamed to Santander UK plc. Gains and losses arising from changes in the credit spread of securities issued by the Santander UK group reverse over the contractual life of the debt, provided that the debt is not repaid at a premium or a discount. The cumulative net gain or loss at 31 December 2021, and net gain or loss for the year attributable to changes in the Santander UK group’s own credit risk on the above securities was £nil (2020: £nil) and has been included in profit and loss to offset credit risk on internal MREL assets held which are required to be recorded at FVTPL in accordance with IFRS 9. At 31 December 2021, the amount that would be required to be contractually paid at maturity of the securities above was £26m higher (2020: £21m lower) than the carrying value.

Deposits by Banks - Parent

Deposits by Banks - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure Of Deposits From Banks [Line Items]
Deposits by Banks	24. DEPOSITS BY BANKS Group 2021 2020 £m £m Items in the course of transmission 414 375 Deposits held as collateral 941 2,071 Other deposits (1) 32,507 18,527 33,862 20,973 (1) Includes drawdown from the TFS of £0.0bn (2020: £6.3bn) and drawdown from the TFSME of £31.9bn (2020: £11.7bn).
Santander UK Group Holdings plc
Disclosure Of Deposits From Banks [Line Items]
Deposits by Banks	DEPOSITS BY BANKSThese consist of amounts due to subsidiaries under loan agreements and are repayable on demand.

Debt Securities in Issue - Pare

Debt Securities in Issue - Parent	12 Months Ended
	Dec. 31, 2021
Debt Securities In Issue [Line Items]
Debt Securities in Issue	26. DEBT SECURITIES IN ISSUE Group 2021 2020 £m £m Medium-term notes: – US$30bn Euro Medium Term Note Programme 1,405 1,694 – Euro 30bn Euro Medium Term Note Programme (1) 4,304 4,292 – US SEC-registered Debt Programme – Santander UK Group Holdings plc (2) 5,978 5,616 – US SEC-registered Debt Programme – Santander UK plc 1,224 4,723 12,911 16,325 Euro 35bn Global Covered Bond Programme (See Note 14) 12,760 19,285 US$20bn Commercial Paper Programmes 2,704 2,824 Certificates of deposit 2,387 2,858 Credit linked notes 59 57 Securitisation programmes (See Note 14) 759 2,330 31,580 43,679 (1) Restated for 2020 to reclassify £673m previously disclosed as Euro 750m Senior Unsecured Notes to Euro 30bn Euro Medium Term Note Programme due to an administrative error.
Santander UK Group Holdings plc
Debt Securities In Issue [Line Items]
Debt Securities in Issue	DEBT SECURITIES IN ISSUE The Company issues notes in the US from time to time pursuant to a shelf registration statement on Form F-3 filed with the SEC in 2021. 2021 2020 £m £m Medium-term notes: – Euro 30bn Euro Medium Term Note Programme 3,028 3,161 – US SEC-registered Debt Programme – Santander UK Group Holdings plc 2,985 4,809 6,013 7,970

Subordinated Liabilities - Pare

Subordinated Liabilities - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure Of Subordinated Liabilities [Line Items]
Subordinated Liabilities	27. SUBORDINATED LIABILITIES Group 2021 2020 £m £m £325m Sterling preference shares 344 344 Undated subordinated liabilities 240 557 Dated subordinated liabilities 1,644 1,655 2,228 2,556 In 2021, the Santander UK group repurchased certain debt securities and subordinated liabilities as part of ongoing liability management exercises, resulting in a loss of £1m. In 2020, the Santander UK group repurchased certain debt securities and subordinated liabilities as part of ongoing liability management exercises, resulting in a loss of £24m . The above securities will, in the event of the winding up of the issuer, be subordinated to the claims of depositors and all other creditors of the issuer, other than creditors whose claims rank equally with, or are junior to, the claims of the holders of the subordinated liabilities. The subordination amongst each of the subordinated liabilities upon a winding up of the issuer is specified in their respective terms and conditions. In 2021 and 2020, the Santander UK group had no defaults of principal, interest or other breaches with respect to its subordinated liabilities. No repayment or purchase by the issuer of the subordinated liabilities may be made prior to their stated maturity without the consent of the PRA. Undated subordinated liabilities Group 2021 2020 First call date £m £m 10.0625% Exchangeable capital securities n/a 205 205 7.125% 30 Year Step-up perpetual callable subordinated notes 2030 35 352 240 557 In common with other debt securities issued by Santander UK group companies and notwithstanding the issuer’s first call dates in the table above, in the event of certain tax changes affecting the treatment of payments of interest on subordinated liabilities in the UK, the 7.125% 30 Year Step-up perpetual callable subordinated notes are redeemable at any time, and the 10.0625% Exchangeable capital securities are redeemable on any interest payment date – each in whole at the option of Santander UK plc, at their principal amount together with any accrued interest. The 10.0625% Exchangeable capital securities are exchangeable into fully paid 10.375% non-cumulative non-redeemable sterling preference shares of £1 each, at the option of Santander UK plc, on the business day immediately following any interest payment date. Dated subordinated liabilities Group 2021 2020 Maturity £m £m 5% Subordinated notes (US$1,500m) 2023 548 542 4.75% Subordinated notes (US$1,000m) 2025 541 536 7.95% Subordinated notes (US$1,000m) 2029 221 242 6.50% Subordinated notes 2030 28 31 5.875% Subordinated notes 2031 9 10 5.625% Subordinated notes (US$500m) 2045 297 294 1,644 1,655 The dated subordinated liabilities are redeemable in whole at the option of Santander UK plc in the event of certain tax changes affecting the treatment of payments of interest on the subordinated liabilities in the UK, at their principal amount together with any accrued interest. Each of the subordinated liabilities issued by Santander UK Group Holdings plc has been downstreamed to Santander UK plc by means of Santander UK plc issuing equivalent subordinated liabilities to Santander UK Group Holdings plc.
Santander UK Group Holdings plc
Disclosure Of Subordinated Liabilities [Line Items]
Subordinated Liabilities	SUBORDINATED LIABILITIES 2021 2020 Dated subordinated liabilities Maturity £m £m 4.75% Subordinated notes (US$1,000m) 2025 541 536 5.625% Subordinated notes (US$500m) 2045 297 294 838 830

Notes to Cash Flows - Parent

Notes to Cash Flows - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Notes to Cash Flows	35. NOTES TO CASH FLOWS Changes in liabilities arising from financing activities The table below shows the changes in liabilities arising from financing activities. The changes in equity arising from financing activities are set out in the Consolidated Statement of Changes in Equity. Group 2021 2020 Balance sheet line item Balance sheet line item Debt securities in issue Subordinated liabilities Other equity instruments Lease liabilities Dividends paid Total Debt securities in issue Subordinated liabilities Other equity instruments Lease liabilities Dividends paid Total (1) £m £m £m £m £m £m £m £m £m £m £m £m At 1 January 43,679 2,556 2,241 100 — 48,576 50,171 3,528 2,241 138 — 56,078 Proceeds from issue of debt securities 2,847 — — — — 2,847 5,586 — — — — 5,586 Repayment of debt securities (13,724) — — — — (13,724) (12,348) — — — — (12,348) Repayment of subordinated liabilities — (4) — — — (4) — (939) — — — (939) Issue of other equity instruments — — 450 — — 450 — — — — — — Repurchase of other equity instruments — — (500) — — (500) — — — — — — Payment of lease liability — — — (25) — (25) — — — (46) — (46) Dividends paid — — — — (1,506) (1,506) — — — — (282) (282) Liability-related other changes (473) (4) — 59 — (418) (243) (10) — 8 — (245) Non-cash changes: — — – Unrealised foreign exchange (930) 14 — — — (916) 359 (6) — — — 353 – Other changes 181 (334) — — 1,506 1,353 154 (17) — — 282 419 At 31 December 31,580 2,228 2,191 134 — 36,133 43,679 2,556 2,241 100 — 48,576 (1) Restated for 2020 to include changes in liabilities arising from financing activities relating to lease liabilities. In addition, in 2021, there was a disposal of non-controlling interests of £181m . Footnotes to the cash flow For 2021, Principal elements of lease payments are included as a separate line item in the Consolidated Cash Flow Statement. As a result, cash flows of £46m for 2020 (2019: £55m) have been reclassified from 'Other liabilities' within operating activities to 'Principal elements of lease payments' within financing activities. Total cash outflow for leases was £28m (2020: £49m). Net cash flows from operating activities includes interest received of £4,873m (2020: £5,176m, 2019: £5,856m), interest paid of £1,085m (2020: £1,900m, 2019: £2,587m) and dividends received of £nil (2020: £nil, 2019: £nil). Restatements in the cash flow
Santander UK Group Holdings plc
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Notes to Cash Flows	NOTES TO CASH FLOWS Changes in liabilities arising from financing activities In addition to the changes in equity arising from financing activities, as set out in the Company Statement of Changes in Equity, the table below shows the changes in liabilities arising from financing activities. 2021 2020 Balance sheet line item Balance sheet line item Debt securities in issue Subordinated liabilities Other equity instruments Dividends paid Total Debt securities in issue Subordinated liabilities Other equity instruments Dividends paid Total £m £m £m £m £m £m £m £m £m £m At 1 January 9,379 830 2,241 — 12,450 8,957 1,142 2,241 — 12,340 Proceeds from issue of debt securities 2,788 — — — 2,788 1,409 — — — 1,409 Repayment of debt securities (1,814) — — — (1,814) (969) — — — (969) Repayment of subordinated liabilities — — — — — — (281) — — (281) Issue of other equity instruments — — 450 — 450 — — — — — Repurchase of other equity instruments — — (500) — (500) — — — — — Dividends paid — — — (1,489) (1,489) — — — (250) (250) Liability-related other changes (28) — — — (28) (3) — — — (3) Non-cash changes: – Unrealised foreign exchange (124) 8 — — (116) (17) (28) — — (45) – Other changes 9 — — 1,489 1,498 2 (3) — 250 249 At 31 December 10,210 838 2,191 — 13,239 9,379 830 2,241 — 12,450 Footnotes to the cash flow Net cash flows from operating activities includes interest received of £245m (2020: £314m), interest paid of £240m (2020: £317m) and dividends received of £1,497m (2020: £260m). Restatements in cash flow For 2021, the MREL bond issuances that were down streamed to Santander UK plc are now included in ‘Purchase of financial assets at amortised cost and financial assets at FV’ in the ‘Cash flows from investing activities’ section of the cash flow statement. As a result, £1,424m of cash outflows for 2020 (2019: £nil) have been reclassified from ‘Net changes in operating assets and liabilities’ in the ‘Cash flows from operating activities’ section.

Contingent Liabilities and Co_2

Contingent Liabilities and Commitments - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure of contingent liabilities [line items]
Contingent Liabilities and Commitments	31. CONTINGENT LIABILITIES AND COMMITMENTS Group 2021 2020 £m £m Guarantees given to third parties 363 939 Formal standby facilities, credit lines and other commitments 37,385 42,231 37,748 43,170 Capital support arrangements At 31 December 2021 Santander UK plc, Cater Allen Limited and certain other non-regulated subsidiaries of Santander UK plc were party to a capital support deed dated 13 November 2018 (the RFB Sub-Group Capital Support Deed). These parties were permitted by the PRA to form a core UK group as defined in the PRA Rulebook, a permission which expired on 31st December 2021. Exposures of each of the regulated entities to other members of the core UK group were exempt from large exposure limits that would otherwise apply and these exposures were risk-weighted at 0%. The purpose of the RFB Sub-Group Capital Support Deed was to facilitate the prompt transfer of available capital resources from, or repayment of liabilities by, the non-regulated parties to any of the regulated parties in the event that one of the regulated parties breached or was at risk of breaching its capital resources or risk concentrations requirements. A new RFB Sub-Group Capital Support Deed was entered into on 17 December 2021 and effective from 1 January 2022. This reflected the latest version of associated regulation and the addition of two further Santander UK plc subsidiaries including Santander ISA Managers Limited, an entity regulated by the FCA. The parties to the new RFB Sub-Group Capital Support Deed were granted a new permission by the PRA to form a core UK group from 1 January 2022 to 31 December 2024, following expiry of the previous core UK group permission on 31 December 2021. Where applicable this new permission also provides for intra-group exposures to be excluded from the leverage exposure measure. At 31 December 2021 Santander UK Group Holdings plc and Santander Financial Services plc, the regulated entities, and Santander Equity Investments Limited were party to a capital support deed dated 13 November 2018 (the Non-RFB Capital Support Deed). These parties were permitted by the PRA to form a core UK group as defined in the PRA Rulebook, a permission which expired on 31 December 2021. Exposures of each of the regulated entities to other members of the core UK group were exempt from large exposure limits that would otherwise apply and these exposures were risk-weighted at 0%. The purpose of the NRFB Capital Support Deed was to facilitate the prompt transfer of available capital resources from, or repayment of liabilities by, the non-regulated parties to any of the regulated parties in the event that one of the regulated parties breached or was at risk of breaching its capital resources or risk concentrations requirements. Santander UK Group Holdings plc became a PRA-regulated firm from 12 December 2021. A new NRFB Capital Support Deed was entered into on 17 December 2021 and effective from 1 January 2022, reflecting the latest version of associated regulation. The parties to the new NRFB Capital Support Deed remained unchanged and were granted a new permission by the PRA to form a core UK group from 1 January 2022 to 31 December 2024, following expiry of the previous core UK group permission on 31 December 2021. Liquidity support arrangements We monitor and manage liquidity risk for the Santander UK plc group and Santander Financial Services plc separately. Under this model, and the PRA’s liquidity rules, Santander UK plc and its subsidiary Cater Allen Limited form the RFB Domestic Liquidity Sub-group (the RFB DoLSub), which allows the entities to collectively meet regulatory requirements for the purpose of managing liquidity risk. Each member of the RFB DoLSub will support the other by transferring surplus liquidity in times of stress. Guarantees given to third parties Guarantees given to third parties consist primarily of letters of credit, bonds and guarantees granted as part of normal product facilities which are offered to customers. Formal standby facilities, credit lines and other commitments Standby facilities, credit lines and other commitments are also granted as part of normal product facilities which are offered to customers. Retail facilities comprise undrawn facilities granted on flexible mortgages, bank overdrafts and credit cards. On flexible mortgages, the credit limit is set at the point of granting the loan through property value and affordability assessments. Ongoing assessments are made to ensure that credit limits remain appropriate considering any change in the security value or the customer’s financial circumstances. For unsecured overdraft facilities and credit cards, the facilities are granted based on new business risk assessment and are reviewed more frequently based on internal, as well as external data. The delinquency status of the account would result in the withdrawal of the facility. Corporate facilities can comprise standby and revolving facilities which are subject to ongoing compliance with covenants and may require the provision of agreed security. Failure to comply with these terms can result in the withdrawal of the unutilised facility headroom. FSCS The FSCS is the UK’s independent statutory compensation fund for customers of authorised financial services firms and pays compensation if a firm is unable to pay certain claims against it. The FSCS is funded by levies on the industry (and recoveries and borrowings where appropriate). Loan representations and warranties In connection with the securitisations and covered bond transactions described in Note 14, the Santander UK group entities selling the relevant loans into the applicable securitisation or covered bond portfolios make representations and warranties with respect to such loans, in each case as of the date of the sale of the loans into the applicable portfolio. These representations and warranties cover, among other things, the ownership of the loan by the relevant Santander UK group entity, absence of a material breach or default by the relevant borrower under the loan, the loan’s compliance with applicable laws and absence of material disputes with respect to the relevant borrower, asset and loan. The specific representations and warranties made by Santander UK group companies which act as sellers of loans in these securitisations and covered bond transactions depend in each case on the nature of the transaction and the requirements of the transaction structure. In addition, market conditions and credit rating agency requirements may affect the representations and warranties required of the relevant Santander UK group companies in these transactions. In the event that there is a material breach of the representations and warranties given by Santander UK plc as seller of loans under the residential mortgage-backed securitisations or the covered bond programmes included in Note 14, or if such representations and warranties prove to be materially untrue at the date when they were given (being the sale date of the relevant mortgage loans), Santander UK plc may be required to repurchase the affected mortgage loans (generally at their outstanding principal balance plus accrued interest). These securitisations and covered bond programmes are collateralised by prime residential mortgage loans. Santander UK plc is principally a retail prime lender and has no appetite or product offering for any type of sub-prime business. In addition, Santander UK plc’s credit policy explicitly prohibits such lending. Similarly, under the auto loan securitisations in Note 14, in the event that there is a breach or inaccuracy in respect of a representation or warranty relating to the loans, the relevant Santander UK group entity who sold the auto loans into the securitisation portfolio will be required to repurchase such loans from the structure (also at their outstanding principal balance plus accrued interest). In addition to breaches of representation and warranties, under the auto loan securitisations, the seller may also have a repurchase obligation if certain portfolio limits are breached (which include, amongst other things, limits as to the size of a loan given to an individual customer, LTV ratio, average term to maturity and average seasoning). In the case of a repurchase of a loan from the relevant securitisation or covered bond programmes, the Santander UK group may bear any subsequent credit loss on such loan. The Santander UK group manages and monitors its securitisation and covered bond activities closely to minimise potential claims. Other legal actions and regulatory matters Santander UK engages in discussion, and co-operates, with the FCA, PRA, CMA and other regulators and government agencies in various jurisdictions in their supervision and review of Santander UK including reviews exercised under statutory powers, regarding its interaction with past and present customers, both as part of general thematic work and in relation to specific products, services and activities. During the ordinary course of business, Santander UK is also subject to complaints and threatened legal proceedings brought by or on behalf of current or former employees, customers, investors or other third parties, in addition to legal and regulatory reviews, challenges and tax or enforcement investigations or proceedings in various jurisdictions. All such matters are assessed periodically to determine the likelihood of Santander UK incurring a liability. In those instances where it is concluded that it is not yet probable that a quantifiable payment will be made, for example because the facts are unclear or further time is required to fully assess the merits of the case or to reasonably quantify the expected payment, no provision is made. In addition, where it is not currently practicable to estimate the possible financial effect of these matters, no provision is made. Payment Protection Insurance In relation to a specific PPI portfolio of complaints, a legal dispute regarding allocation of liability remains in its early stages. The dispute relates to the liability for PPI mis-selling complaints relating to pre-2005 PPI policies underwritten by AXA France IARD and AXA France Vie (together, AXA France - previously Financial Insurance Company Ltd and Financial Assurance Company Ltd respectively) and involves Santander Cards UK Limited (a former GE Capital Corporation entity and distributor of pre-2005 PPI known as GE Capital Bank Limited which was acquired by Banco Santander SA in 2008 and subsequently transferred to Santander UK plc) and a Banco Santander SA subsidiary Santander Insurance Services UK Limited (together the Santander Entities). During the relevant period, AXA France were owned by Genworth Financial International Holdings, Inc (Genworth). ###### In September 2015 AXA S.A. acquired AXA France from Genworth. In July 2017, the Santander Entities notified AXA France that they did not accept liability for losses on PPI policies relating to this period. Santander UK plc entered into a Complaints Handling Agreement (CHA) with AXA France pursuant to which it agreed to handle complaints on their behalf, and AXA France agreed to pay redress assessed to be due to relevant policyholders on a without prejudice basis. A standstill agreement was entered into between the Santander Entities and AXA France as a condition of the CHA. In July 2020, Genworth announced that it had agreed to pay AXA circa £624m in respect of PPI mis-selling losses in settlement of the related dispute concerning obligations under the sale and purchase agreement pursuant to which Genworth sold AXA France to AXA. The CHA between Santander UK plc and AXA France terminated on 26 December 2020. On 30 December 2020, AXA France provided written notice to the Santander Entities to terminate the standstill agreement. During 2021, AXA France commenced litigation against the Santander Entities seeking recovery of £636m and any further losses relating to pre-2005 PPI. The Santander Entities acknowledged service indicating their intention to defend the claim in full and have issued an application for AXA France’s claim to be struck out/summarily dismissed, which is being heard by the Commercial Court in February 2022. This dispute remains at an early stage and there are ongoing factual issues to be resolved which may have legal consequences including in relation to liability. These issues create uncertainties which mean that it is difficult to reliably predict the outcome or the timing of the resolution of the matter. The Litigation and other regulatory provision in Note 29 includes our best estimate of the Santander Entities’ liability to the specific portfolio. Further information has not been provided on the basis that it would be seriously prejudicial to the Santander Entities’ interests in connection with the dispute. In addition, and in relation to PPI more generally the Litigation and other regulatory provision includes an amount relating to litigation challenging the FCA’s industry guidance on the treatment of Plevin / recurring non-disclosure assessments. This provision is based on current stock levels, future projected claims, and average redress. There remains a risk that volumes received in future may be higher than forecast. The provision in Note 29 includes our best estimate of Santander UK’s liability for the specific issue. The actual cost of customer compensation could differ from the amount provided. German dividend tax arbitrage transactions In June 2018 the Cologne Criminal Prosecution Office and the German Federal Tax Office commenced an investigation in relation to the historical involvement of Santander UK plc, Santander Financial Services plc and Cater Allen International Limited (all subsidiaries of Santander UK Group Holdings plc) in German dividend tax arbitrage transactions (known as cum/ex transactions). These transactions allegedly exploited a loophole of a specific German settlement mechanism through short-selling and complex derivative structuring which resulted in the German government either refunding withholding tax where such tax had not been paid or refunding it more than once. The German authorities are investigating numerous institutions and individuals in connection with alleged transactions and practices which may be found to be illegal under German law. During 2021 we continued to cooperate with the German authorities and, with the assistance of external experts, to progress an internal investigation into the matters in question. From Santander UK plc’s perspective, the investigation is focused principally on the period 2009-2011 and remains on-going. There remain factual issues to be resolved which may have legal consequences including potentially material financial penalties. These issues create uncertainties which mean that it is difficult to predict the resolution of the matter including timing or the significance of the possible impact. Consumer credit The Santander UK group’s unsecured lending and other consumer credit business is governed by consumer credit law and related regulations, including the CCA. Claims brought by customers in relation to these requirements, including potential breaches, could result in costs to the Santander UK group where such potential breaches are not found to be de minimis. The CCA includes very detailed and prescriptive requirements for lenders, including in relation to post contractual data. Customer remediation provisions include an amount of £6m (2020: £47m ) arising from a systems-related historical issue identified by Santander UK, relating to compliance with certain requirements of the CCA. This provision has been based on detailed reviews of relevant systems related to consumer credit business operations, supported by external legal and regulatory advice. The Customer remediation provision in Note 29 includes our best estimate of Santander UK’s liability for the specific issue. The actual cost of customer compensation could differ from the amount provided. It is not practicable to provide an estimate of the risk and amount of any further financial impact. FCA civil regulatory investigation into Santander UK plc financial crime systems and controls, and compliance with the Money Laundering Regulations 2007 In 2021, Santander UK plc continued to cooperate with an FCA civil regulatory investigation which commenced in July 2017 into our compliance with the Money Laundering Regulations 2007 and potential breaches of FCA principles and rules relating to anti-money laundering and financial crime systems and controls. The FCA’s investigation focuses primarily on the period 2012 to 2017 and includes consideration of high-risk customers including Money Service Bureaus. It is not currently possible to make a reliable assessment of any liability resulting from the investigation including any financial penalty. Taxation The Santander UK group engages in discussion, and co-operates, with HM Revenue & Customs (HMRC) in their oversight of the Santander UK group’s tax matters. The Santander UK group adopted the UK’s Code of Practice on Taxation for Banks in 2010. Certain leases in which the Santander UK group is or was the lessor have been under review by HMRC in connection with claims for tax allowances. Under the terms of the lease agreements, the Santander UK group is fully indemnified in all material respects by the respective lessees for any liability arising from the disallowance of tax allowances plus accrued interest. During 2021, an outline agreement in principle in respect of a number of these lease arrangements was reached directly between the lessee and HMRC. It is anticipated that this agreement will be executed in H1 2022 which would result in a final payment by the lessee to HMRC in the region of £50m and conclude the review by HMRC. There is the possibility that the Santander UK Group would need to make the payment to HMRC and reclaim this from the lessee under the indemnity arrangements. Certain other lease arrangements, where the tax liabilities are considered immaterial, remain under review. Whilst legal opinions have been obtained to support the Santander UK group’s position, the matter remains uncertain pending formal resolution with HMRC and any subsequent litigation. These matters moved to formal litigation in 2017, as required under the terms of the leases, and it is currently anticipated that hearings will be held at the First Tier Tax Tribunal in 2022. Other On 2 November 2015, Visa Europe Ltd agreed to sell 100% of its share capital to Visa Inc. The deal closed on 21 June 2016. As a member and shareholder of Visa Europe Ltd, Santander UK received upfront consideration made up of cash and convertible preferred stock. Conversion of the preferred stock into Class A Common Stock of Visa Inc. depends on the outcome of litigation against Visa involving UK & Ireland (UK&I) multilateral interchange fees (MIFs). Following ring-fencing, all Visa stock is now held by Santander Equity Investments Limited (SEIL), outside the ring fenced bank. In valuing the preferred stock, SEIL makes adjustments for illiquidity and the potential for changes in conversion rate due to litigation costs. In June 2020, the Supreme Court issued a judgement finding that MIFs restricted competition. In 2020, this resulted in a change to the calculation of the fair value adjustments, which reduced the fair value of the convertible preferred stock by £10m. There has not been any further change to the calculation of the fair value adjustment in 2021. In September 2020, pursuant to the scheduled release assessment, Visa released half of the value of the convertible preferred stock. As a result of this release, SEIL was issued with 5,211 units of Series A Convertible Participating Preferred Stock (Series A Preferred Stock). In 2021, SEIL sold al l 5,211 units of Series A Preferred Stock for £82m . In addition, Santander UK and certain other UK&I banks have agreed to indemnify Visa Inc. in the event that the preferred stock is insufficient to meet the costs of this litigation. Visa Inc. has recourse to this indemnity once more than €1bn of losses relating to UK&I MIFs have arisen or once the total value of the preferred stock issued to UK&I banks on closing has been reduced to nil . Whilst Santander UK's liability under this indemnity is capped at €39.85m , Visa Inc. may have recourse to a general indemnity in place under Visa Europe Operating Regulations for damages not satisfied through the above mechanism. At this stage, it is unclear whether the litigation will give rise to more than €1bn of losses relating to UK&I MIFs which means it is difficult to predict the resolution of the matter including the timing or the significance of the possible impact. As part of the sale of subsidiaries, businesses and other entities, and as is normal in such circumstances, entities within the Santander UK group have given warranties and indemnities to the purchasers. Obligations under stock borrowing and lending agreements Obligations under stock borrowing and lending agreements represent contractual commitments to return stock borrowed. These obligations are offset by a contractual right to receive stock under other contractual agreements. See Note 36. Other off-balance sheet commitments The Santander UK group has commitments to lend at fixed interest rates which expose us to interest rate risk. For more, see the Risk review.
Santander UK Group Holdings plc
Disclosure of contingent liabilities [line items]
Contingent Liabilities and Commitments	CONTINGENT LIABILITIES AND COMMITMENTSDetails of the capital support arrangements entered into by the Company are set out in Note 31

Share Capital - Parent

Share Capital - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure of classes of share capital [line items]
Share Capital	32. SHARE CAPITAL Group Ordinary shares Issued and fully paid share capital No. £m At 31 December 2020, 1 January 2021 and 31 December 2021 7,060,000,000 7,060
Santander UK Group Holdings plc
Disclosure of classes of share capital [line items]
Share Capital	SHARE CAPITALDetails of the Company’s share capital are set out in Note 32

Other Equity Instruments - Pare

Other Equity Instruments - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure Of Other Equity Instruments [Line Items]
Other Equity Instruments	33. OTHER EQUITY INSTRUMENTS Group Interest rate 2021 2020 % Next call date £m £m AT1 securities: - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 6.75 June 2024 496 496 - £750m Fixed Rate Reset Perpetual AT1 Capital Securities 7.375 June 2022 745 745 - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 5.33 n/a — 500 - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 6.30 March 2025 500 500 - £450m Fixed Rate Reset Perpetual AT1 Capital Securities 4.25 March 2026 450 — 2,191 2,241 AT1 securities The AT1 securities are perpetual and pay a distribution on 24 March, June, September and December. At each distribution payment date, the Company can decide whether to pay the distribution, which is non-cumulative, in whole or in part. The distribution rate resets every five years. The securities will be automatically written down and the investors will lose their entire investment in the securities should the CET1 capital ratio of the Santander UK prudential consolidation group fall below 7%. They are redeemable at the option of the Company on their first call date or on any reset date thereafter in the cases of the 6.75% and 7.375% Fixed Rate Reset Perpetual AT1 Capital Securities, and on any distribution payment date thereafter in the case of the 6.30% Fixed Rate Reset Perpetual AT1 Capital Securities and on any day falling in the period commencing on (and including) 24 March 2026 and ending on (and including) the First Reset Date; or on any Distribution Payment Date subsequent to the First Reset Date, in the case of the 4.25% Fixed Rate Reset Perpetual AT1 Capital Securities . N o such redemption may be made without the consent of the PRA. The £450m 4.25% Fixed Rate Reset Perpetual AT1 Capital Securities and the £500m 6.30% Fixed Rate Reset Perpetual AT1 Capital Securities were fully subscribed by the Company’s immediate parent company, Banco Santander SA. £100m of the £750m 7.375% Fixed Rate Reset Perpetual AT1 Capital Securities were subscribed by Banco Santander SA. In March 2021, Santander UK Group Holdings plc purchased and redeemed the £500m 5.33% Fixed Rate Reset Perpetual AT1 Capital Securities and issued £450m 4.25% Fixed Rate Reset Perpetual AT1 Capital Securities, which were fully subscribed by the Company’s immediate parent company, Banco Santander SA.
Santander UK Group Holdings plc
Disclosure Of Other Equity Instruments [Line Items]
Other Equity Instruments	OTHER EQUITY INSTRUMENTSDetails of the Company’s other equity instruments are set out in Note 33

Transactions with Directors a_2

Transactions with Directors and Other Key Management Personnel - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure Of Directors And Key Management Remuneration [Line Items]
Transactions with Directors and Other Key Management Personnel	38. TRANSACTIONS WITH DIRECTORS AND OTHER KEY MANAGEMENT PERSONNEL The Directors of Santander UK Group Holdings plc did not receive any remuneration in respect of their services to the Company. The remuneration disclosures in these financial statements reflect their remuneration in respect of the Santander UK plc group. a) Remuneration of Directors and Other Key Management Personnel The remuneration of the Directors and Other Key Management Personnel of the Santander UK group is set out in aggregate below. 2021 2020 2019 Directors’ remuneration £ £ £ Salaries and fees 3,835,797 3,906,401 5,045,302 Performance-related payments (1) 5,195,722 748,495 3,896,382 Other fixed remuneration (pension and other allowances & non-cash benefits) 806,103 1,047,986 1,386,439 Expenses 3,705 2,579 42,526 Total remuneration 9,841,327 5,705,461 10,370,649 2021 2020 2019 Directors' and Other Key Management Personnel compensation £ £ £ Short-term employee benefits (2) 23,392,657 17,886,869 23,238,187 Post-employment benefits (3) 913,842 2,107,544 3,674,772 Total compensation 24,306,499 19,994,413 26,912,959 (1) In line with the Code, a proportion of the performance-related payment was deferred. Further details can be found in the Directors Remuneration Report. (2) In addition to the remuneration in the table above, grants of shares in Banco Santander SA were made as buy-outs of deferred performance-related payments of shares in connection with previous employment for one member of Key Management Personnel of £107,225 of which £25,413 vested in the year (2020: two individuals, one to a director of £1,293,678 of which £242,605 vested in the year and one to Key Management Personnel of £924,133 of which £60,500 vested in the year ). (3) No Termination payments were paid in 2021 to key management persons (2020: £nil ; 2019: £1,076,435 for one individual). In 2021, the remuneration, excluding pension contributions, of the highest paid Director, was £4,638,290 (2020: £2,200,138) of which £2,913,000 (2020: £748,495) was performance related. In 2021, the accrued defined benefit pension relating to the highest paid director was £22,119 per annum (2020: £21,309 per annum for the same individual). b) Retirement benefits Defined benefit pension schemes are provided to certain employees. See Note 30 for details of the schemes and the related costs and obligations. One director has a deferred pension benefit accruing under a defined benefit scheme. Ex gratia pensions paid to former Directors of Santander UK plc in 2021, which have been provided for previously, amounted to £370,668 (2020: £366,248; 2019: £335,202). In 1992, the Board decided not to award any new such ex gratia pensions. c) Transactions with Directors, Other Key Management Personnel and each of their connected persons Directors, Other Key Management Personnel (defined as the Executive Committee of Santander UK plc who served during the year) and their connected persons have undertaken the following transactions with the Santander UK group in the ordinary course of business. 2021 2020 No. £000 No. £000 Secured loans, unsecured loans and overdrafts At 1 January 9 1,825 18 4,920 Net movements (5) (1,798) (9) (3,095) At 31 December 4 27 9 1,825 Deposit, bank and instant access accounts and investments At 1 January 16 8,063 32 11,975 Net movements — (1,636) (16) (3,912) At 31 December 16 6,427 16 8,063 In 2021 and 2020, no Director held any interest in the shares of any company in the Santander UK group and no Director exercised or was granted any rights to subscribe for shares in any company in the Santander UK group. In addition, in 2021 and 2020, no Directors exercised share options over shares in Banco Santander SA, the ultimate parent company of the Company. Secured loans, unsecured loans and overdrafts are made to Directors, Other Key Management Personnel and their connected persons, in the ordinary course of business, with terms prevailing for comparable transactions and on the same terms and conditions as applicable to other employees in the Santander UK group. Such loans do not involve more than the normal risk of collectability or present any unfavourable features. Amounts deposited by Directors, Other Key Management Personnel and their connected persons earn interest at the same rates as those offered to the market or on the same terms and conditions applicable to other employees in the Santander UK group. Deposits, bank and instant access accounts and investments are entered into by Directors, Other Key Management Personnel and their connected persons on normal market terms and conditions, or on the same terms and conditions as applicable to other employees in Santander UK group. In 2021, loans were made to two Directors (2020: four Directors), with a principal amount of £15,430 outstanding at 31 December 2021 (2020: £13,994). In 2021, loans were made to two Other Key Management Personnel (2020: five), with a principal amount of £11,678 outstanding at 31 December 2021 (2020: £1,811,171). In 2021 and 2020, there were no other transactions, arrangements or agreements with Santander UK in which Directors, Other Key Management Personnel or their connected persons had a material interest. In addition, in 2021 and 2020, no Director had a material interest in any contract of significance with Santander UK other than a service contract.
Santander UK Group Holdings plc
Disclosure Of Directors And Key Management Remuneration [Line Items]
Transactions with Directors and Other Key Management Personnel	TRANSACTIONS WITH DIRECTORS AND OTHER KEY MANAGEMENT PERSONNELThe Directors of Santander UK Group Holdings plc did not receive any remuneration in respect of their services to the Company. The remuneration disclosures in respect of the Santander UK group are set out in Note 38

Related Party Disclosures - Par

Related Party Disclosures - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure of transactions between related parties [line items]
Related Party Disclosures	39. RELATED PARTY DISCLOSURES a) Parent undertaking and controlling party The Company’s immediate and ultimate parent and controlling party is Banco Santander SA, a company incorporated in Spain. The smallest and largest groups into which the Santander UK group’s results are included are the group accounts of Banco Santander SA , copies of which may be obtained from Shareholder Relations, 2 Triton Square, Regent’s Place, London NW1 3AN. b) Transactions with related parties Transactions with related parties during the year and balances outstanding at the year-end: Group Interest, fees and Interest, fees and Amounts owed by Amounts owed to 2021 2020 2019 2021 2020 2019 2021 2020 2021 2020 £m £m £m £m £m £m £m £m £m £m Ultimate parent (210) (120) (150) 34 158 334 1,049 1,857 (1,392) (2,463) Fellow subsidiaries (47) (54) (58) 151 148 158 20 37 (467) (498) Associates & joint ventures (34) (29) (29) 4 — — 3,075 2,234 (918) (1,034) (291) (203) (237) 189 306 492 4,144 4,128 (2,777) (3,995) For more on this, see ‘Balances with other Banco Santander companies’ in the Risk review. In addition, transactions with pension schemes operated by the Santander UK group are described in Note 30. The above transactions were made in the ordinary course of business, on substantially the same terms as for comparable transactions with third party counterparties, and within limits acceptable to the PRA. Such transactions do not involve more than the normal risk of collectability or present any unfavourable features. In 2020, Santander Consumer (UK) plc (SCUK) purchased a 50% share in a new joint venture, Volvo Car Financial Services UK Limited. In 2021, £390m of dealer lending was transferred from SCUK to the new entity. In 2021, SCUK sold its entire 50% shareholding in PSA Finance UK Limited to PSA Financial Services Spain EFC SA, a joint venture between Santander Consumer Finance SA, a fellow subsidiary of Banco Santander SA, and Banque PSA Finance SA. For more details, see Note 34. In 2021, a significant part of the Corporate & Investment Banking business of Santander UK was transferred to the London branch of Banco Santander SA by way of a Part VII banking business transfer scheme. For more details, see Note 43. In 2021, we sold our current head office site in Triton Square, London to a wholly owned subsidiary of our parent.
Santander UK Group Holdings plc
Disclosure of transactions between related parties [line items]
Related Party Disclosures	RELATED PARTY TRANSACTIONSThe Company’s only transactions with related parties arise in connection with the receipt of dividends declared by its subsidiaries, payment of dividends on its own ordinary shares and Perpetual Capital Securities, interest payments to its subsidiary on intercompany loans and interest received from its subsidiaries relating to downstreamed funding of senior debt, as well as any transactions entered into as part of the implementation of Santander UK’s ring-fencing plans.

Events After the Balance Shee_2

Events After the Balance Sheet Date - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure of non-adjusting events after reporting period [line items]
Events After the Balance Sheet Date	44. EVENTS AFTER THE BALANCE SHEET DATE There have been no significant events between 31 December 2021 and the date of approval of these financial statements which would require a change to or additional disclosure in the financial statements.
Santander UK Group Holdings plc
Disclosure of non-adjusting events after reporting period [line items]
Events After the Balance Sheet Date	EVENTS AFTER THE BALANCE SHEET DATESee Note 44

Interest Rate Benchmark Reform

Interest Rate Benchmark Reform - Parent	12 Months Ended
	Dec. 31, 2021
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Interest Rate Benchmark Reform	42. INTEREST RATE BENCHMARK REFORM In September 2019, the IASB amended IFRS 9 'Financial Instruments', IAS 39 'Financial Instruments: Recognition and Measurement' and IFRS 7 'Financial Instruments: Disclosures' to address issues affecting financial reporting in the period before the reform of an interest rate benchmark, including the replacement of an interest rate benchmark with an alternative benchmark rate (the Phase 1 amendments). These Phase 1 amendments provided temporary exceptions to specific hedge accounting requirements because of the uncertainty arising from the reform. After issuing the Phase 1 amendments, in August 2020, the IASB issued further amendments to various IFRSs to address issues that might affect financial reporting during the reform of an interest rate benchmark, including the effects of changes to contractual cash flows or hedging relationships arising from the replacement of an interest rate benchmark with an alternative benchmark rate (the Phase 2 amendments). The Phase 2 amendments do not supersede the Phase 1 amendments. In March 2021, the FCA confirmed that all LIBOR settings will either cease to be provided by any administrator or no longer be representative: – immediately after 31 December 2021, in the case of all sterling, euro, Swiss franc and Japanese yen settings, and the 1-week and 2-month US dollar settings; and – immediately after 30 June 2023, in the case of the remaining US dollar settings (i.e. overnight, 1-month, 3-month, 6-month and 12-month). Under the UK Benchmarks Regulation (BMR), the FCA may designate LIBOR, or individual tenor/currency LIBOR rates, as Article 23A benchmarks if the benchmark has become, or is at risk of becoming, unrepresentative. In September 2021, the FCA designated 1-month, 3-month, and 6-month GBP and JPY LIBOR as Article 23A benchmarks, with effect from 00:01 on 1 January 2022. This enabled the FCA to reduce disruption to holders of legacy contracts through requiring the continued provision of LIBOR rates using a modified methodology. This modified methodology is commonly referred to as a 'synthetic' LIBOR. The synthetic rates will be calculated using the methodology proposed by the FCA in June 2021, being the sum of the forward-looking term rate for the relevant currency/tenor combination and the applicable ISDA spread adjustment. Furthermore, pursuant to the Critical Benchmarks (References and Administrators’ Liability) Act 2021, references to GBP and JPY LIBOR in contracts governed by a law of the United Kingdom are deemed to be references to the applicable synthetic LIBOR rate, subject to the operation of fallback provisions that are intended to transition the contract to an alternative reference rate on a particular date or, for example, on the applicable LIBOR rate becoming unrepresentative. The FCA has permitted legacy use of the 6 synthetic LIBOR settings in all contracts except cleared derivatives and does not propose to apply any limitations or conditionality to the above permissions, at least before the end of 2022. Consequently, the Phase 1 amendments continue to apply to Santander UK's GBP LIBOR cash flow hedges for these legacy contracts and for USD LIBOR cash flow hedges (but not any using 1-week or 2-month USD LIBOR settings). Phase 1 amendments The amendments provide temporary exceptions from applying specific hedge accounting requirements to hedging relationships that are directly affected by the IBOR reform. The exceptions have the effect that IBOR reform should not generally cause hedge accounting to terminate, however any hedge ineffectiveness continues to be recognised in the income statement. The exceptions end at the earlier of: – when the uncertainty regarding the timing and the amount of interest rate benchmark-based cash flows is no longer present, and – discontinuance of the hedge relationship (or reclassification of all amounts from the cash flow hedge reserve). The amendments apply to all hedging relationships directly affected by uncertainties related to IBOR reform and had no impact on hedge relationships for affected hedges. The main assumptions or judgements made by Santander UK in applying the amendments are outlined below. – For cash flow hedges where the hedged items are tough legacy contracts (as explained above), Santander UK management has assumed that the interest rate benchmark on which hedged cash flows are based is not altered as a result of IBOR reform when assessing whether the future cash flows are highly probable. For discontinued hedging relationships, the same assumption has been applied for determining whether the hedged future cash flows are expected to occur. – In making its prospective hedge effectiveness assessments, Santander UK assumes that the interest rate benchmark on which the hedged item and the hedging instrument are based is not altered as a result of IBOR reform. – Santander UK will not discontinue hedge accounting during the period of IBOR-related uncertainty solely because the retrospective effectiveness falls outside the required 80-125% range. – For hedges of a non-contractually specified benchmark portion of an interest rate, Santander UK only considers at inception of such a hedging relationship whether the separately identifiable requirement is met. Phase 2 amendments These amendments apply only to changes required by IBOR reform to financial instruments and hedging relationships. Changes are directly required by IBOR reform if, and only if, the change is necessary as a direct consequent of interest rate benchmark reform, and the new basis for determining the contractual cash flow is economically equivalent to the previous basis. The exceptions given by the amendments mean that IBOR reform did not result in the discontinuation of hedge accounting and any hedge ineffectiveness continued to be recognised in profit or loss for affected hedges at and for the year ended 31 December 2021. The amendments address the accounting issues for financial instruments when IBOR reform is implemented as described below. Practical expedient for changes to contractual cash flows For instruments to which the amortised cost measurement applies, the amendments require entities, as a practical expedient, to account for a change in the basis for determining the contractual cash flows by updating the effective interest rate using the guidance in IFRS 9 resulting in no immediate gain or loss being recognised, provided that, the change is directly required by IBOR reform and takes place on an economically equivalent basis. Whereas the majority of instruments referencing LIBOR or other IBORs transitioned to alternative benchmark interest rates during 2021, legacy contracts and USD LIBOR cash flow hedges remain. Santander UK has no lease contracts which are indexed to LIBOR or other IBORs. The practical expedient was applied to all instruments or contracts that transitioned to alternative benchmark interest rates during 2021 and had no material impact for the Santander UK group. Relief from specific hedge accounting requirements The table below sets out the hedge accounting amendments, and their impact for Santander UK, which provide additional temporary reliefs from applying specific IAS 39 hedge accounting requirements to hedging relationships directly affected by IBOR reform. For GBP LIBOR cash flow hedges of legacy contracts and for USD LIBOR cash flow hedges, the transition to alternative benchmark interest rates will take place during 2022 and, for USD LIBOR cash flow hedges, no later than June 2023. Hedge accounting amendment Impact for the Santander UK group Allow amendment of the designation of a hedging relationship to reflect changes that are required by the reform. The hedge designation must be amended by the end of the reporting period in which the changes are made. This amendment means any change to hedge documentation will not result in discontinuation of hedge accounting nor the designation of a new hedge relationship. It expects the majority of its hedge relationships will transition to alternative benchmark rates during 2021 and Santander UK group used this relief for those hedges that transitioned. When a hedged item in a cash flow hedge is amended to reflect the changes that are required by the reform, the amount accumulated in the cash flow hedge reserve will be deemed to be based on the alternative benchmark rate on which the hedged future cash flows are determined. This amendment would result in the release of the cash flow hedge reserve to profit or loss in the same period or periods in which the hedged cash flows that are now based on the alternative benchmark interest rate affect profit or loss. During the year, most of the Santander UK group’s GBP LIBOR cash flow hedges transitioned to alternative benchmark interest rates. An entity may, on an individual hedge basis, reset to zero the cumulative fair value changes of the hedged item and hedging instrument when ceasing to apply the retrospective effectiveness assessment relief provided by the Phase 1 amendments. The Santander UK group assessed on a hedge-by-hedge basis as the hedging instruments transitioned away from LIBORs or other IBORs during 2021. Resetting the cumulative fair value changes to zero had no effect on the amounts recorded in profit or loss. All hedge ineffectiveness including any outside the 80-125% range arising from IBOR reform has been recognised in profit or loss. When amending the hedge relationships for groups of items, hedged items are allocated to sub-groups based on the alternative benchmark interest rate being hedged, and the benchmark rate for each sub-group is designated as the hedged risk. All hedge relationships have transitioned to alternative benchmark interest rates and hedge documentation was amended accordingly. An alternative benchmark interest rate designated as a non-contractually specified risk component, that is not separately identifiable at the date when it is designated, is deemed to have met the requirements at that date if the entity reasonably expects that it will meet the requirements within a period of 24 months from the date of first designation. The 24-month period will apply to each alternative benchmark interest rate separately. The risk component will, however, be required to be reliably measurable. The amendment eases transition to alternative benchmark interest rates by allowing hedging relationships to be designated and to continue even before the new benchmark interest rates are fully established as market benchmarks. For the Santander UK group, the majority of hedge relationships, where an alternative benchmark interest rate is to be designated as a non-contractually specified risk component, were GBP fair value hedge relationships and most transitioned to SONIA during the year, and this rate was considered separately identifiable. For other changes that are not as a direct consequence of IBOR reform, Santander UK separately assesses those changes to determine if they result in derecognition or discontinuation of hedge accounting by applying the relevant accounting policies as set out in Note 1. Managing LIBOR transition Following the decision by global regulators to phase out IBORs and replace them with alternative reference rates, Santander UK set up a project to oversee the design of alternative reference rate products and the transition for any legacy contracts referencing affected IBOR rates. The CFO sponsored the project and it was driven by senior staff from across the business, including our client-facing business areas, Legal, Compliance, Risk, Operations and Technology, and Finance. It had a formal governance structure, including a Senior Management Forum that met monthly, and thematic and product working groups. ALCO, ERCC and the Board Risk Committee received regular reports. IBOR reform exposed banks to various risks, which were monitored and managed closely. These included: – Conduct risk arising from discussions with clients and market counterparties due to the changes to existing contracts needed to effect IBOR transition – Risk of financial losses to our clients and us if markets were disrupted due to IBOR transition – Pricing risk from potential lack of market data if liquidity in IBORs reduced before some RFRs became liquid – Operational risk arising from changes to IT systems and processes, and the risk of payments being disrupted if IBORs ceased to be available – Accounting risk if hedging relationships failed, and from unrepresentative income statement volatility as financial instruments transition to RFRs. While these risks were increased somewhat by diverging approaches to IBOR transition in different geographies, Santander UK’s main exposures were to GBP LIBOR corporate loans and derivatives, and the IBOR reform developments in different countries were closely monitored. Santander UK also recognised that IBOR transition presented potential challenges for customers. We communicated with customers and launched a website to provide more information and help outline options available. Santander UK also continued to participate actively in industry forums and consultations in 2021. New reference rate products were deployed to support the transition from IBORs and, in 2021, the majority of affected legacy contracts were transitioned from the LIBOR rates ceasing at the end of the year. Santander UK continues to work with its customers to agree the transition of the relatively small number of agreements that remained un-transitioned at the end of 2021. The following tables show the notional amounts of assets, liabilities and off-balance sheet commitments at 31 December 2021 and 31 December 2020 affected by IBOR reform that have yet to transition to an alternative benchmark interest rate. Group 2021 GBP (3) LIBOR USD (3) LIBOR Other (3) Total £m £m £m £m Assets Derivatives (1)(2) — 1,648 — 1,648 Other financial assets at fair value through profit and loss 8 — — 8 Financial assets at amortised cost 1,373 81 1 1,455 1,381 1,729 1 3,111 Liabilities Derivatives (1)(2) 338 1,975 — 2,313 Other financial liabilities at fair value through profit and loss — 5 — 5 Financial liabilities at amortised cost (4) 34 2,401 — 2,435 372 4,381 — 4,753 Off-balance sheet commitments given 338 59 — 397 2020 Assets Derivatives (1)(2) 33,857 4,844 2,149 40,850 Other financial assets at fair value through profit and loss 968 22 — 990 Financial assets at amortised cost 15,062 1,191 90 16,343 Financial assets at fair value through comprehensive income 428 — — 428 50,315 6,057 2,239 58,611 Liabilities Derivatives (1)(2) 35,312 5,381 88 40,781 Other financial liabilities at fair value through profit and loss 1,128 69 — 1,197 Financial liabilities at amortised cost 2,354 3,515 — 5,869 38,794 8,965 88 47,847 Off-balance sheet commitments given 11,405 2,126 573 14,104 (1) Many of the Santander UK group’s derivatives subject to IBOR reform are governed by ISDA definitions. In October 2020 ISDA issued an IBOR fallbacks supplement setting out how the amendments to new alternative benchmark rates will be accomplished, the effect of which is to create fallback provisions in derivatives that describe what floating rates will apply on the permanent discontinuation of certain key IBORs or upon ISDA declaring a non-representative determination of an IBOR. The Santander UK group has adhered to the protocol to implement the fallbacks to derivative contracts that were entered into before the effective date of the supplement (25 January 2021). If derivative counterparties also adhere to the pro tocol, new fallbacks will automatically be implemented in existing derivative contracts when the supplement becomes effective. Following the announcement by the FCA on 5 March 2021 that certain LIBOR settings will permanently cease immediately after 31 December 2021 (and for overnight, 1-month, 3-month, 6-month and 12-month US dollar LIBOR after 30 June 2023), the ISDA fallback spread adjustment is fixed as of the date of the FCA announcement. GBP & JPY LIBOR for certain legacy contracts has been extended until at least the end of 2022 but not for cleared derivative contracts. (2) Derivatives shown in the table above exclude contracts that automatically transitioned under ISDA fall back protocols at 00:01 on 1 January 2022. (3) Cessation dates are: GBP, JPY, NOK LIBOR & 1-week and 2-month USD LIBOR 31/12/2021 remaining USD LIBOR settings 30/06/23, EONIA 03/01/2022; GBP & JPY LIBOR for certain legacy contracts has been extended until at least 31/12/2022. (4) Financial liabilities at amortised cost is comprised of securitisation issuance which was called in January 2022. The following tables show the notional amount of derivatives in hedging relationships directly affected by uncertainties related to IBOR reform. 2021 2020 GBP USD Other Total GBP USD Other Total £m £m £m £m £m £m £m £m Total notional value of hedging instruments: – Cash flow hedges — 2,586 — 2,586 15,198 5,119 — 20,317 – Fair value hedges — 160 — 160 32,223 1,077 778 34,078 — 2,746 — 2,746 47,421 6,196 778 54,395 Maturing after cessation date (1) – Cash flow hedges — 2,586 — 2,586 10,553 2,562 — 13,115 – Fair value hedges — 160 — 160 12,477 162 720 13,359 — 2,746 — 2,746 23,030 2,724 720 26,474 (1) Cessation dates are: GBP, JPY, NOK LIBOR & 1-week and 2-month USD LIBOR 31/12/2021, for remaining USD LIBOR settings 30/06/23, EONIA 03/01/2022; GBP & JPY LIBOR for certain legacy contracts has been extended until at least 31/12/2022. The Santander UK group’s USD LIBOR cash flow hedges extend beyond the anticipated cessation dates for LIBOR. The Santander UK group expects that USD LIBOR will be replaced by SOFR but there remains uncertainty over the timing and amount of the replacement rate cash flows for USD LIBOR cash flow hedges. Hedging relationships impacted by uncertainty about IBOR reform may experience ineffectiveness due to market participants’ expectations of when the shift from the existing IBOR benchmark rate to an alternative benchmark interest rate will occur or because transition of the hedged item and the hedging instrument could occur at different times. The Santander UK group will cease to apply the assumptions that the hedged benchmark interest rate, the cash flows of the hedged item and/or hedging instrument will not be altered because of IBOR reform when the uncertainty arising from IBOR reform is no longer present. This will require amendment to hedge documentation by the end of the reporting period in which the changes occur. Cumulative changes in the hedged cash flows and the hedging instrument based on new alternative benchmark rates will also be remeasured when IBOR reform uncertainty is removed.
Santander UK Group Holdings plc
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Interest Rate Benchmark Reform	INTEREST RATE BENCHMARK REFORM At 31 December 2021, the Company had £2,217m (2020: £2,196m ) of USD LIBOR-linked Financial liabilities at amortised cost that were affected by IBOR reform and have yet to transition to an alternative benchmark interest rate as provided internally to key management personnel. Further details of the significant interest rate benchmarks to which hedging relationships are exposed, the extent of risk exposure that is affected by IBOR reform, the effect of IBOR reform on interest rate risk management and how Santander UK's transition to alternative benchmark interest rates is being managed, are disclosed in Note 42 to the Consolidated Financial Statements and the Banking market risk section of the Risk review.

Accounting Policies (Policies)

Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Significant Accounting Policies [Abstract]
Basis of preparation and accounting developments	Basis of preparation These financial statements incorporate the financial statements of the Company and entities it controls (its subsidiaries) made up to 31 December each year. The consolidated financial statements have been prepared on the going concern basis using the historical cost convention, except for financial assets and liabilities that have been measured at fair value. An assessment of the appropriateness of the adoption of the going concern basis of accounting is disclosed in the statement of going concern in the Directors’ report. On 31 December 2020, International Financial Reporting Standards (IFRSs) as adopted by the European Union at that date were brought into UK law and became UK-adopted International Accounting Standards (IAS), with future changes being subject to endorsement by the UK Endorsement Board. The Company and its subsidiaries transitioned to UK-adopted IAS in its consolidated financial statements on 1 January 2021. This change constitutes a change in accounting framework. Although there was a change in accounting framework, this change had no impact on recognition, measurement or disclosures in the periods reported in these financial statements. Compliance with International Financial Reporting Standards The consolidated financial statements of the Santander UK group and the separate financial statements of the Company comply with UK-adopted IAS. The financial statements are also prepared in accordance with IFRSs as issued by the International Accounting Standards Board (IASB), including interpretations issued by the IFRS Interpretations Committee, as there are no applicable differences from IFRSs as issued by the IASB for the periods presented. Disclosures required by IFRS 7 ‘Financial Instruments: Disclosure’ relating to the nature and extent of risks arising from financial instruments, and IAS 1 ‘Presentation of Financial Statements’ relating to objectives, policies and processes for managing capital, can be found in the risk governance, credit risk, market risk, liquidity risk and capital risk sections of the Risk review and are labelled as audited. Those disclosures form an integral part of these financial statements. Climate change Santander UK continues to develop its assessment of the potential impacts that climate change and the transition to a low carbon economy may have on the assets and liabilities recognised and presented in its financial statements. Santander UK is mindful of its responsibilities as a responsible lender and is focused on ways to meet the objectives of the Paris Agreement on climate change and to support the UK’s transition to a climate-resilient, net zero economy. Santander UK's current climate change strategy focuses on three main areas to achieve Banco Santander's ambition to reach net zero emissions by 2050: 1. Managing climate risks by integrating climate considerations into risk management frameworks, screening and stress testing our portfolio for climate related financial risks, and setting risk appetites to help steer our portfolio in line with the Paris Agreement, 2. Supporting our customers’ transition by developing products and services that promote a reduction in CO 2 emissions, and 3. Reducing emissions in our operations and supply chain by focusing on continuous improvement in our operations, and environmental and energy management systems in accordance with ISO14001 and 15001, promoting responsible procurement practices and employee engagement. Santander UK's current climate change strategy and its view of the risks associated with climate change and the transition to a low carbon economy are reflected in its critical judgements and accounting estimates, although climate change risk did not have a significant impact at 31 December 2021, consistent with management's assessment that climate change and the transition to a low carbon economy are not currently expected to have a meaningful impact on the viability of the Santander UK group in the medium term. At 31 December 2021, management specifically considered the potential impact of climate change and the transition to a low carbon economy on: – Loans and advances to customers (see Note 13 and the credit risk section of the Risk review). Some climate change risks arise due to the requirements of IFRS 9 and others relate to specific portfolios and sectors: – ECL calculations are based on multiple forward-looking economic scenarios developed by management covering a period of 5 years, during which timeframe climate change risks may crystallise. – For Mortgages in Retail Banking and Commercial Real Estate lending in Corporate & Commercial Banking, the value of property collateral might be affected by physical impacts related to the frequency and scale of extreme weather events, such as flood and subsidence risk, or changing environmental performance standards for property. – For automotive loans in Consumer Finance, the residual value of automotive vehicles might be impacted by diesel obsolescence and the transition to electric vehicles. – For corporate lending in Corporate & Commercial Banking, certain sectors give rise to fossil fuel exposures, such as Oil & Gas, Mining & Extraction and Power Generation. – Goodwill impairment assessment (see Note 20). Estimates underpinning the determination of whether or not goodwill balances are impaired are partly based on forecast business performance beyond the time horizon for management's detailed plans. Future changes to Santander UK's climate change strategy may impact Santander UK's critical judgements and accounting estimates and result in material changes to financial results and the carrying values of certain assets and liabilities in future reporting periods. Accounting developments Interest Rate Benchmark Reform In 2019, the IASB issued ‘Interest Rate Benchmark Reform: Amendments to IFRS 9, IAS 39 and IFRS 7’. The Santander UK group applies IAS 39 hedge accounting so the amendments to IFRS 9 do not apply. Although the IAS 39 and IFRS 7 amendments, which apply to all hedging relationships directly affected by uncertainties related to interbank offered rate (IBOR) reform, became effective from 1 January 2020, following their endorsement, the Santander UK group early adopted those amendments in the preparation of the financial statements for the year ended 31 December 2019. The exceptions given by the IAS 39 amendments meant that IBOR reform had no impact on hedge relationships for affected hedges. In 2020, the IASB issued ‘Interest Rate Benchmark Reform – Phase 2 - Amendments to IFRS 9, IAS 39, IFRS 7, IFRS 4 and IFRS 16’. These amendments apply only to changes required by IBOR reform to financial instruments and hedging relationships. Although the amendments became effective from 1 January 2021 and are applied retrospectively without restating comparative information, following their endorsement, the Santander UK group early adopted the amendments in the preparation of the financial statements for the year ended 31 December 2020. The amendments address the accounting issues for financial instruments when IBOR reform is implemented including providing a practical expedient for changes to contractual cash flows, giving relief from specific hedge accounting requirements, and specifying a number of additional disclosures to enable users of financial statements to understand the effect of IBOR reform on an entity’s financial instruments and risk management strategy. Further details of the impact of these amendments on the financial statements for the year ended 31 December 2021 and the additional disclosures required are provided in Note 43. Other changes The Santander UK group adopted IFRS 16 and amendments to IAS 12 in 2019, with the impact included in the statement of changes in equity for that year end. Future developments At 31 December 2021 , for the Santander UK group, there were no significant new or revised standards and interpretations, and amendments thereto, which have been issued but which are not yet effective, or which have otherwise not been early adopted where permitted. Comparative information As required by US public company reporting requirements, these financial statements include two years of comparative information for the consolidated income statement, consolidated statement of comprehensive income, consolidated statement of changes in equity, consolidated statement of cash flows and related notes. Basis of preparation The accounting policies of the Company are the same as those of the Santander UK Group Holdings plc group which are set out in Note 1 to the extent that the Company has similar transactions to the Santander UK Group Holdings plc group, except as set out below.
Consolidation	Consolidation a) Subsidiaries The consolidated financial statements incorporate the financial statements of the Company and entities (including structured entities) controlled by it and its subsidiaries. Control is achieved where the Company (i) has power over the investee; (ii) is exposed, or has rights, to variable returns from its involvement with the investee; and (iii) has the ability to use its power to affect its returns. The Company reassesses whether or not it controls an investee if facts and circumstances indicate that there are changes to one or more of the three elements of control listed above. When the Company has less than a majority of the voting rights of an investee, it has power over the investee when the voting rights are sufficient to give it the practical ability to direct the relevant activities of the investee unilaterally. The Company considers all relevant facts and circumstances in assessing whether or not the Company's voting rights in an investee are sufficient to give it power, including: – The size of the Company's holding of voting rights relative to the size and dispersion of holdings of the other vote holders – Potential voting rights held by the Company, other vote holders or other parties – Rights arising from other contractual arrangements – Any additional facts and circumstances that indicate that the Company has, or does not have, the current ability to direct the relevant activities at the time that decisions need to be made, including voting patterns at previous shareholders' meetings. Consolidation of a subsidiary begins when the Company obtains control over the subsidiary and ceases when the Company loses control of the subsidiary. Specifically, the results of a subsidiary acquired or disposed of during the year are included in the consolidated income statement and the consolidated statement of comprehensive income from the date the Company gains control until the date the Company loses control. Inter-company transactions, balances and unrealised gains on transactions between Santander UK group companies are eliminated; unrealised losses are also eliminated unless the cost cannot be recovered. The acquisition method of accounting is used to account for the acquisition of subsidiaries which meet the definition of a business. The cost of an acquisition is measured at the fair value of the assets given up, shares issued or liabilities undertaken at the date of acquisition. Acquisition-related costs are expensed as incurred. The excess of the cost of acquisition, as well as the fair value of any interest previously held, over the fair value of the Santander UK group’s share of the identifiable net assets of the subsidiary at the date of acquisition is recorded as goodwill. When the Santander UK group loses control of a subsidiary, the profit or loss on disposal is calculated as the difference between (i) the aggregate of the fair value of the consideration received and the fair value of any retained interest and (ii) the previous carrying amount of the assets (including goodwill), less liabilities of the subsidiary and any non-controlling interests. Amounts previously recognised in other comprehensive income in relation to the subsidiary are accounted for (i.e. reclassified to profit or loss or transferred directly to retained earnings) in the same manner as would be required if the relevant assets or liabilities are disposed of. The fair value of any investment retained in a former subsidiary at the date when control is lost is regarded as the fair value on initial recognition for subsequent accounting under IFRS 9 or, when applicable, the costs on initial recognition of an investment in an associate or joint venture. Business combinations between entities under common control (i.e. fellow subsidiaries of Banco Santander SA, the ultimate parent) are outside the scope of IFRS 3 – ‘Business Combinations’, and there is no other guidance for such transactions under IFRS. The Santander UK group elects to account for business combinations between entities under common control at their book values in the acquired entity by including the acquired entity’s results from the date of the business combination and not restating comparatives. Reorganisations of entities within the Santander UK group are also accounted for at their book values. Interests in subsidiaries are eliminated during the preparation of the consolidated financial statements. Interests in subsidiaries in the Company unconsolidated financial statements are held at cost subject to impairment. Credit protection entities established as part of significant risk transfer (SRT) transactions are not consolidated by the Santander UK group in cases where third party investors have the exposure, or rights, to all of the variability of returns from the performance of the entities. b) Joint ventures Joint ventures are joint arrangements whereby the parties that have joint control of the arrangement have rights to its net assets. Joint control is the contractually agreed sharing of control of an arrangement, which exists only when decisions about the relevant activities require unanimous consent of the parties sharing control. Accounting policies of joint ventures have been aligned to the extent there are differences from the Santander UK group’s policies. Investments in joint ventures are accounted for by the equity method of accounting and are initially recorded at cost and adjusted each year to reflect the Santander UK group’s share of their post-acquisition results. When the Santander UK group's share of losses of a joint venture exceeds its interest in that joint venture, the Santander UK group discontinues recognising its share of further losses. Further losses are recognised only to the extent that the Santander UK group has incurred legal or constructive obligations or made payments on behalf of the joint venture.
Foreign currency translation	Foreign currency translation Items included in the financial statements of each entity (including foreign branch operations) in the Santander UK group are measured using the currency that best reflects the economic substance of the underlying events and circumstances relevant to that entity (the functional currency). The consolidated financial statements are presented in sterling, which is the functional currency of the Company. Income statements and cash flows of foreign entities are translated into the Santander UK group’s presentation currency at average exchange rates for the year and their balance sheets are translated at the exchange rates ruling on 31 December. Exchange differences on the translation of the net investment in foreign entities are recognised in other comprehensive income. When a foreign entity is sold, such exchange differences are recognised in the income statement as part of the gain or loss on sale. Foreign currency transactions are translated into the functional currency of the entity involved at the exchange rates prevailing at the dates of the transactions. Foreign exchange gains and losses resulting from the settlement of such transactions and from the translation of monetary assets and liabilities denominated in foreign currencies are recognised in the income statement unless recognised in other comprehensive income in connection with a cash flow hedge. Non-monetary items denominated in a foreign currency measured at historical cost are not retranslated. Exchange rate differences arising on non-monetary items measured at fair value are recognised in the consolidated income statement except for differences arising on equity securities measured at fair value through other comprehensive income (FVOCI), which are recognised in other comprehensive income.
Revenue recognition	Revenue recognition a) Interest income and expense Interest and similar income comprise interest income on financial assets measured at amortised cost, investments in debt instruments measured at FVOCI and interest income on hedging derivatives. Interest expense and similar charges comprises interest expense on financial liabilities measured at amortised cost, and interest expense on hedging derivatives. Interest income on financial assets measured at amortised cost, investments in debt instruments measured at FVOCI and interest expense on financial liabilities other than those at fair value through profit or loss (FVTPL) is determined using the effective interest rate method. The effective interest rate is the rate that discounts the estimated future cash payments or receipts over the expected life of the instrument or, when appropriate, a shorter period, to the gross carrying amount of the financial asset (i.e. its amortised cost before any impairment allowance) or to the amortised cost of a financial liability. When calculating the effective interest rate, the future cash flows are estimated after considering all the contractual terms of the instrument excluding expected credit losses. The calculation includes all amounts paid or received by the Santander UK group that are an integral part of the overall return, direct incremental transaction costs related to the acquisition, issue or disposal of the financial instrument and all other premiums or discounts. Interest income is calculated by applying the effective interest rate to the gross carrying amount of financial assets, except for financial assets that have subsequently become credit-impaired (i.e. Stage 3), for which interest revenue is calculated by applying the effective interest rate to their amortised cost (i.e. net of the ECL provision). For more information on stage allocations of credit risk exposures, see ‘Significant increase in credit risk’ in the ‘Santander UK group level – credit risk management’ section of the Risk review. b) Fee and commission income and expense Fees and commissions that are not an integral part of the effective interest rate are recognised when the service is performed. Most fee and commission income is recognised at a point in time. Certain commitment, upfront and management fees are recognised over time but are not material. For retail and corporate products, fee and commission income consists principally of collection services fees, commission on foreign currencies, commission and other fees received from retailers for processing credit card transactions, fees received from other credit card issuers for providing cash advances for their customers through the Santander UK group’s branch and ATM networks, annual fees payable by credit card holders and fees for non-banking financial products. For insurance products, fee and commission income consists principally of commissions and profit share arising from the sale of building and contents insurance and life protection insurance. Commissions arising from the sale of buildings and contents insurance are recognised over the period of insurance cover, adjusted to take account of cancelled policies. Profit share income from the sale of buildings and contents insurance which is not subject to any adjustment is recognised when the profit share income is earned. Commissions and profit share arising from the sale of life protection insurance is subject to adjustment for cancellations of policies within 3 years from inception. Fee and commission income which forms an integral part of the effective interest rate of a financial instrument (for example certain loan commitment fees) is recognised as an adjustment to the effective interest rate and recorded in ‘Interest income’. c) Dividend income Except for equity securities classified as trading assets or financial assets held at fair value through profit or loss, described below, dividend income is recognised when the right to receive payment is established. This is the ex-dividend date for equity securities. d) Other operating income Other operating income includes all gains and losses from changes in the fair value of financial assets and liabilities held at fair value through profit or loss (comprising financial assets and liabilities held for trading, trading derivatives and other financial assets and liabilities at fair value through profit or loss), together with related interest income, expense, dividends, and changes in fair value of any derivatives managed in conjunction with these assets and liabilities. Changes in fair value of derivatives in a fair value hedging relationship are also recognised in other operating income. Other operating income also includes income from operating lease assets, and profits and losses arising on the sales of property, plant and equipment and subsidiary undertakings.
Borrowing costs	Borrowing costs Borrowing costs directly attributable to the acquisition, construction, or production of qualifying assets, including computer software, which are assets that necessarily take a substantial period of time to develop for their intended use, are added to the cost of those assets, until the assets are substantially ready for their intended use. All other borrowing costs are recognised in profit or loss in the period in which they occur.
Pensions and other post-retirement benefits	Pensions and other post-retirement benefits a) Defined benefit schemes A defined benefit scheme is a pension scheme that guarantees an amount of pension benefit to be provided, usually as a function of one or more factors such as age, years of service or compensation. Pension costs are charged to ‘Administration expenses’, within the line item ‘Operating expenses before impairment losses, provisions and charges’ with the net interest on the defined benefit asset or liability included within ‘Net interest income’ in the income statement. The asset or liability recognised in respect of defined benefit pension schemes is the present value of the defined benefit obligation at the balance sheet date, less the fair value of scheme assets. The defined benefit obligation is calculated annually by independent actuaries using the projected unit credit method. The assets of the schemes are measured at their fair values at the balance sheet date. The present value of the defined benefit obligation is estimated by projecting forward the growth in current accrued pension benefits to reflect inflation and salary growth to the date of pension payment, then discounted to present value using the yield applicable to high-quality AA rated corporate bonds of the same currency and which have terms to maturity closest to the terms of the scheme liabilities, adjusted where necessary to match those terms. In determining the value of scheme liabilities, demographic and financial assumptions are made by management about life expectancy, inflation, discount rates, pension increases and earnings growth, based on past experience and future expectations. Financial assumptions are based on market conditions at the balance sheet date and can generally be derived objectively. Demographic assumptions require a greater degree of estimation and judgement to be applied to externally derived data. Any surplus or deficit of scheme assets over liabilities is recognised in the balance sheet as an asset (surplus) or liability (deficit). An asset is only recognised to the extent that the surplus can be recovered through reduced contributions in the future or through refunds from the scheme. The income statement includes the net interest income/expense on the net defined benefit liability/asset, current service cost and any past service cost and gain or loss on settlement. Remeasurement of defined benefit pension schemes, including return on scheme assets (excludes amounts included in net interest), actuarial gains and losses (arising from changes in demographic assumptions, the impact of scheme experience and changes in financial assumptions) and the effect of the changes to the asset ceiling (if applicable), are recognised in other comprehensive income. Remeasurement recognised in other comprehensive income will not be reclassified to the income statement. Past service costs are recognised as an expense in the income statement at the earlier of when the scheme amendment or curtailment occurs and when the related restructuring costs or termination benefits are recognised. Curtailments include the impact of significant reductions in the number of employees covered by a scheme, or amendments to the terms of the scheme so that a significant element of future service will no longer qualify for benefits or will qualify only for reduced benefits. Curtailment gains and losses on businesses that meet the definition of discontinued operations are included in profit or loss for the year from discontinued operations. Gains and losses on settlements are recognised when the settlement occurs. b) Defined contribution plans A defined contribution plan is a pension scheme under which the Santander UK group pays fixed contributions as they fall due into a separate entity (a fund). The pension paid to the member at retirement is based on the amount in the separate fund for each member. The Santander UK group has no legal or constructive obligations to pay further contributions into the fund to ‘top up’ benefits to a certain guaranteed level. The regular contributions constitute net periodic costs for the year in which they are due and are included in staff costs within Operating expenses in the income statement. c) Post-retirement medical benefit plans Post-retirement medical benefit liabilities are determined using the projected unit credit method, with actuarial valuations updated at each year-end. The expected benefit costs are accrued over the period of employment using an accounting methodology similar to that for the defined benefit pension scheme.
Share-based payments	Share-based payments The Santander UK group engages in cash-settled and equity-settled share-based payment transactions in respect of services received from certain of its employees. Shares of the Santander UK group’s parent, Banco Santander SA are purchased in the open market by the Santander UK group (for the Employee Sharesave scheme) or are purchased by Banco Santander SA or another Banco Santander subsidiary (including awards granted under the Long-Term Incentive Plan and the Deferred Shares Bonus Plan) to satisfy share options or awards as they vest. Options granted under the Employee Sharesave scheme and awards granted under the Transformation Incentive Plan are accounted for as cash-settled share-based payment transactions. Awards granted under the Long-Term Incentive Plan and Deferred Shares Bonus Plan are accounted for as equity-settled share-based payment transactions. The fair value of the services received is measured by reference to the fair value of the shares or share options initially on the date of the grant for both the cash and equity settled share-based payments and then subsequently at each reporting date for the cash-settled share-based payments. The cost of the employee services received in respect of the shares or share options granted is recognised in the income statement in administration expenses over the period that the services are received i.e. the vesting period. A liability equal to the portion of the services received is recognised at the fair value determined at each balance sheet date for cash-settled share-based payments. A liability equal to the amount to be reimbursed to Banco Santander SA is recognised at the fair value determined at the grant date for equity-settled share-based payments. The fair value of the options granted under the Employee Sharesave scheme is determined using an option pricing model, which takes into account the exercise price of the option, the current share price, the risk-free interest rate, the expected volatility of the Banco Santander SA share price over the life of the option and the dividend growth rate. The fair value of the awards granted for the Long-Term Incentive Plan was determined at the grant date using an option pricing model, which takes into account the share price at grant date, the risk-free interest rate, the expected volatility of the Banco Santander SA share price over the life of the award and the dividend growth rate. Vesting conditions included in the terms of the grant are not taken into account in estimating fair value, except for those that include terms related to market conditions. Non-market vesting conditions are taken into account by adjusting the number of shares or share options included in the measurement of the cost of employee service so that, ultimately, the amount recognised in the income statement reflects the number of vested shares or share options. Where vesting conditions are related to market conditions, the charges for the services received are recognised regardless of whether or not the market–related vesting conditions are met, provided that the non-market vesting conditions are met. Where an award has been modified, as a minimum, the expense of the original award continues to be recognised as if it had not been modified. Where the effect of a modification is to increase the fair value of an award or increase the number of equity instruments, the incremental fair value of the award or incremental fair value of the modification of the award is recognised in addition to the expense of the original grant, measured at the date of modification, over the modified vesting period. Cancellations in the vesting period are treated as an acceleration of vesting and recognised immediately for the amount that would otherwise have been recognised for services over the vesting period.
Goodwill and other intangible assets	Goodwill and other intangible assets Goodwill represents the excess of the cost of an acquisition, as well as the fair value of any interest previously held, over the fair value of the share of the identifiable net assets of the acquired subsidiary, associate, or business at the date of acquisition. Goodwill on the acquisition of subsidiaries and businesses is included in intangible assets. Goodwill on acquisitions of associates is included as part of investment in associates. Goodwill is tested for impairment annually, or more frequently when events or changes in circumstances dictate, and carried at cost less accumulated impairment losses. Gains and losses on the disposal of an entity or business include the carrying amount of goodwill relating to the entity or business sold. Other intangible assets are recognised if they arise from contractual or other legal rights or if they are capable of being separated or divided from Santander UK and sold, transferred, licensed, rented or exchanged. The value of such intangible assets, where they are available for use, is amortised on a straight-line basis over their useful economic life of three to seven years and the assets are reviewed annually for impairment indicators and tested for impairment where indicators are present. Other intangible assets that are not yet available for use are tested for impairment annually or more frequently when events or changes in circumstances dictate. Software development costs are capitalised when they are direct costs associated with identifiable and unique software products that are expected to provide future economic benefits and the cost of those products can be measured reliably. These costs include payroll, materials, services and directly attributable overheads. Internally developed software meeting these criteria and externally purchased software are classified in intangible assets on the balance sheet and amortised on a straight-line basis over their useful life of three to seven years, unless the software is an integral part of the related computer hardware, in which case it is treated as property, plant and equipment as described below. Capitalisation of costs ceases when the software is capable of operating as intended. Costs of maintaining software are expensed as incurred.
Property, plant and equipment	Property, plant and equipment Property, plant and equipment include owner-occupied properties (including leasehold properties), office fixtures and equipment and computer software. Property, plant and equipment also includes operating leases where the Santander UK group is the lessor and right-of-use assets where the Santander UK group is the lessee, as described further in ‘Leases’ below. As lessor, the Santander UK group leases properties, vehicles and other equipment which are classified as operating leases because they do not transfer substantially all of the risks and rewards incidental to ownership of the assets. Property, plant and equipment are carried at cost less accumulated depreciation and accumulated impairment losses. A review for indications of impairment is carried out at each reporting date. Gains and losses on disposal are determined by reference to the carrying amount and are reported in other operating income. Repairs and renewals are charged to the income statement when the expenditure is incurred. Internally developed software meeting the criteria set out in ‘Goodwill and other intangible assets’ above and externally purchased software are classified in property, plant and equipment where the software is an integral part of the related computer hardware (for example operating system of a computer). Classes of property, plant and equipment are depreciated on a straight-line basis over their useful life, as follows: Owner-occupied properties Not exceeding 50 years Office fixtures and equipment 3 to 15 years Computer software 3 to 7 years Right-of-use assets (see ‘Leases – The Santander UK group as lessee’ below) Shorter of the lease term or the useful life of the underlying asset Depreciation is not charged on freehold land and assets under construction. Depreciation on operating lease assets where the Santander UK group is the lessor is described in 'Leases' below.
Financial instruments	Financial instruments a) Initial recognition and measurement Financial assets and liabilities are initially recognised when the Santander UK group becomes a party to the contractual terms of the instrument. The Santander UK group determines the classification of its financial assets and liabilities at initial recognition and measures a financial asset or financial liability at its fair value plus or minus, in the case of a financial asset or financial liability not at FVTPL, transaction costs that are incremental and directly attributable to the acquisition or issue of the financial asset or financial liability. Transaction costs of financial assets and financial liabilities carried at FVTPL are expensed in profit or loss. Immediately after initial recognition, an expected credit loss (ECL) allowance is recognised for financial assets measured at amortised cost and investments in debt instruments measured at FVOCI. A regular way purchase is a purchase of a financial asset under a contract whose terms require delivery of the asset within the timeframe established generally by regulation or convention in the marketplace concerned. Regular way purchases of financial assets classified as loans and receivables, issues of equity or financial liabilities measured at amortised cost are recognised on settlement date; all other regular way purchases and issues are recognised on trade date. b) Financial assets and liabilities i) Classification and subsequent measurement The Santander UK group classifies its financial assets in the measurement categories of amortised cost, FVOCI and FVTPL. Financial assets and financial liabilities are classified as FVTPL where there is a requirement to do so or where they are otherwise designated at FVTPL on initial recognition. Financial assets and financial liabilities which are required to be held at FVTPL include: – Financial assets and financial liabilities held for trading – Debt instruments that do not have solely payments of principal and interest (SPPI) characteristics. Otherwise, such instruments are measured at amortised cost or FVOCI, and – Equity instruments that have not been designated as held at FVOCI. Financial assets and financial liabilities are classified as held for trading if they are derivatives or if they are acquired or incurred principally for the purpose of selling or repurchasing in the near-term, or form part of a portfolio of financial instruments that are managed together and for which there is evidence of short-term profit taking. In certain circumstances, other financial assets and financial liabilities are designated at FVTPL where this results in more relevant information. This may arise because it significantly reduces a measurement inconsistency that would otherwise arise from measuring assets or liabilities or recognising the gains or losses on them on a different basis, where the assets and liabilities are managed and their performance evaluated on a fair value basis or, in the case of financial liabilities, where it contains one or more embedded derivatives which are not closely related to the host contract. The classification and measurement requirements for financial asset debt and equity instruments and financial liabilities are set out below. Financial assets: debt instruments Debt instruments are those instruments that meet the definition of a financial liability from the issuer’s perspective, such as loans and government and corporate bonds. Classification and subsequent measurement of debt instruments depend on the Santander UK group’s business model for managing the asset, and the cash flow characteristics of the asset. Business model The business model reflects how the Santander UK group manages the assets in order to generate cash flows and, specifically, whether the Santander UK group’s objective is solely to collect the contractual cash flows from the assets or is to collect both the contractual cash flows and cash flows arising from the sale of the assets. If neither of these is applicable, such as where the financial assets are held for trading purposes, then the financial assets are classified as part of an ‘other’ business model and measured at FVTPL. Factors considered in determining the business model for a group of assets include past experience on how the cash flows for these assets were collected, how the assets’ performance is evaluated and reported to key management personnel, and how risks are assessed and managed. SPPI Where the business model is to hold assets to collect contractual cash flows or to collect contractual cash flows and sell, the Santander UK group assesses whether the assets’ cash flows represent SPPI. In making this assessment, the Santander UK group considers whether the contractual cash flows are consistent with a basic lending arrangement (i.e. interest includes only consideration for the time value of money, credit risk, other basic lending risks and a profit margin that is consistent with a basic lending arrangement). Where the contractual terms introduce exposure to risk or volatility that is inconsistent with a basic lending arrangement, the related asset is classified and measured at FVTPL. Financial assets with embedded derivatives are considered in their entirety when determining whether their cash flows are SPPI. Based on these factors, the Santander UK group classifies its debt instruments into one of the following measurement categories: – Amortised cost – Financial assets that are held for collection of contractual cash flows where those cash flows represent SPPI, and that are not designated at FVTPL, are measured at amortised cost. The carrying amount of these assets is adjusted by any ECL recognised and measured as presented in Note 13. Interest income from these financial assets is included in ‘Interest and similar income’ using the effective interest rate method. When estimates of future cash flows are revised, the carrying amount of the respective financial assets or financial liabilities is adjusted to reflect the new estimate discounted using the original effective interest rate. Any changes are recognised in the income statement. – FVOCI – Financial assets that are held for collection of contractual cash flows and for selling the assets, where the assets’ cash flows represent SPPI, and that are not designated at FVTPL, are measured at FVOCI. Movements in the carrying amount are recognised in OCI, except for the recognition of impairment gains or losses, interest revenue and foreign exchange gains and losses on the instrument’s amortised cost which are recognised in profit or loss. When the financial asset is derecognised, the cumulative gain or loss previously recognised in OCI is reclassified from equity to profit or loss and recognised in ‘Other operating income’. Interest income from these financial assets is included in ‘Interest and similar income’ using the effective interest rate method. – FVTPL – Financial assets that do not meet the criteria for amortised cost or FVOCI are measured at FVTPL. A gain or loss on a debt instrument that is subsequently measured at FVTPL, including any debt instruments designated at fair value, is recognised in profit or loss and presented in the income statement in ‘Other operating income’ in the period in which it arises. The Santander UK group reclassifies financial assets when and only when its business model for managing those assets changes. The reclassification takes place from the start of the first reporting period following the change. Such changes are expected to be very infrequent. Financial assets: equity instruments Equity instruments are instruments that meet the definition of equity from the issuer’s perspective, being instruments that do not contain a contractual obligation to pay cash and that evidence a residual interest in the issuer’s net assets. All equity investments are subsequently measured at FVTPL, except where management has elected, at initial recognition, to irrevocably designate an equity investment at FVOCI. When this election is used, fair value gains and losses are recognised in OCI and are not subsequently reclassified to profit or loss, including on disposal. ECLs (and reversal of ECLs) are not reported separately from other changes in fair value. Dividends, when representing a return on such investments, continue to be recognised in profit or loss as other income when the right to receive payments is established. Gains and losses on equity investments at FVTPL are included in ‘Other operating income’ in the income statement. Financial liabilities Financial liabilities are classified as subsequently measured at amortised cost, except for: – Financial liabilities at FVTPL: this classification is applied to derivatives and other financial liabilities designated as such at initial recognition. Gains or losses on financial liabilities designated at FVTPL are presented partially in other comprehensive income (the amount of change in the fair value of the financial liability that is attributable to changes in the credit risk of that liability) and partially in profit or loss (the remaining amount of change in the fair value of the liability) – Financial liabilities arising from the transfer of financial assets which did not qualify for derecognition, whereby a financial liability is recognised for the consideration received for the transfer. In subsequent periods, the Santander UK group recognises any expense incurred on the financial liability, and – Financial guarantee contracts and loan commitments. Contracts involving the receipt of cash on which customers receive an index-linked return are accounted for as equity index-linked deposits. The principal products are Capital Guaranteed/Protected Products which give the customers a limited participation in the upside growth of an equity index. In the event the index falls in price, a cash principal element is guaranteed/protected. The equity index-linked deposits contain embedded derivatives. These embedded derivatives, in combination with the principal cash deposit element, are designed to replicate the investment performance profile tailored to the return agreed in the contracts with customers. The cash principal element is accounted for as deposits by customers at amortised cost. The embedded derivatives are separated from the host instrument and are separately accounted for as derivatives. Sale and repurchase agreements (including stock borrowing and lending) Securities sold subject to a commitment to repurchase them at a predetermined price (repos) under which substantially all the risks and rewards of ownership are retained by the Santander UK group remain on the balance sheet and a liability is recorded in respect of the consideration received. Securities purchased under commitments to resell (reverse repos) are not recognised on the balance sheet and the consideration paid is recorded as an asset. The difference between the sale and repurchase price is treated as trading income in the income statement, except where the repo is not treated as part of the trading book, in which case the difference is recorded in interest income or expense. Securities lending and borrowing transactions are generally secured, with collateral in the form of securities or cash advanced or received. Securities lent or borrowed are not reflected on the balance sheet. Collateral in the form of cash received or advanced is recorded as a deposit or a loan. Collateral in the form of securities is not recognised. Day One profit adjustments The fair value of a financial instrument on initial recognition is generally its transaction price (that is, the fair value of the consideration given or received). However, sometimes the fair value will be based on other observable current market transactions in the same instrument, without modification or repackaging, or on a valuation technique whose variables include only data from observable markets, such as interest rate yield curves, option volatilities and currency rates. When such evidence exists, the Santander UK group recognises a trading gain or loss at inception (Day One gain or loss), being the difference between the transaction price and the fair value. When significant unobservable parameters are used, the entire Day One gain or loss is deferred and is recognised in the income statement over the life of the transaction until the transaction matures, is closed out, the valuation inputs become observable or an offsetting transaction is entered into. ii) Impairment of debt instrument financial assets The Santander UK group assesses on a forward-looking basis the ECL associated with its debt instrument assets carried at amortised cost and FVOCI and with the exposure arising from financial guarantee contracts and loan commitments. The Santander UK group recognises a loss allowance for such losses at each reporting date. The measurement of ECL reflects: – An unbiased and probability-weighted amount that is determined by evaluating a range of possible outcomes – The time value of money, and – Reasonable and supportable information that is available without undue cost or effort at the reporting date about past events, current conditions and forecasts of future economic conditions. Grouping of instruments for losses measured on a collective basis We typically group instruments and assess them for impairment collectively where they share risk characteristics (as described in the Credit risk section of the Risk review) using one or more statistical models. Where we have used internal capital or similar models as the basis for our ECL models, this typically results in a large number of relatively small homogenous groups which are determined by the permutations of the underlying characteristics in the statistical models. We calculate separate collective provisions for instruments in Stages 1, 2 and 3 where the instrument is not individually assessed, as described below. Individually assessed impairments (IAIs) We assess significant Stage 3 cases individually. We do this for Corporate & Commercial Banking cases, and CIB cases before its transfer, but not for Business Banking cases in Retail Banking which we assess collectively. To calculate the estimated loss, we estimate the future cash flows under several scenarios each of which uses case-specific factors and circumstances. We then probability-weight the net present value of the cash flows under each scenario to arrive at a weighted average provision requirement. We update our assessment process every quarter and more frequently if there are changes in circumstances that might affect the scenarios, cash flows or probabilities we apply. For more on how ECL is calculated, see the Credit risk section of the Risk review. Write-off For secured loans, a write-off is only made when all collection procedures have been exhausted and the security has been sold and/or a claim made on any mortgage indemnity guarantee or other insurance. In the corporate loan portfolio, there may be occasions where a write-off occurs for other reasons, such as following a consensual restructure or refinancing of the debt or where the debt is sold for strategic reasons into the secondary market at a value lower than its face value. There is no threshold based on past due status beyond which all secured loans are written off as there can be significant variations in the time needed to enforce possession and sale of the security, especially due to the different legal frameworks that apply in different regions of the UK. For unsecured loans, a write-off is only made when all internal avenues of collecting the debt have been exhausted. Where appropriate the debt is passed over to external collection agencies. A past due threshold is applied to unsecured debt where accounts that are 180 days past due are written off unless there is a dispute awaiting resolution. Contact is made with customers with the aim to achieve a realistic and sustainable repayment arrangement. Litigation and/or enforcement of security is usually carried out only when the steps described above have been undertaken without success. All write-offs are assessed / made on a case-by-case basis, taking account of the exposure at the date of write-off, after accounting for the value from any collateral or insurance held against the loan. The exception to this is in cases where fraud has occurred, where the exposure is written off once investigations have been completed and the probability of recovery is minimal. The time span between discovery and write-off will be short and may not result in an impairment loss allowance being raised. The write-off policy is regularly reviewed. Write-offs are charged against previously established loss allowances. Recoveries Recoveries of credit impairment losses are not included in the impairment loss allowance but are taken to income and offset against credit impairment losses. Recoveries of credit impairment losses are classified in the income statement as ‘Credit impairment losses’. iii) Modifications of financial assets The treatment of a renegotiation or modification of the contractual cash flows of a financial asset normally depends upon whether the renegotiation or modification is due to financial difficulties of the borrower or for other commercial reasons. – Contractual modifications due to financial difficulties of the borrower: where the Santander UK group modifies the contractual conditions to enable the borrower to fulfil their payment obligations, the asset is not derecognised. The gross carrying amount of the financial asset is recalculated as the present value of the renegotiated/modified contractual cash flows that are discounted at the financial asset’s original EIR and any gain or loss arising from the modification is recognised in the income statement. – Contractual modifications for other commercial reasons: an assessment is performed to determine whether the terms of the new agreement are substantially different from the terms of the existing agreement, after considering changes in the cash flows arising from the modified terms and the overall instrument risk profile. Where terms are substantially different, such modifications are treated as a new transaction resulting in derecognition of the original financial asset, and the recognition of a ‘new’ financial asset with any difference between the carrying amount of the derecognised asset and the fair value of the new asset is recognised in the income statement as a gain or loss on derecognition. Where terms are not substantially different, the carrying value of the financial asset is adjusted to reflect the present value of modified cash flows discounted at the original EIR with any gain or loss arising from modification recognised immediately in the income statement. Any other contractual modifications, such as where a regulatory authority imposes a change in certain contractual terms or due to legal reasons, are assessed on a case-by-case basis to establish whether or not the financial asset should be derecognised. For IBOR reform see Note 42 . iv) Derecognition other than on a modification Financial assets are derecognised when the rights to receive cash flows have expired or the Santander UK group has transferred its contractual right to receive the cash flows from the assets and either: (1) substantially all the risks and rewards of ownership have been transferred; or (2) the Santander UK group has neither retained nor transferred substantially all of the risks and rewards but has transferred control. Financial liabilities are derecognised when extinguished, cancelled or expired. c) Financial guarantee contracts and loan commitments Financial guarantee contracts are contracts that require the issuer to make specified payments to reimburse the holder for a loss it incurs because a specified debtor fails to make payments when due, in accordance with the terms of a debt instrument. Such financial guarantees are given to banks, financial institutions and others on behalf of customers to secure loans, overdrafts and other banking facilities. Financial guarantee contracts are initially measured at fair value and subsequently measured at the higher of the amount of the loss allowance, and the premium received on initial recognition less income recognised in accordance with the principles of IFRS 15. Loan commitments are measured as the amount of the loss allowance (determined in accordance with IFRS 9 as described in Credit risk section of the Risk review). The Santander UK group has not provided any commitment to provide loans at a below-market interest rate, or that can be settled net in cash or by delivering or issuing another financial instrument.
Derivative financial instruments (derivatives)	Derivative financial instruments (derivatives) Derivatives are contracts or agreements whose value is derived from one or more underlying indices or asset values inherent in the contract or agreement, which require no or little initial net investment and are settled at a future date. Transactions are undertaken in interest rate, cross currency, equity, residential property and other index-related swaps, forwards, caps, floors, swaptions, as well as credit default and total return swaps, equity index contracts and exchange traded interest rate futures, and equity index options. Derivatives are held for risk management purposes. Derivatives are classified as held for trading unless they are designated as being in a hedge accounting relationship. The Santander UK group chooses to designate certain derivatives as in a hedging relationship if they meet specific criteria, as further described in ‘Hedge accounting’ below. Derivatives are recognised initially (on the date on which a derivative contract is entered into), and are subsequently remeasured, at their fair value. Fair values of exchange-traded derivatives are obtained from quoted market prices. Fair values of over-the-counter derivatives are estimated using valuation techniques, including discounted cash flow and option pricing models. Certain derivatives may be embedded in hybrid contracts, such as the conversion option in a convertible bond. If the hybrid contract contains a host that is a financial asset, then the Santander UK group assesses the entire contract as described in the financial asset section above for classification and measurement purposes. Otherwise, embedded derivatives are treated as separate derivatives when their economic characteristics and risks are not closely related to those of the host contract; the terms of the embedded derivative would meet the definition of a stand-alone derivative if they were contained in a separate contract; and the combined contract is not held for trading or designated at fair value. These embedded derivatives are measured at fair value with changes in fair value recognised in the income statement. Contracts containing embedded derivatives are not subsequently reassessed for separation unless either there has been a change in the terms of the contract which significantly modifies the cash flows (in which case the contract is reassessed at the time of modification) or the contract has been reclassified (in which case the contract is reassessed at the time of reclassification). All derivatives are carried as assets when their fair value is positive and as liabilities when their fair value is negative, except where netting is permitted. The method of recognising fair value gains and losses depends on whether derivatives are held for trading or are designated as hedging instruments and, if the latter, the nature of the risks being hedged. Gains and losses from changes in the fair value of derivatives held for trading are recognised in the income statement and included in Other operating income.
Offsetting financial assets and liabilities	Offsetting financial assets and liabilitiesFinancial assets and liabilities including derivatives are offset and the net amount reported in the balance sheet when there is a legally enforceable right to set off the recognised amounts and there is an intention to settle on a net basis or realise the asset and settle the liability simultaneously. The Santander UK group is party to a number of arrangements, including master netting arrangements under industry standard agreements which facilitate netting of transactions in jurisdictions where netting agreements are recognised and have legal force. The netting arrangements do not generally result in an offset of balance sheet assets and liabilities for accounting purposes, as transactions are usually settled on a gross basis.
Hedge accounting	Hedge accounting The Santander UK group applies hedge accounting to represent, to the maximum possible extent permitted under accounting standards, the economic effects of its risk management strategies. Derivatives are used to hedge exposures to interest rates, exchange rates and certain indices such as retail price indices. At the time a financial instrument is designated as a hedge (i.e. at the inception of the hedge), the Santander UK group formally documents the relationship between the hedging instrument(s) and hedged item(s), its risk management objective and strategy for undertaking the hedge. The documentation includes the identification of each hedging instrument and respective hedged item, the nature of the risk being hedged (including the benchmark interest rate being hedged in a hedge of interest rate risk) and how the hedging instrument’s effectiveness in offsetting the exposure to changes in the hedged item’s fair value attributable to the hedged risk is to be assessed. Accordingly, the Santander UK group formally assesses, both at the inception of the hedge and on an ongoing basis, whether the hedging derivatives have been and will be highly effective in offsetting changes in the fair value attributable to the hedged risk during the period that the hedge is designated. A hedge is normally regarded as highly effective if, at inception and throughout its life, the Santander UK group can expect, and actual results indicate, that changes in the fair value or cash flow of the hedged items are effectively offset by changes in the fair value or cash flow of the hedging instrument. If at any point it is concluded that it is no longer highly effective in achieving its documented objective, hedge accounting is discontinued. Where derivatives are held for risk management purposes, and when transactions meet the required criteria for documentation and hedge effectiveness, the derivatives may be designated as either: (i) hedges of the change in fair value of recognised assets or liabilities or firm commitments (fair value hedges); (ii) hedges of the variability in highly probable future cash flows attributable to a recognised asset or liability, or a forecast transaction (cash flow hedges); or (iii) a hedge of a net investment in a foreign operation (net investment hedges). The Santander UK group applies fair value and cash flow hedge accounting, but not hedging of a net investment in a foreign operation. a) Fair value hedge accounting Changes in the fair value of derivatives that are designated and qualify as fair value hedges are recorded in the income statement, together with the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk. Where the hedged item is measured at amortised cost, the fair value changes due to the hedged risk adjust the carrying amount of the hedged asset or liability. Changes in the fair value of portfolio hedged items are presented separately in the consolidated balance sheet in macro hedge of interest rate risk and recognised in the income statement within other operating income. If the hedge no longer meets the criteria for hedge accounting, changes in the fair value of the hedged item attributable to the hedged risk are no longer recognised in the income statement. For fair value hedges of interest rate risk, the cumulative adjustment that has been made to the carrying amount of the hedged item is amortised to the income statement using the effective interest method over the period to maturity. For portfolio hedged items, the cumulative adjustment is amortised to the income statement using the straight-line method over the period to maturity. b) Cash flow hedge accounting The effective portion of changes in the fair value of qualifying cash flow hedges is recognised in other comprehensive income in the cash flow hedging reserve. The gain or loss relating to the ineffective portion is recognised immediately in the income statement. Amounts accumulated in equity are reclassified to the income statement in the periods in which the hedged item affects profit or loss. When a hedging instrument expires or is sold, or when a hedge no longer meets the criteria for hedge accounting, any cumulative gain or loss existing in equity at that time remains in equity and is recognised in the income statement when the forecast transaction is ultimately recognised in the income statement. When a forecast transaction is no longer expected to occur, the cumulative gain or loss that was reported in equity is immediately transferred to the income statement. The Santander UK group is exposed to cash flow interest rate risk on its floating rate assets, foreign currency risk on its fixed rate debt issuances denominated in foreign currency and equity price risk arises from the Santander UK group operating the Employee Sharesave scheme. Cash flow hedging is used to hedge the variability in cash flows arising from these risks.
Securitisation transactions	Securitisation transactions The Santander UK group has entered into arrangements where undertakings have issued mortgage-backed and other asset-backed securities or have entered into funding arrangements with lenders in order to finance specific loans and advances to customers. The Santander UK group has also entered into synthetic securitisation arrangements, as part of significant risk transfer (SRT) transactions to reduce its risk-weighted assets, where undertakings have issued credit-linked notes and deposited the funds raised as collateral for credit protection in respect of specific loans and advances to customers. As the Santander UK group has retained substantially all the risks and rewards of the underlying assets, such financial instruments continue to be recognised on the balance sheet, and a liability recognised for the proceeds of the funding transaction, or in the case of SRT transactions, collateral deposited.
Impairment of non-financial assets	Impairment of non-financial assets At each balance sheet date, or more frequently when events or changes in circumstances dictate, property plant and equipment (including operating lease assets) and intangible assets (including goodwill) are assessed for indicators of impairment. If indications are present, these assets are subject to an impairment review. The impairment review comprises a comparison of the carrying amount of the asset or cash generating unit with its recoverable amount: the higher of the asset’s or cash-generating unit’s fair value less costs to sell and its value in use. The cash-generating unit represents the lowest level at which non-financial assets, including goodwill, are monitored for internal management purposes and is not larger than an operating segment. The fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Value in use is calculated by discounting management’s expected future cash flows obtainable as a result of the asset’s continued use (after making allowance for increases in regulatory capital requirements), including those resulting from its ultimate disposal, at a market-based discount rate on a pre-tax basis. The recoverable amounts of goodwill have been based on value in use calculations. The carrying values of property, plant and equipment, goodwill and other intangible assets are written down by the amount of any impairment and the loss is recognised in the income statement in the period in which it occurs. A previously recognised impairment loss relating to property, plant and equipment may be reversed in part or in full when a change in circumstances leads to a change in the estimates used to determine the property, plant and equipment’s recoverable amount. The carrying amount of the property, plant and equipment will only be increased up to the amount that would have been had the original impairment not been recognised. Impairment losses on goodwill are not reversed. For conducting goodwill impairment reviews, cash generating units are the lowest level at which management monitors the return on investment on assets.
Leases	Leases a) The Santander UK group as lessor Operating lease assets are recorded at cost and depreciated over the life of the asset after taking into account anticipated residual value (RV). Operating lease rental income and depreciation is recognised on a straight-line basis over the life of the asset. After initial recognition, residual values are reviewed regularly, and any changes are recognised prospectively through remaining depreciation charges. Amounts due from lessees under finance leases and hire purchase contracts are recorded as receivables at the amount of the Santander UK group’s net investment in the leases. Finance lease income is allocated to accounting periods to reflect a constant periodic rate of return on the Santander UK group’s net investment outstanding in respect of the leases and hire purchase contracts. A provision is recognised to reflect a reduction in any anticipated unguaranteed RV. A provision is also recognised for voluntary termination of the contract by the customer, where appropriate. b) The Santander UK group as lessee The Santander UK group assesses whether a contract is or contains a lease at the inception of the contract and recognises a right-of-use (ROU) asset representing its right to use the underlying leased asset and a lease liability representing its obligation to make lease payments for all leases, except for leases with a term of 12 months or less which are expensed in the income statement on a straight-line basis over the lease terms. Lease payments exclude irrecoverable VAT which is expensed in the income statement as lease payments are made. The lease liability, which is included in Other liabilities on the balance sheet, is initially measured at the present value of the lease payments that are not paid at the commencement date, discounted using the incremental borrowing rate appropriate to the lease term. The lease liability is subsequently measured at amortised cost using the effective interest rate method. Remeasurement of the lease liability occurs if there is a change in the lease payments (when a corresponding adjustment is made to the ROU asset), the lease term or in the assessment of an option to purchase the underlying asset. At inception, the ROU asset, which is included in Property, plant and equipment on the balance sheet, comprises the lease liability, initial direct costs and the obligations to restore the asset, less any incentives granted by the lessor. The ROU asset is depreciated over the shorter of the lease term or the useful life of the underlying asset and is reviewed for impairment as for owned assets. The obligation to restore the asset is included in Provisions on the balance sheet. These provisions are reassessed on a semi-annual basis and will normally run off over the period of the leases concerned. Where a property is disposed of earlier than anticipated, any remaining provision relating to that property is released.
Income taxes, including deferred taxes	Income taxes, including deferred taxes The tax expense represents the sum of the income tax currently payable and deferred income tax. Income tax payable on profits, based on the applicable tax law in each jurisdiction, is recognised as an expense in the period in which profits arise. Taxable profit differs from net profit as reported in the income statement because it excludes items of income or expense that are taxable or deductible in other years and it further excludes items that are never taxable or deductible. The liability for current tax is calculated using tax rates that have been enacted or substantively enacted by the balance sheet date. Current taxes associated with the repurchase of equity instruments are reported directly in equity. A current tax liability for the current or prior period is measured at the amount expected to be paid to the tax authorities. Where the amount of the final tax liability is uncertain or where a position is challenged by a taxation authority, the liability recognised is the most likely outcome. Where a most likely outcome cannot be determined, a weighted average basis is applied. Deferred income tax is the tax expected to be payable or recoverable on income tax losses available to carry forward and on temporary differences arising between the tax bases of assets and liabilities and their carrying amounts in the consolidated financial statements and is accounted for using the balance sheet liability method. Deferred tax liabilities are generally recognised for all taxable temporary differences and deferred tax assets are recognised to the extent that it is probable that taxable profits will be available against which the assets may be utilised as they reverse. Such deferred tax liabilities are not recognised if the temporary difference arises from the initial recognition of goodwill. Deferred tax assets and liabilities are not recognised from the initial recognition of other assets (other than in a business combination) and liabilities in a transaction that affects neither the taxable profit nor the accounting profit. Deferred tax is calculated at the tax rates that are expected to apply in the period when the liability is settled, or the asset is realised based on rates enacted or substantively enacted at the balance sheet date. Deferred tax is charged or credited in the income statement, except when it relates to items recognised in other comprehensive income or directly in equity, in which case the deferred tax is also recognised in other comprehensive income or directly in equity. Deferred tax liabilities are recognised for taxable temporary differences arising on investments in subsidiaries except where the Santander UK group is able to control reversal of the temporary difference and it is probable that it will not reverse in the foreseeable future. The Santander UK group reviews the carrying amount of deferred tax assets at each balance sheet date and reduces it to the extent that it is no longer probable that sufficient taxable profits will be available to allow all or part of the asset to be recovered. Deferred tax relating to actuarial gains and losses on defined benefits is recognised in other comprehensive income. Deferred tax relating to fair value re-measurements of financial instruments accounted for at FVOCI and cash flow hedging instruments is charged or credited directly to other comprehensive income and is subsequently recognised in the income statement when the deferred fair value gain or loss is recognised in the income statement. Deferred and current tax assets and liabilities are only offset when they arise in the same tax reporting group and where there is both the legal right and the intention to settle on a net basis or to realise the asset and settle the liability simultaneously.
Cash and cash equivalents	Cash and cash equivalentsFor the purposes of the cash flow statement, cash and cash equivalents comprise balances with less than three months maturity from the date of acquisition, including cash and non-restricted balances with central banks, treasury bills and other eligible bills, loans and advances to banks and short-term investments in securities. Balances with central banks represent amounts held at the Bank of England as part of the Santander UK group’s liquidity management activities. In addition, it includes certain minimum cash balances held for regulatory purposes required to be maintained with the Bank of England.
Provisions	Provisions Provisions are recognised for present obligations arising as consequences of past events where it is more likely than not that a transfer of economic benefits will be necessary to settle the obligation, and it can be reliably estimated. Customer remediation provisions are made for the estimated cost of making redress payments with respect to the past sales of products, using conclusions such as the number of claims the number of those that will be upheld, the estimated average settlement per case and other related costs. Provision is made for the anticipated cost of restructuring, including redundancy costs, when an obligation exists. An obligation exists when the Santander UK group has a detailed formal plan for restructuring a business, has raised valid expectations in those affected by the restructuring, and has started to implement the plan or announce its main features. When a leasehold property ceases to be used in the business, provision is made where the unavoidable costs of the future obligations relating to the lease are expected to exceed anticipated rental income. The net costs are discounted using market rates of interest to reflect the long-term nature of the cash flows. Loan commitments are measured as the amount of the loss allowance, determined in line with IFRS 9 as set out in the Credit risk section of the Risk review. Contingent liabilities are possible obligations whose existence will be confirmed only by certain future events or present obligations where the transfer of economic benefit is uncertain or cannot be reliably measured. Contingent liabilities are not recognised but are disclosed unless they are remote.
Share capital	Share capital a) Share issue costs Incremental external costs directly attributable to the issue of new shares are deducted from equity net of related income taxes. b) Dividends Dividends on ordinary shares are recognised in equity in the period in which the right to receive payment is established.
Discontinued operations	Discontinued operations A discontinued operation is a component of the Santander UK group that has been disposed of or is classified as held for sale and that represents a separate major line of business or geographical area of operations, is part of a single coordinated plan to dispose of such a line of business or area of operations, or is a subsidiary acquired exclusively with a view to resale. The results of discontinued operations are presented separately in the income statement.
Critical judgements and accounting estimates	CRITICAL JUDGEMENTS AND ACCOUNTING ESTIMATES The preparation of the consolidated financial statements requires management to make judgements and accounting estimates that affect the reported amount of assets and liabilities at the date of the consolidated financial statements and the reported amount of income and expenses during the reporting period. Management evaluates its judgements and accounting estimates, which are based on historical experience and on various other factors that are believed to be reasonable under the circumstances, on an ongoing basis. Actual results may differ from these accounting estimates under different assumptions or conditions. In the course of preparing the consolidated financial statements, no significant judgements have been made in the process of applying the accounting policies, other than those involving estimations about credit impairment losses, provisions and contingent liabilities, pensions and goodwill. Management have considered the impact of Covid-19, climate change and the transition to a low carbon economy on critical judgements and accounting estimates. a) Credit impairment losses The application of the ECL impairment methodology for calculating credit impairment allowances is highly susceptible to change from period to period. The methodology requires management to make judgmental assumptions in determining the estimates. Any significant difference between the estimated amounts and actual amounts could have a material impact on the future financial results and financial condition. The impact of Covid-19 continues to increase the uncertainty around ECL impairment calculations and has required management to make additional judgements and accounting estimates that affect the amount of assets and liabilities at the reporting date and the amount of income and expenses in the reporting period. The key additional judgements due to the impact of Covid-19 continue to mainly reflect the increased uncertainty around forward-looking economic data and the need for additional post model adjustments. Key judgements – Determining an appropriate definition of default – Establishing the criteria for a significant increase in credit risk (SICR) and, for corporate borrowers, internal credit risk rating – Determining appropriate post model adjustments – Assessing individual corporate Stage 3 exposures Key estimates – Forward-looking multiple economic scenario assumptions – Probability weights assigned to multiple economic scenarios For more on each of these key judgements and estimates, including the impact of Covid-19, climate change and the transition to a low carbon economy on them, see 'Critical judgements and accounting estimates applied in calculating ECL' in the ‘Credit risk – credit risk management’ section of the Risk review. Sensitivity of ECL allowance For detailed disclosures, see 'Sensitivity of ECL allowance' in the ‘Credit risk – Santander UK group level – credit risk management’ section of the Risk review. b) Provisions and contingent liabilities Key judgements – Determining whether a present obligation exists – Assessing the likely outcome of future legal decisions Key estimates – Probability, timing, nature and amount of any outflows that may arise from past events Included in Litigation and other regulatory provisions in Note 29 are amounts in respect of management’s best estimates of liability relating to a legal dispute regarding allocation of responsibility for a specific PPI portfolio of complaints, and Plevin related litigation. Note 31 provides disclosure relating to ongoing factual issues and reviews that could impact the timing and amount of any outflows. Note 31 Contingent liabilities and commitments' includes disclosure relating to an investigation in relation to the historical involvement of Santander UK plc, Santander Financial Services plc and Cater Allen International Limited (all subsidiaries of Santander UK Group Holdings plc) in German dividend tax arbitrage transactions, as well as an FCA civil regulatory investigation which commenced in July 2017 into our compliance with the Money Laundering Regulations 2007 and potential breaches of FCA principles and rules relating to anti-money laundering and financial crime systems and controls. It also includes disclosure relating to certain leases in which current and former Santander UK group members were the lessor that are currently under review by HMRC in connection with claims for tax allowances. These judgements are based on the specific facts available and often require specialist professional advice. There can be a wide range of possible outcomes and uncertainties, particularly in relation to legal actions, and regulatory and consumer credit matters. As a result, it is often not possible to make reliable estimates of the likelihood and amount of any potential outflows, or to calculate any resulting sensitivities. For more on each of these key judgements and estimates, see Notes 29 and 31. c) Pensions The Santander UK group operates a number of defined benefit pension schemes as described in Note 30 and estimates their position as described in the accounting policy ‘Pensions and other post retirement benefits’. Key judgements – Setting the criteria for constructing the corporate bond yield curve used to determine the discount rate – Determining the methodology for setting the inflation assumption Key estimates – Discount rate applied to future cash flows – Rate of price inflation – Expected lifetime of the schemes' members – Valuation of pension fund assets whose values are not based on market observable data For more on each of these key judgements and estimates, including the impact of Covid-19 on them, see Note 30. Sensitivity of defined benefit pension scheme estimates For detailed disclosures see ‘Actuarial assumption sensitivities’ in Note 30. The Scheme was invested in certain assets whose values are not based on market observable data, such as investments in private equity funds and property. Due diligence has been conducted to ensure the values obtained in respect of these assets are appropriate and represent fair value. Given the nature of these investments, we are unable to prepare sensitivities on how their values could vary as market conditions or other variables change. d) Goodwill The carrying amount of goodwill is based on the application of judgements including the basis of goodwill impairment calculation assumptions. Santander UK undertakes an annual assessment to evaluate whether the carrying value of goodwill is impaired, carrying out this assessment more frequently if reviews identify indicators of impairment or when events or changes in circumstances dictate. Key judgements: – Determining the basis of goodwill impairment calculation assumptions, including management's planning assumptions considering internal capital allocations needed to support Santander UK's strategy, current market conditions and the macro-economic outlook. Key estimates: – Forecast cash flows for cash generating units, including estimated allocations of regulatory capital – Growth rate beyond initial cash flow projections – Discount rates which factor in risk-free rates and applicable risk premiums All of these variables are subject to fluctuations in external market rates and economic conditions beyond management’s control For more on each of these key judgements and estimates, see Note 20. Sensitivity of goodwill
Profit before tax re-segmentation of short term markets business	The segmental data below is presented in a manner consistent with the internal reporting to the committee which is responsible for allocating resources and assessing performance of the segments and has been identified as the chief operating decision maker. The segmental data is prepared on a statutory basis of accounting, in line with the accounting policies set out in Note 1. Transactions between segments are on normal commercial terms and conditions. Internal charges and internal UK transfer pricing adjustments are reflected in the results of each segment. Revenue sharing agreements are used to allocate external customer revenues to a segment on a reasonable basis. Funds are ordinarily reallocated between segments, resulting in funding cost transfers disclosed in operating income. Interest charged for these funds is based on Santander UK’s cost of wholesale funding. Interest income and interest expense have not been reported separately. The majority of segment revenues are interest income in nature and net interest income is relied on primarily to assess segment performance and to make decisions on the allocation of segment resources.

Accounting Policies - Parent (P

Accounting Policies - Parent (Policies)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Significant Accounting Policies [Line Items]
Basis of preparation	Basis of preparation These financial statements incorporate the financial statements of the Company and entities it controls (its subsidiaries) made up to 31 December each year. The consolidated financial statements have been prepared on the going concern basis using the historical cost convention, except for financial assets and liabilities that have been measured at fair value. An assessment of the appropriateness of the adoption of the going concern basis of accounting is disclosed in the statement of going concern in the Directors’ report. On 31 December 2020, International Financial Reporting Standards (IFRSs) as adopted by the European Union at that date were brought into UK law and became UK-adopted International Accounting Standards (IAS), with future changes being subject to endorsement by the UK Endorsement Board. The Company and its subsidiaries transitioned to UK-adopted IAS in its consolidated financial statements on 1 January 2021. This change constitutes a change in accounting framework. Although there was a change in accounting framework, this change had no impact on recognition, measurement or disclosures in the periods reported in these financial statements. Compliance with International Financial Reporting Standards The consolidated financial statements of the Santander UK group and the separate financial statements of the Company comply with UK-adopted IAS. The financial statements are also prepared in accordance with IFRSs as issued by the International Accounting Standards Board (IASB), including interpretations issued by the IFRS Interpretations Committee, as there are no applicable differences from IFRSs as issued by the IASB for the periods presented. Disclosures required by IFRS 7 ‘Financial Instruments: Disclosure’ relating to the nature and extent of risks arising from financial instruments, and IAS 1 ‘Presentation of Financial Statements’ relating to objectives, policies and processes for managing capital, can be found in the risk governance, credit risk, market risk, liquidity risk and capital risk sections of the Risk review and are labelled as audited. Those disclosures form an integral part of these financial statements. Climate change Santander UK continues to develop its assessment of the potential impacts that climate change and the transition to a low carbon economy may have on the assets and liabilities recognised and presented in its financial statements. Santander UK is mindful of its responsibilities as a responsible lender and is focused on ways to meet the objectives of the Paris Agreement on climate change and to support the UK’s transition to a climate-resilient, net zero economy. Santander UK's current climate change strategy focuses on three main areas to achieve Banco Santander's ambition to reach net zero emissions by 2050: 1. Managing climate risks by integrating climate considerations into risk management frameworks, screening and stress testing our portfolio for climate related financial risks, and setting risk appetites to help steer our portfolio in line with the Paris Agreement, 2. Supporting our customers’ transition by developing products and services that promote a reduction in CO 2 emissions, and 3. Reducing emissions in our operations and supply chain by focusing on continuous improvement in our operations, and environmental and energy management systems in accordance with ISO14001 and 15001, promoting responsible procurement practices and employee engagement. Santander UK's current climate change strategy and its view of the risks associated with climate change and the transition to a low carbon economy are reflected in its critical judgements and accounting estimates, although climate change risk did not have a significant impact at 31 December 2021, consistent with management's assessment that climate change and the transition to a low carbon economy are not currently expected to have a meaningful impact on the viability of the Santander UK group in the medium term. At 31 December 2021, management specifically considered the potential impact of climate change and the transition to a low carbon economy on: – Loans and advances to customers (see Note 13 and the credit risk section of the Risk review). Some climate change risks arise due to the requirements of IFRS 9 and others relate to specific portfolios and sectors: – ECL calculations are based on multiple forward-looking economic scenarios developed by management covering a period of 5 years, during which timeframe climate change risks may crystallise. – For Mortgages in Retail Banking and Commercial Real Estate lending in Corporate & Commercial Banking, the value of property collateral might be affected by physical impacts related to the frequency and scale of extreme weather events, such as flood and subsidence risk, or changing environmental performance standards for property. – For automotive loans in Consumer Finance, the residual value of automotive vehicles might be impacted by diesel obsolescence and the transition to electric vehicles. – For corporate lending in Corporate & Commercial Banking, certain sectors give rise to fossil fuel exposures, such as Oil & Gas, Mining & Extraction and Power Generation. – Goodwill impairment assessment (see Note 20). Estimates underpinning the determination of whether or not goodwill balances are impaired are partly based on forecast business performance beyond the time horizon for management's detailed plans. Future changes to Santander UK's climate change strategy may impact Santander UK's critical judgements and accounting estimates and result in material changes to financial results and the carrying values of certain assets and liabilities in future reporting periods. Accounting developments Interest Rate Benchmark Reform In 2019, the IASB issued ‘Interest Rate Benchmark Reform: Amendments to IFRS 9, IAS 39 and IFRS 7’. The Santander UK group applies IAS 39 hedge accounting so the amendments to IFRS 9 do not apply. Although the IAS 39 and IFRS 7 amendments, which apply to all hedging relationships directly affected by uncertainties related to interbank offered rate (IBOR) reform, became effective from 1 January 2020, following their endorsement, the Santander UK group early adopted those amendments in the preparation of the financial statements for the year ended 31 December 2019. The exceptions given by the IAS 39 amendments meant that IBOR reform had no impact on hedge relationships for affected hedges. In 2020, the IASB issued ‘Interest Rate Benchmark Reform – Phase 2 - Amendments to IFRS 9, IAS 39, IFRS 7, IFRS 4 and IFRS 16’. These amendments apply only to changes required by IBOR reform to financial instruments and hedging relationships. Although the amendments became effective from 1 January 2021 and are applied retrospectively without restating comparative information, following their endorsement, the Santander UK group early adopted the amendments in the preparation of the financial statements for the year ended 31 December 2020. The amendments address the accounting issues for financial instruments when IBOR reform is implemented including providing a practical expedient for changes to contractual cash flows, giving relief from specific hedge accounting requirements, and specifying a number of additional disclosures to enable users of financial statements to understand the effect of IBOR reform on an entity’s financial instruments and risk management strategy. Further details of the impact of these amendments on the financial statements for the year ended 31 December 2021 and the additional disclosures required are provided in Note 43. Other changes The Santander UK group adopted IFRS 16 and amendments to IAS 12 in 2019, with the impact included in the statement of changes in equity for that year end. Future developments At 31 December 2021 , for the Santander UK group, there were no significant new or revised standards and interpretations, and amendments thereto, which have been issued but which are not yet effective, or which have otherwise not been early adopted where permitted. Comparative information As required by US public company reporting requirements, these financial statements include two years of comparative information for the consolidated income statement, consolidated statement of comprehensive income, consolidated statement of changes in equity, consolidated statement of cash flows and related notes. Basis of preparation The accounting policies of the Company are the same as those of the Santander UK Group Holdings plc group which are set out in Note 1 to the extent that the Company has similar transactions to the Santander UK Group Holdings plc group, except as set out below.
Critical judgements and accounting estimates	CRITICAL JUDGEMENTS AND ACCOUNTING ESTIMATES The preparation of the consolidated financial statements requires management to make judgements and accounting estimates that affect the reported amount of assets and liabilities at the date of the consolidated financial statements and the reported amount of income and expenses during the reporting period. Management evaluates its judgements and accounting estimates, which are based on historical experience and on various other factors that are believed to be reasonable under the circumstances, on an ongoing basis. Actual results may differ from these accounting estimates under different assumptions or conditions. In the course of preparing the consolidated financial statements, no significant judgements have been made in the process of applying the accounting policies, other than those involving estimations about credit impairment losses, provisions and contingent liabilities, pensions and goodwill. Management have considered the impact of Covid-19, climate change and the transition to a low carbon economy on critical judgements and accounting estimates. a) Credit impairment losses The application of the ECL impairment methodology for calculating credit impairment allowances is highly susceptible to change from period to period. The methodology requires management to make judgmental assumptions in determining the estimates. Any significant difference between the estimated amounts and actual amounts could have a material impact on the future financial results and financial condition. The impact of Covid-19 continues to increase the uncertainty around ECL impairment calculations and has required management to make additional judgements and accounting estimates that affect the amount of assets and liabilities at the reporting date and the amount of income and expenses in the reporting period. The key additional judgements due to the impact of Covid-19 continue to mainly reflect the increased uncertainty around forward-looking economic data and the need for additional post model adjustments. Key judgements – Determining an appropriate definition of default – Establishing the criteria for a significant increase in credit risk (SICR) and, for corporate borrowers, internal credit risk rating – Determining appropriate post model adjustments – Assessing individual corporate Stage 3 exposures Key estimates – Forward-looking multiple economic scenario assumptions – Probability weights assigned to multiple economic scenarios For more on each of these key judgements and estimates, including the impact of Covid-19, climate change and the transition to a low carbon economy on them, see 'Critical judgements and accounting estimates applied in calculating ECL' in the ‘Credit risk – credit risk management’ section of the Risk review. Sensitivity of ECL allowance For detailed disclosures, see 'Sensitivity of ECL allowance' in the ‘Credit risk – Santander UK group level – credit risk management’ section of the Risk review. b) Provisions and contingent liabilities Key judgements – Determining whether a present obligation exists – Assessing the likely outcome of future legal decisions Key estimates – Probability, timing, nature and amount of any outflows that may arise from past events Included in Litigation and other regulatory provisions in Note 29 are amounts in respect of management’s best estimates of liability relating to a legal dispute regarding allocation of responsibility for a specific PPI portfolio of complaints, and Plevin related litigation. Note 31 provides disclosure relating to ongoing factual issues and reviews that could impact the timing and amount of any outflows. Note 31 Contingent liabilities and commitments' includes disclosure relating to an investigation in relation to the historical involvement of Santander UK plc, Santander Financial Services plc and Cater Allen International Limited (all subsidiaries of Santander UK Group Holdings plc) in German dividend tax arbitrage transactions, as well as an FCA civil regulatory investigation which commenced in July 2017 into our compliance with the Money Laundering Regulations 2007 and potential breaches of FCA principles and rules relating to anti-money laundering and financial crime systems and controls. It also includes disclosure relating to certain leases in which current and former Santander UK group members were the lessor that are currently under review by HMRC in connection with claims for tax allowances. These judgements are based on the specific facts available and often require specialist professional advice. There can be a wide range of possible outcomes and uncertainties, particularly in relation to legal actions, and regulatory and consumer credit matters. As a result, it is often not possible to make reliable estimates of the likelihood and amount of any potential outflows, or to calculate any resulting sensitivities. For more on each of these key judgements and estimates, see Notes 29 and 31. c) Pensions The Santander UK group operates a number of defined benefit pension schemes as described in Note 30 and estimates their position as described in the accounting policy ‘Pensions and other post retirement benefits’. Key judgements – Setting the criteria for constructing the corporate bond yield curve used to determine the discount rate – Determining the methodology for setting the inflation assumption Key estimates – Discount rate applied to future cash flows – Rate of price inflation – Expected lifetime of the schemes' members – Valuation of pension fund assets whose values are not based on market observable data For more on each of these key judgements and estimates, including the impact of Covid-19 on them, see Note 30. Sensitivity of defined benefit pension scheme estimates For detailed disclosures see ‘Actuarial assumption sensitivities’ in Note 30. The Scheme was invested in certain assets whose values are not based on market observable data, such as investments in private equity funds and property. Due diligence has been conducted to ensure the values obtained in respect of these assets are appropriate and represent fair value. Given the nature of these investments, we are unable to prepare sensitivities on how their values could vary as market conditions or other variables change. d) Goodwill The carrying amount of goodwill is based on the application of judgements including the basis of goodwill impairment calculation assumptions. Santander UK undertakes an annual assessment to evaluate whether the carrying value of goodwill is impaired, carrying out this assessment more frequently if reviews identify indicators of impairment or when events or changes in circumstances dictate. Key judgements: – Determining the basis of goodwill impairment calculation assumptions, including management's planning assumptions considering internal capital allocations needed to support Santander UK's strategy, current market conditions and the macro-economic outlook. Key estimates: – Forecast cash flows for cash generating units, including estimated allocations of regulatory capital – Growth rate beyond initial cash flow projections – Discount rates which factor in risk-free rates and applicable risk premiums All of these variables are subject to fluctuations in external market rates and economic conditions beyond management’s control For more on each of these key judgements and estimates, see Note 20. Sensitivity of goodwill
Santander UK Group Holdings plc
Disclosure Of Significant Accounting Policies [Line Items]
Critical judgements and accounting estimates	CRITICAL JUDGEMENTS AND ACCOUNTING ESTIMATES The preparation of the financial statements requires management to make judgements and accounting estimates that affect the reported amount of assets and liabilities at the date of the financial statements and the reported amount of income and expenses during the reporting period. Management evaluates its judgements and accounting estimates, which are based on historical experience and on various other factors that are believed to be reasonable under the circumstances, on an ongoing basis. Actual results may differ from these accounting estimates under different assumptions or conditions. In preparing the financial statements, no significant judgements have been made in the process of applying the accounting policies, other than those involving estimations about interests in other entities. Interests in other entities - Investment in subsidiaries The carrying amount of investments in subsidiaries is based on the application of judgements including the basis of the cost of investment impairment calculation assumptions. Estimates include forecasts used for determining cash flows for the subsidiary's business and discount rates which factor in risk-free rates and applicable risk premiums, which are variables subject to fluctuations in external market rates and economic conditions beyond management’s control. Santander UK undertakes an annual assessment to evaluate whether the carrying value of investments in subsidiaries is impaired, carrying out this assessment more frequently if reviews identify indicators of impairment or when events or changes in circumstances dictate. The estimation of future cash flows and the level to which they are discounted is inherently uncertain and requires significant judgement and is subject to potential change over time. For more on these assumptions, including changes in the assumptions that would trigger an impairment, see Note 45.7.

Credit Risk (Tables)

Credit Risk (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of credit risk exposure [abstract]
Disclosure of Exposures to Credit Risk by Segment	Exposures to credit risk arise in our business segments from: Retail Banking Consumer Finance Corporate & Commercial Banking Corporate Centre In Homes, – We provide residential mortgages for customers with good credit quality (prime lending). – We provide these mostly for owner-occupied homes, with some buy-to-let mortgages provided to non-professional landlords. In Everyday Banking, – We provide unsecured lending to individuals, including personal loans, credit cards and account overdrafts. – We provide banking services to businesses with a turnover of up to £6.5m per annum and relatively simple borrowing needs. We offer overdrafts, credit cards and business loans. – We provide financing for cars, vans, motorbikes and caravans through Santander Consumer (UK) plc (SCUK). – Through our joint ventures, Hyundai Capital UK Ltd and Volvo Car Financial Services UK Limited, we provide retail point of sale customer finance and wholesale finance facilities (stock finance). – Loans, bank accounts, treasury services, invoice discounting, cash transmission, trade finance and asset finance. – We provide these to SMEs and mid-sized corporates with an annual turnover of up to £500m, Commercial Real Estate and Social Housing associations. – Asset and liability management of our balance sheet, as well as our non-core and legacy portfolios being run down. – Exposures include financial institutions, sovereign and other international organisation assets, and structured products, chosen for diversification and liquidity. – Crown Dependencies - mainly residential mortgages to individuals in Jersey and the Isle of Man.
Disclosure of Type of Credit Risk Mitigation by Portfolio	The types of credit risk mitigation, including collateral, across each of our portfolios is: Portfolio Description Residential mortgages Collateral is in the form of a first legal charge over the property. Before we grant a mortgage, the property is valued either by a surveyor or using automated valuation methodologies where our confidence in the accuracy of this method is high. Unsecured lending There is no collateral or security tied to the loan that can be used to mitigate any potential loss if the customer does not pay us back. Business banking services Business banking lending is unsecured. When lending to incorporated businesses, we typically obtain personal guarantees from each director but we do not treat these as collateral. The type of credit risk mitigation, including collateral, is: Portfolio Description Consumer (auto) finance Collateral is in the form of legal ownership of the vehicle for most consumer (auto) finance loans, with the customer being the registered keeper. Only a very small proportion of the business is underwritten as a personal loan. In these cases, there is no collateral or security tied to the loan. We use a leading vehicle valuation company to assess the LTV at the proposal stage to ensure that the value of the vehicle being lent against is appropriate. The types of credit risk mitigation, including collateral, across each of our portfolios are as follows. In addition, from time to time at a portfolio level we execute significant risk transfer transactions, which typically reduce RWAs. Portfolio Description SME and mid corporate Includes secured and unsecured lending. We can take mortgage debentures or a first charge on commercial property as collateral. Before agreeing the loan, we get an independent professional valuation which assesses the property. Loan agreements typically allow us to obtain revaluations during the term of the loan. We can also take guarantees, but we do not treat them as collateral unless they are supported by a tangible asset which is charged to us. We also lend against assets (like vehicles and equipment) and invoices for some customers. We value assets before we lend. For invoices, we review the customers' ledgers regularly and lend against debtors who meet agreed criteria. We consider the UK Government guarantee supporting losses on amounts lent under its Coronavirus Loan Schemes as collateral (80% for CBILS, CLBILS and RLS, and 100% for BBLS). Commercial Real Estate We take a first legal charge on commercial property as collateral. The loan is subject to strict criteria, including the property condition, age and location, tenant quality, lease terms and length, and the sponsor’s experience and creditworthiness. Before agreeing the loan, we visit the property and get an independent professional valuation which assesses the property, the tenant and future demand. Loan agreements typically allow us to obtain revaluations during the term of the loan. Social Housing We take a first legal charge on portfolios of residential real estate owned and let by UK Housing Associations as collateral, in most cases. We revalue this every three to five years (in line with industry practice), using the standard methods for property used for Social Housing. The types of credit risk mitigation, including collateral, across each of our portfolios are as follows. In addition, from time to time at a portfolio level we execute significant risk transfer transactions, which typically reduce RWAs. Portfolio Description Sovereign and Supranational In line with market practice, there is no collateral against these assets. Structured Products These are our High Quality Liquid Assets (HQLA) and Legacy Treasury asset portfolios. These assets are primarily ABS and covered bonds, which benefit from senior positions in the creditor hierarchy. Their credit rating reflects the over-collateralisation in the structure, and the assets that underpin their cash flows and repayment schedules. Social Housing We manage the risk on this portfolio in the same way as for the Social Housing portfolio in Corporate & Commercial Banking. Financial Institutions We use standard legal agreements to reduce credit risk via netting and collateralisation on derivatives, repos and reverse repos, and stock borrowing/lending. We also reduce risk by clearing trades through central counterparties (CCPs) where possible. Legacy Portfolios in run off We often hold collateral through a first legal charge over the underlying asset or cash. We get independent third-party valuations on fixed charge security in line with industry guidelines. Crown Dependencies We manage the risk on this portfolio in the same way as for mortgages in Retail Banking. The types of credit risk mitigation, including collateral, across each of our portfolios were as follows. Portfolio Description Large Corporates Most of these corporate loans and products were unsecured. We also had a structured finance portfolio, where we typically held legal charges over assets we financed. We monitored borrowers in line with expected performance and applicable covenants, so we detected any financial distress early. Financial Institutions Financial Institutions exposures were minimal and were managed in the same way as Large Corporates.
Disclosure of Types of Forbearance	We may offer the following types of forbearance, but only if our assessments show the customer can meet the revised payments: Action Description Term extension We can extend the term of the loan, making each monthly payment smaller. For retail customers, where applicable they must also meet our policies for maximum loan term and age when they finish repaying. Customers with interest-only mortgages have to make arrangements to repay the principal at the end of the mortgage. For corporate customers, we expect the customer to be able to pay the interest in the short-term and have a realistic chance of repaying the full balance in the long-term at a minimum. We may offer term extensions if the customer is up to date with their payments but showing signs of financial difficulties. We may also offer this option if the loan is about to mature and near-term refinancing is not possible on market terms. Interest-only For retail customers, interest-only is only offered as a short-term standard collections arrangement since March 2015. We now record any related shortfall in monthly payments as arrears and report them to the credit reference agencies. As a result, we do not classify interest-only arrangements agreed since March 2015 as forbearance. We continue to manage and report all interest-only arrangements offered before then as forbearance. For corporate customers, we can agree to let a customer pay only the interest on the loan for a short time – usually less than a year. We only agree to this if we believe their financial problems are temporary and they are going to recover. After the interest-only period, we expect the customer to go back to making full payments of interest and capital once they are in a stronger financial position. Other payment rescheduling, including capitalisation For retail customers, we offer two main types, which are often combined with term extensions and, in the past, interest-only concessions: – If the customer cannot afford to increase their monthly payment enough to pay off their arrears in a reasonable time but has been making their monthly payments (usually for at least six months), then we can add the arrears to the mortgage balance. – We can also add to the mortgage balance at the time of forbearance, unpaid property charges which are due to a landlord and which we pay on behalf of the customer to avoid the lease being forfeited. For corporate customers, we may agree to lower or stop their payments until they have had time to recover. We may: – Reschedule payments to better match the customer’s cash flow – for example if the business is seasonal – Provide a temporary increase in facilities to cover peak demand ahead of the customer’s trading improving. We might do this by adding their arrears to their loan balance (we call this arrears capitalisation) or drawing from an overdraft. We may also offer other types of forbearance, including providing new facilities, interest rate concessions, seasonal profiling and interest roll-up. In rare cases, we agree to forgive or reduce part of the debt.
Disclosure of Other Ways to Manage Debt when Cutomer are in Financial Difficulty	When customers are in financial difficulty, we can also manage debt in other ways, depending on the facts of the specific case: Action Description Waiving or changing covenants If a borrower breaks a covenant, we can either waive it or change it, taking their latest and future financial position into account. We may also add a condition on the use of any surplus cash (after operating costs) to pay down their debt to us. Asking for more collateral or guarantees If a borrower has unencumbered assets, we may accept new or extra collateral in return for revised financing terms. We may also take a guarantee from other companies in the same group and/or major shareholders. We only do this where we believe the guarantor will be able to meet their commitment. Asking for more equity Where a borrower can no longer pay the interest on their debt, we may accept fresh equity capital from new or existing investors to change the capital structure in return for better terms on the existing debt.
Disclosure of Key Metrics to Measure and Control Credit Risk	We use a number of key metrics to measure and control credit risk, as follows: Metric Description Expected Credit Loss (ECL) ECL tells us what credit risk is likely to cost us either over the next 12 months on qualifying exposures, or defaults over the lifetime of the exposure where there is evidence of a SICR since origination. We explain how we calculate ECL below. Stages 1, 2 and 3 We assess each facility’s credit risk profile to determine which stage to allocate them to, and we monitor where there is a SICR and transfers between the Stages including monitoring of coverage ratios for each stage. We explain how we allocate a facility to Stage 1, 2 or 3 below. Stage 3 ratio The Stage 3 ratio is the sum of Stage 3 drawn and Stage 3 undrawn assets divided by the sum of total drawn assets and Stage 3 undrawn assets. The Stage 3 ratio is the main indicator of credit quality performance. Expected Loss (EL) EL is based on the regulatory capital rules of CRD IV and gives us another view of credit risk. It is the product of the probability of default, exposure at default and loss given default. We calculate each factor in accordance with CRD IV and include direct and indirect costs. We base them on our risk models and our assessment of each customer’s credit quality. There are differences between regulatory EL and IFRS 9 ECL, which we set out below. The rest of our Risk review, impairments, losses and loss allowances refer to calculations in accordance with IFRS, unless we specifically say they relate to CRD IV. For our IFRS accounting policy on impairment, see Note 1 to the Consolidated Financial Statements.
Disclosure of Key Differences between Regulatory EL and IFRS 9 ECL Models	There are differences between the regulatory EL and the IFRS 9 ECL approaches. Although our IFRS 9 models use the existing Basel advanced IRB risk components, we need to make several adjustments to ensure the outcome is in line with the IFRS 9 requirements, i.e. the financial reporting standard we use, as follows. Basel advanced IRB EL IFRS 9 ECL Rating philosophy Mix of point-in-time, through-the-cycle or hybrid Point-in-time, forward-looking. Considers a range of economic scenarios Parameters calibration Contains regulatory floors and downturn calibration Unbiased estimate, based on conditions known at the balance sheet date Calculation timing Considers aggregation of possible default events in the next 12 months Considers monthly calculation of parameters, for all possible future default dates. First 12 months are used for Stage 1, full lifetime for Stages 2 and 3 Probability of Default (PD) PD in the next 12 months Includes forward-looking economic data and removes conservatism. PD in next 12 months for Stage 1, lifetime for Stages 2 and 3 Loss Given Default (LGD) Lifetime LGD for defaults in the next 12 months Modelled without regulatory floors and exclusion of indirect costs Exposure at Default (EAD) Exposure at the point of default if the customer defaults in the next 12 months Floored at amount owed, except on some revolving facilities. Recognises ability for exposure to reduce from the balance sheet date to default date SICR Does not include SICR concept Includes SICR concept Discounting applied At the weighted average cost of capital to the default date At the effective interest rate (EIR) to the balance sheet date
Schedule of Macroeconomic Assumptions for Each Five Scenarios	The table below sets out our macroeconomic assumptions for each of the five scenarios at 31 December 2021: Upside 1 Base case Downside 1 Downside 2 Downside 3 % % % % % GDP (1) 2020 (actual) (9.7) (9.7) (9.7) (9.7) (9.7) 2021 7.0 6.9 6.8 6.2 5.6 2022 4.8 4.6 4.1 (0.7) (7.5) 2023 2.2 1.7 0.9 0.5 3.1 2024 1.9 1.5 0.5 1.6 1.5 2025 2.1 1.6 0.5 1.7 1.5 Bank Rate (1) 2020 (actual) 0.10 0.10 0.10 0.10 0.10 2021 0.25 0.25 0.25 0.25 0.25 2022 0.75 0.75 0.75 1.00 (0.50) 2023 0.75 0.75 0.75 2.00 0.00 2024 1.25 0.75 1.00 3.00 0.00 2025 1.75 0.75 1.00 2.75 0.00 HPI (1) 2020 (actual) 6.9 6.9 6.9 6.9 6.9 2021 5.4 5.0 5.4 5.4 (2.5) 2022 (0.8) 2.0 (1.8) (8.3) (19.6) 2023 (2.0) 2.0 (4.6) (13.1) (9.3) 2024 1.0 2.0 (3.1) (4.8) 2.4 2025 3.8 2.0 (0.7) 4.3 3.3 Unemployment (1) 2020 (actual) 5.2 5.2 5.2 5.2 5.2 2021 4.4 4.7 4.4 4.4 6.8 2022 4.4 4.5 4.8 6.9 11.4 2023 4.2 4.4 5.0 6.9 8.7 2024 3.9 4.3 5.1 6.4 8.0 2025 3.7 4.3 5.4 6.1 7.4 The table below sets out our macroeconomic assumptions for each of the five scenarios at 31 December 2020: Upside 1 Base case Downside 1 Downside 2 Downside 3 % % % % % GDP (1) 2020 (10.5) (11.5) (10.5) (11.1) (11.5) 2021 4.8 4.5 4.0 (0.8) (8.0) 2022 4.9 6.1 3.6 3.2 3.1 2023 3.0 2.2 1.5 2.7 1.5 2024 2.0 1.5 0.4 1.5 1.5 Bank Rate (1) 2020 0.10 0.10 0.10 0.10 0.10 2021 0.25 0.10 0.10 0.75 (0.50) 2022 0.75 0.10 0.10 1.75 0.00 2023 1.25 0.10 0.10 3.00 0.00 2024 1.75 0.25 0.25 2.75 0.00 HPI (1) 2020 3.7 3.5 3.7 3.7 3.5 2021 (4.6) (2.0) (5.4) (11.3) (19.7) 2022 (4.1) 1.5 (6.6) (14.5) (8.2) 2023 2.4 2.0 (1.8) (3.8) 1.3 2024 5.5 2.0 0.5 4.9 3.1 Unemployment (1) 2020 6.3 6.8 6.3 6.3 6.8 2021 6.1 7.5 6.5 8.5 11.4 2022 5.3 6.2 6.1 7.9 8.7 2023 4.4 5.6 5.7 6.9 8.0 2024 4.1 5.5 5.8 6.5 7.4 (1) GDP is the calendar year annual growth rate, HPI is Q4 annual growth rate and all other data points are at 31 December in the year indicated.
Schedule of Macroeconomic Asumptions and the Evolution Throughout the Forecast Period	Our macroeconomic assumptions and their evolution throughout the forecast period for 2021 and 2020 were: Upside 1 Base case Downside 1 Downside 2 Downside 3 2021 % % % % % House price growth 5-year average increase/decrease 1.30 2.00 (1.78) (3.27) (6.00) Peak/(trough) at (1) (3.07) 0.00 (9.87) (24.03) (32.12) GDP 5-year average increase/decrease 2.33 1.89 0.93 0.49 (0.58) Cumulative growth/(fall) to peak/(trough) (2) 12.19 9.83 4.75 2.48 (2.85) Unemployment rate 5-year end period 3.60 4.30 5.65 5.95 6.80 Peak/(trough) at (1) 4.45 4.70 5.65 7.27 11.90 Bank of England bank rate 5-year end period 2.00 0.75 1.00 2.25 0.25 Peak/(trough) at (1) 2.00 0.75 1.00 3.00 (0.50) Upside 1 Base case Downside 1 Downside 2 Downside 3 2020 % % % % % House price growth 5-year average increase/decrease 0.49 1.38 (2.01) (4.54) (4.44) Peak/(trough) at (1) 2.45 7.11 (9.65) (20.72) (20.32) GDP 5-year average increase/decrease 0.75 0.39 (0.38) (0.98) (2.82) Cumulative growth/(fall) to peak/(trough) (2) 3.82 1.96 (1.88) (4.80) (13.33) Unemployment rate 5-year end period 4.14 5.50 5.84 6.52 7.40 Peak/(trough) at (1) 6.28 7.90 6.51 8.78 11.90 Bank of England bank rate 5-year end period 1.75 0.25 0.25 2.75 0.00 Peak/(trough) at (1) 1.75 0.25 0.25 3.00 (0.50) (1) For GDP and house price growth it is the peak to trough change within the 5 year period; for the unemployment rate it is the peak; and for Bank Rate it is the peak or trough. (2) This is the cumulative growth for the 5 year period.
Disclosure of Scenario Weights Applied To Scenarios	The scenario weights we applied for 2021 and 2020 were: Upside 1 Base case Downside 1 Downside 2 Downside 3 Scenario weights % % % % % 2021 5 45 25 20 5 2020 5 45 15 25 10
Schedule of Macroeconomic Asumptions and the Evolution Throughout the Forecast Period for CIB Portfolio	Our macroeconomic assumptions and their evolution throughout the forecast period for our CIB portfolio at 31 December 2020 were: GDP assumption % 2020 Long Run global growth scenario (1) 1.3 (1) The Long Run scenario is the average annual global growth rate over the 5 year period 2020 to 2024.
Disclosure of Definition of Default by Segment	We define a financial instrument as in default (i.e. credit impaired) for purposes of calculating ECL if it is more than three months past due, or if we have data to make us doubt the customer can keep up with their payments i.e. they are unlikely to pay. The data we have on customers varies across our business segments. It typically includes where: Retail Banking and Consumer Finance – They have been reported bankrupt or insolvent. This excludes accounts which are up to date and are not defaulted – Their loan term has ended, but they still owe us money more than three months later – They have had forbearance while in default, but have not caught up with the payments they had missed before that, or they have had multiple forbearance – We have suspended their fees and interest because they are in financial difficulties – We have repossessed the property Corporate & Commercial Banking and Corporate Centre – They have had a winding up notice issued, or something happens that is likely to trigger insolvency – such as another lender calls in a loan – Something happens that makes them less likely to be able to pay us – such as they lose an important client or contract – They have regularly missed or delayed payments, even though they have not gone over the three-month limit for default – Their loan is unlikely to be refinanced or repaid in full on maturity – Their loan has an excessive LTV that is unlikely to be resolved, such as by a change in planning policy, pay-downs, or increase in market value
Disclosure of Quantitative Criteria to Identify When Exposure Has Increased Credit Risk	For each portfolio, the quantitative criteria we used for 2021 were: Retail Banking Consumer Finance (2) Corporate & Commercial Banking Corporate Centre Homes Everyday Banking (1) Personal loans Credit cards Overdrafts 30bps 30bps 340bps 260bps 300bps 30bps Internal rating method (1) For larger business banking customers we apply the same criteria that we use for Corporate & Commercial Banking. (2) Consumer Finance use the comparison of lifetime PDs to determine Stage allocation, unlike other products which first turn the lifetime PD into an average yearly PD (annualised) and then do the comparison.
Disclosure of Qualitative Criteria to Identify When Exposure Has Increased Credit Risk	We also use qualitative criteria to identify where an exposure has increased in credit risk, independent of any changes in PD. For each portfolio, the criteria we used for2021 and 2020 were: Retail Banking Consumer Finance Corporate & Commercial Banking Corporate Centre Homes Everyday Banking (1) Personal loans Credit cards Overdrafts - In forbearance - 30 Days past due (DPD) in last 12m - Bankrupt - £100+ arrears - In Collections - £50+ arrears - In forbearance - In Collections - £100+ arrears - Behaviour score indicators - Fees suspended - Debit dormant >35 days - Any excess in month - In forbearance - Deceased or Insolvent - Court ‘Return of goods’ order or Police watchlist - Agreement terminated - Payment holiday - Cash Collection - In forbearance - Watchlist: proactive management - Default at proxy origination - Watchlist: proactive management (1) For larger business banking customers we apply the same criteria that we use for Corporate & Commercial Banking.
Disclosure of ECL by Segment	Modelled ECL Individually assessed PMAs Total ECL 2021 £m £m £m £m Retail Banking 265 1 123 389 – Homes 119 1 71 191 – Everyday Banking 146 — 52 198 Consumer Finance 51 — 1 52 Corporate & Commercial Banking 106 100 217 423 Corporate Centre 2 — — 2 Total 424 101 341 866 2020 £m £m £m £m Retail Banking 472 3 113 588 – Homes 220 3 57 280 – Everyday Banking 252 — 56 308 Consumer Finance 110 — 8 118 Corporate & Commercial Banking 195 157 251 603 Corporate & Investment Banking 26 — 7 33 Corporate Centre — — 35 35 Total 803 160 414 1,377 2021 compared to 2020
Disclosure of Most Significant PMAs Applied	The PMAs that we applied at 31 December 2021 and 31 December 2020 were: 2021 2020 PMAs £m £m Non Covid-19 PMAs Long-term indeterminate arrears 14 29 12+ months in arrears 29 34 Cladding risk 15 — Mortgages affordability 18 — UPL loss floor 21 31 Other PMA 8 30 Total non Covid-19 PMAs 105 124 Covid-19 PMAs Corporate lending to segments affected by Covid-19 176 193 Payment holidays — 27 Corporate single large exposure 23 35 Model underestimation 28 20 SME debt burden 9 — Other Covid-19 PMAs — 15 Total Covid-19 PMAs 236 290
Disclosure of Base Expected Credit Losses to Probability Weighted Estimated Credit Losses	As described above, prior to the transfer in Q4 2021 our CIB segment used a single forward-looking economic scenario. However, three scenarios were still used in the model, with a PMA held to increase provisions to the level required in the single scenario. In order to present a consolidated view in a single table and show variation from the forward-looking component, the three scenarios were presented in the table with the overlay value added to each scenario. As all other segments use five scenarios, interpolation is also required. Data from the CIB Upside scenario is presented in the Upside 1 Column, the Downside scenario is in the Downside 3 column, the Base case is in the Base case column and values in Downside 1 and Downside 2 are interpolated from the Base case and Downside scenarios. Weighted Upside 1 Base case Downside 1 Downside 2 Downside 3 2021 £m £m £m £m £m £m Exposure 319,319 319,319 319,319 319,319 319,319 319,319 Retail Banking 214,979 214,979 214,979 214,979 214,979 214,979 – Homes 193,247 193,247 193,247 193,247 193,247 193,247 – Everyday Banking 21,732 21,732 21,732 21,732 21,732 21,732 Consumer Finance 5,298 5,298 5,298 5,298 5,298 5,298 Corporate & Commercial Banking 24,691 24,691 24,691 24,691 24,691 24,691 Corporate Centre 74,351 74,351 74,351 74,351 74,351 74,351 ECL 866 740 738 849 1,123 1,288 Retail Banking 389 307 286 375 510 662 – Homes 191 134 125 177 283 437 – Everyday Banking 198 173 161 198 227 225 Consumer Finance 52 50 51 51 53 54 Corporate & Commercial Banking 423 381 399 421 558 570 Corporate Centre 2 2 2 2 2 2 % % % % % % Proportion of assets in Stage 2 5.2 4.9 4.8 5.1 6.1 6.9 Retail Banking 5.4 5.2 5.1 5.4 6.5 7.6 – Homes 5.8 5.5 5.5 5.7 6.8 8.1 – Everyday Banking 2.6 2.3 2.1 3.0 3.5 3.0 Consumer Finance 3.8 3.8 3.8 3.8 3.8 3.8 Corporate & Commercial Banking 17.8 16.3 16.2 16.9 20.8 20.9 Corporate Centre 0.3 0.3 0.3 0.3 0.3 0.3 Weighted Upside 1 Base case Downside 1 Downside 2 Downside 3 2020 £m £m £m £m £m £m Exposure 328,792 328,792 328,792 328,792 328,792 328,792 Retail Banking 205,062 205,062 205,062 205,062 205,062 205,062 – Homes 183,077 183,077 183,077 183,077 183,077 183,077 – Everyday Banking 21,985 21,985 21,985 21,985 21,985 21,985 Consumer Finance 8,261 8,261 8,261 8,261 8,261 8,261 Corporate & Commercial Banking 24,503 24,503 24,503 24,503 24,503 24,503 Corporate & Investment Banking 11,646 11,646 11,646 11,646 11,646 11,646 Corporate Centre 79,320 79,320 79,320 79,320 79,320 79,320 ECL 1,377 1,130 1,222 1,300 1,613 1,802 Retail Banking 588 496 470 544 731 740 – Homes 280 213 207 253 390 415 – Everyday Banking 308 283 263 291 341 325 Consumer Finance 118 115 117 116 119 123 Corporate & Commercial Banking 603 485 575 567 671 824 Corporate & Investment Banking 33 5 26 40 53 66 Corporate Centre 35 29 34 33 39 49 % % % % % % Proportion of assets in Stage 2 5.2 4.5 4.6 4.6 6.5 6.7 Retail Banking 5.4 4.6 4.5 4.6 7.2 7.2 – Homes 5.7 4.8 4.8 4.8 7.6 7.4 – Everyday Banking 2.8 2.6 2.3 2.8 3.5 5.1 Consumer Finance 4.6 4.6 4.6 4.6 4.6 4.8 Corporate & Commercial Banking 22.4 20.1 20.8 20.2 24.5 28.6 Corporate & Investment Banking 1.7 1.7 1.7 1.7 1.7 1.7 Corporate Centre — — — — — —
Schedule of Impact on Profit Before Tax of Applying an Immediate and Permanent House Price Increase or Decrease to Our Base Case Economic Scenario Explanatory	The table below shows the ECL impact on profit before tax of applying an immediate and permanent house price increase/decrease to our unweighted base case economic scenario, and assumes no changes to the staging allocation of exposures. Increase/decrease in house prices +20% +10% -10% -20% Increase/(decrease) in profit before tax £m £m £m £m 2021 64 40 (69) (197) 2020 63 38 (66) (183)
Disclosure of Factors to Measure ECL	For accounts not in default at the reporting date, we estimate a monthly ECL for each exposure and for each month over the forecast period. The lifetime ECL is the sum of the monthly ECLs over the forecast period, while the 12-month ECL is limited to the first 12 months. We calculate each monthly ECL as the discounted value for the relevant forecast month of the product of the following factors: Factor Description Survival rate (SR) The probability that the exposure has not closed or defaulted since the reporting date. Probability of default (PD) The likelihood of a borrower defaulting in the following month, assuming it has not closed or defaulted since the reporting date. For each month in the forecast period, we estimate the monthly PD from a range of factors. These include the current risk grade for the exposure, which becomes less relevant further into the forecast period, as well as the expected evolution of the account risk with maturity and factors for changing economics. We support this with historical data analysis. Exposure at default (EAD) The amount we expect to be owed if a default event was to occur. We determine EAD for each month of the forecast period by the expected payment profile, which varies by product type. For amortising products, we base it on the borrower’s contractual repayments over the forecast period. We adjust this for any expected overpayments on Stage 1 accounts that the borrower may make and for any arrears we expect if the account was to default. For revolving products, or amortising products with an off-balance sheet element, we determine EAD using the balance at default and the contractual exposure limit. We vary these assumptions by product type and base them on analysis of recent default data. Loss given default (LGD) Our expected loss if a default event were to occur. We express it as a percentage and calculate it based on factors that we have observed to affect the likelihood and/or value of any subsequent write-offs, which vary according to whether the product is secured or unsecured. If the product is secured, we take into account collateral values as well as the historical discounts to market/book values due to forced sales type.
Disclosure of Maximum and Net Exposure to Credit Risk	The tables below show the main differences between our maximum and net exposure to credit risk. They show the effects of collateral, netting, and risk transfer to mitigate our exposure. The tables only show the financial assets that credit risk affects and to which the impairment requirements in IFRS 9 are applied. For balance sheet assets, the maximum exposure to credit risk is the carrying value after impairment loss allowances. Off-balance sheet exposures are mortgage offers, guarantees, formal standby facilities, credit lines and other commitments. For off-balance sheet guarantees, the maximum exposure is the maximum amount that we would have to pay if the guarantees were called on. For formal standby facilities, credit lines and other commitments that are irrevocable over the life of the facility, the maximum exposure is the total amount of the commitment. Maximum exposure Balance sheet asset Off-balance sheet Collateral (1) Gross Loss allowance Net Gross Loss allowance Net Cash Non-cash Netting (2) Net 2021 £bn £bn £bn £bn £bn £bn £bn £bn £bn £bn Cash and balances at central banks 50.5 — 50.5 — — — — — — 50.5 Financial assets at amortised cost: – Loans and advances to customers: (3) – Loans secured on residential properties (4) 178.0 (0.2) 177.8 16.0 — 16.0 — (181.2) — 12.6 – Corporate loans 19.3 (0.4) 18.9 7.7 — 7.7 (0.1) (16.8) — 9.7 – Finance leases 3.9 (0.1) 3.8 0.3 — 0.3 — (4.7) — (0.6) – Accrued interest and other adjustments 0.7 — 0.7 — — — — — — 0.7 – Other unsecured loans 9.4 (0.2) 9.2 13.3 — 13.3 — — — 22.5 – Amounts due from fellow Banco Santander group subsidiaries and joint ventures 3.1 — 3.1 — — — — — — 3.1 Total loans and advances to customers 214.4 (0.9) 213.5 37.3 — 37.3 (0.1) (202.7) — 48.0 – Loans and advances to banks 1.4 — 1.4 0.4 — 0.4 — — — 1.8 – Reverse repurchase agreements – non trading 12.7 — 12.7 — — — — (12.2) (0.4) 0.1 – Other financial assets at amortised cost 0.5 — 0.5 — — — — — — 0.5 Total financial assets at amortised cost 229.0 (0.9) 228.1 37.7 — 37.7 (0.1) (214.9) (0.4) 50.4 Financial assets at fair value at FVOCI: – Debt securities 5.9 — 5.9 — — — — — — 5.9 Total financial assets at FVOCI 5.9 — 5.9 — — — — — — 5.9 Total 285.4 (0.9) 284.5 37.7 — 37.7 (0.1) (214.9) (0.4) 106.8 2020 Cash and balances at central banks 43.5 — 43.5 — — — — — — 43.5 Financial assets at amortised cost: – Loans and advances to customers: (3) – Loans secured on residential properties (4) 170.0 (0.3) 169.7 13.3 — 13.3 — (173.3) — 9.7 – Corporate loans 23.6 (0.6) 23.0 15.4 (0.1) 15.3 (0.1) (20.4) — 17.8 – Finance leases 6.6 (0.1) 6.5 0.2 — 0.2 (0.1) (5.8) — 0.8 – Accrued interest and other adjustments 0.9 — 0.9 — — — — — — 0.9 – Other unsecured loans 10.2 (0.3) 9.9 13.3 — 13.3 — — — 23.2 – Amounts due from fellow Banco Santander group subsidiaries and joint ventures 2.2 — 2.2 — — — — — — 2.2 Total loans and advances to customers 213.5 (1.3) 212.2 42.2 (0.1) 42.1 (0.2) (199.5) — 54.6 – Loans and advances to banks 2.0 — 2.0 1.0 — 1.0 — — — 3.0 – Reverse repurchase agreements – non trading 19.6 — 19.6 — — — — (19.5) (0.1) — – Other financial assets at amortised cost 1.2 — 1.2 — — — — — — 1.2 Total financial assets at amortised cost 236.3 (1.3) 235.0 43.2 (0.1) 43.1 (0.2) (219.0) (0.1) 58.8 Financial assets at FVOCI: – Debt securities 9.0 — 9.0 — — — — — — 9.0 Total financial assets at FVOCI 9.0 — 9.0 — — — — — — 9.0 Total 288.8 (1.3) 287.5 43.2 (0.1) 43.1 (0.2) (219.0) (0.1) 111.3 (1) The forms of collateral we take to reduce credit risk include: residential and commercial property; other physical assets, including motor vehicles; liquid securities, including those transferred under reverse repurchase agreements; cash, including cash used as collateral for derivative transactions; and receivables. Charges on residential property are most of the collateral we take. (2) We can reduce credit risk exposures by applying netting. We do this mainly for derivative and repurchase transactions with financial institutions. For derivatives and securities finance transactions, we use standard master netting agreements. They allow us to set off our credit risk exposure to a counterparty against our obligations to the counterparty in relation to transactions under the master netting agreement in the event of default. This gives us a lower net credit exposure. They may also reduce settlement exposure. For more on this, see ‘Credit risk mitigation’ in the ‘Credit risk - Credit risk management’ section. (3) Balances include interest we have charged to the customer’s account and accrued interest that we have not charged to the account yet. (4) The collateral value we have shown against advances secured on residential property is limited to the balance of each associated individual loan. It does not include the impact of over–collateralisation (where the collateral has a higher value than the loan balance) and includes collateral we would receive on draw down of certain off–balance sheet commitments.
Disclosure of Difference Between Maximum and Net Exposure to Credit Risk	The tables below show the main differences between our maximum and net exposure to credit risk on the financial assets that credit risk affects and to which the impairment requirements in IFRS 9 are not applied. Balance sheet asset gross Collateral (1) Netting (2) Net Cash Non-cash 2021 £bn £bn £bn £bn £bn Financial assets at FVTPL: – Derivative financial instruments 1.7 — (0.7) (0.6) 0.4 – Other financial assets at FVTPL 0.7 — — — 0.7 Total 2.4 — (0.7) (0.6) 1.1 2020 Financial assets at FVTPL: – Derivative financial instruments 3.5 — (1.8) (0.8) 0.9 – Other financial assets at FVTPL 0.8 — — — 0.8 Total 4.3 — (1.8) (0.8) 1.7 (1) The forms of collateral we take to reduce credit risk include: liquid securities, including those transferred under reverse repurchase agreements; cash, including cash used as collateral for derivative transactions; and receivables. (2) We can reduce credit risk exposures by applying netting. We do this mainly for derivative and repurchase transactions with financial institutions. For derivatives and securities finance transactions, we use standard master netting agreements. They allow us to set off our credit risk exposure to a counterparty against our obligations to the counterparty in relation to transactions under the master netting agreement in the event of default. This gives us a lower net credit exposure. They may also reduce settlement exposure. For more on this, see ‘Credit risk mitigation’ in the ‘Credit risk – Credit risk management’ section.
Disclosure of Equivalent Credit Rating Grade used by Standard and Poors Ratings Services	In the final column of the table we show the approximate equivalent credit rating grade used by Standard & Poor’s Ratings Services (S&P). PD range Mid Lower Upper S&P equivalent Santander UK risk grade % % % 9 0.010 0.000 0.021 AAA to AA+ 8 0.032 0.021 0.066 AA to AA- 7 0.100 0.066 0.208 A+ to BBB 6 0.316 0.208 0.658 BBB- to BB 5 1.000 0.658 2.081 BB- 4 3.162 2.081 6.581 B+ to B 3 10.000 6.581 20.811 B- 2 31.623 20.811 99.999 CCC to C 1 (Default) 100.000 100.000 100.000 D
Disclosure of Credit Rating of Financial Assets Subject to Credit Risk	The tables below show the credit rating of our financial assets to which the impairment requirements in IFRS 9 apply. PMAs are incorporated in the balances. For more on the credit rating profiles of key portfolios, see the credit risk review section for each business segment. Santander UK risk grade Loss allowance Total 9 8 7 6 5 4 3 to 1 Other (1) 2021 £bn £bn £bn £bn £bn £bn £bn £bn £bn £bn Exposures On balance sheet Cash and balances at central banks 50.5 — — — — — — — — 50.5 – Stage 1 50.5 — — — — — — — — 50.5 Financial assets at amortised cost: – Loans and advances to customers (2) 9.0 33.0 85.8 48.6 12.9 10.2 6.0 8.9 (0.9) 213.5 – Stage 1 9.0 32.2 84.3 45.5 10.1 5.0 0.6 8.3 (0.1) 194.9 – Stage 2 — 0.8 1.5 3.1 2.8 5.2 2.8 0.3 (0.4) 16.1 – Stage 3 — — — — — — 2.6 0.3 (0.4) 2.5 Of which mortgages: 9.0 30.2 80.5 43.1 6.5 4.7 3.2 0.8 (0.2) 177.8 – Stage 1 9.0 30.0 79.2 40.2 4.2 1.6 0.1 0.8 — 165.1 – Stage 2 — 0.2 1.3 2.9 2.3 3.1 1.3 — (0.1) 11.0 – Stage 3 — — — — — — 1.8 — (0.1) 1.7 – Loans and advances to banks 0.2 0.2 1.0 — — — — — — 1.4 – Stage 1 0.2 0.2 1.0 — — — — — — 1.4 – Reverse repo agreements – non trading 9.7 0.1 1.1 0.6 — — — 1.2 — 12.7 – Stage 1 9.7 0.1 1.1 0.6 — — — 1.2 — 12.7 – Other financial assets at amortised cost 0.5 — — — — — — — — 0.5 – Stage 1 0.5 — — — — — — — — 0.5 Total financial assets at amortised cost 19.4 33.3 87.9 49.2 12.9 10.2 6.0 10.1 (0.9) 228.1 Financial assets at FVOCI: 3.6 2.1 0.2 — — — — — — 5.9 – Stage 1 3.6 2.1 0.2 — — — — — — 5.9 Total on balance sheet 73.5 35.4 88.1 49.2 12.9 10.2 6.0 10.1 (0.9) 284.5 Total off–balance sheet 0.1 7.3 7.0 6.8 4.5 1.3 0.5 10.2 — 37.7 – Stage 1 0.1 7.0 6.7 6.6 4.3 1.0 0.2 10.2 — 36.1 – Stage 2 — 0.3 0.3 0.2 0.2 0.3 0.2 — — 1.5 – Stage 3 — — — — — — 0.1 — — 0.1 Total exposures 73.6 42.7 95.1 56.0 17.4 11.5 6.5 20.3 (0.9) 322.2 ECL On balance sheet Cash and balances at central banks — — — — — — — — — – Stage 1 — — — — — — — — — Financial assets at amortised cost: – Loans and advances to customers (2) — — — — 0.3 0.1 0.5 — 0.9 – Stage 1 — — — — 0.1 — — — 0.1 – Stage 2 — — — — 0.2 0.1 0.1 — 0.4 – Stage 3 — — — — — — 0.4 — 0.4 Of which mortgages: — — — — — 0.1 0.1 — 0.2 – Stage 1 — — — — — — — — — – Stage 2 — — — — — 0.1 — — 0.1 – Stage 3 — — — — — — 0.1 — 0.1 – Loans and advances to banks — — — — — — — — — – Stage 1 — — — — — — — — — – Reverse repo agreements – non trading — — — — — — — — — – Stage 1 — — — — — — — — — – Other financial assets at amortised cost — — — — — — — — — – Stage 1 — — — — — — — — — Total financial assets at amortised cost — — — — 0.3 0.1 0.5 — 0.9 Financial assets at FVOCI: — — — — — — — — — – Stage 1 — — — — — — — — — Total on balance sheet — — — — 0.3 0.1 0.5 — 0.9 Total off–balance sheet — — — — — — — — – Stage 1 — — — — — — — — — – Stage 2 — — — — — — — — – Stage 3 — — — — — — — — — Total ECL — — — — 0.3 0.1 0.5 — 0.9 Santander UK risk grade 9 8 7 6 5 4 3 to 1 Other (1) Total 2021 % % % % % % % % % Coverage ratio On balance sheet Cash and balances at central banks — — — — — — — — — – Stage 1 — — — — — — — — — Financial assets at amortised cost: — — — — — — — — — – Loans and advances to customers (2) — — — — 2.3 1.0 8.3 — 0.4 – Stage 1 — — — — 1.0 — — — 0.1 – Stage 2 — — — — 7.1 1.9 3.6 — 2.5 – Stage 3 — — — — — — 15.4 — 16.0 Of which mortgages: — — — — — 2.1 3.1 — 0.1 – Stage 1 — — — — — — — — — – Stage 2 — — — — — 3.2 — — 0.9 – Stage 3 — — — — — — 5.6 — 5.9 – Loans and advances to banks — — — — — — — — — – Stage 1 — — — — — — — — — – Reverse repo agreements – non trading — — — — — — — — — – Stage 1 — — — — — — — — — – Other financial assets at amortised cost — — — — — — — — — – Stage 1 — — — — — — — — — Total financial assets at amortised cost — — — — 2.3 1.0 8.3 — 0.4 Financial assets at FVOCI: — — — — — — — — — – Stage 1 — — — — — — — — — Total on balance sheet — — — — 2.3 1.0 8.3 — 0.3 Total off–balance sheet — — — — — — — — — – Stage 1 — — — — — — — — — – Stage 2 — — — — — — — — — – Stage 3 — — — — — — — — — Total coverage ratio — — — — 1.7 0.9 7.7 — 0.3 Santander UK risk grade Loss allowance 9 8 7 6 5 4 3 to 1 Other (1) Total 2020 £bn £bn £bn £bn £bn £bn £bn £bn £bn £bn Exposures On balance sheet Cash and balances at central banks 43.5 — — — — — — — — 43.5 – Stage 1 43.5 — — — — — — — — 43.5 Financial assets at amortised cost: – Loans and advances to customers⁽²⁾ 8.0 28.2 75.8 44.8 13.6 27.4 8.2 7.5 (1.3) 212.2 – Stage 1 8.0 28.1 75.4 43.3 10.9 19.4 1.1 7.3 (0.2) 193.3 – Stage 2 — 0.1 0.4 1.5 2.7 8.0 4.2 0.2 (0.5) 16.6 – Stage 3 — — — — — — 2.9 — (0.6) 2.3 Of which mortgages: 7.9 24.8 69.3 37.6 5.7 19.9 4.5 0.3 (0.3) 169.7 – Stage 1 7.9 24.8 69.0 36.2 4.0 15.0 0.6 0.3 — 157.8 – Stage 2 — — 0.3 1.4 1.7 4.9 2.1 — (0.2) 10.2 – Stage 3 — — — — — — 1.8 — (0.1) 1.7 – Loans and advances to banks 0.1 0.1 0.7 — — — — 1.1 — 2.0 – Stage 1 0.1 0.1 0.7 — — — — 1.1 — 2.0 – Reverse repo agreements – non trading 12.2 3.3 1.5 2.4 — — — 0.2 — 19.6 – Stage 1 12.2 3.3 1.5 2.4 — — — 0.2 — 19.6 – Other financial assets at amortised cost 1.2 — — — — — — — — 1.2 – Stage 1 1.2 — — — — — — — — 1.2 Total financial assets at amortised cost 21.5 31.6 78.0 47.2 13.6 27.4 8.2 8.8 (1.3) 235.0 Financial assets at FVOCI: 5.3 3.4 0.2 0.1 — — — — — 9.0 – Stage 1 5.3 3.4 0.2 0.1 — — — — — 9.0 Total on balance sheet 70.3 35.0 78.2 47.3 13.6 27.4 8.2 8.8 (1.3) 287.5 Total off–balance sheet 0.4 8.8 9.5 8.8 5.1 1.6 0.5 8.5 (0.1) 43.1 – Stage 1 0.4 8.8 9.5 8.6 4.7 1.1 0.2 8.5 — 41.8 – Stage 2 — — — 0.2 0.4 0.5 0.2 — (0.1) 1.2 – Stage 3 — — — — — — 0.1 — — 0.1 Total exposures 70.7 43.8 87.7 56.1 18.7 29.0 8.7 17.3 (1.4) 330.6 Santander UK risk grade 9 8 7 6 5 4 3 to 1 Other (1) Total 2020 £bn £bn £bn £bn £bn £bn £bn £bn £bn ECL On balance sheet Cash and balances at central banks — — — — — — — — — – Stage 1 — — — — — — — — — Financial assets at amortised cost: – Loans and advances to customers⁽²⁾ — — — 0.1 0.1 0.2 0.9 — 1.3 – Stage 1 — — — 0.1 — — 0.1 — 0.2 – Stage 2 — — — — 0.1 0.2 0.2 — 0.5 – Stage 3 — — — — — — 0.6 — 0.6 Of which mortgages: — — — — — 0.1 0.2 — 0.3 – Stage 1 — — — — — — — — — – Stage 2 — — — — — 0.1 0.1 — 0.2 – Stage 3 — — — — — — 0.1 — 0.1 – Loans and advances to banks — — — — — — — — — – Stage 1 — — — — — — — — — – Reverse repo agreements – non trading — — — — — — — — — – Stage 1 — — — — — — — — — – Other financial assets at amortised cost — — — — — — — — — – Stage 1 — — — — — — — — — Total financial assets at amortised cost — — — 0.1 0.1 0.2 0.9 — 1.3 Financial assets at FVOCI: — — — — — — — — — – Stage 1 — — — — — — — — — Total on balance sheet — — — 0.1 0.1 0.2 0.9 — 1.3 Total off–balance sheet — — — — — — 0.1 — 0.1 – Stage 1 — — — — — — — — — – Stage 2 — — — — — — 0.1 — 0.1 – Stage 3 — — — — — — — — — Total ECL — — — 0.1 0.1 0.2 1 — 1.4 2020 % % % % % % % % % Coverage ratio On balance sheet Cash and balances at central banks — — — — — — — — — – Stage 1 — — — — — — — — — Financial assets at amortised cost: – Loans and advances to customers⁽²⁾ — — — 0.2 0.7 0.7 11.0 — 0.4 – Stage 1 — — — 0.2 — — 9.1 — 0.1 – Stage 2 — — — — 3.7 2.5 4.8 — 3.0 – Stage 3 — — — — — — 20.7 — 26.1 Of which mortgages: — — — — — 0.5 4.4 — 0.2 – Stage 1 — — — — — — — — — – Stage 2 — — — — — 2.0 4.8 — 2.0 – Stage 3 — — — — — — 5.6 — 5.9 – Loans and advances to banks — — — — — — — — — – Stage 1 — — — — — — — — — – Reverse repo agreements – non trading — — — — — — — — — – Stage 1 — — — — — — — — — – Other financial assets at amortised cost — — — — — — — — — – Stage 1 — — — — — — — — — Total financial assets at amortised cost — — — 0.2 0.7 0.7 11.0 — 0.6 Financial assets at FVOCI: — — — — — — — — — – Stage 1 — — — — — — — — — Total on balance sheet — — — 0.2 0.7 0.7 11.0 — 0.5 Total off–balance sheet — — — — — — 20.0 — 0.2 – Stage 1 — — — — — — — — — – Stage 2 — — — — — — 50.0 — 8.3 – Stage 3 — — — — — — — — — Total coverage ratio — — — 0.2 0.5 0.7 11.5 — 0.4 (1) Includes cash at hand and smaller cases mainly in the consumer (auto) finance and commercial mortgages portfolios, as well as loans written as part of the UK Government Covid-19 support schemes for micro-SMEs. We use scorecards for these items, rather than rating models. (2) Includes interest we have charged to the customer’s account and accrued interest we have not charged to the account yet.
Disclosure of Credit Performance	Customer Loans Gross write- Loan Loss Allowances Total Stage 1 Stage 2 Stage 3 2021 £bn £bn £bn £bn £m £m Retail Banking 185.6 171.8 11.7 2.1 108 389 – Homes 177.3 164.4 11.1 1.8 5 191 – Everyday Banking (1) 8.3 7.4 0.6 0.3 103 198 Consumer Finance 5.0 4.8 0.2 — 25 52 Corporate & Commercial Banking 17.0 11.8 4.4 0.8 58 423 Corporate Centre 3.0 2.8 0.2 — — 2 210.6 191.2 16.5 2.9 191 866 Undrawn Balances 37.8 36.2 1.5 0.1 Stage 1, Stage 2 and Stage 3 (2) ratios % 90.79 7.83 1.43 2020 £bn £bn £bn £bn £m £m Retail Banking 178.5 165.6 11.0 1.9 155 588 – Homes 169.8 157.6 10.4 1.8 14 280 – Everyday Banking (1) 8.7 8.0 0.6 0.1 141 308 Consumer Finance 8.0 7.6 0.4 — 25 118 Corporate & Commercial Banking 17.6 11.1 5.5 1.0 51 603 Corporate & Investment Banking 2.8 2.6 0.2 — 22 33 Corporate Centre 3.5 3.5 — — — 35 210.4 190.4 17.1 2.9 253 1,377 Undrawn Balances 43.2 41.8 1.3 0.1 Stage 1, Stage 2 and Stage 3 (2) ratios % 90.49 8.12 1.42 (1) Everyday Banking includes BBLS lending through Business Banking. (2) Stage 3 ratio = (Stage3 drawn + Stage 3 undrawn assets)/(total drawn assets + Stage 3 undrawn assets). 2021 2020 £m £m Mortgage loans and advances to customers of which: 177,297 169,801 – Stage 1 164,381 157,614 – Stage 2 11,118 10,388 – Stage 3 1,798 1,799 Loss allowances (1) 191 280 % % Stage 1 ratio (2) 92.72 92.82 Stage 2 ratio (2) 6.27 6.12 Stage 3 ratio (3) 1.02 1.07 (1) The ECL allowance is for both on and off–balance sheet exposures . (2) Stage 1/Stage 2 exposures as a percentage of customer loans. (3) The sum of Stage 3 drawn and Stage 3 undrawn assets divided by the sum of total drawn assets and Stage 3 undrawn assets . Portfolio of particular interest (1) Total Interest-only Part interest-only, part repayment (2) (3) Flexible (3) LTV >100% Buy-to-let Other 2021 £m £m £m £m £m £m £m Mortgage portfolio 177,297 40,906 13,865 8,549 531 14,893 118,874 – Stage 1 164,381 36,459 12,614 7,509 357 14,363 111,947 – Stage 2 11,118 3,630 1,024 796 109 489 6,225 – Stage 3 1,798 817 227 244 65 41 702 Stage 3 ratio (4) 1.02 % 2.02 % 1.64 % 3.06 % 12.29 % 0.27 % 0.59 % PIPs 2 1 1 — 1 — — Simple average LTV (indexed) 41 % 44 % 43 % 23 % 116 % 59 % 41 % 2020 Mortgage portfolio 169,801 38,722 13,498 9,953 737 11,608 113,378 – Stage 1 157,614 33,609 12,118 8,731 426 11,180 108,003 – Stage 2 10,388 4,230 1,132 989 221 393 4,763 – Stage 3 1,799 883 248 233 90 35 612 Stage 3 ratio (4) 1.07 % 2.30 % 1.84 % 2.48 % 12.25 % 0.30 % 0.54 % PIPs 10 5 2 1 4 — 2 Simple average LTV (indexed) 42 % 44 % 44 % 26 % 117 % 59 % 43 % (1) Where a loan falls into more than one category, we include it in all the categories that apply. As a result, the sum of the mortgages in the segments of particular interest and the other portfolio does not agree to the total mortgage portfolio. (2) Mortgage balance includes both the interest-only part of £10,270m (2020: £10,037m) and the non-interest-only part of the loan. (3) Includes legacy Alliance & Leicester flexible loans that work in a more limited way than our current Flexi loan product. (4) The sum of Stage 3 drawn and Stage 3 undrawn assets divided by the sum of total drawn assets and Stage 3 undrawn assets. Business banking Other unsecured Personal Credit Overdrafts Total other unsecured Total 2021 £m £m £m £m £m £m Loans and advances to customers of which: 3,532 2,000 2,341 438 4,779 8,311 – Stage 1 3,076 1,910 2,125 299 4,334 7,410 – Stage 2 201 73 181 120 374 575 – Stage 3 255 17 35 19 71 326 Loss allowances (1) 22 47 89 40 176 198 Stage 3 undrawn exposures — 26 26 Stage 3 ratio (2) 7.20 % 2.03 % 4.23 % Gross write-offs 6 97 103 2020 Loans and advances to customers of which: 3,855 2,038 2,349 408 4,795 8,650 – Stage 1 3,845 1,881 1,975 253 4,109 7,954 – Stage 2 6 139 335 138 612 618 – Stage 3 4 18 39 17 74 78 Loss allowances (1) 9 80 158 61 299 308 Stage 3 undrawn exposures — 27 27 Stage 3 ratio (2) 0.10 % 2.09 % 1.24 % Gross write-offs 12 129 141 (1) The ECL allowance is for both on and off–balance sheet exposures (2) The sum of Stage 3 drawn and Stage 3 undrawn assets divided by the sum of total drawn assets and Stage 3 undrawn assets . 2021 2020 £m £m Loans and advances to customers of which: 4,984 8,024 – Stage 1 4,760 7,587 – Stage 2 200 379 – Stage 3 24 58 Loss allowances (1) 52 118 Stage 3 undrawn exposures — — Stage 3 ratio (2) 0.49 % 0.72 % Gross write offs 25 25 (1) The ECL allowance is for both on and off–balance sheet exposures. (2) The sum of Stage 3 drawn and Stage 3 undrawn assets divided by the sum of total drawn assets and Stage 3 undrawn assets. We monitor exposures that show potentially higher risk characteristics using our Watchlist process. The table below shows the exposures we monitor, and those we classify as Stage 3 by portfolio at 31 December 2021 and 31 December 2020. 2021 Committed exposure Watchlist Fully performing Enhanced monitoring Proactive management Stage 3 Total (1) Loss allowances £m £m £m £m £m £m SME and mid corporate 11,131 531 2,144 723 14,529 378 Commercial Real Estate 3,989 193 212 103 4,497 43 Social Housing 5,345 — 165 — 5,510 2 20,465 724 2,521 826 24,536 423 2020 SME and mid corporate 10,844 340 2,409 853 14,446 478 Commercial Real Estate 4,191 233 561 167 5,152 125 Social Housing 5,012 — 73 — 5,085 — 20,047 573 3,043 1,020 24,683 603 (1) Includes committed facilities and derivatives. We monitor exposures that show potentially higher risk characteristics using our Watchlist process. The table below shows the exposures we monitor, and those we classify as Stage 3 by portfolio at 31 December 2021 and 31 December 2020. 2021 Committed exposure Watchlist Fully performing Enhanced monitoring Proactive management Stage 3 Total (1) Loss allowances £m £m £m £m £m £m Sovereign and Supranational 58,466 — — — 58,466 — Structured Products 1,875 — — — 1,875 — Social Housing 2,858 — — — 2,858 1 Financial Institutions 1,403 — — — 1,403 — Legacy Portfolios in run-off 48 — — 2 50 1 Derivatives — — — — — — Crown Dependencies 742 — — — 742 — 65,392 — — 2 65,394 2 2020 Sovereign and Supranational 53,250 — — — 53,250 — Structured Products 2,482 — — — 2,482 35 Social Housing 3,748 69 — — 3,817 — Financial Institutions 712 — — — 712 — Legacy Portfolios in run-off 156 — — — 156 — Derivatives — — — — — — Crown Dependencies 275 — — — 275 — 60,623 69 — — 60,692 35 (1) Includes committed facilities and derivatives. We monitor exposures that show potentially higher risk characteristics using our Watchlist process. The table below shows the exposures we monitor, and those we classify as Stage 3 by portfolio at 31 December 2020. 2020 Committed exposure Watchlist Fully performing Enhanced monitoring Proactive management Stage 3 Total (1) Loss allowances £m £m £m £m £m £m Large Corporate 9,398 252 1,260 — 10,910 33 Financial Institutions 1,479 — — — 1,479 — 10,877 252 1,260 — 12,389 33
Disclosure of IFRS 9 Credit Quality	Total on-balance sheet exposures at 31 December 2021 comprised £210.6bn of customer loans, loans and advances to banks of £1.4bn, £13.2bn of sovereign assets measured at amortised cost, £5.9bn of assets measured at FVOCI, and £50.5bn of cash and balances at central banks. Stage 1 Stage 2 Stage 3 Total 2021 £m £m £m £m Exposures On-balance sheet Retail Banking 171,791 11,693 2,124 185,608 – Homes 164,381 11,118 1,798 177,297 – Everyday Banking 7,410 575 326 8,311 Consumer Finance 4,760 200 24 4,984 Corporate & Commercial Banking 11,812 4,395 790 16,997 Corporate Centre 73,771 209 2 73,982 Total on-balance sheet 262,134 16,497 2,940 281,571 Off-balance sheet Retail Banking (1) 29,123 204 44 29,371 – Homes (1) 15,851 81 18 15,950 – Everyday Banking 13,272 123 26 13,421 Consumer Finance 314 — — 314 Corporate & Commercial Banking 6,391 1,266 37 7,694 Corporate Centre 323 46 — 369 Total off-balance sheet (2) 36,151 1,516 81 37,748 Total exposures 298,285 18,013 3,021 319,319 ECL On-balance sheet Retail Banking 53 178 137 368 – Homes 9 88 89 186 – Everyday Banking 44 90 48 182 Consumer Finance 18 17 17 52 Corporate & Commercial Banking 44 119 244 407 Corporate Centre — — 1 1 Total on-balance sheet 115 314 399 828 Off-balance sheet Retail Banking 12 8 1 21 – Homes 5 — — 5 – Everyday Banking 7 8 1 16 Consumer Finance — — — — Corporate & Commercial Banking 5 8 3 16 Total off-balance sheet 18 16 4 38 Total ECL 133 330 403 866 % % % % Coverage ratio (3) On-balance sheet Retail Banking — 1.5 6.5 0.2 – Homes — 0.8 4.9 0.1 – Everyday Banking 0.6 15.7 14.7 2.2 Consumer Finance 0.4 8.5 70.8 1.0 Corporate & Commercial Banking 0.4 2.7 30.9 2.4 Corporate Centre — — 50.0 — Total on-balance sheet — 1.9 13.6 0.3 Off-balance sheet Retail Banking — 3.9 2.3 0.1 – Homes — — — — – Everyday Banking 0.1 6.5 3.8 0.1 Consumer Finance — — — — Corporate & Commercial Banking 0.1 0.6 8.1 0.2 Total off-balance sheet — 1.1 4.9 0.1 Total coverage — 1.8 13.3 0.3 (1) Off-balance sheet exposures include £10.6bn of residential mortgage offers in the pipeline. (2) Off-balance sheet amounts consist of contingent liabilities and commitments. For more, see Note 31 to the Consolidated Financial Statements. (3) ECL as a percentage of the related exposure. Total on-balance sheet exposures at 31 December 2020 comprised £210.4bn of customer loans, loans and advances to banks of £2.0bn, £20.8bn of sovereign assets measured at amortised cost, £9.0bn of assets measured at FVOCI, and £43.5bn of cash and balances at central banks. Stage 1 Stage 2 Stage 3 Total 2020 £m £m £m £m Exposures On-balance sheet Retail Banking 165,570 11,005 1,877 178,452 – Homes 157,614 10,388 1,799 169,801 – Everyday Banking 7,956 617 78 8,651 Consumer Finance 7,587 379 58 8,024 Corporate & Commercial Banking 11,167 5,498 961 17,626 Corporate & Investment Banking 2,587 198 — 2,785 Corporate Centre 78,708 27 — 78,735 Total on-balance sheet 265,619 17,107 2,896 285,622 Off-balance sheet Retail Banking (1) 26,313 256 41 26,610 – Homes (1) 13,180 82 14 13,276 – Everyday Banking 13,133 174 27 13,334 Consumer Finance 237 — — 237 Corporate & Commercial Banking 6,050 768 59 6,877 Corporate & Investment Banking 8,630 231 — 8,861 Corporate Centre 567 18 — 585 Total off-balance sheet (2) 41,797 1,273 100 43,170 Total exposures 307,416 18,380 2,996 328,792 ECL On-balance sheet Retail Banking 56 313 181 550 – Homes 15 130 132 277 – Everyday Banking 41 183 49 273 Consumer Finance 44 37 37 118 Corporate & Commercial Banking 46 189 342 577 Corporate & Investment Banking 5 17 — 22 Corporate Centre 35 — — 35 Total on-balance sheet 186 556 560 1,302 Off-balance sheet Retail Banking 18 19 1 38 – Homes 2 1 — 3 – Everyday Banking 16 18 1 35 Consumer Finance — — — — Corporate & Commercial Banking 8 10 8 26 Corporate & Investment Banking 4 7 — 11 Total off-balance sheet 30 36 9 75 Total ECL 216 592 569 1,377 % % % % Coverage ratio (3) On-balance sheet Retail Banking — 2.8 9.6 0.3 – Homes — 1.3 7.3 0.2 – Everyday Banking 0.5 29.7 62.8 3.2 Consumer Finance 0.6 9.8 63.8 1.5 Corporate & Commercial Banking 0.4 3.4 35.6 3.3 Corporate & Investment Banking 0.2 8.6 — 0.8 Corporate Centre — — — — Total on-balance sheet 0.1 3.3 19.3 0.5 Off-balance sheet Retail Banking 0.1 7.4 2.4 0.1 – Homes — 1.2 — — – Everyday Banking 0.1 10.3 3.7 0.3 Consumer Finance — — — — Corporate & Commercial Banking 0.1 1.3 13.6 0.4 Corporate & Investment Banking — 3.0 — 0.1 Total off-balance sheet 0.1 2.8 9.0 0.2 Total coverage 0.1 3.2 19.0 0.4 (1) Off-balance sheet exposures include £7.7bn of residential mortgage offers in the pipeline. (2) Off-balance sheet amounts consist of contingent liabilities and commitments. For more, see Note 31 to the Consolidated Financial Statements. (3) ECL as a percentage of the related exposure.
Disclosure of Stage 2 Exposures by Classification	The following table analyses our Stage 2 exposures and ECL by the reason the exposure is classified as Stage 2. Retail Banking Consumer Finance Corporate & Commercial Banking Corporate & Investment Banking Corporate Centre Total Exposure ECL Coverage Exposure ECL Coverage Exposure ECL Coverage Exposure ECL Coverage Exposure ECL Coverage Exposure ECL Coverage 2021 £m £m % £m £m % £m £m % £m £m % £m £m % £m £m % PD deterioration 5,644 125 2.2 42 6 14.3 1,522 20 1.3 — — — 214 — — 7,422 151 2.0 Forbearance 664 4 0.6 11 2 18.2 272 8 2.9 — — — — — — 947 14 1.5 Other 603 5 0.8 130 3 2.3 445 19 4.3 — — — 2 — — 1,180 27 2.3 30 DPD 745 33 4.4 17 5 29.4 313 2 0.6 — — — 39 — — 1,114 40 3.6 Payment holiday — — — — — — — — — — — — — — — — — — Mortgage affordability 4,241 19 0.4 — — — — — — — — — — — — 4,241 19 0.4 High risk corporate — — — — 1 — 3,109 78 2.5 — — — — — — 3,109 79 2.5 11,897 186 1.6 200 17 8.5 5,661 127 2.2 — — — 255 — — 18,013 330 1.8 2020 PD deterioration 7,752 246 3.2 88 13 14.8 2,128 40 1.9 — — — 32 — — 10,000 299 3.0 Forbearance 612 3 0.5 — — — 151 5 3.3 — — — 4 — — 767 8 1.0 Other 1,199 11 0.9 248 11 4.4 611 66 10.8 429 24 5.6 6 — — 2,493 112 4.5 30 DPD 870 46 5.3 27 12 44.4 250 5 2.0 — — — 3 — — 1,150 63 5.5 Payment holiday 828 26 3.1 16 1 6.3 — — — — — — — — — 844 27 3.2 Mortgage affordability — — — — — — — — — — — — — — — — — — High risk corporate — — — — — — 3,126 83 2.7 — — — — — — 3,126 83 2.7 11,261 332 2.9 379 37 9.8 6,266 199 3.2 429 24 5.6 45 — — 18,380 592 3.2
Disclosure of Stage 2 Exposures by Cure Period	The following table analyses our Stage 2 exposures and the related ECL by whether or not they are in a cure period at the balance sheet date. 2021 2020 Exposure ECL Coverage Exposure ECL Coverage £m £m % £m £m % Stage 2 not in cure period 13,351 286 2.1 17,036 554 3.3 Stage 2 in cure period (for transfer to Stage 1) 4,662 44 0.9 1,344 38 2.8 18,013 330 1.8 18,380 592 3.2
Disclosure of ECL Reconciliation	The table below shows the relationships between disclosures in this Credit risk review section which refer to drawn exposures and the associated ECL, and the total assets as presented in the Consolidated Balance Sheet. On-balance sheet Off-balance sheet Exposures Loss Net carrying Exposures Loss allowance 2021 £m £m £m £m £m Retail Banking (1) 185,608 368 185,240 29,371 21 – Homes (1) 177,297 186 177,111 15,950 5 – Everyday Banking (2) 8,311 182 8,129 13,421 16 Consumer Finance 4,984 52 4,932 314 — Corporate & Commercial Banking 16,997 407 16,590 7,694 16 Corporate Centre 73,982 1 73,981 369 1 Total exposures presented in Credit Quality tables 281,571 828 280,743 37,748 38 Other items (3) 3,736 Adjusted net carrying amount 284,479 Assets classified at FVTPL 2,396 Non-financial assets 6,801 Total assets per the Consolidated Balance Sheet 293,676 2020 Retail Banking (1) 178,452 550 177,902 26,610 38 – Homes (1) 169,801 277 169,524 13,276 3 – Everyday Banking (2) 8,651 273 8,378 13,334 35 Consumer Finance 8,024 118 7,906 237 — Corporate & Commercial Banking 17,626 577 17,049 6,877 26 Corporate & Investment Banking 2,785 22 2,763 8,861 11 Corporate Centre 78,735 35 78,700 585 — Total exposures presented in Credit Quality tables 285,622 1,302 284,320 43,170 75 Other items (3) 3,111 Adjusted net carrying amount 287,431 Assets classified at FVTPL 4,285 Non-financial assets 7,348 Total assets per the Consolidated Balance Sheet 299,064 (1) Off-balance sheet exposures include offers in the pipeline and undrawn flexible mortgages products. (2) Off-balance sheet exposures include credit cards. (3) These assets mainly relate to loans as part of a joint venture agreement and the accrued interest on them. They carry low credit risk and therefore have an immaterial ECL. The following table shows changes in total on and off-balance sheet exposures, subject to ECL assessment, and the corresponding ECL, in the period. The table presents total gross carrying amounts and ECLs at a Santander UK group level. We present segmental views in the sections below. Stage 1 Stage 2 Stage 3 Total Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL £m £m £m £m £m £m £m £m At 1 January 2021 307,416 216 18,380 592 2,996 569 328,792 1,377 Transfers from Stage 1 to Stage 2 (3) (6,805) (9) 6,805 9 — — — — Transfers from Stage 2 to Stage 1 (3) 5,883 167 (5,883) (167) — — — — Transfers to Stage 3 (3) (572) (3) (532) (20) 1,104 23 — — Transfers from Stage 3 (3) 14 2 455 62 (469) (64) — — Transfers of financial instruments (1,480) 157 845 (116) 635 (41) — — Net ECL remeasurement on stage transfer (4) — (133) — 26 — 64 — (43) Change in economic scenarios (2) — (7) — (151) — (12) — (170) Changes to model — — — — — — — — New lending and assets purchased (5) 50,863 31 936 26 24 19 51,823 76 Redemptions, repayments and assets sold (7) (63,659) (70) (3,441) (67) (519) (68) (67,619) (205) Changes in risk parameters and other movements (6) 5,145 (61) 1,293 20 182 63 6,620 22 Assets written off (7) — — — — (297) (191) (297) (191) At 31 December 2021 298,285 133 18,013 330 3,021 403 319,319 866 Net movement in the period (9,131) (83) (367) (262) 25 (166) (9,473) (511) ECL charge/(release) to the Income Statement (83) (262) 25 (320) Less: Discount unwind — — (11) (11) Less: Recoveries net of collection costs — — 87 87 ECL charge/(release) to the Income Statement from continued operations (83) (262) 101 (244) Discontinued operations ECL adjustment 11 — — 11 Total ECL charge/(release) to the Income Statement (72) (262) 101 (233) At 1 January 2020 301,599 147 12,354 348 2,369 368 316,322 863 Transfers from Stage 1 to Stage 2 (3) (9,814) (47) 9,814 47 — — — — Transfers from Stage 2 to Stage 1 (3) 3,178 110 (3,178) (110) — — — — Transfers to Stage 3 (3) (385) (8) (1,126) (61) 1,511 69 — — Transfers from Stage 3 (3) 12 2 326 21 (338) (23) — — Transfers of financial instruments (7,009) 57 5,836 (103) 1,173 46 — — Net remeasurement of ECL on stage transfer (4) — (101) — 239 — 241 — 379 Change in economic scenarios (2) — 15 — 139 — 10 — 164 Changes to model — — — — — 25 — 25 New lending and assets purchased (5) 55,546 40 1,372 64 104 51 57,022 155 Redemptions, repayments and assets sold (7) (47,671) (30) (2,250) (42) (441) (18) (50,362) (90) Changes in risk parameters and other movements (6) 4,953 88 1,068 (53) 184 99 6,205 134 Assets written off (7) (2) — — — (393) (253) (395) (253) At 31 December 2020 307,416 216 18,380 592 2,996 569 328,792 1,377 Net movement in the period 5,817 69 6,026 244 627 201 12,470 514 ECL charge/(release) to the Income Statement 69 244 454 767 Less: Discount unwind — — (14) (14) Less: Recoveries net of collection costs — — (108) (108) ECL charge/(release) to the Income Statement from continued operations 69 244 332 645 Discontinued operations ECL adjustment — — (6) (6) Total ECL charge/(release) to the Income Statement 69 244 326 639 (1) Exposures that have attracted an ECL, and as reported in the Credit Quality table above. (2) Changes to assumptions in the period. Isolates the impact on ECL from changes to the economic variables for each scenario, the scenarios themselves, and the probability weights from all other movements. Also includes the impact of quarterly revaluation of collateral. The impact of changes in economics on exposure Stage allocations are shown in Transfers of financial instruments. (3) Total impact of facilities that moved Stage(s) in the period. This means, for example, that where risk parameter changes (model inputs) or model changes (methodology) result in a facility moving Stage, the full impact is reflected here (rather than in Other). Stage flow analysis only applies to facilities that existed at both the start and end of the period. Transfers between Stages are based on opening balances and ECL at the start of the period. (4) Relates to the revaluation of ECL following the transfer of an exposure from one Stage to another. (5) Exposures and ECL of facilities that did not exist at the start of the period but did at the end. Amounts in Stage 2 and 3 represent assets which deteriorated in the period after origination in Stage 1. (6) Residual movements on existing facilities that did not change Stage in the period, and which were not acquired in the period. Includes the net increase or decrease in the period of cash at central banks, the impact of changes in risk parameters in the period, unwind of discount rates and increases in ECL requirements of accounts which ultimately were written off in the period. (7) Exposures and ECL for facilities that existed at the start of the period but not at the end . The following table shows changes in total on and off-balance sheet exposures subject to ECL assessment, and the corresponding ECL, for Retail Banking in the period. The footnotes to the Santander UK group level analysis on page 127 Stage 1 Stage 2 Stage 3 Total Exposures ⁽¹⁾ ECL Exposures ⁽¹⁾ ECL Exposures ⁽¹⁾ ECL Exposures ⁽¹⁾ ECL £m £m £m £m £m £m £m £m At 1 January 2021 191,883 74 11,261 332 1,918 182 205,062 588 Transfers from Stage 1 to Stage 2 (3) (5,653) (4) 5,653 4 — — — — Transfers from Stage 2 to Stage 1 (3) 4,200 101 (4,200) (101) — — — — Transfers to Stage 3 (3) (526) (2) (488) (16) 1,014 18 — — Transfers from Stage 3 (3) 9 1 364 21 (373) (22) — — Transfers of financial instruments (1,970) 96 1,329 (92) 641 (4) — — Net ECL remeasurement on stage transfer (4) — (95) — 48 — 33 — (14) Change in economic scenarios (2) — (7) — (85) — (12) — (104) Changes to model — — — — — — — — New lending and assets purchased (5) 35,442 19 417 14 9 4 35,868 37 Redemptions, repayments and assets sold (7) (28,094) (13) (1,537) (22) (361) (21) (29,992) (56) Changes in risk parameters and other movements (6) 3,653 (10) 427 (8) 90 64 4,170 46 Assets written off (7) — 1 — (1) (129) (108) (129) (108) At 31 December 2021 200,914 65 11,897 186 2,168 138 214,979 389 Net movement in the period 9,031 (9) 636 (146) 250 (44) 9,917 (199) Charge/(release) to the Income Statement (10) (145) 64 (91) Less: Discount unwind — — (7) (7) Less: Recoveries net of collection costs — — — — Total ECL charge/(release) to the Income Statement (10) (145) 57 (98) At 1 January 2020 186,088 60 8,872 231 1,859 170 196,819 461 Transfers from Stage 1 to Stage 2 (3) (5,087) (7) 5,087 7 — — — — Transfers from Stage 2 to Stage 1 (3) 2,168 82 (2,168) (82) — — — — Transfers to Stage 3 (3) (272) (4) (520) (22) 792 26 — — Transfers from Stage 3 (3) 8 1 323 20 (331) (21) — — Transfers of financial instruments: (3,183) 72 2,722 (77) 461 5 — — Net ECL remeasurement on stage transfer (4) — (80) — 145 — 42 — 107 Change in economic scenarios (2) — 8 — 81 — 9 — 98 Changes to model — — — — — 25 — 25 New lending and assets purchased (5) 31,499 15 345 30 5 4 31,849 49 Redemptions, repayments and assets sold (7) (23,699) (12) (987) (25) (314) (20) (25,000) (57) Changes in risk parameters and other movements (6) 1,178 12 309 (54) 110 102 1,597 60 Assets written off (7) — (1) — 1 (203) (155) (203) (155) At 31 December 2020 191,883 74 11,261 332 1,918 182 205,062 588 Net movement in the period 5,795 14 2,389 101 59 12 8,243 127 Charge/(release) to the Income Statement 15 100 167 282 Less: Discount unwind — — (7) (7) Less: Recoveries net of collection costs — — (11) (11) Total ECL charge/(release) to the Income Statement 15 100 149 264 The following table shows changes in total on and off-balance sheet exposures subject to ECL assessment, and the corresponding ECL, for residential mortgages in the period. The footnotes to the Santander UK group level analysis on page 127 Stage 1 Stage 2 Stage 3 Total Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL £m £m £m £m £m £m £m £m At 1 January 2021 170,794 17 10,470 131 1,813 132 183,077 280 Transfers from Stage 1 to Stage 2 (3) (5,439) (2) 5,439 2 — — — — Transfers from Stage 2 to Stage 1 (3) 3,782 21 (3,782) (21) — — — — Transfers to Stage 3 (3) (242) (2) (451) (4) 693 6 — — Transfers from Stage 3 (3) 3 — 353 15 (356) (15) — — Transfers of financial instruments (1,896) 17 1,559 (8) 337 (9) — — Net ECL remeasurement on stage transfer (4) — (18) — 10 — 9 — 1 Change in economic scenarios (2) — (1) — (67) — (12) — (80) Changes to model — — — — — — — — New lending and assets purchased (5) 33,292 6 332 2 1 — 33,625 8 Redemptions, repayments and assets sold (7) (25,073) (3) (1,435) (6) (332) (16) (26,840) (25) Changes in risk parameters and other movements (6) 3,115 (4) 273 26 13 (10) 3,401 12 Assets written off (7) — — — — (16) (5) (16) (5) At 31 December 2021 180,232 14 11,199 88 1,816 89 193,247 191 Net movement in the period 9,438 (3) 729 (43) 3 (43) 10,170 (89) Charge/(release) to the Income Statement (3) (43) (38) (84) Less: Discount unwind — — (2) (2) Less: Recoveries net of collection costs — — (1) (1) Total ECL charge/(release) to the Income Statement (3) (43) (41) (87) At 1 January 2020 168,830 14 8,224 101 1,734 103 178,788 218 Transfers from Stage 1 to Stage 2 (3) (4,686) (2) 4,686 2 — — — — Transfers from Stage 2 to Stage 1 (3) 1,911 17 (1,911) (17) — — — — Transfers to Stage 3 (3) (229) (3) (491) (11) 720 14 — — Transfers from Stage 3 (3) 4 — 311 14 (315) (14) — — Transfers of financial instruments (3,000) 12 2,595 (12) 405 — — — Net ECL remeasurement on stage transfer (4) — (15) — 50 — 16 — 51 Change in economic scenarios (2) — 7 — 13 — 10 — 30 Changes to model — — — — — 25 — 25 New lending and assets purchased (5) 26,102 4 237 5 1 — 26,340 9 Redemptions, repayments and assets sold (7) (20,679) (4) (856) (7) (297) (15) (21,832) (26) Changes in risk parameters and other movements (6) (459) (1) 270 (19) 24 7 (165) (13) Assets written off (7) — — — — (54) (14) (54) (14) At 31 December 2020 170,794 17 10,470 131 1,813 132 183,077 280 Net movement in the period 1,964 3 2,246 30 79 29 4,289 62 Charge/(release) to the Income Statement 3 30 43 76 Less: Discount unwind — — (2) (2) Less: Recoveries net of collection costs — — (1) (1) Total ECL charge/(release) to the Income Statement 3 30 40 73 The following table shows changes in total on and off-balance sheet exposures subject to ECL assessment, and the corresponding ECL, for Everyday Banking in the period. The footnotes to the Santander UK group level analysis on page 127 Stage 1 Stage 2 Stage 3 Total Exposures ⁽¹⁾ ECL Exposures ⁽¹⁾ ECL Exposures ⁽¹⁾ ECL Exposures ⁽¹⁾ ECL £m £m £m £m £m £m £m £m At 1 January 2021 21,089 57 791 201 105 50 21,985 308 Transfers from Stage 1 to Stage 2 (3) (214) (2) 214 2 — — — — Transfers from Stage 2 to Stage 1 (3) 418 81 (418) (81) — — — — Transfers to Stage 3 (3) (284) (1) (36) (10) 320 11 — — Transfers from Stage 3 (3) 5 1 11 5 (16) (6) — — Transfers of financial instruments (75) 79 (229) (84) 304 5 — — Net ECL remeasurement on stage transfer (4) — (78) — 39 — 23 — (16) Change in economic scenarios (2) — (4) — (19) — — — (23) Changes to model — — — — — — — — New lending and assets purchased (5) 2,150 13 84 12 9 4 2,243 29 Redemptions, repayments and assets sold (7) (3,023) (11) (101) (16) (29) (5) (3,153) (32) Changes in risk parameters and other movements (6) 541 (6) 153 (34) 77 74 771 34 Assets written off (7) — 1 — (1) (114) (102) (114) (102) At 31 December 2021 20,682 51 698 98 352 49 21,732 198 Net movement in the period (407) (6) (93) (103) 247 (1) (253) (110) Charge/(release) to the Income Statement (7) (102) 101 (8) Less: Discount unwind — — (4) (4) Less: Recoveries net of collection costs — — (51) (51) Total ECL charge/(release) to the Income Statement (7) (102) 46 (63) At 1 January 2020 17,258 46 648 130 125 67 18,031 243 Transfers from Stage 1 to Stage 2 (3) (402) (5) 402 5 — — — — Transfers from Stage 2 to Stage 1 (3) 257 65 (257) (65) — — — — Transfers to Stage 3 (3) (42) (1) (29) (11) 71 12 — — Transfers from Stage 3 (3) 4 1 11 5 (15) (6) — — Transfers of financial instruments: (183) 60 127 (66) 56 6 — — Net ECL remeasurement on stage transfer (4) — (63) — 95 — 25 — 57 Change in economic scenarios (2) — — — 68 — — — 68 Changes to model — — — — — — — — New lending and assets purchased (5) 5,398 11 107 25 5 4 5,510 40 Redemptions, repayments and assets sold (7) (3,020) (8) (130) (19) (19) (5) (3,169) (32) Changes in risk parameters and other movements (6) 1,636 12 39 (33) 87 94 1,762 73 Assets written off (7) — (1) — 1 (149) (141) (149) (141) At 31 December 2020 21,089 57 791 201 105 50 21,985 308 Net movement in the period 3,831 11 143 71 (20) (17) 3,954 65 Charge/(release) to the Income Statement 12 70 124 206 Less: Discount unwind — — (4) (4) Less: Recoveries net of collection costs — — (52) (52) Total ECL charge/(release) to the Income Statement 12 70 68 150 The following table shows changes in total on and off-balance sheet exposures subject to ECL assessment, and the corresponding ECL, for Consumer Finance in the period. The footnotes to the Santander UK group level analysis on page 127 Stage 1 Stage 2 Stage 3 Total Exposures ⁽¹⁾ ECL Exposures ⁽¹⁾ ECL Exposures ⁽¹⁾ ECL Exposures ⁽¹⁾ ECL £m £m £m £m £m £m £m £m At 1 January 2021 7,824 44 379 37 58 37 8,261 118 Transfers from Stage 1 to Stage 2 (3) (98) (1) 98 1 — — — — Transfers from Stage 2 to Stage 1 (3) 105 6 (105) (6) — — — — Transfers to Stage 3 (3) (8) — (8) (2) 16 2 — — Transfers from Stage 3 (3) 5 — 3 2 (8) (2) — — Transfers of financial instruments 4 5 (12) (5) 8 — — — Net ECL remeasurement on stage transfer (4) — — — — — — — — Change in economic scenarios (2) — — — (2) — — — (2) Changes to model — — — — — — — — New lending and assets purchased (5) 2,212 6 70 4 3 2 2,285 12 Redemptions, repayments and assets sold (7) (4,063) (19) (142) (6) (19) (3) (4,224) (28) Changes in risk parameters and other movements (6) (903) (18) (95) (12) 11 6 (987) (24) Assets written off (7) — — — 1 (37) (25) (37) (24) At 31 December 2021 5,074 18 200 17 24 17 5,298 52 Net movement in the period (2,750) (26) (179) (20) (34) (20) (2,963) (66) Charge/(release) to the Income Statement (26) (21) 5 (42) Less: Discount unwind — — — — Less: Recoveries net of collection costs — — 9 9 Total ECL charge/(release) to the Income Statement (26) (21) 14 (33) At 1 January 2020 7,315 29 604 28 42 31 7,961 88 Transfers from Stage 1 to Stage 2 (3) (154) (1) 154 1 — — — — Transfers from Stage 2 to Stage 1 (3) 375 4 (375) (4) — — — — Transfers to Stage 3 (3) (33) (3) (20) (5) 53 8 — — Transfers from Stage 3 (3) — — 1 1 (1) (1) — — Transfers of financial instruments: 188 — (240) (7) 52 7 — — Net ECL remeasurement on stage transfer (4) — — — — — — — — Change in economic scenarios (2) — — — — — — — — Changes to model — — — — — — — — New lending and assets purchased (5) 3,486 14 134 6 4 2 3,624 22 Redemptions, repayments and assets sold (7) (2,136) (4) (151) 3 (5) 29 (2,292) 28 Changes in risk parameters and other movements (6) (1,027) 5 32 8 (10) (8) (1,005) 5 Assets written off (7) (2) — — (1) (25) (24) (27) (25) At 31 December 2020 7,824 44 379 37 58 37 8,261 118 Net movement in the period 509 15 (225) 9 16 6 300 30 Charge/(release) to the Income Statement 15 10 30 55 Less: Discount unwind — — 6 6 Less: Recoveries net of collection costs — — (17) (17) Total ECL charge/(release) to the Income Statement 15 10 19 44 The following tables show changes in total on and off-balance sheet exposures and ECL in the period. The footnotes to the Santander UK group level table on page 127 Stage 1 Stage 2 Stage 3 Total Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL £m £m £m £m £m £m £m £m At 1 January 2021 17,217 54 6,266 199 1,020 350 24,503 603 Transfers from Stage 1 to Stage 2 (3) (914) (4) 914 4 — — — — Transfers from Stage 2 to Stage 1 (3) 1,579 60 (1,579) (60) — — — — Transfers to Stage 3 (3) (38) — (37) (3) 75 3 — — Transfers from Stage 3 (3) 1 — 88 40 (89) (40) — — Transfers of financial instruments 628 56 (614) (19) (14) (37) — — Net ECL remeasurement on stage transfer (4) — (39) — (22) — 31 — (30) Change in economic scenarios (2) — (2) — (62) — (1) — (65) Changes to model — — — — — — — — New lending and assets purchased (5) 12,783 5 448 8 12 13 13,243 26 Redemptions, repayments and assets sold (7) (15,067) (9) (1,330) (17) (140) (43) (16,537) (69) Changes in risk parameters and other movements (6) 2,642 (16) 891 40 55 (7) 3,588 17 Assets written off (7) — — — — (106) (59) (106) (59) At 31 December 2021 18,203 49 5,661 127 827 247 24,691 423 Net movement in the period 986 (5) (605) (72) (193) (103) 188 (180) ECL charge/(release) to the Income Statement (5) (72) (44) (121) Less: Discount unwind — — (4) (4) Less: Recoveries net of collection costs — — 34 34 Total ECL charge/(release) to the Income Statement (5) (72) (14) (91) Stage 1 Stage 2 Stage 3 Total Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL £m £m £m £m £m £m £m £m At 1 January 2020 21,281 53 2,385 51 452 158 24,118 262 Transfers from Stage 1 to Stage 2 (3) (4,443) (37) 4,443 37 — — — — Transfers from Stage 2 to Stage 1 (3) 528 20 (528) (20) — — — — Transfers to Stage 3 (3) (78) (1) (543) (21) 621 22 — — Transfers from Stage 3 (3) 4 1 1 — (5) (1) — — Transfers of financial instruments (3,989) (17) 3,373 (4) 616 21 — — Net ECL remeasurement on stage transfer (4) — (18) — 92 — 198 — 272 Change in economic scenarios (2) — 7 — 44 — — — 51 Changes to model — — — — — — — — New lending and assets purchased (5) 7,984 10 805 28 94 44 8,883 82 Redemptions, repayments and assets sold (7) (6,487) (13) (818) (18) (118) (25) (7,423) (56) Changes in risk parameters and other movements (6) (1,572) 32 521 6 97 5 (954) 43 Assets written off (7) — — — — (121) (51) (121) (51) At 31 December 2020 17,217 54 6,266 199 1,020 350 24,503 603 Net movement in the period (4,064) 1 3,881 148 568 192 385 341 ECL charge/(release) to the Income Statement 1 148 243 392 Less: Discount unwind — — (5) (5) Less: Recoveries net of collection costs — — (93) (93) Total ECL charge/(release) to the Income Statement 1 148 145 294 The following tables show changes in total on and off-balance sheet exposures and ECL in the period. The footnotes to the Santander UK group level table on page 127 Stage 1 Stage 2 Stage 3 Total Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL £m £m £m £m £m £m £m £m At 1 January 2021 79,275 35 45 — — — 79,320 35 Transfers from Stage 1 to Stage 2 (3) (141) — 141 — — — — — Transfers from Stage 2 to Stage 1 (3) — — — — — — — — Transfers to Stage 3 (3) — — — — — — — — Transfers from Stage 3 (3) — — — — — — — — Transfers of financial instruments (141) — 141 — — — — — Net ECL remeasurement on stage transfer (4) — — — — — — — — Change in economic scenarios (2) — — — — — — — — Changes to model — — — — — — — — New lending and assets purchased (5) 425 1 2 — — — 427 1 Redemptions, repayments and assets sold (7) (5,326) (18) (27) — 1 1 (5,352) (17) Changes in risk parameters and other movements (6) (139) (17) 94 — 1 — (44) (17) Assets written off (7) — — — — — — — — At 31 December 2021 74,094 1 255 — 2 1 74,351 2 Net movement in the period (5,181) (34) 210 — 2 1 (4,969) (33) ECL charge/(release) to the Income Statement (34) — 1 (33) Less: Discount unwind — — — — Less: Recoveries net of collection costs — — 22 22 Total ECL charge/(release) to the Income Statement (34) — 23 (11) £m £m £m £m £m £m £m £m At 1 January 2020 73,943 1 97 1 — — 74,040 2 Transfers from Stage 1 to Stage 2 (3) (87) (2) 87 2 — — — — Transfers from Stage 2 to Stage 1 (3) 106 4 (106) (4) — — — — Transfers to Stage 3 (3) (2) — (3) (1) 5 1 — — Transfers from Stage 3 (3) 1 1 1 — (2) (1) — — Transfers of financial instruments 18 3 (21) (3) 3 — — — Net ECL remeasurement on stage transfer (4) — (4) — 3 — 1 — — Change in economic scenarios (2) — — — 6 — — — 6 Changes to model — — — — — — — — New lending and assets purchased (5) 11,457 1 45 — 1 — 11,503 1 Redemptions, repayments and assets sold (7) (10,344) (1) (7) (1) (3) (1) (10,354) (3) Changes in risk parameters and other movements (6) 4,201 35 (69) (6) 1 — 4,133 29 Assets written off (7) — — — — (2) — (2) — At 31 December 2020 79,275 35 45 — — — 79,320 35 Net movement in the period 5,332 34 (52) (1) — — 5,280 33 ECL charge/(release) to the Income Statement 34 (1) — 33 Less: Discount unwind — — — — Less: Recoveries net of collection costs — — 3 3 Total ECL charge/(release) to the Income Statement 34 (1) 3 36 The following tables show changes in total on and off-balance sheet exposures and ECL in the period. The footnotes to the Santander UK group level table on page 127 Stage 1 Stage 2 Stage 3 Total Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL Exposures (1) ECL £m £m £m £m £m £m £m £m At 1 January 2020 12,972 4 397 37 15 9 13,384 50 Transfers from Stage 1 to Stage 2 (3) (43) — 43 — — — — — Transfers from Stage 2 to Stage 1 (3) — — — — — — — — Transfers to Stage 3 (3) — — (40) (13) 40 13 — — Transfers from Stage 3 (3) — — — — — — — — Transfers of financial instruments (43) — 3 (13) 40 13 — — Net ECL remeasurement on stage transfer (4) — — — — — — — — Change in economic scenarios (2) — — — 8 — — — 8 Changes to model — — — — — — — — New lending and assets purchased (5) 1,119 1 43 — — — 1,162 1 Redemptions, repayments and assets sold (7) (5,005) (1) (287) (1) (1) — (5,293) (2) Changes in risk parameters and other movements (6) 2,174 5 273 (7) (12) — 2,435 (2) Assets written off (7) — — — — (42) (22) (42) (22) At 31 December 2020 11,217 9 429 24 — — 11,646 33 Net movement in the period (1,755) 5 32 (13) (15) (9) (1,738) (17) ECL charge/(release) to the Income Statement 5 (13) 13 5 Less: Discount unwind — — — — Less: Recoveries net of collection costs — — 2 2 Total ECL charge/(release) to the Income Statement 5 (13) 15 7
Disclosure of Country Risk Exposures	The tables below show our total exposures, which are the total of balance sheet and off–balance sheet values. We calculate balance sheet values in accordance with IFRS (i.e. after netting allowed under IAS 32) except for credit provisions which we add back. Off–balance sheet values are undrawn facilities and letters of credit. We classify location by country of risk – the country where each client has its main business or assets. That is unless there is a full risk transfer guarantee in place, in which case we use the guarantor’s country of domicile. If a client has operations in many countries, we use their country of incorporation. The tables below exclude balances with other Banco Santander group members. We show them separately in the ‘Balances with other Banco Santander group members’ section. 2021 2020 Financial institutions Financial institutions Governments Banks (1) Other Retail Corporate Total (2) Governments Banks (1) Other Retail Corporate Total (2) £bn £bn £bn £bn £bn £bn £bn £bn £bn £bn £bn £bn Eurozone Ireland — — 5.3 — — 5.3 — — 6.0 — 0.1 6.1 Italy — — — — — — — — — — — — Spain — — — — 0.1 0.1 — — — — 0.1 0.1 France 0.1 0.3 0.2 — — 0.6 0.1 0.5 0.2 — — 0.8 Germany — 0.5 — — — 0.5 — 0.7 0.1 — 0.1 0.9 Luxembourg — — 0.1 — — 0.1 — 0.1 1.3 — 0.1 1.5 Other (3) 0.3 0.8 — — — 1.1 0.4 1.1 — — 0.4 1.9 0.4 1.6 5.6 — 0.1 7.7 0.5 2.4 7.6 — 0.8 11.3 Other countries UK 50.2 2.1 9.9 217.8 28.7 308.7 44.4 2.8 15.5 209.3 40.4 312.4 US 0.5 0.8 — — — 1.3 0.8 0.9 0.1 — 0.3 2.1 Japan 1.0 0.2 — — — 1.2 2.4 1.0 — — — 3.4 Switzerland — — — — — — — — — — — — Denmark — — — — — — — — — — — — Other 0.3 0.2 0.1 0.7 0.1 1.4 0.3 0.5 0.1 0.3 0.7 1.9 52.0 3.3 10.0 218.5 28.8 312.6 47.9 5.2 15.7 209.6 41.4 319.8 Total 52.4 4.9 15.6 218.5 28.9 320.3 48.4 7.6 23.3 209.6 42.2 331.1 (1) Excludes balances with central banks. (2) Excludes cash at hand, interests in other entities, intangible assets, property, plant and equipment, tax assets, retirement benefit assets and other assets. Loans are included gross of credit provisions.
Disclosure of Balances with Other Banco Santander Group Companies	At 31 December 2021 and 31 December 2020, we had gross balances with other Banco Santander group members as follows: 2021 2020 Financial institutions Financial institutions Banks Other Corporate Total Banks Other Corporate Total £bn £bn £bn £bn £bn £bn £bn £bn Assets Spain 1.0 — — 1.0 1.8 — — 1.8 UK — 3.1 — 3.1 — 2.3 — 2.3 1.0 3.1 — 4.1 1.8 2.3 — 4.1 Liabilities Spain 1.4 0.1 — 1.5 2.5 0.1 — 2.6 UK — 1.2 — 1.2 — 1.3 — 1.3 Uruguay 0.1 — — 0.1 0.1 — — 0.1 1.5 1.3 — 2.8 2.6 1.4 — 4.0
Disclosure of Borrower Profile	In this table, ‘Home movers’ include both existing customers moving house and taking out a new mortgage with us, and customers who switch their mortgage to us when they move house. ‘Remortgagers’ are new customers who are taking a new mortgage with us. Stock New business 2021 2020 2021 2020 £m % £m % £m % £m % Home movers 75,879 43 72,439 42 13,537 43 10,116 41 Remortgagers 51,336 29 51,796 31 8,031 25 6,861 27 First-time buyers 35,189 20 33,958 20 6,206 19 5,354 21 Buy-to-let 14,893 8 11,608 7 4,239 13 2,622 11 177,297 100 169,801 100 32,013 100 24,953 100
Disclosure of Interest Rate Profile of Mortgage Assets Stock	The interest rate profile of our mortgage asset stock was: 2021 2020 £m % £m % Fixed rate 149,517 84 136,045 80 Variable rate 17,124 10 21,152 13 Standard Variable Rate (SVR) 7,876 4 10,682 6 Follow on Rate (FoR) 2,780 2 1,922 1 177,297 100 169,801 100
Disclosure of Geographic Distribution of Mortgage Assets Stock	The geographical distribution of our mortgage asset stock was: Stock New business 2021 2020 2021 2020 Region £bn £bn £bn £bn London 45.3 42.6 8.3 6.1 Midlands and East Anglia 24.1 22.9 4.7 3.7 North 23.5 23.1 3.8 3.3 Northern Ireland 3.0 3.1 0.3 0.2 Scotland 6.6 6.7 1.0 0.8 South East excluding London 56.4 53.6 10.5 8.3 South West, Wales and other 18.4 17.8 3.4 2.6 177.3 169.8 32.0 25.0 Average loan size for new business £'000 £'000 South East including London 306 284 Rest of the UK 175 166 UK as a whole 234 218
Disclosure of Mortgage Assets Stock of Larger Loans	The mortgage asset stock of larger loans was: South East including London UK 2021 2020 2021 2020 Individual mortgage loan size £m £m £m £m <£0.25m 45,108 45,553 105,147 105,493 £0.25m to £0.50m 39,367 36,241 52,495 47,903 £0.50m to £1.0m 14,036 12,214 16,221 14,076 £1.0m to £2.0m 2,872 1,934 3,103 2,085 >£2.0m 318 236 331 244 101,701 96,178 177,297 169,801
Disclosure of LTV Distribution of Mortgage Assets Stock	This table shows the LTV distribution for the gross carrying amount and the related ECL of our total mortgage portfolio and Stage 3 mortgages, as well as the LTV distribution for new business. We also show the collateral value and simple average LTV for our mortgage stock, Stage 3 stock and new business. We use our estimate of the property value at the balance sheet date. We include fees that have been added to the loan in the LTV calculation. For flexible products, we only include the drawn amount, not undrawn limits. 2021 2020 Stock Stage 3 New Stock Stage 3 New Total ECL Total ECL Business Total ECL Total ECL Business LTV £m £m £m £m £m £m £m £m £m £m Up to 50% 80,058 25 944 9 4,997 74,620 28 858 11 4,180 >50-75% 79,027 63 614 28 15,831 69,771 90 633 36 10,088 >75-85% 14,035 26 106 12 6,896 18,508 41 125 19 5,858 >85-100% 3,646 26 69 14 4,239 6,165 44 93 22 4,781 >100% 531 51 65 26 50 737 77 90 44 46 177,297 191 1,798 89 32,013 169,801 280 1,799 132 24,953 Collateral value of residential properties (1) 177,222 1,786 32,012 169,694 1,783 24,953 % % % % % % Simple Average (2) LTV (indexed) 41 38 64 42 41 64 (1) Collateral value shown is limited to the balance of each related loan. Excludes the impact of over-collateralisation, where the collateral is higher than the loan. Includes collateral against loans in negative equity of £455m (2020: £629m). (2) Total of all LTV% divided by the total of all accounts.
Disclosure of Loan Modifications	The following table (audited) sets out the financial assets that were forborne while they had a loss allowance measured at lifetime ECL. 2021 2020 £m £m Financial assets modified in the period: – Amortised cost before modification 424 305 – Net modification loss 9 7 Financial assets modified since initial recognition: – Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period 152 114 Since March 2020, we have provided mortgage customers with payment holiday terms in line with UK Government and FCA guidance. The following table provides information on such loan modifications. For more on this, see 'Covid-19 Support schemes' in 'Santander UK group level - Credit risk review'. 2021 2020 £m £m Financial assets modified in the period: – Amortised cost before modification 658 37,085 – Net modification loss — — Financial assets modified since initial recognition: – Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period 8 99 The following table (audited) sets out the financial assets that were forborne while they had a loss allowance measured at lifetime ECL. Business banking Credit cards Overdrafts Total 2021 £m £m £m £m Financial assets modified in the period: – Amortised cost before modification — 13 9 22 – Net modification gain — 5 4 9 Financial assets modified since initial recognition: – Gross carrying amount of financial assets for which the loss allowance changed to 12m ECL in the period — 4 2 6 2020 Financial assets modified in the period: – Amortised cost before modification — 18 8 26 – Net modification gain — 8 4 12 Financial assets modified since initial recognition: – Gross carrying amount of financial assets for which the loss allowance changed to 12m ECL in the period — 2 2 4 Since March 2020, we have provided business banking and other unsecured lending customers with payment holiday terms. The following table provides information on such loan modifications. For more on this, see 'Covid-19 Support measures' in 'Santander UK group level - Credit risk review'. Business banking Other unsecured Total 2021 £m £m £m Financial assets modified in the period: – Amortised cost before modification — 9 9 – Net modification gain — — — Financial assets modified since initial recognition: – Gross carrying amount of financial assets for which the loss allowance changed to 12m ECL in the period — 1 1 2020 Financial assets modified in the period: – Amortised cost before modification — 300 300 – Net modification gain — — — Financial assets modified since initial recognition: – Gross carrying amount of financial assets for which the loss allowance changed to 12m ECL in the period — 6 6 Since March 2020, we have provided Consumer Finance customers with payment holiday terms. The following table provides information on such loan modifications. For more on this, see 'Covid-19 Support measures' in 'Santander UK group level - Credit risk review'. 2021 2020 £m £m Financial assets modified in the period: – Amortised cost before modification 54 403 – Net modification loss — 6 Financial assets modified since initial recognition: – Gross carrying amount of financial assets for which the ECL allowance changed to 12-month measurement in the period 226 403 The following table (audited)sets out the financial assets that were forborne while they had a loss allowance measured at lifetime ECL. 2021 2020 £m £m Financial assets modified in the period: – Amortised cost before modification 243 201 – Net modification gain/ (loss) (5) (5) Financial assets modified since initial recognition: – Gross carrying amount of financial assets for which the loss allowance changed to 12-month ECL in the period 29 40 We only make forbearance arrangements for lending to customers. The balances (audited) at 31 December 2021 and 31 December 2020, analysed by their staging at the period–end and the forbearance we applied, were: 2021 2020 £m £m Stock (1) – Term extension 150 141 – Interest-only 239 175 – Other payment rescheduling 204 180 593 496 Of which: – Stage 1 20 13 – Stage 2 303 179 – Stage 3 270 304 593 496 Proportion of portfolio 2.4 % 2.0 % (1) We base forbearance type on the first forbearance we applied. Tables only show accounts open at the period-end. Amounts are drawn balances and include off balance sheet balances. The following table (audited) sets out the financial assets that were forborne while they had a loss allowance measured at lifetime ECL. 2020 £m Financial assets modified in the period: – Amortised cost before modification 23 – Net modification gain/ (loss) 1 Financial assets modified since initial recognition: – Gross carrying amount of financial assets for which the loss allowance changed to 12-month ECL in the period — We only make forbearance arrangements for lending to customers. The balances (audited) at 31 December 2020, analysed by their staging at the period–end and the forbearance we applied, were: 2020 £m Stock (1) – Term extension 23 – Interest-only — – Other payment rescheduling — 23 Of which: – Stage 1 — – Stage 2 23 – Stage 3 — 23 Proportion of portfolio 0.2 % (1) We base forbearance type on the first forbearance we applied. Tables only show accounts open at the period-end. Amounts are drawn balances and include off balance sheet balances.
Disclosure of Forbearance Balances	The balances at 31 December 2021 and 31 December 2020, analysed by their staging at the period-end and the forbearance we applied, were: Capitalisation Term extension Interest-only Concessionary interest rate Total (2) Loss allowances 2021 £m £m £m £m £m £m Stage 2 388 444 273 4 1,109 12 Stage 3 217 75 73 111 476 26 605 519 346 115 1,585 38 Proportion of portfolio 0.3 % 0.3 % 0.2 % 0.1 % 0.9 % 2020 Stage 2 409 393 310 0 1,112 13 Stage 3 219 83 86 28 416 29 628 476 396 28 1,528 42 Proportion of portfolio 0.4 % 0.3 % 0.2 % — % 0.9 % (1) We base forbearance type on the first forbearance on the accounts. (2) The total is audited. The balances at 31 December 2021 and 31 December 2020 were: Interest-only (2) Flexible LTV >100% Buy-to-Let 2021 £m £m £m £m Total 419 35 13 11 – Stage 2 280 24 3 8 – Stage 3 139 11 10 3 2020 Total 285 48 10 9 – Stage 2 184 34 3 6 – Stage 3 101 14 7 3 (1) Where a loan falls into more than one category, we have included it in all the categories that apply. (2) Comprises full interest-only loans and part interest-only, part repayment loans. The balances (audited) at 31 December 2021 and 31 December 2020 were: Other unsecured Business banking Personal loans Credit cards Overdrafts Total other Total 2021 £m £m £m £m £m £m Total 2 1 38 15 54 56 – Stage 2 — — 7 3 10 10 – Stage 3 2 1 31 12 44 46 2020 Total 4 — 43 16 59 63 – Stage 2 — — 10 5 15 15 – Stage 3 4 — 33 11 44 48 The balances (audited) at 31 December 2021 and 31 December 2020 were: 2021 2020 £m £m Total — 9 – Stage 2 — 4 – Stage 3 — 5
Disclosure of Interest-Only Sub Analysis	Full interest-only new business in the period 2021 2020 £m £m Full interest-only loans 6,339 4,267 Full interest-only maturity profile Term Within Between Between Greater than Total 2021 £m £m £m £m £m £m Full interest-only portfolio 393 1,902 3,825 19,784 15,002 40,906 – of which value weighted average LTV (indexed) is >75% 13 106 113 1,020 1,356 2,608 2020 Full interest-only portfolio 374 1,736 3,722 20,490 12,400 38,722 – of which value weighted average LTV (indexed) is >75% 13 131 154 1,405 1,018 2,721
Disclosure of Segments Exposures by Credit Rating	These tables show our credit risk exposure according to our internal rating scale (see ‘Credit quality’ in the ‘Santander UK group level – credit risk review’ section) for each portfolio. On this scale, the higher the rating, the better the quality of the counterparty. Santander UK risk grade 9 8 7 6 5 4 3 to 1 Other (1) Total 2021 £m £m £m £m £m £m £m £m £m SME and mid corporate — 592 954 3,060 3,166 3,559 2,465 733 14,529 Commercial Real Estate — — 55 21 2,172 2,064 181 4 4,497 Social Housing 52 2,985 2,471 — — 2 — — 5,510 52 3,577 3,480 3,081 5,338 5,625 2,646 737 24,536 Of which: Stage 1 52 2,889 3,168 2,750 4,796 3,389 428 577 18,049 Stage 2 — 688 312 331 542 2,236 1,392 160 5,661 Stage 3 — — — — — — 826 — 826 2020 SME and mid corporate — 468 1,288 2,640 2,820 3,518 2,790 922 14,446 Commercial Real Estate — — 65 214 696 3,684 484 9 5,152 Social Housing 112 2,631 2,334 — — 2 — 6 5,085 112 3,099 3,687 2,854 3,516 7,204 3,274 937 24,683 Of which: Stage 1 112 3,060 3,626 2,589 2,776 4,027 454 752 17,396 Stage 2 — 39 61 265 740 3,177 1,800 185 6,267 Stage 3 — — — — — — 1,020 — 1,020 (1) Smaller exposures mainly in the commercial mortgage portfolio. We use scorecards for them, instead of a rating model. These tables show our credit risk exposure according to our internal rating scale (see ‘Credit quality’ in the ‘Santander UK group level – credit risk review’ section) for each portfolio. On this scale, the higher the rating, the better the quality of the counterparty. Santander UK risk grade 9 8 7 6 5 4 3 to 1 Other (1) Total 2021 £m £m £m £m £m £m £m £m £m Sovereign and Supranational 57,415 1,051 — — — — — — 58,466 Structured Products 573 1,064 197 41 — — — — 1,875 Social Housing — 1,290 1,568 — — — — — 2,858 Financial Institutions 501 534 361 7 — — — — 1,403 Legacy Portfolios in run-off (2) — — — 6 — — — 44 50 Derivatives — — — — — — — — — Crown Dependencies — — — — — — — 742 742 58,489 3,939 2,126 54 — — — 786 65,394 Of which: Stage 1 58,489 3,732 2,082 54 — — — 780 65,137 Stage 2 — 207 44 — — — — 4 255 Stage 3 — — — — — — — 2 2 2020 Sovereign and Supranational 50,867 2,383 — — — — — — 53,250 Structured Products 1,168 1,044 229 41 — — — — 2,482 Social Housing 2 2,001 1,814 — — — — — 3,817 Financial Institutions 497 200 9 6 — — — — 712 Legacy Portfolios in run-off (2) — — — — — — — 156 156 Derivatives — — — — — — — — — Crown Dependencies — — — — — — — 275 275 52,534 5,628 2,052 47 — — — 431 60,692 Of which: Stage 1 52,534 5,583 2,052 47 — — — 431 60,647 Stage 2 — 45 — — — — — — 45 Stage 3 — — — — — — — — — (1) Smaller exposures mainly in the commercial mortgage portfolio, and Crown Dependencies residential mortgages portfolio. We use scorecards for them, instead of a rating model. (2) Commercial mortgages and residual structured and asset finance loans (shipping, aviation and structured finance). These tables show our credit risk exposure according to our internal rating scale (see ‘Credit quality’ in the ‘Santander UK group level – credit risk review’ section) for each portfolio. On this scale, the higher the rating, the better the quality of the counterparty. Santander UK risk grade 9 8 7 6 5 4 3 to 1 Other Total 2020 £m £m £m £m £m £m £m £m £m Large Corporate 174 1,826 3,267 3,882 1,523 157 81 — 10,910 Financial Institutions 367 444 639 23 6 — — — 1,479 541 2,270 3,906 3,905 1,529 157 81 — 12,389
Disclosure of Segments Exposures by Geographical Distribution	We typically classify geographical location according to the counterparty’s country of domicile unless a full risk transfer guarantee is in place, in which case we use the guarantor’s country of domicile instead. 2021 2020 UK Europe US Rest of World Total UK Europe US Rest of World Total £m £m £m £m £m £m £m £m £m £m SME and mid corporate 14,486 43 — — 14,529 14,399 47 — — 14,446 Commercial Real Estate 4,497 — — — 4,497 5,151 — — 1 5,152 Social Housing 5,510 — — — 5,510 5,085 — — — 5,085 24,493 43 — — 24,536 24,635 47 — 1 24,683 We typically classify geographical location according to the counterparty’s country of domicile unless a full risk transfer guarantee is in place, in which case we use the guarantor’s country of domicile instead. 2021 2020 UK Europe US Rest of World Total UK Europe US Rest of World Total £m £m £m £m £m £m £m £m £m £m Sovereign and Supranational 54,651 950 469 2,396 58,466 46,912 1,516 849 3,973 53,250 Structured Products 1,219 656 — — 1,875 1,683 799 — 0 2,482 Social Housing 2,858 — — — 2,858 3,817 — — — 3,817 Financial Institutions 536 572 81 214 1,403 301 365 6 40 712 Legacy Portfolios in run-off 50 — — — 50 60 — — 96 156 Derivatives — — — — — — — — — — Crown Dependencies — — — 742 742 — — — 275 275 59,314 2,178 550 3,352 65,394 52,773 2,680 855 4,384 60,692 We typically classify geographical location according to the counterparty’s country of domicile unless a full risk transfer guarantee is in place, in which case we use the guarantor’s country of domicile instead. 2020 UK Europe US Rest of World Total £m £m £m £m £m Large Corporate 9,838 1,052 — 20 10,910 Financial Institutions 655 439 131 254 1,479 10,493 1,491 131 274 12,389
Disclosure of Segment by Exposure by Gross and Net Credit Exposure	Gross exposure Collateral Net exposure Stage 3 Stage 3 Stage 3 2021 £m £m £m SME and mid corporate 723 354 369 Commercial Real Estate 103 85 18 826 439 387 2020 SME and mid corporate 853 286 567 Commercial Real Estate 167 105 62 1,020 391 629 Gross exposure Collateral Net exposure Stage 3 Stage 3 Stage 3 2021 £m £m £m Legacy Portfolios in run–off 2 — 2 Crown Dependencies — — — 2 — 2 2020 Legacy Portfolios in run–off — — — Crown Dependencies — — — — — — Gross exposure Collateral Net exposure Stage 3 Stage 3 Stage 3 2020 £m £m £m Large Corporate — — — — — —

Market Risk (Tables)

Market Risk (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Market Risk Exposure [Abstract]
Summary of Key Non-Traded Market Risks	Our key non-traded market risks are: Key risks Description Interest rate risk Yield curve risk: comes from timing mismatches in repricing fixed and variable rate assets, liabilities and off-balance sheet instruments. It also comes from investing non-rate sensitive liabilities in interest-earning assets. We mainly measure yield curve risk with NIM and EVE sensitivities, which are measures commonly used in the financial services industry. We also use other risk measures, such as Value at Risk (VaR) which is a statistical measure based on a historical simulation of events, and stress testing. Our NIM and EVE sensitivities cover all the material yield curve risk in our banking book balance sheet. Basis risk: comes from pricing assets using a different rate index to the liabilities that fund them. We are exposed to basis risks associated with Bank of England bank rate, reserve rate linked assets we deposit with central banks, the Sterling Overnight Index Average (SONIA) rate, and LIBOR rates of different terms. LIBOR for Sterling, Swiss Francs and Japanese Yen were replaced with Risk Free Rates at the end of 2021. We will have some legacy positions using synthetic LIBOR in 2022, but there should be no basis risk incurred on re-hedging these positions. We are also very advanced with the transition of our loan and derivative portfolios. As the transition progresses, we continue to monitor our basis risk positions. Spread risk Spread risk arises when the value of assets or liabilities which are accounted for at fair value (either through Other Comprehensive Income or through Profit and Loss) are affected by changes in the spread. We measure these spreads as the difference between the discount rate we use to value the asset or liability, and an underlying interest rate curve. Foreign exchange risk Our banking businesses operate mainly in sterling markets, so we do not create significant foreign exchange exposures. The only exception to this is money we raise in foreign currencies. For more on this, see ‘Wholesale funding’ in the ‘Liquidity risk’ section. Income statement We measure most of the assets and liabilities in our banking book balance sheet at amortised cost. We sometimes manage their risk profile by using derivatives. As all derivatives are accounted for at fair value, the mismatch in their accounting treatment can lead to volatility in our Income Statement. This happens even if the derivative is an economic hedge of the asset or liability.
Summary of Detailed Information about VaR	VaR (audited) VaR – VaR indicates the losses that we might suffer because of unfavourable changes in the markets under normal (non-stressed) market conditions. – We run a historical simulation using historical daily price moves, at a 99% confidence level for example, to find how much we might lose – the VaR. – For any given day’s position, we expect to suffer losses greater than the VaR estimate 1% of the time – once every 100 trading days, or two to three times a year. – This gives us a consistent way of assessing risk for all relevant market risk factors in our portfolios.
Summary of NIM and EVE Sensitivity of Interest Rate Risk	The table below shows how our base case income and valuation would be affected by a 25 basis points (bps) and a 50 bps parallel shift (both up and down) applied instantaneously to the yield curve at 31 December 2021 and 31 December 2020 for the Santander UK plc group and SFS . Sensitivity to parallel shifts represents the amount of risk in a way that we think is both simple and scalable. From 2021, we have typically focused on a 25bps stress for non-traded market risk controls that reflects a more plausible yield curve stress in the current low rate environment. We continue to monitor sensitivities to other parallel and non-parallel shifts as well as scenarios. Sensitivities to a 50bps shift are also provided this year as a bridge to previous year's disclosures. Santander UK plc group 2021 2020 +25bps -25bps +50bps -50bps +25bps -25bps +50bps -50bps £m £m £m £m £m £m £m £m NIM sensitivity (audited) 89 (94) 167 (205) 116 (23) 225 (15) EVE sensitivity 89 (125) 148 (301) 190 (369) 367 (585) SFS NIM sensitivity (audited) 4 (4) 8 (8) 3 (1) 6 (1) EVE sensitivity 1 (2) 2 (5) (2) (3) (4) (7)

Liquidity Risk (Tables)

Liquidity Risk (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Liquidity Risk Exposure [Abstract]
Summary of Reconciliation of Wholesale Funding to Balance Sheet	This table reconciles our wholesale funding to our balance sheet at 31 December 2021 and 31 December 2020. Balance sheet line item Funding Deposits by banks (3) Deposits by customers (1) Repurchase agreements - non trading Financial Debt Subordinated Other equity instruments and non- controlling interests (2) 2021 £bn £bn £bn £bn £bn £bn £bn £bn Deposits by banks 0.2 0.2 — — — — — — Certificates of deposit and commercial paper 5.1 — — — — 5.1 — — Senior unsecured – public benchmark 12.4 — — — — 12.4 — — – privately placed 0.6 — — — 0.5 0.1 — — Covered bonds 12.5 — — — — 12.5 — — Securitisation and structured issuance 0.7 — — — — 0.7 — — Term Funding Scheme — — — — — — — — TFSME 31.9 31.9 — — — — — — Subordinated liabilities and equity 4.4 — — — — — 2.0 2.4 Total wholesale funding 67.8 32.1 — — 0.5 30.8 2.0 2.4 Repos 11.7 — — 11.7 — — — — Foreign exchange and hedge accounting 1.0 — — — — 0.8 0.2 — Other 2.1 1.8 — — 0.3 — — — Balance sheet total 82.6 33.9 — 11.7 0.8 31.6 2.2 2.4 2020 Deposits by banks — — — — — — — — Certificates of deposit and commercial paper 5.7 — — — — 5.7 — — Senior unsecured – public benchmark 15.5 — — — — 15.5 — — – privately placed 1.1 — — — 0.9 0.2 — — Covered bonds 17.9 — — — — 17.9 — — Securitisation and structured issuance 2.8 — — — 0.5 2.3 — — Term Funding Scheme 6.3 6.3 — — — — — — TFSME 11.7 11.7 — — — — — — Subordinated liabilities and equity 4.7 — — — — — 2.2 2.5 Total wholesale funding 65.7 18.0 — — 1.4 41.6 2.2 2.5 Repos 15.8 — — 15.8 — — — — Foreign exchange and hedge accounting 2.5 — — — — 2.1 0.4 — Other 3.0 3.0 — — — — — — Balance sheet total 87.0 21.0 — 15.8 1.4 43.7 2.6 2.5 (1) This is included in our balance sheet total of £192,914m (2020: £193,088m). (2) Consists of £nil (2020: £nil) fixed/floating rate non-cumulative callable preference shares, £235m (2020: £235m) Step-up Callable Perpetual Reserve Capital Instruments and £2,191m (2020: £2,241m) Perpetual Capital Securities (net of issuance costs). See Notes 33 and 34 to the Consolidated Financial Statements. (3) Other consists of items in the course of transmission and other deposits, excluding the TFS. See Note 24 to the Consolidated Financial Statements.
Summary of Sources of Wholesale Funding by Maturity	This table shows our main sources of wholesale funding. It does not include securities finance agreements. The table is based on exchange rates at issue and scheduled repayments and call dates. It does not reflect the final contractual maturity of the funding. ≤ 1 >1 and ≤ 3 months >3 and ≤ 6 months >6 and ≤ 9 months >9 and ≤ 12 months Sub-total >1 and >2 and >5 years Total 2021 £bn £bn £bn £bn £bn £bn £bn £bn £bn £bn Santander UK Group Holdings plc (1) Senior unsecured – public benchmark 0.8 — 0.4 — — 1.2 3.0 4.1 1.8 10.1 – privately placed — — — — — — — — 0.1 0.1 Subordinated liabilities and equity (incl. AT1) — — 0.8 — — 0.8 — 1.9 0.3 3.0 0.8 — 1.2 — — 2.0 3.0 6.0 2.2 13.2 Santander UK plc Deposits by banks 0.2 — — — — 0.2 — — — 0.2 Certificates of deposit and commercial paper 1.3 3.0 0.7 0.1 — 5.1 — — — 5.1 Senior unsecured – public benchmark 0.6 — — — — 0.6 0.3 1.1 0.3 2.3 – privately placed — — — — — — — 0.3 0.2 0.5 Covered bonds — — 0.8 — 0.9 1.7 1.9 5.6 3.3 12.5 Securitisation & structured issuance (2) 0.2 — 0.1 0.1 — 0.4 0.2 0.1 — 0.7 Term Funding Scheme (TFS) — — — — — — — — — — TFSME — — — — — — — 28.0 3.9 31.9 Subordinated liabilities — 0.2 — — — 0.2 0.5 — 0.7 1.4 2.3 3.2 1.6 0.2 0.9 8.2 2.9 35.1 8.4 54.6 Other group entities Securitisation & structured issuance (3) — — — — — — — — — — Total at 31 December 2021 3.1 3.2 2.8 0.2 0.9 10.2 5.9 41.1 10.6 67.8 Of which: – Secured 0.2 — 0.9 0.1 0.9 2.1 2.1 33.7 7.2 45.1 – Unsecured 2.9 3.2 1.9 0.1 — 8.1 3.8 7.4 3.4 22.7 3.1 3.2 2.8 0.2 0.9 10.2 5.9 41.1 10.6 67.8 2020 Total at 31 December 2020 2.2 5.6 8.0 4.1 1.2 21.1 7.9 28.3 8.4 65.7 Of which: – Secured 0.4 1.6 5.2 3.0 0.2 10.4 5.3 18.6 4.4 38.7 – Unsecured 1.8 4.0 2.8 1.1 1.0 10.7 2.6 9.7 4.0 27.0 (1) 95% of senior unsecured debt issued from Santander UK Group Holdings plc has been downstreamed to Santander UK plc as ‘secondary non-preferential debt’ in line with the guidelines from the Bank of England for Internal MREL. (2) Includes funding from mortgage-backed securitisation vehicles where Santander UK plc is the asset originator. (3) Includes funding from asset-backed securitisation vehicles where entities other than Santander UK plc are the asset originator.
Summary of Wholesale Funding by Currency	This table shows our wholesale funding by major currency at 31 December 2021 and 31 December 2020. 2021 2020 Sterling US Dollar Euro Other Sterling US Dollar Euro Other % % % % % % % % Santander UK Group Holdings plc Senior unsecured – public benchmark 10 59 31 — 11 61 28 — – privately placed — — — 100 — — — 100 Subordinated liabilities and equity (incl. AT1) 75 25 — — 75 25 — — 24 51 24 1 27 51 21 1 Santander UK plc Deposits by banks 32 68 — — — — — — Certificates of deposit and commercial paper 45 53 2 — 51 44 4 1 Senior unsecured – public benchmark 14 46 40 — 10 73 17 — – privately placed 92 — 6 2 41 37 10 12 Covered bonds 44 8 48 — 48 5 46 1 Securitisation & structured issuance 74 26 — — 77 23 — — Term Funding Scheme — — — — 100 — — — TFSME 100 — — — 100 — — — Subordinated liabilities 57 43 — — 63 37 — — 77 10 13 — 63 18 19 — Other group entities Securitisation & structured issuance — — — — 100 — — — Total 67 18 15 — 57 24 19 —
Summary of External Term Issuance, Sterling Equivalent	In 2021, our external term issuance (sterling equivalent) was: Sterling US Dollar Euro Other Total 2021 Total 2020 £bn £bn £bn £bn £bn £bn Santander UK Group Holdings plc Senior unsecured – public benchmark — 2.2 0.6 — 2.8 1.4 Subordinated debt and equity (inc. AT1) 0.5 — — — 0.5 — 0.5 2.2 0.6 — 3.3 1.4 Santander UK plc Securitisations and other secured funding — — — — — — Covered bonds — — — — — 3.0 Senior unsecured – public benchmark — — — — — 1.0 – privately placed 0.1 — — — 0.1 — TFSME 20.2 — — — 20.2 11.7 20.3 — — — 20.3 15.7 Other group entities Securitisations — — — — — — Total gross issuances 20.8 2.2 0.6 — 23.6 17.1
Summary of Balance Sheet Encumbered and Unencumbered Assets Explanatory	On-balance sheet encumbered and unencumbered assets (audited) Encumbered with counterparties other than central banks Unencumbered assets not pre-positioned with central banks Covered Securitis- Other Total Assets positioned at central banks (3) Readily Other Cannot be Total Total 2021 £m £m £m £m £m £m £m £m £m £m Cash and balances at central banks (1)(2) — — 1,580 1,580 935 47,979 — — 48,914 50,494 Financial assets at FVTPL: – Derivative financial instruments — — — — — — — 1,720 1,720 1,720 – Other financial assets at FVTPL — — — — — — — 676 676 676 Financial assets at amortised cost: – Loans and advances to customers 15,713 3,720 84 19,517 80,623 74,890 18,893 19,602 194,008 213,525 – Loans and advances to banks — — 478 478 — — — 942 942 1,420 – Repurchase agreements – non trading — — — — — — — 12,683 12,683 12,683 – Other financial assets at amortised cost — — — — — 506 — — 506 506 Financial assets at FVOCI — — 4,434 4,434 — 1,417 — — 1,417 5,851 Interests in other entities — — — — — — — 201 201 201 Intangible assets — — — — — — — 1,545 1,545 1,545 Property, plant and equipment — — — — — — 1,555 — 1,555 1,555 Current tax assets — — — — — — — 351 351 351 Retirement benefit assets — — — — — — — 1,573 1,573 1,573 Other assets — — — — — — — 1,576 1,576 1,576 Total assets 15,713 3,720 6,576 26,009 81,558 124,792 20,448 40,869 267,667 293,676 2020 Cash and balances at central banks (1)(2) — — 985 985 871 41,681 — — 42,552 43,537 Financial assets at FVTPL: – Derivative financial instruments — — — — — — — 3,451 3,451 3,451 – Other financial assets at FVTPL — — — — — — — 834 834 834 Financial assets at amortised cost: – Loans and advances to customers 23,669 7,469 149 31,287 61,292 77,833 19,801 21,965 180,891 212,178 – Loans and advances to banks — — 804 804 — — — 1,200 1,200 2,004 – Repurchase agreements – non trading — — — — — — — 19,599 19,599 19,599 – Other financial assets at amortised cost — — 648 648 — 515 — — 515 1,163 Financial assets at FVOCI — — 5,677 5,677 — 3,273 — — 3,273 8,950 Interests in other entities — — — — — — — 172 172 172 Intangible assets — — — — — — — 1,649 1,649 1,649 Property, plant and equipment — — — — — — 1,740 — 1,740 1,740 Current tax assets — — — — — — — 271 271 271 Retirement benefit assets — — — — — — — 496 496 496 Other assets — — — — — — — 3,020 3,020 3,020 Total assets 23,669 7,469 8,263 39,401 62,163 123,302 21,541 52,657 259,663 299,064 (1) Encumbered cash and balances at central banks include minimum cash balances we have to hold at central banks for regulatory purposes. (2) Readily realisable cash and balances at central banks are amounts held at central banks as part of our liquidity management activities. (3) Comprises pre-positioned assets and encumbered assets.

Capital Risk (Tables)

Capital Risk (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Capital Risk Exposure [Abstract]
Summary of Regulatory Capital Resources	This table shows our qualifying regulatory capital: 2021 2020 £m £m CET1 capital instruments and reserves: – Capital instruments 7,060 7,060 – Retained earnings 6,754 6,030 – Accumulated other reserves and non-controlling interests 138 679 CET1 capital before regulatory adjustments 13,952 13,769 CET1 regulatory adjustments: – Additional value adjustments (25) (21) – Goodwill (net of tax) (1,130) (1,150) – Other intangibles (195) (199) – Fair value reserves related to gains or losses on cash flow hedges (110) (486) – Negative amounts resulting from the calculation of regulatory expected loss amounts (585) (368) – Gains or losses on liabilities valued at fair value resulting from changes in own credit standing — (6) – Deferred tax assets that rely on future profitability excluding timing differences (2) (9) – Defined benefit pension fund assets (1,061) (364) – Dividend accrual (17) (18) – IFRS 9 Transitional Adjustment 21 73 – Deductions for non-controlling interests — (162) CET1 capital 10,848 11,059 AT1 capital instruments: – Capital instruments 2,191 2,241 – Amount of qualifying items subject to phase out from AT1 163 324 – Regulatory deductions for instruments issued by subsidiary undertakings (48) (93) AT1 capital 2,306 2,472 Tier 1 capital 13,154 13,531 Tier 2 capital instruments: – Capital instruments 2,263 2,076 – Amount of qualifying items subject to phase out from Tier 2 35 352 – Regulatory deductions for instruments issued by subsidiary undertakings or subject to CRDIV amortisation and repurchases (725) (571) Tier 2 capital 1,573 1,857 Total regulatory capital 14,727 15,388

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Significant Accounting Policies [Abstract]
Schedule of Useful Lives or Depreciation Rates Used for Property, Plant and Equipment	Classes of property, plant and equipment are depreciated on a straight-line basis over their useful life, as follows: Owner-occupied properties Not exceeding 50 years Office fixtures and equipment 3 to 15 years Computer software 3 to 7 years Right-of-use assets (see ‘Leases – The Santander UK group as lessee’ below) Shorter of the lease term or the useful life of the underlying asset
Disclosure of Information about Key Judgements and Key Estimates	Key judgements – Determining an appropriate definition of default – Establishing the criteria for a significant increase in credit risk (SICR) and, for corporate borrowers, internal credit risk rating – Determining appropriate post model adjustments – Assessing individual corporate Stage 3 exposures Key estimates – Forward-looking multiple economic scenario assumptions – Probability weights assigned to multiple economic scenarios Key judgements – Determining whether a present obligation exists – Assessing the likely outcome of future legal decisions Key estimates – Probability, timing, nature and amount of any outflows that may arise from past events Key judgements – Setting the criteria for constructing the corporate bond yield curve used to determine the discount rate – Determining the methodology for setting the inflation assumption Key estimates – Discount rate applied to future cash flows – Rate of price inflation – Expected lifetime of the schemes' members – Valuation of pension fund assets whose values are not based on market observable data Key judgements: – Determining the basis of goodwill impairment calculation assumptions, including management's planning assumptions considering internal capital allocations needed to support Santander UK's strategy, current market conditions and the macro-economic outlook. Key estimates: – Forecast cash flows for cash generating units, including estimated allocations of regulatory capital – Growth rate beyond initial cash flow projections – Discount rates which factor in risk-free rates and applicable risk premiums All of these variables are subject to fluctuations in external market rates and economic conditions beyond management’s control

Segments (Tables)

Segments (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of operating segments [abstract]
Summary of Results by Segment	Results by segment Retail Banking Consumer Finance Corporate & Commercial Banking Corporate & Investment Banking Corporate Centre Total 2021 £m £m £m £m £m £m Net interest income/(expense) 3,374 233 401 — (11) 3,997 Non-interest income 201 178 109 — 59 547 Total operating income 3,575 411 510 — 48 4,544 Operating expenses before credit impairment write-backs, provisions and charges (1,703) (163) (365) — (309) (2,540) Credit impairment write-backs 98 33 91 — 11 233 Provisions for other liabilities and charges (187) 4 (34) — (162) (379) Total operating credit impairment write-backs, provisions and charges (89) 37 57 — (151) (146) Profit/(loss) from continuing operations before tax 1,783 285 202 — (412) 1,858 Revenue from external customers 4,061 489 553 — (559) 4,544 Inter-segment revenue (486) (78) (43) — 607 — Total operating income 3,575 411 510 — 48 4,544 Revenue from external customers includes the following fee and commission income disaggregated by income type: (1) – Current account and debit card fees 428 — 50 — — 478 – Insurance, protection and investments 67 — — — — 67 – Credit cards 73 — — — — 73 – Non-banking and other fees (2) 2 10 62 — 2 76 Total fee and commission income 570 10 112 — 2 694 Fee and commission expense (384) — (22) — (8) (414) Net fee and commission income/(expense) 186 10 90 — (6) 280 Customer loans 185,608 4,984 16,997 — 3,027 210,616 Total assets (3) 193,214 8,873 16,997 — 74,592 293,676 Customer deposits 156,991 — 25,597 — 9,588 192,176 Total liabilities 157,622 1,173 25,613 — 92,890 277,298 Average number of full-time equivalent staff 16,149 670 2,281 528 216 19,844 (1) The disaggregation of fees and commission income as shown above is not included in reports provided to the chief operating decision maker but is provided to show the split by reportable segments. (2) Non-banking and other fees include mortgages (except mortgage account fees), consumer finance, commitment commission, asset finance, invoice finance and trade finance. (3) Includes customer loans, net of credit impairment loss allowances. Retail Banking (5) Consumer Finance (5) Corporate & Commercial Banking Corporate & Investment Banking (4) Corporate Centre Total 2020 £m £m £m £m £m £m Net interest income/(expense) 2,758 264 363 — (4) 3,381 Non-interest income 245 127 94 — (12) 454 Total operating income/(expense) 3,003 391 457 — (16) 3,835 Operating expenses before credit impairment losses, provisions and charges (1,792) (166) (324) — (143) (2,425) Credit impairment losses (264) (44) (294) — (37) (639) Provisions for other liabilities and charges (160) (8) (6) — (89) (263) Total operating credit impairment losses, provisions and charges (424) (52) (300) — (126) (902) Profit/(loss) from continuing operations before tax 787 173 (167) — (285) 508 Revenue from external customers 3,685 501 549 — (900) 3,835 Inter-segment revenue (682) (110) (92) — 884 — Total operating income/(expense) 3,003 391 457 — (16) 3,835 Revenue from external customers includes the following fee and commission income disaggregated by income type: (1) – Current account and debit card fees 442 — 42 — — 484 – Insurance, protection and investments 65 — — — — 65 – Credit cards 66 — — — — 66 – Non-banking and other fees (2) 3 10 50 — 3 66 Total fee and commission income 576 10 92 — 3 681 Fee and commission expense (337) — (22) — (4) (363) Net fee and commission income 239 10 70 — (1) 318 Customer loans 178,451 8,025 17,626 2,784 3,483 210,369 Total assets (3) 186,226 11,143 17,626 2,784 81,285 299,064 Customer deposits 152,167 — 24,985 6,506 8,074 191,732 Total liabilities 152,687 2,397 25,011 6,517 96,207 282,819 Average number of full-time equivalent staff 18,198 640 2,405 716 180 22,139 2019 Net interest income 2,581 246 422 — (22) 3,227 Non-interest income 531 155 109 — 10 805 Total operating income 3,112 401 531 — (12) 4,032 Operating expenses before credit impairment losses, provisions and charges (1,860) (179) (334) — (93) (2,466) Credit impairment (losses)/write-backs (129) (27) (45) — 3 (198) Provisions for other liabilities and charges (273) (8) (24) — (123) (428) Total operating credit impairment losses, provisions and (charges)/releases (402) (35) (69) — (120) (626) Profit/(loss) from continuing operations before tax 850 187 128 — (225) 940 Revenue from external customers 3,748 525 633 — (874) 4,032 Inter-segment revenue (636) (124) (102) — 862 — Total operating income 3,112 401 531 — (12) 4,032 Revenue from external customers includes the following fee and commission income disaggregated by income type: (1) – Current account and debit card fees 711 — 43 — — 754 – Insurance, protection and investments 69 — — — — 69 – Credit card fees 86 — — — — 86 – Non-banking and other fees (2) 33 13 65 — 23 134 Total fee and commission income 899 13 108 — 23 1,043 Fee and commission expense (372) — (24) — (20) (416) Net fee and commission income 527 13 84 — 3 627 Customer loans 171,078 7,684 18,391 4,041 4,104 205,298 Total assets (3) 178,665 10,748 18,391 4,046 76,638 288,488 Customer deposits 142,735 — 20,546 6,102 8,438 177,821 Total liabilities 143,570 2,748 20,572 6,233 99,024 272,147 Average number of full-time equivalent staff 19,669 612 2,464 804 157 23,706 (1) The disaggregation of fees and commission income as shown above is not included in reports provided to the chief operating decision maker but is provided to show the split by reportable segments. (2) Non-banking and other fees include mortgages (except mortgage account fees), consumer finance, commitment commission, asset finance, invoice finance and trade finance. (3) Includes cust omer loans, net of credit impairment loss allowances. (4) Restated to reflect the presentation of CIB as a discontinued operation, as set out in Note 43. (5) Restated to reflect the resegmentation of the Retail Banking segment into the Retail Banking and Consumer Finance segments described above.

Net Interest Income (Tables)

Net Interest Income (Tables)	12 Months Ended
	Dec. 31, 2021
Analysis of income and expense [abstract]
Summary of Net Interest Income	Group 2021 2020 (3) 2019 (3) £m £m £m Interest and similar income: Loans and advances to customers (3) 4,685 4,772 5,137 Loans and advances to banks 54 62 182 Reverse repurchase agreements – non trading 35 118 244 Other 56 119 309 Total interest and similar income (1) 4,830 5,071 5,872 Interest expense and similar charges: Deposits by customers (331) (884) (1,331) Deposits by banks (23) (28) (103) Repurchase agreements – non trading (3) (43) (126) Debt securities in issue (372) (614) (938) Subordinated liabilities (92) (111) (137) Other (12) (10) (10) Total interest expense and similar charges (2) (833) (1,690) (2,645) Net interest income 3,997 3,381 3,227 (1) This includes £22m (2020: £38m) of interest income on financial assets at FVOCI. (2) This includes £317m (2020: £451m) of interest expense on derivatives hedging debt issuances and £3m (2020: £3m ) of interest expense on lease liabilities.

Net Fee and Commission Income (

Net Fee and Commission Income (Tables)	12 Months Ended
	Dec. 31, 2021
Fee and commission income (expense) [abstract]
Summary of Net Fee and Commission Income	Group 2021 2020 (2) 2019 (2) £m £m £m Fee and commission income: Current account and debit card fees 478 484 754 Insurance, protection and investments 67 65 69 Credit cards 73 66 86 Non-banking and other fees (1) 76 66 134 Total fee and commission income 694 681 1,043 Total fee and commission expense (414) (363) (416) Net fee and commission income 280 318 627 (1) Non-banking and other fees include mortgages (except mortgage account fees) , consumer finance, commitment commission, asset finance, invoice finance and trade finance.

Other Operating Income (Tables)

Other Operating Income (Tables)	12 Months Ended
	Dec. 31, 2021
Net Trading And Other Income [Abstract]
Other Operating Income	Group 2021 2020 (1) 2019 (1) £m £m £m Net losses on financial instruments designated at fair value through profit or loss (68) (26) (102) Net gains on financial instruments mandatorily at fair value through profit or loss 50 64 95 Hedge ineffectiveness 8 19 8 Net profit on sale of financial assets at fair value through other comprehensive income 6 17 15 Income from operating lease assets 136 126 124 Other 135 (64) 38 267 136 178 (1) Restated to reflect the presentation of discontinued operations, as set out in Note 43.

Operating Expenses Before Cre_3

Operating Expenses Before Credit Impairment Losses, Provisions and Charges (Tables)	12 Months Ended
	Dec. 31, 2021
Expenses by nature [abstract]
Summary of Operating Expenses Before Credit Impairment Losses, Provisions and Charges	Group 31 December 2021 2020 (1) 2019 (1) £m £m £m Staff costs: Wages and salaries 759 802 815 Performance-related payments 184 99 160 Social security costs 113 102 112 Pensions costs: – defined contribution plans 65 67 67 – defined benefit plans (2) 38 38 35 Other share-based payments 1 4 7 Other personnel costs 42 34 41 1,202 1,146 1,237 Other administration expenses 831 710 684 Depreciation, amortisation and impairment 507 569 545 2,540 2,425 2,466 (1) Adjusted to reflect the presentation of discontinued operations as set out in Note 43. (2) Pension costs for defined benefit plans include £5m for curtailment as set out in Note 30.
Deferred Performance Awards	’Performance-related payments’ include bonuses paid in cash and share awards granted under the arrangements described in Note 37. Included in this are equity-settled share-based payments, none of which related to option-based schemes. These are disclosed in the table below as ‘Share awards’. Performance-related payments above include amounts related to deferred performance awards as follows: Costs recognised in 2021 Costs expected to be recognised in 2022 or later Arising from awards in current year Arising from awards in prior year Total Arising from awards in current year Arising from awards in prior year Total £m £m £m £m £m £m Cash 3 5 8 9 6 15 Shares 3 5 8 8 6 14 6 10 16 17 12 29
Disclosure of Amount of Bonus Awarded to Employees	The following table shows the amount of bonus awarded to employees for the performance year 2021. In the case of deferred cash and share awards, the final amount paid to an employee is influenced by forfeiture provisions and any performance conditions to which these awards are subject. The deferred share award amount is based on the fair value of these awards at the date of grant. Expenses charged in the year Expenses deferred to future periods Total 2021 2020 2021 2020 2021 2020 £m £m £m £m £m £m Cash award – not deferred 156 79 — — 156 79 – deferred 8 9 15 11 23 20 Shares award – not deferred 12 3 — — 12 3 – deferred 8 8 14 11 22 19 Total discretionary bonus 184 99 29 22 213 121

Audit and Other Services (Table

Audit and Other Services (Tables)	12 Months Ended
	Dec. 31, 2021
Audit And Other Services [Abstract]
Summary of Audit and Other Services	Group 2021 2020 2019 £m £m £m Audit fees: Fees payable to the Company's auditor and its associates for the audit of the Santander UK group's annual accounts 12.1 10.5 8.5 Fees payable to the Company’s auditor and its associates for other services to the Santander UK group: – Audit of the Santander UK group’s subsidiaries 1.2 1.8 1.9 Total audit fees (1) 13.3 12.3 10.4 Non-audit fees: Audit-related assurance services 1.7 1.7 1.7 Other assurance services 0.5 0.5 0.4 Other non-audit services 0.2 0.0 0.2 Total non-audit fees 2.4 2.2 2.3 (1) 2021 audit fees included £1.2m (2020: £0.8m, 2019: £0.3m) which related to the prior year.

Credit Impairment Losses and _2

Credit Impairment Losses and Provisions (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Credit Impairment Loss And Provisions [Abstract]
Summary of Impairment Losses and Provisions	Group 31 December 2021 2020 (1) 2019 (1) £m £m £m Credit impairment (write-backs)/losses: Loans and advances to customers (186) 666 216 Recoveries of loans and advances, net of collection costs (17) (24) (40) Off-balance sheet exposures (See Note 29) (30) (3) 22 (233) 639 198 Provisions for other liabilities and charges (excluding off-balance sheet credit exposures) (See Note 29) 388 257 422 Provisions for residual value and voluntary termination (9) 6 6 379 263 428 146 902 626 (1) Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Taxation (Tables)

Taxation (Tables)	12 Months Ended
	Dec. 31, 2021
Major components of tax expense (income) [abstract]
Disclosure of Income Tax and Deferred Taxes Explanatory	Group 2021 2020 (1) 2019 (1) £m £m £m Current tax: UK corporation tax on profit for the year 400 92 244 Adjustments in respect of prior years (30) (27) (30) Total current tax 370 65 214 Deferred tax: Charge for the year 101 35 51 Adjustments in respect of prior years 14 1 (4) Total deferred tax 115 36 47 Tax on profit from continuing operations 485 101 261 (1) Adjusted to reflect the presentation of discontinued operations as set out in Note 43.
Schedule of Tax on Profit Before Tax Differs from Theoretical Amount that Arise Using Basic Corporation Tax Rate	The Santander UK group’s effective tax rate for 2021 was 26.1% (2020: 19.9%, 2019(1): 27.8%). The tax on profit before tax differs from the theoretical amount that would arise using the basic corporation tax rate as follows: Group 31 December 2021 2020 (1) 2019 (1) £m £m £m Profit from continuing operations before tax 1,858 508 940 Tax calculated at a tax rate of 19% (2020: 19%, 2019: 19%) 353 97 179 Bank surcharge on profits 106 23 60 Non-deductible preference dividends paid 9 8 8 Non-deductible UK Bank Levy 14 20 24 Non-deductible conduct remediation, fines and penalties 6 (4) 44 Other non-deductible costs and non-taxable income 33 23 29 Effect of change in tax rate on deferred tax provision 8 6 (10) Tax relief on dividends in respect of other equity instruments (40) (40) (39) Adjustment to prior year provisions (4) (32) (34) Tax on profit from continuing operations 485 101 261 (1) Adjusted to reflect the presentation of discontinued operations as set out in Note 43.
Disclosure of Movement in Current Tax Assets and Liabilities	Movements in current tax assets and liabilities during the year were as follows: Group 2021 2020 £m £m Assets 271 186 Liabilities — — At 1 January 271 186 Income statement charge (including discontinued operations) (382) (78) Other comprehensive income credit 33 1 Corporate income tax paid 418 161 Other movements 11 1 351 271 Assets 351 271 Liabilities — — At 31 December 351 271
Schedule of Deferred Taxes	The table below shows the deferred tax assets and liabilities including the movement in the deferred tax account during the year. Deferred tax balances are presented in the balance sheet after offsetting assets and liabilities where the Santander UK group has the legal right to offset and intends to settle on a net basis. Group Fair value of financial instruments Pension remeasurement Cash flow hedges Fair value reserve Tax losses carried forward Accelerated tax depreciation Other temporary differences Total £m £m £m £m £m £m £m £m At 1 January 2021 (65) (27) (100) (10) 15 39 41 (107) Income statement (charge)/credit (58) (67) — (1) (7) 39 (21) (115) Transfers/reclassifications — 5 (16) 1 — (10) (19) (39) Credited/(charged) to other comprehensive income — (419) 109 (2) — — — (312) At 31 December 2021 (123) (508) (7) (12) 8 68 1 (573) At 1 January 2020 (52) (98) (58) (8) 13 18 40 (145) Income statement (charge)/credit (13) (62) — — 2 21 16 (36) Transfers/reclassifications — — 12 — — — (15) (3) Credited/(charged) to other comprehensive income — 133 (54) (2) — — — 77 At 31 December 2020 (65) (27) (100) (10) 15 39 41 (107)

Dividends on Ordinary Shares (T

Dividends on Ordinary Shares (Tables)	12 Months Ended
	Dec. 31, 2021
Dividends On Ordinary Shares [Abstract]
Disclosure of Dividends on Ordinary Shares Declared and Paid	Dividends on ordinary shares declared and paid in the year were as follows: Group Group 2021 2020 2019 2021 2020 2019 Pence per share Pence per share Pence per share £m £m £m In respect of current year – first interim 4.05 1.46 1.95 286 103 138 – second interim 15.01 — 1.76 1,060 — 124 19.06 1.46 3.71 1,346 103 262

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of nature and extent of risks arising from financial instruments [abstract]
Notional Amounts and Fair Values of Derivatives	Group 2021 2020 Fair value Fair value Notional amount Assets Liabilities Notional amount Assets Liabilities £m £m £m £m £m £m Derivatives held for trading: Exchange rate contracts 11,750 159 183 15,465 395 431 Interest rate contracts 25,617 489 708 40,630 926 837 Equity and credit contracts 1,138 166 57 1,319 124 83 Total derivatives held for trading 38,505 814 948 57,414 1,445 1,351 Derivatives held for hedging Designated as fair value hedges: Exchange rate contracts 590 39 — 789 84 6 Interest rate contracts 80,651 908 737 93,748 1,225 1,885 Equity derivative contracts — — — 81,241 947 737 94,537 1,309 1,891 Designated as cash flow hedges: Exchange rate contracts 22,239 996 338 27,020 1,978 409 Interest rate contracts 21,329 177 216 19,407 467 23 Equity derivative contracts 47 7 1 13 6 — 43,615 1,180 555 46,440 2,451 432 Total derivatives held for hedging 124,856 2,127 1,292 140,977 3,760 2,323 Derivative netting (1) — (1,221) (1,221) — (1,754) (1,754) Total derivatives 163,361 1,720 1,019 198,391 3,451 1,920 (1) Derivative netting excludes the effect of cash collateral, which is offset against the gross derivative position. The amount of cash collateral received that had been offset against the gross derivative assets was £189m (2020: £330m) and the amount of cash collateral paid that had been offset against the gross derivative liabilities was £202m (2020: £651m).
Disclosure of Analysis of the Notional and Fair Values of Derivatives by Trading and Settlement Method	The table below analyses the notional and fair values of derivatives by trading and settlement method. Notional Traded over the counter Asset Liability Traded on recognised exchanges Settled by central counterparties Not settled by central counterparties Total Traded on recognised exchanges Traded over the counter Traded on recognised exchanges Traded over the counter 2021 £m £m £m £m £m £m £m £m Exchange rate contracts — — 34,579 34,579 — 1,193 — 522 Interest rate contracts — 117,560 10,037 127,597 — 353 — 441 Equity and credit contracts — — 1,185 1,185 — 174 — 56 — 117,560 45,801 163,361 — 1,720 — 1,019 2020 Exchange rate contracts — — 43,274 43,274 — 2,457 — 846 Interest rate contracts — 144,343 9,442 153,785 — 864 — 991 Equity and credit contracts — — 1,332 1,332 — 130 — 83 — 144,343 54,048 198,391 — 3,451 — 1,920
Disclosure of Maturity Profile and Average Price/Rate of Hedging Instruments Used in Hedging Strategies	The following table sets out the maturity profile and average price/rate of the hedging instruments used in the Santander UK group’s hedging strategies: Group 2021 Hedging Instruments ≤1 month >1 and ≤3 months >3 and ≤12 months >1 and ≤5 years >5 years Total Fair value hedges: Interest rate risk Interest rate contracts- Nominal amount (£m) 3,121 6,223 21,442 44,644 4,991 80,421 Average fixed interest rate - GBP 0.59 % 0.42 % 0.09 % 0.88 % 3.13 % Average fixed interest rate - EUR 0.51 % 1.74 % 1.08 % 0.81 % 2.61 % Average fixed interest rate - USD 1.91 % 0.96 % 1.44 % 2.76 % 4.05 % Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) — — 107 381 102 590 Interest rate contracts - Nominal amount (£m) — — — 193 37 230 Average GBP - EUR exchange rate — — 1.21 1.16 1.17 Average fixed interest rate - EUR — — 3.29 % 2.03 % 2.62 % Cash flow hedges: Interest rate risk Interest rate contracts - Nominal amount (£m) 1,010 481 871 7,532 5,137 15,031 Average fixed interest rate - GBP 1.97 0.44 % 0.08 % 1.39 % 0.97 % FX risk Exchange rate contracts- Nominal amount (£m) 2,703 936 2,057 6,715 2,124 14,535 Interest rate contracts- Nominal amount (£m) — — — 2,438 887 3,325 Average GBP - JPY exchange rate — 142.91 148.86 — — Average GBP - EUR exchange rate 1.17 — 1.18 1.16 1.17 Average GBP - USD exchange rate 1.34 1.34 1.33 1.34 1.39 Equity risk Equity derivative contracts - Nominal amount (£m) — — 2 41 4 47 Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) 620 — 840 4,765 1,479 7,704 Interest rate contracts - Nominal amount (£m) — — — 2,049 924 2,973 Average GBP - EUR exchange rate 1.28 — 1.39 1.20 1.20 — Average GBP - USD exchange rate — — — 1.61 1.38 Average fixed interest rate - GBP 2.26 % — 1.17 % 2.72 % 3.41 % 2020 Fair value hedges: Interest rate risk Interest rate contracts- Nominal amount (£m) 2,429 7,617 27,791 47,749 7,889 93,475 Average fixed interest rate - GBP 0.69 % 0.65 % 0.82 % 0.73 % 3.61 % Average fixed interest rate - EUR 1.18 % 0.23 % 3.02 % 0.98 % 2.34 % Average fixed interest rate - USD 1.87 % 1.72 % 2.89 % 2.49 % 4.16 % Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) — 0 132 461 196 789 Interest rate contracts - Nominal amount (£m) — — — 236 37 273 Average GBP - EUR exchange rate — — 1.14 1.17 1.17 Average fixed interest rate - EUR — — 4.64 % 1.78 % 3.56 % Cash flow hedges: Interest rate risk Interest rate contracts - Nominal amount (£m) — 897 2,528 7,964 1,061 12,450 Average fixed interest rate - GBP — 0.46 % 0.57 % 1.45 % 1.33 % FX risk Exchange rate contracts- Nominal amount (£m) 1,439 2,015 3,877 7,113 1,119 15,563 Interest rate contracts- Nominal amount (£m) — — — 366 — 366 Average GBP - JPY exchange rate — 137.98 135.61 132.27 — Average GBP - EUR exchange rate — — 0.00 1.16 1.18 Average GBP - USD exchange rate 1.29 1.32 1.32 1.30 — Equity risk Equity derivative contracts - Nominal amount (£m) — — 0 12 1 13 Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) 732 — 2,583 6,550 1,592 11,457 Interest rate contracts - Nominal amount (£m) 732 — 882 4,062 915 6,591 Average GBP - EUR exchange rate — — 1.35 1.25 1.20 Average GBP - USD exchange rate 1.46 — 0.00 1.61 1.38 Average fixed interest rate - GBP 2.01 % — 3.18 % 2.48 % 3.39 %
Net Gains or Losses Arising From Hedges Included in Operating Income	Net gains or losses arising from fair value and cash flow hedges included in other operating income Group 2021 2020 2019 £m £m £m Fair value hedging: Gains/(losses) on hedging instruments 846 (299) (360) (Losses)/gains on hedged items attributable to hedged risks (804) 364 414 Fair value hedging ineffectiveness 42 65 54 Cash flow hedging ineffectiveness (34) (46) (46) 8 19 8
Disclosure of Information about Hedging Ineffectiveness by Risk Category Explanatory	Hedge ineffectiveness can be analysed by risk category as follows: Group 2021 2020 Change in FV of hedging instruments Change in FV of hedged items Recognised in income statement Change in FV of hedging instruments Change in FV of hedged items Recognised in income statement £m £m £m £m £m £m Fair value hedges: Interest rate risk 868 (838) 30 (358) 384 26 Interest rate/FX risk (22) 34 12 59 (20) 39 846 (804) 42 (299) 364 65 Group 2021 2020 Hedging Instruments Hedging Instruments Income statement line item affected by reclassification Change in FV Recognised in OCI Recognised in income statement Reclassified from reserves to income Change in FV Recognised in OCI Recognised in income statement Reclassified from reserves to income £m £m £m £m £m £m £m £m Cash flow hedges: Interest rate risk Net interest income (312) 306 (6) 70 185 (179) 6 33 FX risk Net interest income/other operating income (54) 54 — (158) (42) 38 (4) 2 Equity risk Operating expenses (1) 1 — 2 2 (2) — (5) Interest rate/FX risk Net interest income/other operating income (542) 514 (28) (273) 782 (830) (48) 773 (909) 875 (34) (359) 927 (973) (46) 803
Disclosure of Reconciliation by Risk Category of Components of Equity and Analysis of Other Comprehensive Income Items Resulting from Hedge Accounting Explanatory	The following table provides a reconciliation by risk category of components of equity and analysis of OCI items (before tax) resulting from hedge accounting. Group 2021 2020 £m £m Balance at 1 January 649 479 Effective portion of changes in fair value: – Interest rate risk (306) 179 – Foreign currency risk (54) (38) – Equity risk (1) 2 – Interest rate/foreign currency risk (514) 830 (875) 973 Income statement transfers: – Interest rate risk (70) (33) – Foreign currency risk 158 (2) – Equity risk (2) 5 – Interest rate/foreign currency risk 273 (773) 359 (803) Balances at 31 December 133 649
Disclosure of detailed information about hedges	Santander UK hedges its exposures to various risks, including interest rate risk and foreign currency risk, as set out in the following table. Group 2021 2020 Accumulated amount of FV hedge adjustments Change in value to calculate hedge ineffectiveness Accumulated amount of FV hedge adjustments Change in value to calculate hedge ineffectiveness Carrying value Hedged item Portfolio hedge of interest rate risks Of which Discontinued hedges Carrying value Hedged item Portfolio hedge of interest rate risks Of which Discontinued hedges £m £m £m £m £m £m £m £m £m £m Fair value hedges Interest rate risk: Loans and advances to customers 58,455 — 88 500 (1,096) 54,118 — 1,202 904 332 Other financial assets at amortised cost 160 — 2 3 (12) 772 — 36 13 121 Reverse repurchase agreements – non trading 9,570 — (5) — (6) 12,149 — 1 — 3 Other financial assets at FVOCI 3,728 23 — 47 (112) 5,129 155 — 74 88 Deposits by customers — — — — 14 (4,305) (15) (10) (10) (13) Debt securities in issue (4,373) (188) (115) (230) 325 (8,889) (518) (137) (305) (120) Subordinated liabilities (293) (75) (8) (70) 49 (636) (185) (41) (166) (27) Interest rate/FX risk: Other financial assets at FVOCI 227 — — 1 (20) 299 5 — — 15 Debt securities in issue (423) (55) — (47) 55 (621) (94) — (76) (34) Subordinated liabilities 2 2 — 2 (1) 3 3 — 3 (1) 67,053 (293) (38) 206 (804) 58,019 (649) 1,051 437 364 Group 2021 2020 Change in value to calculate hedge ineffectiveness Cash flow Balances on cash flow hedge reserve for discontinued hedges Change in value to calculate hedge ineffectiveness Cash flow Balances on cash flow hedge reserve for discontinued hedges Hedged item balance sheet line item £m £m £m £m £m £m Cash flow hedges: Interest rate risk: Loans and advances to customers 236 (135) (2) (183) 165 1 Cash and balances at central banks 71 (80) — (2) 1 — Reverse repurchase agreements – non trading — — — (2) 1 — Deposits by banks (1) 1 — 7 (2) — Repurchase agreements – non trading — — — 1 (1) — FX risk: Other financial assets at FVOCI (194) (1) — 40 6 — Not applicable – highly probable forecast transactions 148 1 — 33 3 — Deposits by customers 4 — — (7) — — Debt securities in issue 90 67 6 (13) (46) — Repurchase agreements – non trading 6 — — (15) — — Equity risk: Other liabilities 1 3 — (2) 6 — Interest rate/FX risk: Debt securities in issue/loans and advances to customers 503 144 (4) (701) 322 (2) Subordinated liabilities/loans and advances to customers 11 133 80 (130) 194 — 875 133 80 (974) 649 (1)

Other Financial Assets at Fai_3

Other Financial Assets at Fair Value Through Profit or Loss (Tables)	12 Months Ended
	Dec. 31, 2021
Financial assets at fair value through profit or loss [abstract]
Summary of Other Financial Assets at Fair Value Through Profit or Loss	Group 2021 2020 £m £m Loans and advances to customers: Loans to housing associations 12 13 Other loans 502 579 514 592 Debt securities 112 112 Equity securities 50 130 676 834

Loans and Advances to Custome_2

Loans and Advances to Customers (Tables)	12 Months Ended
	Dec. 31, 2021
Net Loans And Advances To Customers [Abstract]
Summary of Net Loans and Advances to Customers	Group 2021 2020 £m £m Loans secured on residential properties 178,039 170,089 Corporate loans 19,282 23,613 Finance leases 3,916 6,554 Secured advances — — Other unsecured loans 9,405 10,169 Accrued interest and other adjustments 656 861 Amounts due from fellow Banco Santander subsidiaries and joint ventures 3,080 2,249 Loans and advances to customers 214,378 213,535 Credit impairment loss allowances on loans and advances to customers (828) (1,303) RV and voluntary termination provisions on finance leases (25) (54) Net loans and advances to customers 213,525 212,178
Disclosure of Finance Lease and Hire Purchase Contract Receivables	Finance lease and hire purchase contract receivables may be analysed as follows: Group 2021 2020 Gross investment Unearned finance income Net investment Gross investment Unearned finance income Net investment £m £m £m £m £m £m No later than one year 1,906 (5) 1,901 3,468 (297) 3,171 Later than one year and not later than two years 1,324 (201) 1,123 1,829 (173) 1,656 Later than two years and not later than three years 772 (141) 631 1,099 (106) 993 Later than three years and not later than four years 343 (82) 261 575 (55) 520 Later than four years and not later than five years 38 (38) — 231 (25) 206 Later than five years — — — 8 — 8 4,383 (467) 3,916 7,210 (656) 6,554
Disclosure of Maturity Analysis of Operating Lease Payments	At 31 December 2021 and 2020 , the Santander UK group had contracted with lessees for the following future undiscounted minimum lease payments receivable under operating leases. Group 2021 2020 £m No later than one year 31 17 Later than one year and not later than two years 27 17 Later than two years and not later than three years 22 16 Later than three years and not later than four years 15 11 Later than four years and not later than five years 11 10 Later than five years 28 30 134 101

Securitisations and Covered B_2

Securitisations and Covered Bonds (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Securitisations And Covered Bonds [Abstract]
Analysis of Securitisations and Covered Bonds	The Santander UK group’s principal securitisation programmes and covered bond programme, together with the balances of the advances subject to securitisation (or for the covered bond programme assigned) and the carrying value of the notes in issue at 31 December 2021 and 2020 are listed below. Gross assets External notes in issue Notes issued to Santander UK plc/subsidiaries as collateral 2021 2020 2021 2020 2021 2020 £m £m £m £m £m £m Mortgage-backed master trust structures: – Holmes 2,294 3,073 430 829 183 334 – Fosse 2,154 2,258 288 290 1,402 1,402 – Langton — 2,782 — — — 2,355 4,448 8,113 718 1,119 1,585 4,091 Other asset-backed securitisation structures: – Motor 38 189 41 104 — 97 – Auto ABS UK Loans — 1,460 — 1,107 — 361 38 1,649 41 1,211 — 458 Total securitisation programmes 4,486 9,762 759 2,330 1,585 4,549 Covered bond programmes – Euro 35bn Global Covered Bond Programme 15,713 23,670 12,760 19,285 — — Total securitisation and covered bond programmes (See Note 26) 20,199 33,432 13,519 21,615 1,585 4,549
Summary of Issuances and Redemptions of Securitisation and Covered Bond Programme	The following table sets out the internal and external issuances and redemptions in 2021 and 2020 for each securitisation and covered bond programme. Internal issuances External issuances Internal redemptions External redemptions 2021 2020 2021 2020 2021 2020 2021 2020 £bn £bn £bn £bn £bn £bn £bn £bn Mortgage-backed master trust structures: – Holmes — — — — 0.2 0.3 0.4 0.9 – Langton — — — — 2.4 — — — Other asset-backed securitisation structures: – Motor — — — — 0.1 0.1 0.1 0.2 – Auto ABS UK Loans — — — 0.3 0.1 — 0.1 0.1 Covered bond programme — — — 3.0 — — 6.5 2.7 — — — 3.3 2.8 0.4 7.1 3.9

Transfers of Financial Assets_2

Transfers of Financial Assets Not Qualifying for Derecognition (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of transferred financial assets that are not derecognised in their entirety [abstract]
Carrying Amount of Financial Assets that Did Not Qualify for Derecognition and their Associated Financial Liabilities	The following table analyses the carrying amount of financial assets that did not qualify for derecognition and their associated financial liabilities: Group 2021 2020 Assets Liabilities Assets Liabilities Nature of transaction £m £m £m £m Sale and repurchase agreements 171 (172) 1,597 (1,340) Securities lending agreements 1,892 (1,742) 918 (752) Securitisations (See Notes 14 and 26) 4,486 (759) 6,980 (2,330) 6,549 (2,673) 9,495 (4,422)

Reverse Repurchase Agreements_2

Reverse Repurchase Agreements - Non Trading (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Reserve Repurchase Agreements Non-Trading [Abstract]
Summary of Reverse Repurchase Agreements - Non Trading	Group 2021 2020 £m £m Agreements with banks 447 1,258 Agreements with customers 12,236 18,341 12,683 19,599

Other Financial Assets at Amo_3

Other Financial Assets at Amortised Cost (Tables)	12 Months Ended
	Dec. 31, 2021
Financial assets at fair value through profit or loss [abstract]
Summary of Other Financial Assets at Amortised Cost	Group 2021 2020 £m £m Asset backed securities 443 491 Debt securities 63 672 506 1,163

Financial Assets at Fair Valu_2

Financial Assets at Fair Value Through Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2021
Financial assets at fair value through other comprehensive income [abstract]
Summary of Financial Assets at Fair Value Through Other Comprehensive Income	Group 2021 2020 £m £m Debt securities 5,833 8,929 Loans and advances to customers 18 21 5,851 8,950

Interests in Other Entities (Ta

Interests in Other Entities (Tables)	12 Months Ended
	Dec. 31, 2021
Investments accounted for using equity method [abstract]
Schedule of Interests in Other Entities	Group 2021 2020 £m £m Joint Ventures 201 172 201 172
Schedule of Subsidiaries With Significant Non-Controlling Interests	2021 2020 £m £m Profit attributable to non-controlling interests — 19 Accumulated non-controlling interests of the subsidiary — 162 Dividends paid to non-controlling interests — 15 Summarised financial information: Total assets — 3,451 Total liabilities — 3,127 Profit for the year — 38 Total comprehensive income for the year — 33

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of detailed information about intangible assets [abstract]
Schedule of Goodwill	Group Cost Accumulated impairment Net book value £m £m £m At 31 December 2020, 1 January 2021 and 31 December 2021 1,285 (82) 1,203
Schedule of Goodwill for Cash Generating Units	Basis of the recoverable amount The recoverable amount of all CGUs was determined based on its value in use (VIU) methodology at each testing date. For each CGU, the VIU is calculated by discounting management’s cash flow projections for the CGU. The cash flow projections also take account of increased internal capital allocations needed to achieve internal and regulatory capital targets including the leverage ratio. The key assumptions used in the VIU calculation for each CGU are set out below. The Retail Banking segment consists of the Private Banking CGU and the rest of Retail Banking, known as the Personal Financial Services CGU. Key assumptions in the Value in use calculation Goodwill Discount rate Growth rate beyond initial cash flow projections 2021 2020 2021 2020 2021 2020 CGU £m £m % % % % Personal Financial Services 1,169 1,169 13.6 13.6 1.6 1.6 Private Banking 30 30 16.3 8.9 1.6 1.6 Other 4 4 13.6 13.6 1.6 1.6 1,203 1,203
Reasonably Possible Changes in Key Cash Flow Projection Assumptions	Reasonably possible changes in key assumptions CGU Input Key assumptions Associated risks Reasonably possible change Personal Financial Services Cash flow projections – BoE Bank Rate – UK house price growth – UK mortgage loan market growth – UK unemployment rate – Position in the market – Regulatory capital levels. – Uncertain market outlook – Persistent low interest rate environment – Customer remediation and regulatory action outcomes – Uncertain regulatory capital requirements. – Cash flow projections decrease by 5% (2020: 5%). Discount rate – Discount rate used is a reasonable estimate of a suitable market rate for the profile of the business. – Market rates of interest rise. – Discount rate increases by 100 basis points (2020: 100 basis points). At 31 December 2021 and 31 December 2020, a reasonably possible change in the key assumptions in relation to the VIU calculation for the goodwill balance in the Personal Financial Services CGU would have resulted in an impairment as follows. Impairment 2021 2020 CGU Reasonably possible change £m £m Personal Financial Services Cash flow projections decrease by 5% (2020: 5%) — — Discount rate increases by 100 basis points (2020: 100 basis points) 276 — 2021 Carrying value Value in use Headroom Increase in post tax discount rate Decrease in cash flows CGU £m £m £m bps % Personal Financial Services 8,433 9,100 667 68 7 2020 Personal Financial Services 6,758 8,602 1,844 239 22
Disclosure of Intangible Assets	b) Other intangibles Group Cost Accumulated amortisation / impairment Net book value £m £m £m At 1 January 2021 1,317 (871) 446 Additions 83 — 83 Disposals (54) 53 (1) Charge — (159) (159) Impairment — (27) (27) At 31 December 2021 1,346 (1,004) 342 At 1 January 2020 1,263 (690) 573 Additions 101 — 101 Disposals (47) 47 — Charge — (198) (198) Impairment — (30) (30) At 31 December 2020 1,317 (871) 446

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2021
Property, plant and equipment [abstract]
Disclosure of detailed information about investment property	Group Property Office fixtures and equipment Computer software Operating lease assets Right-of-use assets Total (2) £m £m £m £m £m £m Cost: At 1 January 2021 1,275 1,362 436 720 222 4,015 Additions 126 28 1 284 65 504 Disposals (420) (334) — (249) (29) (1,032) At 31 December 2021 981 1,056 437 755 258 3,487 Accumulated depreciation: At 1 January 2021 491 1,053 434 178 119 2,275 Charge for the year (1) 32 87 1 81 20 221 Impairment during the year 46 28 — — 23 97 Disposals (234) (305) — (99) (23) (661) At 31 December 2021 335 863 435 160 139 1,932 Net book value 646 193 2 595 119 1,555 Cost: At 1 January 2020 1,275 1,442 439 738 214 4,108 Additions 61 24 2 185 10 282 Disposals (61) (104) (5) (203) (2) (375) At 31 December 2020 1,275 1,362 436 720 222 4,015 Accumulated depreciation: At 1 January 2020 457 1,022 434 164 60 2,137 Charge for the year (1) 56 111 — 92 59 318 Impairment during the year 24 — — — — 24 Disposals (46) (80) — (78) — (204) At 31 December 2020 491 1,053 434 178 119 2,275 Net book value 784 309 2 542 103 1,740 (1) Following a review of the estimated useful lives of property as part of Santander UK's transformation program, the charge for the period includes accelerated property depreciation of £9m (2020: £9m). (2) Property, plant and equipment includes assets under construction of £106m (2020: £55m).

Other Financial Liabilities a_3

Other Financial Liabilities at Fair Value Through Profit or Loss (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of financial liabilities [abstract]
Summary of Other Financial Liabilities at Fair Value Through Profit or Loss	Group 2021 2020 £m £m US$30bn Euro Medium Term Note Programme 5 102 Structured Notes Programmes 413 805 Eurobonds 142 150 Structured deposits 223 375 Collateral and associated financial guarantees 20 2 803 1,434

Deposits by Customers (Tables)

Deposits by Customers (Tables)	12 Months Ended
	Dec. 31, 2021
Deposits from customers [abstract]
Schedule of Deposits by Customers	Group 2021 2020 £m £m Demand and time deposits (1) 191,764 191,774 Amounts due to fellow Banco Santander subsidiaries and joint ventures 1,150 1,314 192,914 193,088 (1) Includes equity index-linked deposits of £549m (2020: £577m). The capital amount guaranteed/protected and the amount of return guaranteed in respect of the equity index-linked deposits were £549m and £2m (2020: £577m and £2m) respectively.

Deposits by Banks (Tables)

Deposits by Banks (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Deposits From Banks [Abstract]
Schedule of Deposits by Banks	Group 2021 2020 £m £m Items in the course of transmission 414 375 Deposits held as collateral 941 2,071 Other deposits (1) 32,507 18,527 33,862 20,973 (1) Includes drawdown from the TFS of £0.0bn (2020: £6.3bn) and drawdown from the TFSME of £31.9bn (2020: £11.7bn).

Repurchase Agreements - Non T_2

Repurchase Agreements - Non Trading (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Repurchase Agreements [Abstract]
Summary of Repurchase Agreements - Non Trading	Group 2021 2020 £m £m Agreements with banks 4,145 6,358 Agreements with customers 7,573 9,490 11,718 15,848

Debt Securities in Issue (Table

Debt Securities in Issue (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Securities In Issue [Abstract]
Summary of Debt Securities in Issue	Group 2021 2020 £m £m Medium-term notes: – US$30bn Euro Medium Term Note Programme 1,405 1,694 – Euro 30bn Euro Medium Term Note Programme (1) 4,304 4,292 – US SEC-registered Debt Programme – Santander UK Group Holdings plc (2) 5,978 5,616 – US SEC-registered Debt Programme – Santander UK plc 1,224 4,723 12,911 16,325 Euro 35bn Global Covered Bond Programme (See Note 14) 12,760 19,285 US$20bn Commercial Paper Programmes 2,704 2,824 Certificates of deposit 2,387 2,858 Credit linked notes 59 57 Securitisation programmes (See Note 14) 759 2,330 31,580 43,679 (1) Restated for 2020 to reclassify £673m previously disclosed as Euro 750m Senior Unsecured Notes to Euro 30bn Euro Medium Term Note Programme due to an administrative error.

Subordinated Liabilities (Table

Subordinated Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Subordinated liabilities [abstract]
Schedule of Subordinated Liabilities	Group 2021 2020 £m £m £325m Sterling preference shares 344 344 Undated subordinated liabilities 240 557 Dated subordinated liabilities 1,644 1,655 2,228 2,556
Disclosure of Undated Subordinated Liabilities Explanatory	Group 2021 2020 First call date £m £m 10.0625% Exchangeable capital securities n/a 205 205 7.125% 30 Year Step-up perpetual callable subordinated notes 2030 35 352 240 557
Disclosure of Dated Subordinated Liabilities Explanatory	Group 2021 2020 Maturity £m £m 5% Subordinated notes (US$1,500m) 2023 548 542 4.75% Subordinated notes (US$1,000m) 2025 541 536 7.95% Subordinated notes (US$1,000m) 2029 221 242 6.50% Subordinated notes 2030 28 31 5.875% Subordinated notes 2031 9 10 5.625% Subordinated notes (US$500m) 2045 297 294 1,644 1,655

Other Liabilities (Tables)

Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Subclassifications of assets, liabilities and equities [abstract]
Disclosure Of Other Liabilities Explanatory	Group 2021 2020 £m £m Lease liabilities 134 100 Other 2,064 2,243 2,198 2,343

Provisions (Tables)

Provisions (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of other provisions [abstract]
Summary of Provisions Reconciliation	Group Customer remediation (2) Litigation and other regulatory (2) Bank Levy Property ECL on undrawn facilities and guarantees Restructuring Other (2) Total £m £m £m £m £m £m £m £m At 1 January 2021 69 198 38 45 75 39 4 468 Additional provisions (See Note 8) 25 72 53 52 — 81 109 392 Provisions released (See Note 8) — — — (2) (30) — (2) (34) Utilisation and other (50) (104) (103) (21) (7) (91) (97) (473) Recharge (1) — — 13 — — — — 13 At 31 December 2021 44 166 1 74 38 29 14 366 (1) Recharge in respect of the UK Bank Levy paid on behalf of other UK entities in the Banco Santander group (2) For 2021, operational loss provisions as they relate to customer accounts are included in 'Customer remediation', and 'Restructuring' provisions are now shown separately. As a result, provisions of £61m, £121m and £39m at 1 January 2021 have been reclassified from 'Regulatory and other' to 'Customer remediation', 'Litigation and other regulatory' and 'Restructuring' provisions, respectively, and £8m and £76m of 'Conduct remediation' provisions at 1 January 2021 have been reclassified to 'Customer remediation' and 'Litigation and other regulatory' provisions, respectively.

Retirement Benefit Plans (Table

Retirement Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of net defined benefit liability (asset) [abstract]
Summary of Retirement Benefit Plans	The amounts recognised in the balance sheet were as follows: Group 2021 2020 £m £m Assets/(liabilities) Funded defined benefit pension scheme - surplus 1,573 496 Funded defined benefit pension scheme - deficit — (361) Unfunded pension and post-retirement medical benefits (37) (42) Total net assets 1,536 93
Disclosure of Pension Remeasurements Included in Other Comprehensive income	Remeasurement losses/(gains) recognised in other comprehensive income during the year were as follows: Group 2021 2020 2019 £m £m £m Pension remeasurement (1,263) 505 523
Disclosure of Total Defined Benefit Plan Amount Charged to the Income Statement	The total amount charged to the income statement was as follows: Group 2021 2020 2019 £m £m £m Net interest income (5) (10) (24) Current service cost 38 36 34 Past service and GMP costs — 1 1 Past service curtailment costs 5 — — Administration costs 8 8 8 46 35 19
Summary of Amounts Recognised in Other Comprehensive Income	The amounts recognised in other comprehensive income were as follows: Group 2021 2020 2019 £m £m £m Return on plan assets (excluding amounts included in net interest expense) (452) (1,328) (873) Actuarial (gains)/losses arising from changes in demographic assumptions (17) 34 42 Actuarial gains arising from experience adjustments (19) (141) (40) Actuarial (gains)/losses arising from changes in financial assumptions (775) 1,940 1,394 Pension remeasurement (1,263) 505 523
Disclosure Of Movements In The Present Value Of Defined Benefit Obligations	Movements in the present value of defined benefit scheme obligations were as follows: Group 2021 2020 £m £m At 1 January (13,894) (12,165) Current service cost paid by Santander UK plc (29) (24) Current service cost paid by other subsidiaries (9) (12) Interest cost (188) (253) Employer salary sacrifice contributions (9) (2) Past service cost — (1) Past service curtailment costs (5) — Remeasurement due to actuarial movements arising from: – Changes in demographic assumptions 17 (34) – Experience adjustments 19 141 – Changes in financial assumptions 775 (1,940) Benefits paid 398 396 Derecognition of pension scheme liabilities arising from the sale of PSA 41 — At 31 December (12,884) (13,894)
Disclosure of Movements in Fair Value of Schemes' Assets	Movements in the fair value of the schemes’ assets were as follows: Group 2021 2020 £m £m At 1 January 13,987 12,555 Interest income 193 263 Contributions paid by employer and scheme members 247 245 Administration costs paid (8) (8) Return on plan assets (excluding amounts included in net interest expense) 452 1,328 Benefits paid (398) (396) Derecognition of pension scheme assets arising from the sale of PSA (53) — At 31 December 14,420 13,987
Disclosure of Fair Value of Plan Assets	The composition and fair value of the schemes’ assets by category was: Group Quoted prices in active markets Prices not quoted in active markets Total Valuation 2021 £m % £m % £m % Technique UK equities 38 — — — 38 — A Overseas equities 1,401 10 1,065 7 2,466 17 A,C Corporate bonds 1,607 11 312 2 1,919 13 A,C Government fixed interest bonds 2,788 19 — — 2,788 19 A Government index-linked bonds 9,159 64 — — 9,159 64 A Property — — 1,409 10 1,409 10 B Derivatives — — (83) (1) (83) (1) A Cash — — 2,290 16 2,290 16 A Repurchase agreements (1) — — (6,582) (45) (6,582) (45) A Infrastructure — — 390 3 390 3 B,C Annuities — — 298 2 298 2 D Longevity swap — — (8) — (8) — D Other — — 336 2 336 2 C 14,993 104 (573) (4) 14,420 100 2020 UK equities 40 — — — 40 — A Overseas equities 1,271 9 1,004 7 2,275 16 A,C Corporate bonds 1,121 8 457 3 1,578 11 A,C Government fixed interest bonds 1,618 12 — — 1,618 12 A Government index-linked bonds 6,695 48 — — 6,695 48 A Property — — 1,454 10 1,454 10 B Derivatives — — 312 2 312 2 A Cash — — 1,161 8 1,161 8 A Repurchase agreements (1) — — (2,198) (15) (2,198) (15) A Infrastructure — — 406 3 406 3 B,C Annuities — — 317 2 317 2 D Longevity swap — — — — — — D Other — — 329 3 329 3 C 10,745 77 3,242 23 13,987 100 (1) Sale and repurchase agreements net of purchase and resale agreements.
Summary of Principal Actuarial Assumptions Used for Defined Benefit Schemes	The principal actuarial assumptions used for the defined benefit schemes were: Group 2021 2020 2019 % % % To determine benefit obligations (1) : – Discount rate for scheme liabilities 1.9 1.3 2.1 – General price inflation 3.4 3.0 3.0 – General salary increase 1.0 1.0 1.0 – Expected rate of pension increase 3.2 2.9 2.9 Years Years Years Longevity at 60 for current pensioners, on the valuation date: – Males 27.5 27.5 27.3 – Females 30.1 30.0 29.8 Longevity at 60 for future pensioners currently aged 40, on the valuation date: – Males 29.0 29.0 28.9 – Females 31.6 31.5 31.3 (1) The discount rate and inflation related assumptions set out in the table at 31 December 2021 reflect the assumptions calculated based on the Scheme’s duration and cash flow profile as a whole. The actual assumptions used were determined for each section independently based on each section’s duration and cash flow profile.
Summary of Actuarial Assumption Sensitivities	The sensitivity analyses below have been determined based on reasonably possible changes of the respective assumptions occurring at the end of the reporting period, while holding all other assumptions constant. (Decrease)/increase Change in pension obligation at period end from 2021 2020 Assumption £m £m Discount rate 25 bps increase (571) (662) General price inflation (1) 25 bps increase 392 480 Mortality Each additional year of longevity assumed 478 515 (1) The general price inflation sensitivity of £365m at 31 December 2020 has been restated to correct an administrative error. The correction does not impact the actual reported values.
Disclosure of Defined Benefit Plan Expected Future Benefit Payments	The benefits expected to be paid in each of the next five years, and in the aggregate for the five years thereafter are: Year ending 31 December £m 2022 387 2023 335 2024 356 2025 381 2026 401 Five years ending 2031 2,240

Contingent Liabilities and Co_3

Contingent Liabilities and Commitments (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of contingent liabilities [abstract]
Summary of Contingent Liabilities and Commitments	Group 2021 2020 £m £m Guarantees given to third parties 363 939 Formal standby facilities, credit lines and other commitments 37,385 42,231 37,748 43,170

Share Capital (Tables)

Share Capital (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of classes of share capital [abstract]
Schedule of Share Capital Issued and Fully Paid	Group Ordinary shares Issued and fully paid share capital No. £m At 31 December 2020, 1 January 2021 and 31 December 2021 7,060,000,000 7,060

Other Equity Instruments (Table

Other Equity Instruments (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of classes of share capital [abstract]
Summary of other equity instruments	Group Interest rate 2021 2020 % Next call date £m £m AT1 securities: - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 6.75 June 2024 496 496 - £750m Fixed Rate Reset Perpetual AT1 Capital Securities 7.375 June 2022 745 745 - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 5.33 n/a — 500 - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 6.30 March 2025 500 500 - £450m Fixed Rate Reset Perpetual AT1 Capital Securities 4.25 March 2026 450 — 2,191 2,241

Non-Controlling Interests (Tabl

Non-Controlling Interests (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Noncontrolling Interests [Abstract]
Schedule of Amounts Attributable to Non-Controlling Interests	Initial interest rate 2021 2020 % First call date £m £m Santander UK plc issued: – £300m Step-up Callable Perpetual Reserve Capital Instruments 7.037 February 2026 235 235 PSA Finance UK Limited — 162 235 397

Notes to Cash Flows (Tables)

Notes to Cash Flows (Tables)	12 Months Ended
	Dec. 31, 2021
Cash Flows Explanatory Notes [Abstract]
Summary of Changes in Liabilities Arising from Financing Activities	The table below shows the changes in liabilities arising from financing activities. The changes in equity arising from financing activities are set out in the Consolidated Statement of Changes in Equity. Group 2021 2020 Balance sheet line item Balance sheet line item Debt securities in issue Subordinated liabilities Other equity instruments Lease liabilities Dividends paid Total Debt securities in issue Subordinated liabilities Other equity instruments Lease liabilities Dividends paid Total (1) £m £m £m £m £m £m £m £m £m £m £m £m At 1 January 43,679 2,556 2,241 100 — 48,576 50,171 3,528 2,241 138 — 56,078 Proceeds from issue of debt securities 2,847 — — — — 2,847 5,586 — — — — 5,586 Repayment of debt securities (13,724) — — — — (13,724) (12,348) — — — — (12,348) Repayment of subordinated liabilities — (4) — — — (4) — (939) — — — (939) Issue of other equity instruments — — 450 — — 450 — — — — — — Repurchase of other equity instruments — — (500) — — (500) — — — — — — Payment of lease liability — — — (25) — (25) — — — (46) — (46) Dividends paid — — — — (1,506) (1,506) — — — — (282) (282) Liability-related other changes (473) (4) — 59 — (418) (243) (10) — 8 — (245) Non-cash changes: — — – Unrealised foreign exchange (930) 14 — — — (916) 359 (6) — — — 353 – Other changes 181 (334) — — 1,506 1,353 154 (17) — — 282 419 At 31 December 31,580 2,228 2,191 134 — 36,133 43,679 2,556 2,241 100 — 48,576 (1) Restated for 2020 to include changes in liabilities arising from financing activities relating to lease liabilities.

Assets Charged as Security fo_2

Assets Charged as Security for Liabilities and Collateral Accepted as Security for Assets (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Assets Pledged As Security [Abstract]
Financial Assets Charged as Security Under On-Balance Sheet and Off-Balance	The financial assets below are analysed between those assets accounted for on-balance sheet and off-balance sheet. Group 2021 2020 £m £m On-balance sheet: Cash and balances at central banks 1,580 985 Loans and advances to banks 478 804 Loans and advances to customers – securitisations and covered bonds (See Note 14) 19,432 31,138 Loans and advances to customers – other 41,953 23,690 Other financial assets at amortised cost — 648 Financial assets at fair value through other comprehensive income 4,435 5,677 Total on-balance sheet 67,878 62,942 Total off-balance sheet 14,449 24,701
Schedule of Collateral Held as Security For Assets	The collateral held as security for assets, analysed between those liabilities accounted for on balance sheet and off-balance sheet, was: Group 2021 2020 £m £m On-balance sheet: Deposits by banks 941 2,071 Total on-balance sheet 941 2,071 Total off-balance sheet 18,240 31,043

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of terms and conditions of share-based payment arrangement [abstract]
Summary of Movement in Share Options	The table below summarises movements in the number of options, and changes in weighted average exercise price over the same period. 2021 2020 Number of options Weighted average exercise price Number of options Weighted average exercise price ‘000 £ ‘000 £ Outstanding at 1 January 21,162 2.32 23,373 3.03 Granted 9,414 2.43 11,642 1.65 Exercised (48) 1.86 (860) 2.75 Forfeited/expired (4,535) 2.95 (12,993) 2.96 Outstanding at 31 December 25,993 2.25 21,162 2.32 Exercisable at 31 December 1,321 2.75 1,805 3.59
Summary of Range of Exercise Prices and Weighted Average Remaining Contractual Life of the Options Outstanding	The following table summarises the range of exercise prices and weighted average remaining contractual life of the options at 31 December 2021 and 2020. 2021 2020 Weighted average remaining contractual life Weighted average exercise price Weighted average remaining contractual life Weighted average exercise price Range of exercise prices Years £ Years £ £1 to £2 3 1.65 4 1.65 £2 to £3 3 2.81 2 2.81 £3 to £4 1 3.38 1 3.38 £4 to £5 1 4.02 1 4.02

Transactions with Directors a_3

Transactions with Directors and Other Key Management Personnel (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Remuneration Of Directors And Other Key Management Personnel [Abstract]
Summary of Remuneration of the Directors and Other Key Management Personnel	The remuneration of the Directors and Other Key Management Personnel of the Santander UK group is set out in aggregate below. 2021 2020 2019 Directors’ remuneration £ £ £ Salaries and fees 3,835,797 3,906,401 5,045,302 Performance-related payments (1) 5,195,722 748,495 3,896,382 Other fixed remuneration (pension and other allowances & non-cash benefits) 806,103 1,047,986 1,386,439 Expenses 3,705 2,579 42,526 Total remuneration 9,841,327 5,705,461 10,370,649 2021 2020 2019 Directors' and Other Key Management Personnel compensation £ £ £ Short-term employee benefits (2) 23,392,657 17,886,869 23,238,187 Post-employment benefits (3) 913,842 2,107,544 3,674,772 Total compensation 24,306,499 19,994,413 26,912,959 (1) In line with the Code, a proportion of the performance-related payment was deferred. Further details can be found in the Directors Remuneration Report. (2) In addition to the remuneration in the table above, grants of shares in Banco Santander SA were made as buy-outs of deferred performance-related payments of shares in connection with previous employment for one member of Key Management Personnel of £107,225 of which £25,413 vested in the year (2020: two individuals, one to a director of £1,293,678 of which £242,605 vested in the year and one to Key Management Personnel of £924,133 of which £60,500 vested in the year ). (3) No Termination payments were paid in 2021 to key management persons (2020: £nil ; 2019: £1,076,435 for one individual).
Summary of Transactions with Directors, Other Key Management Personnel	Directors, Other Key Management Personnel (defined as the Executive Committee of Santander UK plc who served during the year) and their connected persons have undertaken the following transactions with the Santander UK group in the ordinary course of business. 2021 2020 No. £000 No. £000 Secured loans, unsecured loans and overdrafts At 1 January 9 1,825 18 4,920 Net movements (5) (1,798) (9) (3,095) At 31 December 4 27 9 1,825 Deposit, bank and instant access accounts and investments At 1 January 16 8,063 32 11,975 Net movements — (1,636) (16) (3,912) At 31 December 16 6,427 16 8,063

Related Party Disclosures (Tabl

Related Party Disclosures (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of transactions between related parties [abstract]
Summary of Transactions With Related Parties	Transactions with related parties during the year and balances outstanding at the year-end: Group Interest, fees and Interest, fees and Amounts owed by Amounts owed to 2021 2020 2019 2021 2020 2019 2021 2020 2021 2020 £m £m £m £m £m £m £m £m £m £m Ultimate parent (210) (120) (150) 34 158 334 1,049 1,857 (1,392) (2,463) Fellow subsidiaries (47) (54) (58) 151 148 158 20 37 (467) (498) Associates & joint ventures (34) (29) (29) 4 — — 3,075 2,234 (918) (1,034) (291) (203) (237) 189 306 492 4,144 4,128 (2,777) (3,995)

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Abstract]
Fair Values of Financial Instruments Carried at Amortised Cost	Group 2021 2020 Fair value Carrying Fair value Carrying Level 1 Level 2 Level 3 Total value Level 1 Level 2 Level 3 Total value £m £m £m £m £m £m £m £m £m £m Assets Loans and advances to customers — — 216,279 216,279 213,525 — — 214,730 214,730 212,178 Loans and advances to banks — 1,420 — 1,420 1,420 — 2,004 — 2,004 2,004 Reverse repurchase agreements - non trading — 12,453 226 12,679 12,683 — 19,382 226 19,608 19,599 Other financial assets at amortised cost 164 348 — 512 506 799 393 — 1,192 1,163 164 14,221 216,505 230,890 228,134 799 21,779 214,956 237,534 234,944 Liabilities Deposits by customers — 52 192,887 192,939 192,914 — 109 193,102 193,211 193,088 Deposits by banks — 33,780 82 33,862 33,862 — 20,966 16 20,982 20,973 Repurchase agreements - non trading — 11,718 — 11,718 11,718 — 15,847 — 15,847 15,848 Debt securities in issue 4,070 27,084 1,218 32,372 31,580 — 43,500 1,430 44,930 43,679 Subordinated liabilities 1,019 1,512 238 2,769 2,228 — 2,830 239 3,069 2,556 5,089 74,146 194,425 273,660 272,302 — 83,252 194,787 278,039 276,144
Fair Values of Financial Instruments Measured at Fair Value on a Recurring Basis	The following tables summarise the fair values of the financial assets and liabilities accounted for at fair value at 31 December 2021 and 31 December 2020, analysed by their levels in the fair value hierarchy - Level 1, Level 2 and Level 3. Group 2021 2020 Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Valuation £m £m £m £m £m £m £m £m technique Assets Derivative financial instruments Exchange rate contracts — 1,193 1 1,194 — 2,455 2 2,457 A Interest rate contracts — 1,574 — 1,574 — 2,604 14 2,618 A & C Equity and credit contracts — 118 55 173 — 71 59 130 B & D Netting — (1,221) — (1,221) — (1,754) — (1,754) — 1,664 56 1,720 — 3,376 75 3,451 Other financial assets at FVTPL Loans and advances to customers — 440 74 514 — 493 99 592 A Debt securities — 1 111 112 — 3 109 112 A, B & D Equity securities — — 50 50 83 — 47 130 B Reverse repurchase agreements – non trading — — — — — — — — A — 441 235 676 83 496 255 834 Financial assets at FVOCI Debt securities 5,833 — — 5,833 8,501 428 — 8,929 D Loans and advances to customers — — 18 18 — — 21 21 D 5,833 — 18 5,851 8,501 428 21 8,950 Total assets at fair value 5,833 2,105 309 8,247 8,584 4,300 351 13,235 Liabilities Derivative financial instruments Exchange rate contracts — 521 — 521 — 846 — 846 A Interest rate contracts — 1,659 2 1,661 — 2,742 3 2,745 A & C Equity and credit contracts — 28 30 58 — 54 29 83 B & D Netting — (1,221) — (1,221) — (1,754) — (1,754) — 987 32 1,019 — 1,888 32 1,920 Other financial liabilities at FVTPL Debt securities in issue — 555 5 560 — 1,051 6 1,057 A Structured deposits — 223 — 223 — 375 — 375 A Repurchase agreements – non trading — — — — — — — — A Collateral and associated financial guarantees — 19 1 20 — — 2 2 D — 797 6 803 — 1,426 8 1,434 Total liabilities at fair value — 1,784 38 1,822 — 3,314 40 3,354
Summary of Fair Value Adjustment	The magnitude and types of fair value adjustment are listed in the following table: 2021 2020 £m £m Risk-related: - Bid-offer and trade specific adjustments (9) (8) - Uncertainty 40 45 - Credit risk adjustment 6 11 - Funding fair value adjustment 3 3 40 51 Model-related — — Day One profit — — 40 51
Disclosure Of Analysis Of Financial Instruments Valued Using Internal Models Based On Information Other Than Market Data	The table below provides an analysis of financial instruments valued using internal models based on information other than market data together with further details on the valuation techniques used for each type of instrument. Each instrument is initially valued at transaction price: Balance sheet value Fair value movements recognised in profit/(loss) 2021 2020 2021 2020 2019 Balance sheet line item Category Financial instrument product type £m £m £m £m £m 1. Derivative assets Equity and credit contracts Reversionary property interests 45 51 — 3 2 2. FVTPL assets Loans and advances to customers Roll-up mortgage portfolio 48 56 (5) 6 — 3. FVTPL assets Loans and advances to customers Other loans 26 43 (2) 3 1 4. FVTPL assets Debt securities Reversionary property securities 91 107 5 6 (17) 5. FVTPL assets Equity securities Unlisted equity shares 50 47 1 12 42 6. FVTPL assets Debt securities Credit linked notes 20 2 (5) (16) 7 7. FVOCI assets Loans and advances to customers Other loans 18 21 (3) (4) (2) 8. Derivative liabilities Equity contracts Property options and forwards (30) (29) (1) (3) — 9. FVTPL liabilities Financial guarantees Credit protection guarantee (1) (2) 5 16 (7) 267 296 (5) 23 26 Other Level 3 assets 11 24 2 7 15 Other Level 3 liabilities (7) (9) 2 (3) (7) Total net assets 271 311 (1) 27 34 Total income/(expense) (1) 27 34
Summary of Reconciliation of Fair Value Measurement in Level 3 of the Fair Value Hierarchy	The following table sets out the movements in Level 3 financial instruments in 2021 and 2020: Assets Liabilities Derivatives Other financial assets at FVTPL Financial assets at FVOCI Assets held for sale Total Derivatives Other financial liabilities at FVTPL Liabilities held for sale Total £m £m £m £m £m £m £m £m £m At 1 January 2021 75 255 21 — 351 (32) (8) — (40) Total (losses)/gains recognised: - Fair value movements 2 (6) (3) — (7) — 6 — 6 - Foreign exchange and other movements — 2 — — 2 — 1 — 1 Transfers in — — — — — — — — — Transfers out — — — — — — — — — Netting (1) — 23 — — 23 — (5) — (5) Additions — — — — — — — — — Sales — (16) — — (16) — — — — Settlements (21) (23) — — (44) — — — — At 31 December 2021 56 235 18 — 309 (32) (6) — (38) Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year 2 (4) (3) — (5) — 7 — 7 At 1 January 2020 84 505 56 — 645 (35) (61) — (96) Total gains/(losses) recognised: - Fair value movements 10 11 (4) — 17 (7) 17 — 10 - Foreign exchange and other movements — (9) — — (9) — 8 — 8 Transfers in 1 1 — — 2 — — — — Transfers out — (81) — — (81) — 28 — 28 Netting (1) — (42) — — (42) — — — — Additions 9 — — — 9 — (2) — (2) Sales — (19) (19) — (38) — — — — Settlements (29) (111) (12) — (152) 10 2 — 12 At 31 December 2020 75 255 21 — 351 (32) (8) — (40) Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year 10 2 (4) — 8 (7) 25 — 18 (1) This relates to the effect of netting on the fair value of the credit linked notes due to a legal right of set-off between the principal amounts of the senior notes and the associated cash deposits. For more, see ‘ii) Credit protection entities’ in Note 19.
Effects Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives Level Three	Significant unobservable input Sensitivity Assumption value Favourable changes Unfavourable changes Fair value Range (1) Weighted average Shift 2021 £m Assumption description £m £m 1. Derivative assets – Equity and credit contracts: 45 HPI Forward growth rate 0%-5% 2.56 % 1 % 6 (6) – Reversionary property derivatives HPI Spot rate (2) n/a 483 10 % 6 (6) 2. FVTPL – Loans and advances to customers: 48 HPI Forward growth rate 0%-5% 2.68 % 1 % 2 (2) – Roll-up mortgage portfolio 3. FVTPL – Loans and advances to customers: 26 Credit spreads 0.07% - 1.44% 0.50 % 20 % — — – Other loans 4. FVTPL – Debt securities: 91 HPI Forward growth rate 0% -5% 2.56 % 1 % 1 (1) – Reversionary property securities HPI Spot rate (2) n/a 483 10 % 4 (4) 5. FVTPL - Equity securities: 50 Contingent litigation risk 0% - 100% 45 % 20 % 7 (7) – Unlisted equity shares 7. FVOCI - Loans and advances to customers: 18 Credit spreads 0.15% - 0.19% 0.04 % 20 % — — – Other loans 8. Derivative liabilities – Equity contracts: (30) HPI Forward growth rate 0% -5% 2.39 % 1 % 2 (2) – Property-related options and forwards HPI Spot rate (2) n/a 469 10 % 3 (3) 2020 1. Derivative assets – Equity and credit contracts: 51 HPI Forward growth rate 0% - 5% 2.57 % 1 % 8 (8) – Reversionary property derivatives HPI Spot rate (2) n/a 445 10 % 7 (7) 2. FVTPL – Loans and advances to customers: 56 HPI Forward growth rate 0% - 5% 2.69 % 1 % 2 (2) – Roll-up mortgage portfolio 3. FVTPL – Loans and advances to customers: 43 Credit spreads 0.07% - 1.55% 0.44 % 20 % — — – Other loans 4. FVTPL – Debt securities: 107 HPI Forward growth rate 0% - 5% 2.57 % 1 % 1 (1) – Reversionary property securities HPI Spot rate (2) n/a 445 10 % 5 (5) 5. FVTPL - Equity securities: 47 Contingent litigation risk 0% - 100% 49 % 20 % 8 (8) – Unlisted equity shares 7. FVOCI - Loans and advances to customers: 21 Credit spreads 0.15% - 0.53% 0.32 % 20 % — — – Other loans 8. Derivative liabilities – Equity contracts: (29) HPI Forward growth rate 0% - 5% 2.42 % 1 % 2 (2) –Property-related options and forwards HPI Spot rate (2) n/a 433 10 % 3 (3) (1) The range of actual assumption values used to calculate the weighted average disclosure. (2) The HPI spot rate in the weighted average column represents the HPI spot rate index level at 31 December 2021 and 2020.
Maturities of Undiscounted Cash Flows for Financial Liabilities and Off Balance Sheet Commitments	Group On demand Not later than 3 months Later than 3 months and not later than 1 year Later than 1 year and not later than 5 years Later than 5 years Total 2021 £m £m £m £m £m £m Financial liabilities Derivative financial instruments — 96 61 392 517 1,066 Other financial liabilities at fair value through profit or loss — 6 8 553 236 803 Deposits by customers 180,907 3,706 5,690 1,920 741 192,964 Deposits by banks 1,386 536 57 31,984 — 33,963 Repurchase agreements – non trading — 11,419 299 — — 11,718 Debt securities in issue — 5,011 2,752 16,754 8,057 32,574 Subordinated liabilities — 32 98 1,547 2,020 3,697 Lease liabilities — — 32 79 32 143 Total financial liabilities 182,293 20,806 8,997 53,229 11,603 276,928 Off-balance sheet commitments given 20,545 5,359 5,747 5,523 574 37,748 2020 Financial liabilities Derivative financial instruments — 320 134 584 950 1,988 Other financial liabilities at fair value through profit or loss — 1 107 570 759 1,437 Deposits by customers 179,499 4,251 5,994 2,767 682 193,193 Deposits by banks 2,426 1,894 2,535 14,044 207 21,106 Repurchase agreements – non trading — 15,350 500 — — 15,850 Debt securities in issue — 5,759 11,042 19,269 8,921 44,991 Subordinated liabilities — 30 92 1,221 2,718 4,061 Lease liabilities — — 18 57 37 112 Total financial liabilities 181,925 27,605 20,422 38,512 14,274 282,738 Off-balance sheet commitments given 21,055 4,493 4,983 11,493 1,146 43,170

Offsetting Financial Assets a_2

Offsetting Financial Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of offsetting of financial liabilities [abstract]
Summary of Information about Impact of Offsetting of Financial Assets and Liabilities	Group Amounts subject to enforceable netting arrangements Effects of offsetting on balance sheet Related amounts not offset Assets not subject to enforceable netting arrangements (2) Gross Amounts Net amounts Financial Financial collateral (1) Net Balance sheet total (3) 2021 £m £m £m £m £m £m £m £m Assets Derivative financial assets 2,870 (1,221) 1,649 (582) (693) 374 72 1,721 Reverse repurchase, securities borrowing & similar agreements: - Amortised cost 14,882 (2,199) 12,683 (435) (12,248) — — 12,683 - Fair value — — — — — — — — Loans and advances to customers and banks (4) 4,316 (923) 3,393 — — 3,393 211,552 214,945 22,068 (4,343) 17,725 (1,017) (12,941) 3,767 211,624 229,349 Liabilities Derivative financial liabilities 2,197 (1,221) 976 (582) (351) 43 43 1,019 Repurchase, securities lending & similar agreements: - Amortised cost 13,917 (2,199) 11,718 (435) (11,283) — — 11,718 - Fair value — — — — — — — — Deposits by customers and banks (4) 2,683 (923) 1,760 — — 1,760 225,016 226,776 18,797 (4,343) 14,454 (1,017) (11,634) 1,803 225,059 239,513 2020 Assets Derivative financial assets 5,116 (1,754) 3,362 (820) (1,840) 702 89 3,451 Reverse repurchase, securities borrowing & similar agreements: - Amortised cost 26,084 (6,485) 19,599 (129) (19,470) — — 19,599 - Fair value — — — — — — — — Loans and advances to customers and banks (4) 7,524 (1,073) 6,451 — — 6,451 207,731 214,182 38,724 (9,312) 29,412 (949) (21,310) 7,153 207,820 237,232 Liabilities Derivative financial liabilities 3,597 (1,754) 1,843 (820) (839) 184 77 1,920 Repurchase, securities lending & similar agreements: - Amortised cost 22,333 (6,485) 15,848 (129) (15,719) — — 15,848 - Fair value — — — — — — — — Deposits by customers and banks (4) 3,222 (1,073) 2,149 — (502) 1,647 211,912 214,061 29,152 (9,312) 19,840 (949) (17,060) 1,831 211,989 231,829 (1) Financial collateral is reflected at its fair value but has been limited to the net balance sheet exposure so as not to include any over-collateralisation. (2) This column includes contractual rights of set-off that are subject to uncertainty under the laws of the relevant jurisdiction. (3) The balance sheet total is the sum of ‘Net amounts reported on the balance sheet’ that are subject to enforceable netting arrangements and ‘Amounts not subject to enforceable netting arrangements’.

Interest Rate Benchmark Refor_2

Interest Rate Benchmark Reform (Tables)	12 Months Ended
	Dec. 31, 2021
Interest Rate Benchmark Reform [Abstract]
Summary of Hedge Accounting Adjustments, IBOR	The table below sets out the hedge accounting amendments, and their impact for Santander UK, which provide additional temporary reliefs from applying specific IAS 39 hedge accounting requirements to hedging relationships directly affected by IBOR reform. For GBP LIBOR cash flow hedges of legacy contracts and for USD LIBOR cash flow hedges, the transition to alternative benchmark interest rates will take place during 2022 and, for USD LIBOR cash flow hedges, no later than June 2023. Hedge accounting amendment Impact for the Santander UK group Allow amendment of the designation of a hedging relationship to reflect changes that are required by the reform. The hedge designation must be amended by the end of the reporting period in which the changes are made. This amendment means any change to hedge documentation will not result in discontinuation of hedge accounting nor the designation of a new hedge relationship. It expects the majority of its hedge relationships will transition to alternative benchmark rates during 2021 and Santander UK group used this relief for those hedges that transitioned. When a hedged item in a cash flow hedge is amended to reflect the changes that are required by the reform, the amount accumulated in the cash flow hedge reserve will be deemed to be based on the alternative benchmark rate on which the hedged future cash flows are determined. This amendment would result in the release of the cash flow hedge reserve to profit or loss in the same period or periods in which the hedged cash flows that are now based on the alternative benchmark interest rate affect profit or loss. During the year, most of the Santander UK group’s GBP LIBOR cash flow hedges transitioned to alternative benchmark interest rates. An entity may, on an individual hedge basis, reset to zero the cumulative fair value changes of the hedged item and hedging instrument when ceasing to apply the retrospective effectiveness assessment relief provided by the Phase 1 amendments. The Santander UK group assessed on a hedge-by-hedge basis as the hedging instruments transitioned away from LIBORs or other IBORs during 2021. Resetting the cumulative fair value changes to zero had no effect on the amounts recorded in profit or loss. All hedge ineffectiveness including any outside the 80-125% range arising from IBOR reform has been recognised in profit or loss. When amending the hedge relationships for groups of items, hedged items are allocated to sub-groups based on the alternative benchmark interest rate being hedged, and the benchmark rate for each sub-group is designated as the hedged risk. All hedge relationships have transitioned to alternative benchmark interest rates and hedge documentation was amended accordingly. An alternative benchmark interest rate designated as a non-contractually specified risk component, that is not separately identifiable at the date when it is designated, is deemed to have met the requirements at that date if the entity reasonably expects that it will meet the requirements within a period of 24 months from the date of first designation. The 24-month period will apply to each alternative benchmark interest rate separately. The risk component will, however, be required to be reliably measurable. The amendment eases transition to alternative benchmark interest rates by allowing hedging relationships to be designated and to continue even before the new benchmark interest rates are fully established as market benchmarks. For the Santander UK group, the majority of hedge relationships, where an alternative benchmark interest rate is to be designated as a non-contractually specified risk component, were GBP fair value hedge relationships and most transitioned to SONIA during the year, and this rate was considered separately identifiable.
Schedule of Amounts Affected by IBOR Reform	Group 2021 GBP (3) LIBOR USD (3) LIBOR Other (3) Total £m £m £m £m Assets Derivatives (1)(2) — 1,648 — 1,648 Other financial assets at fair value through profit and loss 8 — — 8 Financial assets at amortised cost 1,373 81 1 1,455 1,381 1,729 1 3,111 Liabilities Derivatives (1)(2) 338 1,975 — 2,313 Other financial liabilities at fair value through profit and loss — 5 — 5 Financial liabilities at amortised cost (4) 34 2,401 — 2,435 372 4,381 — 4,753 Off-balance sheet commitments given 338 59 — 397 2020 Assets Derivatives (1)(2) 33,857 4,844 2,149 40,850 Other financial assets at fair value through profit and loss 968 22 — 990 Financial assets at amortised cost 15,062 1,191 90 16,343 Financial assets at fair value through comprehensive income 428 — — 428 50,315 6,057 2,239 58,611 Liabilities Derivatives (1)(2) 35,312 5,381 88 40,781 Other financial liabilities at fair value through profit and loss 1,128 69 — 1,197 Financial liabilities at amortised cost 2,354 3,515 — 5,869 38,794 8,965 88 47,847 Off-balance sheet commitments given 11,405 2,126 573 14,104 (1) Many of the Santander UK group’s derivatives subject to IBOR reform are governed by ISDA definitions. In October 2020 ISDA issued an IBOR fallbacks supplement setting out how the amendments to new alternative benchmark rates will be accomplished, the effect of which is to create fallback provisions in derivatives that describe what floating rates will apply on the permanent discontinuation of certain key IBORs or upon ISDA declaring a non-representative determination of an IBOR. The Santander UK group has adhered to the protocol to implement the fallbacks to derivative contracts that were entered into before the effective date of the supplement (25 January 2021). If derivative counterparties also adhere to the pro tocol, new fallbacks will automatically be implemented in existing derivative contracts when the supplement becomes effective. Following the announcement by the FCA on 5 March 2021 that certain LIBOR settings will permanently cease immediately after 31 December 2021 (and for overnight, 1-month, 3-month, 6-month and 12-month US dollar LIBOR after 30 June 2023), the ISDA fallback spread adjustment is fixed as of the date of the FCA announcement. GBP & JPY LIBOR for certain legacy contracts has been extended until at least the end of 2022 but not for cleared derivative contracts. (2) Derivatives shown in the table above exclude contracts that automatically transitioned under ISDA fall back protocols at 00:01 on 1 January 2022. (3) Cessation dates are: GBP, JPY, NOK LIBOR & 1-week and 2-month USD LIBOR 31/12/2021 remaining USD LIBOR settings 30/06/23, EONIA 03/01/2022; GBP & JPY LIBOR for certain legacy contracts has been extended until at least 31/12/2022.
Schedule of Derivatives directly Affected by IBOR Reform Uncertainties	The following tables show the notional amount of derivatives in hedging relationships directly affected by uncertainties related to IBOR reform. 2021 2020 GBP USD Other Total GBP USD Other Total £m £m £m £m £m £m £m £m Total notional value of hedging instruments: – Cash flow hedges — 2,586 — 2,586 15,198 5,119 — 20,317 – Fair value hedges — 160 — 160 32,223 1,077 778 34,078 — 2,746 — 2,746 47,421 6,196 778 54,395 Maturing after cessation date (1) – Cash flow hedges — 2,586 — 2,586 10,553 2,562 — 13,115 – Fair value hedges — 160 — 160 12,477 162 720 13,359 — 2,746 — 2,746 23,030 2,724 720 26,474

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2021
Discontinued Operations and Assets and Liabilities Held for Sale [Abstract]
Disclosure of financial performance relating to discontinued operations	31 December 2021, the Corporate & Investment Banking business met the requirements for presentation as discontinued operations. The financial performance and cash flow information relating to the discontinued operations were as follows: 2021 2020 2019 £m £m £m Net interest income 33 55 68 Net fee and commission income 34 65 62 Other operating income 2 2 8 Total operating income 69 122 138 Operating expenses before credit impairment losses, provisions and charges (32) (62) (60) Credit impairment losses 11 (6) (22) Provisions for other liabilities and charges (4) (10) (15) Total operating credit impairment losses, provisions and charges 7 (16) (37) Profit from discontinued operations before tax 44 44 41 Tax on profit from discontinued operations (12) (13) (11) Profit from discontinued operations after tax 32 31 30

Other Financial Assets at Fai_4

Other Financial Assets at Fair Value Through Profit or Loss - Parent (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Financial Assets Designated As Measured At Fair Value Through Profit Or Loss [Line Items]
Summary of Other Financial Assets at Fair Value Through Profit or Loss	Group 2021 2020 £m £m Loans and advances to customers: Loans to housing associations 12 13 Other loans 502 579 514 592 Debt securities 112 112 Equity securities 50 130 676 834
Santander UK Group Holdings plc
Disclosure Of Financial Assets Designated As Measured At Fair Value Through Profit Or Loss [Line Items]
Summary of Other Financial Assets at Fair Value Through Profit or Loss	2021 2020 £m £m Debt securities 4,190 1,425 4,190 1,425

Interests in Other Entities -_2

Interests in Other Entities - Parent (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of subsidiaries [line items]
Disclosure of Key Assumptions in VIU Calculation	Key assumptions in the VIU calculation Carrying value of investment Discount rate Growth rate beyond initial cash flow projections 2021 2020 2021 2020 2021 2020 Investment £m £m % % % % Santander UK plc 11,267 11,267 13.6 14.0 1.6 1.6 Santander Financial Services plc 337 337 15.6 13.7 1.6 1.6 Other 31 26 11,635 11,630
Santander UK Group Holdings plc
Disclosure of subsidiaries [line items]
Disclosure of Interests in Subsidiaries	2021 2020 £m £m Interests in ordinary shares of subsidiaries 11,635 11,630 £500m Fixed Rate Reset Perpetual AT1 Capital Securities 495 495 £750m Fixed Rate Reset Perpetual AT1 Capital Securities 750 750 £500m Fixed Rate Reset Perpetual AT1 Capital Securities 210 210 £500m Fixed Rate Reset Perpetual AT1 Capital Securities 500 500 13,590 13,585 The Company’s interests in subsidiaries was as follows: Cost Impairment Net book value £m £m £m At 31 December 2021 11,645 (10) 11,635 At 31 December 2020 11,645 (15) 11,630
Disclosure of Key Assumptions in Calculating VIU for Investments	Impairment 2021 2020 Subsidiary Reasonably possible change £m £m Santander UK plc Cash flow projections decrease by 5% (2020: 5%) — 109 Discount rate increases by 100 basis points (2020: 100 basis points) 381 637 GDP growth rate decreases by 10 basis points (2020: 10 basis points) — — Impairment 2021 2020 Subsidiary Reasonably possible change £m £m Santander Financial Services plc Cash flow projections decrease by 5% (2020: 5%) — — Discount rate increases by 100 basis points (2020: 100 basis points) — 5
Disclosure of Sensitivity of VIU Changes to Current Assumptions to Achieve Nil Headroom	2021 Carrying value Value in use Headroom Increase in post tax discount rate Decrease in cash flows Subsidiary £m £m £m bps % Santander UK plc 11,267 12,147 880 67 7 2020 Santander UK plc 11,267 11,745 478 40 4 2021 Carrying value Value in use Headroom Increase in post tax discount rate Decrease in cash flows Subsidiary £m £m £m bps % Santander Financial Services plc 337 376 39 145 10 2020 Santander Financial Services plc 337 363 26 82 7

Other Financial Liabilities a_4

Other Financial Liabilities at Fair Value Through Profit or Loss - Parent (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Summary of Other Financial Liabilities at Fair Value Through Profit or Loss	Group 2021 2020 £m £m US$30bn Euro Medium Term Note Programme 5 102 Structured Notes Programmes 413 805 Eurobonds 142 150 Structured deposits 223 375 Collateral and associated financial guarantees 20 2 803 1,434
Santander UK Group Holdings plc
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Summary of Other Financial Liabilities at Fair Value Through Profit or Loss	2021 2020 £m £m Medium-term notes 4,190 1,425 4,190 1,425

Debt Securities in Issue - Pa_2

Debt Securities in Issue - Parent (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Securities In Issue [Line Items]
Summary of Debt Securities in Issue	Group 2021 2020 £m £m Medium-term notes: – US$30bn Euro Medium Term Note Programme 1,405 1,694 – Euro 30bn Euro Medium Term Note Programme (1) 4,304 4,292 – US SEC-registered Debt Programme – Santander UK Group Holdings plc (2) 5,978 5,616 – US SEC-registered Debt Programme – Santander UK plc 1,224 4,723 12,911 16,325 Euro 35bn Global Covered Bond Programme (See Note 14) 12,760 19,285 US$20bn Commercial Paper Programmes 2,704 2,824 Certificates of deposit 2,387 2,858 Credit linked notes 59 57 Securitisation programmes (See Note 14) 759 2,330 31,580 43,679 (1) Restated for 2020 to reclassify £673m previously disclosed as Euro 750m Senior Unsecured Notes to Euro 30bn Euro Medium Term Note Programme due to an administrative error.
Santander UK Group Holdings plc
Debt Securities In Issue [Line Items]
Summary of Debt Securities in Issue	The Company issues notes in the US from time to time pursuant to a shelf registration statement on Form F-3 filed with the SEC in 2021. 2021 2020 £m £m Medium-term notes: – Euro 30bn Euro Medium Term Note Programme 3,028 3,161 – US SEC-registered Debt Programme – Santander UK Group Holdings plc 2,985 4,809 6,013 7,970

Subordinated Liabilities - Pa_2

Subordinated Liabilities - Parent (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Subordinated Liabilities [Line Items]
Schedule of Subordinated Liabilities	Group 2021 2020 £m £m £325m Sterling preference shares 344 344 Undated subordinated liabilities 240 557 Dated subordinated liabilities 1,644 1,655 2,228 2,556
Santander UK Group Holdings plc
Disclosure Of Subordinated Liabilities [Line Items]
Schedule of Subordinated Liabilities	2021 2020 Dated subordinated liabilities Maturity £m £m 4.75% Subordinated notes (US$1,000m) 2025 541 536 5.625% Subordinated notes (US$500m) 2045 297 294 838 830

Notes to Cash Flows - Parent (T

Notes to Cash Flows - Parent (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Summary of Changes in Liabilities Arising from Financing Activities	The table below shows the changes in liabilities arising from financing activities. The changes in equity arising from financing activities are set out in the Consolidated Statement of Changes in Equity. Group 2021 2020 Balance sheet line item Balance sheet line item Debt securities in issue Subordinated liabilities Other equity instruments Lease liabilities Dividends paid Total Debt securities in issue Subordinated liabilities Other equity instruments Lease liabilities Dividends paid Total (1) £m £m £m £m £m £m £m £m £m £m £m £m At 1 January 43,679 2,556 2,241 100 — 48,576 50,171 3,528 2,241 138 — 56,078 Proceeds from issue of debt securities 2,847 — — — — 2,847 5,586 — — — — 5,586 Repayment of debt securities (13,724) — — — — (13,724) (12,348) — — — — (12,348) Repayment of subordinated liabilities — (4) — — — (4) — (939) — — — (939) Issue of other equity instruments — — 450 — — 450 — — — — — — Repurchase of other equity instruments — — (500) — — (500) — — — — — — Payment of lease liability — — — (25) — (25) — — — (46) — (46) Dividends paid — — — — (1,506) (1,506) — — — — (282) (282) Liability-related other changes (473) (4) — 59 — (418) (243) (10) — 8 — (245) Non-cash changes: — — – Unrealised foreign exchange (930) 14 — — — (916) 359 (6) — — — 353 – Other changes 181 (334) — — 1,506 1,353 154 (17) — — 282 419 At 31 December 31,580 2,228 2,191 134 — 36,133 43,679 2,556 2,241 100 — 48,576 (1) Restated for 2020 to include changes in liabilities arising from financing activities relating to lease liabilities.
Santander UK Group Holdings plc
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Summary of Changes in Liabilities Arising from Financing Activities	In addition to the changes in equity arising from financing activities, as set out in the Company Statement of Changes in Equity, the table below shows the changes in liabilities arising from financing activities. 2021 2020 Balance sheet line item Balance sheet line item Debt securities in issue Subordinated liabilities Other equity instruments Dividends paid Total Debt securities in issue Subordinated liabilities Other equity instruments Dividends paid Total £m £m £m £m £m £m £m £m £m £m At 1 January 9,379 830 2,241 — 12,450 8,957 1,142 2,241 — 12,340 Proceeds from issue of debt securities 2,788 — — — 2,788 1,409 — — — 1,409 Repayment of debt securities (1,814) — — — (1,814) (969) — — — (969) Repayment of subordinated liabilities — — — — — — (281) — — (281) Issue of other equity instruments — — 450 — 450 — — — — — Repurchase of other equity instruments — — (500) — (500) — — — — — Dividends paid — — — (1,489) (1,489) — — — (250) (250) Liability-related other changes (28) — — — (28) (3) — — — (3) Non-cash changes: – Unrealised foreign exchange (124) 8 — — (116) (17) (28) — — (45) – Other changes 9 — — 1,489 1,498 2 (3) — 250 249 At 31 December 10,210 838 2,191 — 13,239 9,379 830 2,241 — 12,450

Credit Risk - Disclosure of Exp

Credit Risk - Disclosure of Exposures to Credit Risk by Segment (Details) - Maximum £ in Millions	12 Months Ended
	Dec. 31, 2021GBP (£)
Everyday Banking
Disclosure of credit risk exposure [line items]
Customers, annual turnover	£ 6.5
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Customers, annual turnover	£ 500

Credit Risk - Disclosure of Key

Credit Risk - Disclosure of Key Metrics to Measure and Control Credit Risk (Details) - Credit risk	12 Months Ended
	Dec. 31, 2021
Expected Credit Loss (ECL)
Disclosure of credit risk exposure [line items]
Metric	Expected Credit Loss (ECL)
Description	ECL tells us what credit risk is likely to cost us either over the next 12 months on qualifying exposures, or defaults over the lifetime of the exposure where there is evidence of a SICR since origination. We explain how we calculate ECL below.
Stages 1, 2 and 3
Disclosure of credit risk exposure [line items]
Metric	Stages 1, 2 and 3
Description	We assess each facility’s credit risk profile to determine which stage to allocate them to, and we monitor where there is a SICR and transfers between the Stages including monitoring of coverage ratios for each stage. We explain how we allocate a facility to Stage 1, 2 or 3 below.
Stage 3 ratio
Disclosure of credit risk exposure [line items]
Metric	Stage 3 ratio
Description	The Stage 3 ratio is the sum of Stage 3 drawn and Stage 3 undrawn assets divided by the sum of total drawn assets and Stage 3 undrawn assets. The Stage 3 ratio is the main indicator of credit quality performance.
Expected Loss (EL)
Disclosure of credit risk exposure [line items]
Metric	Expected Loss (EL)
Description	EL is based on the regulatory capital rules of CRD IV and gives us another view of credit risk. It is the product of the probability of default, exposure at default and loss given default. We calculate each factor in accordance with CRD IV and include direct and indirect costs. We base them on our risk models and our assessment of each customer’s credit quality. There are differences between regulatory EL and IFRS 9 ECL, which we set out below. The rest of our Risk review, impairments, losses and loss allowances refer to calculations in accordance with IFRS, unless we specifically say they relate to CRD IV. For our IFRS accounting policy on impairment, see Note 1 to the Consolidated Financial Statements.

Credit Risk - Disclosure of K_2

Credit Risk - Disclosure of Key Differences between Regulatory EL and IFRS 9 ECL Models (Details) - Credit risk	12 Months Ended
	Dec. 31, 2021
Rating philosophy
Disclosure of credit risk exposure [line items]
Metric	Rating philosophy
Rating philosophy | Basel advanced IRB EL
Disclosure of credit risk exposure [line items]
Description	Mix of point-in-time, through-the-cycle or hybrid
Rating philosophy | IFRS 9 ECL
Disclosure of credit risk exposure [line items]
Description	Point-in-time, forward-looking. Considers a range of economic scenarios
Parameters calibration
Disclosure of credit risk exposure [line items]
Metric	Parameters calibration
Parameters calibration | Basel advanced IRB EL
Disclosure of credit risk exposure [line items]
Description	Contains regulatory floors and downturn calibration
Parameters calibration | IFRS 9 ECL
Disclosure of credit risk exposure [line items]
Description	Unbiased estimate, based on conditions known at the balance sheet date
Calculation timing
Disclosure of credit risk exposure [line items]
Metric	Calculation timing
Calculation timing | Basel advanced IRB EL
Disclosure of credit risk exposure [line items]
Description	Considers aggregation of possible default events in the next 12 months
Calculation timing | IFRS 9 ECL
Disclosure of credit risk exposure [line items]
Description	Considers monthly calculation of parameters, for all possible future default dates. First 12 months are used for Stage 1, full lifetime for Stages 2 and 3
Probability of Default (PD)
Disclosure of credit risk exposure [line items]
Metric	Probability of Default (PD)
Description	The likelihood of a borrower defaulting in the following month, assuming it has not closed or defaulted since the reporting date. For each month in the forecast period, we estimate the monthly PD from a range of factors. These include the current risk grade for the exposure, which becomes less relevant further into the forecast period, as well as the expected evolution of the account risk with maturity and factors for changing economics. We support this with historical data analysis.
Probability of Default (PD) | Basel advanced IRB EL
Disclosure of credit risk exposure [line items]
Description	PD in the next 12 months
Probability of Default (PD) | IFRS 9 ECL
Disclosure of credit risk exposure [line items]
Description	Includes forward-looking economic data and removes conservatism. PD in next 12 months for Stage 1, lifetime for Stages 2 and 3
Loss Given Default (LGD)
Disclosure of credit risk exposure [line items]
Metric	Loss Given Default (LGD)
Description	Our expected loss if a default event were to occur. We express it as a percentage and calculate it based on factors that we have observed to affect the likelihood and/or value of any subsequent write-offs, which vary according to whether the product is secured or unsecured. If the product is secured, we take into account collateral values as well as the historical discounts to market/book values due to forced sales type.
Loss Given Default (LGD) | Basel advanced IRB EL
Disclosure of credit risk exposure [line items]
Description	Lifetime LGD for defaults in the next 12 months
Loss Given Default (LGD) | IFRS 9 ECL
Disclosure of credit risk exposure [line items]
Description	Modelled without regulatory floors and exclusion of indirect costs
Exposure at default (EAD)
Disclosure of credit risk exposure [line items]
Metric	Exposure at Default (EAD)
Description	The amount we expect to be owed if a default event was to occur. We determine EAD for each month of the forecast period by the expected payment profile, which varies by product type. For amortising products, we base it on the borrower’s contractual repayments over the forecast period. We adjust this for any expected overpayments on Stage 1 accounts that the borrower may make and for any arrears we expect if the account was to default. For revolving products, or amortising products with an off-balance sheet element, we determine EAD using the balance at default and the contractual exposure limit. We vary these assumptions by product type and base them on analysis of recent default data.
Exposure at default (EAD) | Basel advanced IRB EL
Disclosure of credit risk exposure [line items]
Description	Exposure at the point of default if the customer defaults in the next 12 months
Exposure at default (EAD) | IFRS 9 ECL
Disclosure of credit risk exposure [line items]
Description	Floored at amount owed, except on some revolving facilities. Recognises ability for exposure to reduce from the balance sheet date to default date
SICR
Disclosure of credit risk exposure [line items]
Metric	SICR
SICR | Basel advanced IRB EL
Disclosure of credit risk exposure [line items]
Description	Does not include SICR concept
SICR | IFRS 9 ECL
Disclosure of credit risk exposure [line items]
Description	Includes SICR concept
Discounting applied
Disclosure of credit risk exposure [line items]
Metric	Discounting applied
Discounting applied | Basel advanced IRB EL
Disclosure of credit risk exposure [line items]
Description	At the weighted average cost of capital to the default date
Discounting applied | IFRS 9 ECL
Disclosure of credit risk exposure [line items]
Description	At the effective interest rate (EIR) to the balance sheet date

Credit Risk - Schedule of Macro

Credit Risk - Schedule of Macroeconomic Assumptions for Each Five Scenarios (Details)	Dec. 31, 2021	Dec. 31, 2020
Upside 1
Disclosure of credit risk exposure [line items]
GDP growth, 2020	(9.70%)	(10.50%)
GDP growth, 2021	7.00%	4.80%
GDP growth, 2022	4.80%	4.90%
GDP growth, 2023	2.20%	3.00%
GDP growth, 2024	1.90%	2.00%
GDP growth, 2025	2.10%
Bank of England base rate, 2020	0.10%	0.10%
Bank of England base rate, 2021	0.25%	0.25%
Bank of England base rate, 2022	0.75%	0.75%
Bank of England base rate, 2023	0.75%	1.25%
Bank of England base rate, 2024	1.25%	1.75%
Bank of England base rate, 2025	1.75%
House price growth, 2020	6.90%	3.70%
House price growth, 2021	5.40%	(4.60%)
House price growth, 2022	(0.80%)	(4.10%)
House price growth, 2023	(2.00%)	2.40%
House price growth, 2024	1.00%	5.50%
House price growth, 2025	3.80%
Unemployment rate, 2020	5.20%	6.30%
Unemployment rate, 2021	4.40%	6.10%
Unemployment rate, 2022	4.40%	5.30%
Unemployment rate, 2023	4.20%	4.40%
Unemployment rate, 2024	3.90%	4.10%
Unemployment rate, 2025	3.70%
Base case
Disclosure of credit risk exposure [line items]
GDP growth, 2020	(9.70%)	(11.50%)
GDP growth, 2021	6.90%	4.50%
GDP growth, 2022	4.60%	6.10%
GDP growth, 2023	1.70%	2.20%
GDP growth, 2024	1.50%	1.50%
GDP growth, 2025	1.60%
Bank of England base rate, 2020	0.10%	0.10%
Bank of England base rate, 2021	0.25%	0.10%
Bank of England base rate, 2022	0.75%	0.10%
Bank of England base rate, 2023	0.75%	0.10%
Bank of England base rate, 2024	0.75%	0.25%
Bank of England base rate, 2025	0.75%
House price growth, 2020	6.90%	3.50%
House price growth, 2021	5.00%	(2.00%)
House price growth, 2022	2.00%	1.50%
House price growth, 2023	2.00%	2.00%
House price growth, 2024	2.00%	2.00%
House price growth, 2025	2.00%
Unemployment rate, 2020	5.20%	6.80%
Unemployment rate, 2021	4.70%	7.50%
Unemployment rate, 2022	4.50%	6.20%
Unemployment rate, 2023	4.40%	5.60%
Unemployment rate, 2024	4.30%	5.50%
Unemployment rate, 2025	4.30%
Downside 1
Disclosure of credit risk exposure [line items]
GDP growth, 2020	(9.70%)	(10.50%)
GDP growth, 2021	6.80%	4.00%
GDP growth, 2022	4.10%	3.60%
GDP growth, 2023	0.90%	1.50%
GDP growth, 2024	0.50%	0.40%
GDP growth, 2025	0.50%
Bank of England base rate, 2020	0.10%	0.10%
Bank of England base rate, 2021	0.25%	0.10%
Bank of England base rate, 2022	0.75%	0.10%
Bank of England base rate, 2023	0.75%	0.10%
Bank of England base rate, 2024	1.00%	0.25%
Bank of England base rate, 2025	1.00%
House price growth, 2020	6.90%	3.70%
House price growth, 2021	5.40%	(5.40%)
House price growth, 2022	(1.80%)	(6.60%)
House price growth, 2023	(4.60%)	(1.80%)
House price growth, 2024	(3.10%)	0.50%
House price growth, 2025	(0.70%)
Unemployment rate, 2020	5.20%	6.30%
Unemployment rate, 2021	4.40%	6.50%
Unemployment rate, 2022	4.80%	6.10%
Unemployment rate, 2023	5.00%	5.70%
Unemployment rate, 2024	5.10%	5.80%
Unemployment rate, 2025	5.40%
Downside 2
Disclosure of credit risk exposure [line items]
GDP growth, 2020	(9.70%)	(11.10%)
GDP growth, 2021	6.20%	(0.80%)
GDP growth, 2022	(0.70%)	3.20%
GDP growth, 2023	0.50%	2.70%
GDP growth, 2024	1.60%	1.50%
GDP growth, 2025	1.70%
Bank of England base rate, 2020	0.10%	0.10%
Bank of England base rate, 2021	0.25%	0.75%
Bank of England base rate, 2022	1.00%	1.75%
Bank of England base rate, 2023	2.00%	3.00%
Bank of England base rate, 2024	3.00%	2.75%
Bank of England base rate, 2025	2.75%
House price growth, 2020	6.90%	3.70%
House price growth, 2021	5.40%	(11.30%)
House price growth, 2022	(8.30%)	(14.50%)
House price growth, 2023	(13.10%)	(3.80%)
House price growth, 2024	(4.80%)	4.90%
House price growth, 2025	4.30%
Unemployment rate, 2020	5.20%	6.30%
Unemployment rate, 2021	4.40%	8.50%
Unemployment rate, 2022	6.90%	7.90%
Unemployment rate, 2023	6.90%	6.90%
Unemployment rate, 2024	6.40%	6.50%
Unemployment rate, 2025	6.10%
Downside 3
Disclosure of credit risk exposure [line items]
GDP growth, 2020	(9.70%)	(11.50%)
GDP growth, 2021	5.60%	(8.00%)
GDP growth, 2022	(7.50%)	3.10%
GDP growth, 2023	3.10%	1.50%
GDP growth, 2024	1.50%	1.50%
GDP growth, 2025	1.50%
Bank of England base rate, 2020	0.10%	0.10%
Bank of England base rate, 2021	0.25%	(0.50%)
Bank of England base rate, 2022	(0.50%)	0.00%
Bank of England base rate, 2023	0.00%	0.00%
Bank of England base rate, 2024	0.00%	0.00%
Bank of England base rate, 2025	0.00%
House price growth, 2020	6.90%	3.50%
House price growth, 2021	(2.50%)	(19.70%)
House price growth, 2022	(19.60%)	(8.20%)
House price growth, 2023	(9.30%)	1.30%
House price growth, 2024	2.40%	3.10%
House price growth, 2025	3.30%
Unemployment rate, 2020	5.20%	6.80%
Unemployment rate, 2021	6.80%	11.40%
Unemployment rate, 2022	11.40%	8.70%
Unemployment rate, 2023	8.70%	8.00%
Unemployment rate, 2024	8.00%	7.40%
Unemployment rate, 2025	7.40%

Credit Risk - Schedule of Mac_2

Credit Risk - Schedule of Macroeconomic Asumptions and the Evolution Throughout the Forecast Period (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Upside 1
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease	1.30%	0.49%
House price growth, Peak/(trough) at	(3.07%)	2.45%
GDP, 5-year average increase/decrease	2.33%	0.75%
GDP, Cumulative growth/(fall) to peak/(trough)	12.19%	3.82%
Unemployment rate, 5-year end period	3.60%	4.14%
Unemployment rate, Peak/(trough) at	4.45%	6.28%
Bank of England bank rate, 5-year end period	2.00%	1.75%
Bank of England bank rate, Peak/(trough) at	2.00%	1.75%
Base case
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease	2.00%	1.38%
House price growth, Peak/(trough) at	0.00%	7.11%
GDP, 5-year average increase/decrease	1.89%	0.39%
GDP, Cumulative growth/(fall) to peak/(trough)	9.83%	1.96%
Unemployment rate, 5-year end period	4.30%	5.50%
Unemployment rate, Peak/(trough) at	4.70%	7.90%
Bank of England bank rate, 5-year end period	0.75%	0.25%
Bank of England bank rate, Peak/(trough) at	0.75%	0.25%
Downside 1
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease	(1.78%)	(2.01%)
House price growth, Peak/(trough) at	(9.87%)	(9.65%)
GDP, 5-year average increase/decrease	0.93%	(0.38%)
GDP, Cumulative growth/(fall) to peak/(trough)	4.75%	(1.88%)
Unemployment rate, 5-year end period	5.65%	5.84%
Unemployment rate, Peak/(trough) at	5.65%	6.51%
Bank of England bank rate, 5-year end period	1.00%	0.25%
Bank of England bank rate, Peak/(trough) at	1.00%	0.25%
Downside 2
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease	(3.27%)	(4.54%)
House price growth, Peak/(trough) at	(24.03%)	(20.72%)
GDP, 5-year average increase/decrease	0.49%	(0.98%)
GDP, Cumulative growth/(fall) to peak/(trough)	2.48%	(4.80%)
Unemployment rate, 5-year end period	5.95%	6.52%
Unemployment rate, Peak/(trough) at	7.27%	8.78%
Bank of England bank rate, 5-year end period	2.25%	2.75%
Bank of England bank rate, Peak/(trough) at	3.00%	3.00%
Downside 3
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease	(6.00%)	(4.44%)
House price growth, Peak/(trough) at	(32.12%)	(20.32%)
GDP, 5-year average increase/decrease	(0.58%)	(2.82%)
GDP, Cumulative growth/(fall) to peak/(trough)	(2.85%)	(13.33%)
Unemployment rate, 5-year end period	6.80%	7.40%
Unemployment rate, Peak/(trough) at	11.90%	11.90%
Bank of England bank rate, 5-year end period	0.25%	0.00%
Bank of England bank rate, Peak/(trough) at	(0.50%)	(0.50%)

Credit Risk - Disclosure of Sce

Credit Risk - Disclosure of Scenario Weights Applied To Scenarios (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Upside 1
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	5.00%	5.00%
Base case
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	45.00%	45.00%
Downside 1
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	25.00%	15.00%
Downside 2
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	20.00%	25.00%
Downside 3
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	5.00%	10.00%

Credit Risk - Schedule of Mac_3

Credit Risk - Schedule of Macroeconomic Asumptions and the Evolution Throughout the Forecast Period, CIB Portfolio (Details)	12 Months Ended
	Dec. 31, 2020
CIB Business | Long Run Global Growth Scenario
Disclosure of credit risk exposure [line items]
GDP, Long Run global growth scenario	1.30%

Credit Risk - Disclosure of Qua

Credit Risk - Disclosure of Quantitative Criteria of Credit Risk Exposure (Details) - Probability of Default (PD)	12 Months Ended
	Dec. 31, 2021
Homes
Disclosure of credit risk exposure [line items]
PD threshold for measuring significant increase in credit risk	0.30%
Consumer Finance
Disclosure of credit risk exposure [line items]
PD threshold for measuring significant increase in credit risk	3.00%
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
PD threshold for measuring significant increase in credit risk	0.30%
Personal loans | Everyday Banking
Disclosure of credit risk exposure [line items]
PD threshold for measuring significant increase in credit risk	0.30%
Credit cards | Everyday Banking
Disclosure of credit risk exposure [line items]
PD threshold for measuring significant increase in credit risk	3.40%
Overdrafts | Everyday Banking
Disclosure of credit risk exposure [line items]
PD threshold for measuring significant increase in credit risk	2.60%

Credit Risk - Disclosure of Q_2

Credit Risk - Disclosure of Qualitative Criteria of Credit Risk Exposure (Details)	12 Months Ended
	Dec. 31, 2021
Homes
Disclosure of credit risk exposure [line items]
Qualitative criteria for measuring SICR	- In forbearance- Default in last 24m- 30 Days past due (DPD) in last 12m- Bankrupt- £100+ arrears
Consumer Finance
Disclosure of credit risk exposure [line items]
Qualitative criteria for measuring SICR	- In forbearance- Deceased or Insolvent- Court ‘Return of goods’ order or Police watchlist- Agreement terminated- Payment holiday- Cash Collection
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Qualitative criteria for measuring SICR	- In forbearance- Default in last 12m- Watchlist: proactive management- Default at proxy origination
Corporate Centre
Disclosure of credit risk exposure [line items]
Qualitative criteria for measuring SICR	- Watchlist: proactive management
Personal loans | Everyday Banking
Disclosure of credit risk exposure [line items]
Qualitative criteria for measuring SICR	- In Collections- Default in last 12m- £50+ arrears
Credit cards | Everyday Banking
Disclosure of credit risk exposure [line items]
Qualitative criteria for measuring SICR	- In forbearance- Default in last 12m- In Collections- £100+ arrears- Behaviour score indicators
Overdrafts | Everyday Banking
Disclosure of credit risk exposure [line items]
Qualitative criteria for measuring SICR	- Fees suspended- Default in last 12m- Debit dormant >35 days- Any excess in month

Credit Risk - Disclosure of ECL

Credit Risk - Disclosure of ECL by Segment (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Modelled ECL	£ 424	£ 803
Individually assessed	101	160
PMAs	341	414
Total ECL	866	1,377
Retail Banking
Disclosure of credit risk exposure [line items]
Modelled ECL	265	472
Individually assessed	1	3
PMAs	123	113
Total ECL	389	588
Homes
Disclosure of credit risk exposure [line items]
Modelled ECL	119	220
Individually assessed	1	3
PMAs	71	57
Total ECL	191	280
Everyday Banking
Disclosure of credit risk exposure [line items]
Modelled ECL	146	252
Individually assessed	0	0
PMAs	52	56
Total ECL	198	308
Consumer Finance
Disclosure of credit risk exposure [line items]
Modelled ECL	51	110
Individually assessed	0	0
PMAs	1	8
Total ECL	52	118
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Modelled ECL	106	195
Individually assessed	100	157
PMAs	217	251
Total ECL	423	603
Corporate Centre
Disclosure of credit risk exposure [line items]
Modelled ECL	2	0
Individually assessed	0	0
PMAs	0	35
Total ECL	£ 2	35
Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Modelled ECL		26
Individually assessed		0
PMAs		7
Total ECL		£ 33

Credit Risk - Disclosure of Mos

Credit Risk - Disclosure of Most Significant Post Model Adjustments Applied (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
PMAs	£ 341	£ 414
Non Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	105	124
Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	236	290
Long-term indeterminate arrears | Non Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	14	29
12+ months in arrears | Non Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	29	34
Cladding risk | Non Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	15	0
Mortgages affordability | Non Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	18	0
UPL loss floor | Non Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	21	31
Other PMA | Non Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	8	30
Other PMA | Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	0	15
Corporate lending to segments affected by Covid-19 | Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	176	193
Payment holidays | Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	0	27
Corporate single large exposure | Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	23	35
Model underestimation | Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs		20
SME debt burden | Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	£ 9	£ 0

Credit Risk - Group Level Credi

Credit Risk - Group Level Credit Risk Management, Additional Information (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
PMAs	£ 341	£ 414
Individually assessed	101	160
Stage 3 ECL
Disclosure of credit risk exposure [line items]
Individually assessed	100	157
Minimum | Stage 3 ECL
Disclosure of credit risk exposure [line items]
ECL under reasonably possible judgements	38
Maximum | Stage 3 ECL
Disclosure of credit risk exposure [line items]
ECL under reasonably possible judgements	155
Non Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	105	124
Non Covid-19 PMAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
PMAs	14	29
Non Covid-19 PMAs | Long-term indeterminate arrears | No delay in repossession
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	11
Non Covid-19 PMAs | Long-term indeterminate arrears | Three-year repossession delay
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	15
Non Covid-19 PMAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
PMAs	29	34
Non Covid-19 PMAs | 12+ months in arrears | No delay in repossession
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	21
Non Covid-19 PMAs | 12+ months in arrears | Three-year repossession delay
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	32
Non Covid-19 PMAs | Cladding risk
Disclosure of credit risk exposure [line items]
PMAs	£ 15	0
Decrease in valuation of high risk flats, percent	20.00%
Decrease in valuation of medium risk flats, percent	10.00%
Non Covid-19 PMAs | Mortgages affordability
Disclosure of credit risk exposure [line items]
PMAs	£ 18	0
Mortgages moved from stage 1 to stage 2	4,200
Non Covid-19 PMAs | Mortgages affordability | Different sensitivities to PD uplifts | Minimum
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	14
Non Covid-19 PMAs | Mortgages affordability | Different sensitivities to PD uplifts | Maximum
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	27
Non Covid-19 PMAs | UPL loss floor
Disclosure of credit risk exposure [line items]
PMAs	21	31
Non Covid-19 PMAs | UPL loss floor | Increased PD stress factor
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	16
Covid-19 PMAs
Disclosure of credit risk exposure [line items]
PMAs	236	290
Covid-19 PMAs | Corporate lending to segments affected by Covid-19
Disclosure of credit risk exposure [line items]
PMAs	176	193
Covid-19 PMAs | Corporate lending to segments affected by Covid-19 | Lowest observed PD stress factor
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	23
Covid-19 PMAs | Corporate lending to segments affected by Covid-19 | Highest observed PD stress factor
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	287
Covid-19 PMAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
PMAs	23	35
Covid-19 PMAs | Corporate single large exposure | One average losses
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	12
Covid-19 PMAs | Corporate single large exposure | Three average losses
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	35
Covid-19 PMAs | Model underestimation
Disclosure of credit risk exposure [line items]
PMAs		20
Covid-19 PMAs | Model underestimation | Full lifetime losses
Disclosure of credit risk exposure [line items]
PMAs	28
Covid-19 PMAs | Model underestimation | Corrected model underestimation
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	12
Covid-19 PMAs | Model underestimation | Model uplift estimation
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	29
Covid-19 PMAs | SME debt burden
Disclosure of credit risk exposure [line items]
PMAs	9	£ 0
Covid-19 PMAs | SME debt burden | Full lifetime losses
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	3
Covid-19 PMAs | SME debt burden | 50% coverage on all accounts
Disclosure of credit risk exposure [line items]
Post model adjustments under reasonably possible judgements	£ 15

Credit Risk - Disclosure of Bas

Credit Risk - Disclosure of Base Expected Credit Losses to Probability Weighted Estimated Credit Losses (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Exposure	£ 213,525	£ 212,178
Homes
Disclosure of credit risk exposure [line items]
Exposure	177,297	169,801
Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	8,311	8,650
Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	4,984	8,024
Weighted
Disclosure of credit risk exposure [line items]
Exposure	319,319	328,792
ECL	£ 866	£ 1,377
Proportion of assets in Stage 2	5.20%	5.20%
Weighted | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 214,979	£ 205,062
ECL	£ 389	£ 588
Proportion of assets in Stage 2 - of which: mortgages	5.40%	5.40%
Weighted | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 193,247	£ 183,077
ECL - of which: mortgages	£ 191	£ 280
Proportion of assets in Stage 2 - of which: mortgages	5.80%	5.70%
Weighted | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 21,732	£ 21,985
ECL	£ 198	£ 308
Proportion of assets in Stage 2	2.60%	2.80%
Weighted | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,298	£ 8,261
ECL	£ 52	£ 118
Proportion of assets in Stage 2	3.80%	4.60%
Weighted | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 24,691	£ 24,503
ECL	£ 423	£ 603
Proportion of assets in Stage 2	17.80%	22.40%
Weighted | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 74,351	£ 79,320
ECL	£ 2	£ 35
Proportion of assets in Stage 2	0.30%	0.00%
Weighted | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure		£ 11,646
ECL		£ 33
Proportion of assets in Stage 2		1.70%
Upside 1
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
ECL	£ 740	£ 1,130
Proportion of assets in Stage 2	4.90%	4.50%
Upside 1 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 214,979	£ 205,062
ECL	£ 307	£ 496
Proportion of assets in Stage 2 - of which: mortgages	5.20%	4.60%
Upside 1 | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 193,247	£ 183,077
ECL - of which: mortgages	£ 134	£ 213
Proportion of assets in Stage 2 - of which: mortgages	5.50%	4.80%
Upside 1 | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 21,732	£ 21,985
ECL	£ 173	£ 283
Proportion of assets in Stage 2	2.30%	2.60%
Upside 1 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,298	£ 8,261
ECL	£ 50	£ 115
Proportion of assets in Stage 2	3.80%	4.60%
Upside 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 24,691	£ 24,503
ECL	£ 381	£ 485
Proportion of assets in Stage 2	16.30%	20.10%
Upside 1 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 74,351	£ 79,320
ECL	£ 2	£ 29
Proportion of assets in Stage 2	0.30%	0.00%
Upside 1 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure		£ 11,646
ECL		£ 5
Proportion of assets in Stage 2		1.70%
Base case
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
ECL	£ 738	£ 1,222
Proportion of assets in Stage 2	4.80%	4.60%
Base case | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 214,979	£ 205,062
ECL	£ 286	£ 470
Proportion of assets in Stage 2 - of which: mortgages	5.10%	4.50%
Base case | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 193,247	£ 183,077
ECL - of which: mortgages	£ 125	£ 207
Proportion of assets in Stage 2 - of which: mortgages	5.50%	4.80%
Base case | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 21,732	£ 21,985
ECL	£ 161	£ 263
Proportion of assets in Stage 2	2.10%	2.30%
Base case | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,298	£ 8,261
ECL	£ 51	£ 117
Proportion of assets in Stage 2	3.80%	4.60%
Base case | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 24,691	£ 24,503
ECL	£ 399	£ 575
Proportion of assets in Stage 2	16.20%	20.80%
Base case | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 74,351	£ 79,320
ECL	£ 2	£ 34
Proportion of assets in Stage 2	0.30%	0.00%
Base case | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure		£ 11,646
ECL		£ 26
Proportion of assets in Stage 2		1.70%
Downside 1
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
ECL	£ 849	£ 1,300
Proportion of assets in Stage 2	5.10%	4.60%
Downside 1 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 214,979	£ 205,062
ECL	£ 375	£ 544
Proportion of assets in Stage 2 - of which: mortgages	5.40%	4.60%
Downside 1 | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 193,247	£ 183,077
ECL - of which: mortgages	£ 177	£ 253
Proportion of assets in Stage 2 - of which: mortgages	5.70%	4.80%
Downside 1 | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 21,732	£ 21,985
ECL	£ 198	£ 291
Proportion of assets in Stage 2	3.00%	2.80%
Downside 1 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,298	£ 8,261
ECL	£ 51	£ 116
Proportion of assets in Stage 2	3.80%	4.60%
Downside 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 24,691	£ 24,503
ECL	£ 421	£ 567
Proportion of assets in Stage 2	16.90%	20.20%
Downside 1 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 74,351	£ 79,320
ECL	£ 2	£ 33
Proportion of assets in Stage 2	0.30%	0.00%
Downside 1 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure		£ 11,646
ECL		£ 40
Proportion of assets in Stage 2		1.70%
Downside 2
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
ECL	£ 1,123	£ 1,613
Proportion of assets in Stage 2	6.10%	6.50%
Downside 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 214,979	£ 205,062
ECL	£ 510	£ 731
Proportion of assets in Stage 2 - of which: mortgages	6.50%	7.20%
Downside 2 | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 193,247	£ 183,077
ECL - of which: mortgages	£ 283	£ 390
Proportion of assets in Stage 2 - of which: mortgages	6.80%	7.60%
Downside 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 21,732	£ 21,985
ECL	£ 227	£ 341
Proportion of assets in Stage 2	3.50%	3.50%
Downside 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,298	£ 8,261
ECL	£ 53	£ 119
Proportion of assets in Stage 2	3.80%	4.60%
Downside 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 24,691	£ 24,503
ECL	£ 558	£ 671
Proportion of assets in Stage 2	20.80%	24.50%
Downside 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 74,351	£ 79,320
ECL	£ 2	£ 39
Proportion of assets in Stage 2	0.30%	0.00%
Downside 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure		£ 11,646
ECL		£ 53
Proportion of assets in Stage 2		1.70%
Downside 3
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
ECL	£ 1,288	£ 1,802
Proportion of assets in Stage 2	6.90%	6.70%
Downside 3 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 214,979	£ 205,062
ECL	£ 662	£ 740
Proportion of assets in Stage 2 - of which: mortgages	7.60%	7.20%
Downside 3 | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 193,247	£ 183,077
ECL - of which: mortgages	£ 437	£ 415
Proportion of assets in Stage 2 - of which: mortgages	8.10%	7.40%
Downside 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 21,732	£ 21,985
ECL	£ 225	£ 325
Proportion of assets in Stage 2	3.00%	5.10%
Downside 3 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,298	£ 8,261
ECL	£ 54	£ 123
Proportion of assets in Stage 2	3.80%	4.80%
Downside 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 24,691	£ 24,503
ECL	£ 570	£ 824
Proportion of assets in Stage 2	20.90%	28.60%
Downside 3 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 74,351	£ 79,320
ECL	£ 2	£ 49
Proportion of assets in Stage 2	0.30%	0.00%
Downside 3 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure		£ 11,646
ECL		£ 66
Proportion of assets in Stage 2		1.70%

Credit Risk - Disclosure of Inc

Credit Risk - Disclosure of Increase (Decrease in Profit Before Tax (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [abstract]
Increase in profit before tax due to 20 percentage increase in HPI rate	£ 64	£ 63
Increase in profit before tax due to 10 percentage increase in HPI rate	40	38
Decrease in profit before tax due to 10 percentage decrease in HPI rate	(69)	(66)
Decrease in profit before tax due to 20 percentage decrease in HPI rate	£ (197)	£ (183)

Credit Risk - Disclosure of Fac

Credit Risk - Disclosure of Factors to Measure ECL (Details) - Credit risk	12 Months Ended
	Dec. 31, 2021
Survival rate (SR)
Disclosure of credit risk exposure [line items]
Factor	Survival rate (SR)
Description	The probability that the exposure has not closed or defaulted since the reporting date.
Probability of Default (PD)
Disclosure of credit risk exposure [line items]
Factor	Probability of default (PD)
Description	The likelihood of a borrower defaulting in the following month, assuming it has not closed or defaulted since the reporting date. For each month in the forecast period, we estimate the monthly PD from a range of factors. These include the current risk grade for the exposure, which becomes less relevant further into the forecast period, as well as the expected evolution of the account risk with maturity and factors for changing economics. We support this with historical data analysis.
Exposure at default (EAD)
Disclosure of credit risk exposure [line items]
Factor	Exposure at default (EAD)
Description	The amount we expect to be owed if a default event was to occur. We determine EAD for each month of the forecast period by the expected payment profile, which varies by product type. For amortising products, we base it on the borrower’s contractual repayments over the forecast period. We adjust this for any expected overpayments on Stage 1 accounts that the borrower may make and for any arrears we expect if the account was to default. For revolving products, or amortising products with an off-balance sheet element, we determine EAD using the balance at default and the contractual exposure limit. We vary these assumptions by product type and base them on analysis of recent default data.
Loss Given Default (LGD)
Disclosure of credit risk exposure [line items]
Factor	Loss given default (LGD)
Description	Our expected loss if a default event were to occur. We express it as a percentage and calculate it based on factors that we have observed to affect the likelihood and/or value of any subsequent write-offs, which vary according to whether the product is secured or unsecured. If the product is secured, we take into account collateral values as well as the historical discounts to market/book values due to forced sales type.

Credit Risk - Disclosure Of Max

Credit Risk - Disclosure Of Maximum And Net Exposure To Credit Risk - IFRS 9 (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Collateral cash	£ (11,634)	£ (17,060)
Netting	(1,017)	(949)
Net exposure	319,319	328,792
Credit risk
Disclosure of credit risk exposure [line items]
Collateral cash	(100)	(200)
Collateral non-cash	(214,900)	(219,000)
Netting	(400)	(100)
Net exposure	106,800	111,300
Credit risk | Cash and balances at central banks
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	50,500	43,500
Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	5,900	9,000
On-balance sheet | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	284,500	287,500
On-balance sheet | Credit risk | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	285,400	288,800
On-balance sheet | Credit risk | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(900)	(1,300)
On-balance sheet | Credit risk | Cash and balances at central banks
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	50,500	43,500
On-balance sheet | Credit risk | Cash and balances at central banks | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	50,500	43,500
On-balance sheet | Credit risk | Cash and balances at central banks | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
On-balance sheet | Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	5,900	9,000
On-balance sheet | Credit risk | Financial assets at FVOCI | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	5,900	9,000
On-balance sheet | Credit risk | Financial assets at FVOCI | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Off-balance sheet | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	37,700	43,100
Off-balance sheet | Credit risk | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	37,700	43,200
Off-balance sheet | Credit risk | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	(100)
Off-balance sheet | Credit risk | Cash and balances at central banks
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Off-balance sheet | Credit risk | Cash and balances at central banks | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Off-balance sheet | Credit risk | Cash and balances at central banks | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Off-balance sheet | Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Off-balance sheet | Credit risk | Financial assets at FVOCI | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Off-balance sheet | Credit risk | Financial assets at FVOCI | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Credit risk
Disclosure of credit risk exposure [line items]
Collateral cash	(100)	(200)
Collateral non-cash	(214,900)	(219,000)
Netting	(400)	(100)
Net exposure	50,400	58,800
Financial assets at amortised cost | Credit risk | Loans and advances to customers
Disclosure of credit risk exposure [line items]
Collateral cash	(100)	(200)
Collateral non-cash	(202,700)	(199,500)
Netting	0	0
Net exposure	48,000	54,600
Financial assets at amortised cost | Credit risk | Loans and advances to customers | Loans secured on residential properties
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	(181,200)	(173,300)
Netting	0	0
Net exposure	12,600	9,700
Financial assets at amortised cost | Credit risk | Loans and advances to customers | Corporate loans
Disclosure of credit risk exposure [line items]
Collateral cash	(100)	(100)
Collateral non-cash	(16,800)	(20,400)
Netting	0	0
Net exposure	9,700	17,800
Financial assets at amortised cost | Credit risk | Loans and advances to customers | Finance leases
Disclosure of credit risk exposure [line items]
Collateral cash	0	(100)
Collateral non-cash	(4,700)	(5,800)
Netting	0	0
Net exposure	(600)	800
Financial assets at amortised cost | Credit risk | Loans and advances to customers | Accrued interest and other adjustments
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	700	900
Financial assets at amortised cost | Credit risk | Loans and advances to customers | Other unsecured
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	22,500	23,200
Financial assets at amortised cost | Credit risk | Loans and advances to customers | Amounts due from fellow Banco Santander group subsidiaries and joint ventures
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	3,100	2,200
Financial assets at amortised cost | Credit risk | Loans and advances to banks
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	1,800	3,000
Financial assets at amortised cost | Credit risk | Reverse repurchase agreements - non trading
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	(12,200)	(19,500)
Netting	(400)	(100)
Net exposure	100	0
Financial assets at amortised cost | Credit risk | Other financial assets at amortised cost
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	500	1,200
Financial assets at amortised cost | On-balance sheet | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	228,100	235,000
Financial assets at amortised cost | On-balance sheet | Credit risk | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	229,000	236,300
Financial assets at amortised cost | On-balance sheet | Credit risk | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(900)	(1,300)
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	213,500	212,200
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Loans secured on residential properties
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	177,800	169,700
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Corporate loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	18,900	23,000
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Finance leases
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	3,800	6,500
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Accrued interest and other adjustments
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	700	900
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Other unsecured
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	9,200	9,900
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Amounts due from fellow Banco Santander group subsidiaries and joint ventures
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	3,100	2,200
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	214,400	213,500
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Loans secured on residential properties
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	178,000	170,000
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Corporate loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	19,300	23,600
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Finance leases
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	3,900	6,600
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Accrued interest and other adjustments
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	700	900
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Other unsecured
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	9,400	10,200
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Amounts due from fellow Banco Santander group subsidiaries and joint ventures
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	3,100	2,200
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(900)	(1,300)
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Loans secured on residential properties
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(200)	(300)
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Corporate loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(400)	(600)
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Finance leases
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(100)	(100)
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Accrued interest and other adjustments
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Other unsecured
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(200)	(300)
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Amounts due from fellow Banco Santander group subsidiaries and joint ventures
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to banks
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	1,400	2,000
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to banks | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	1,400	2,000
Financial assets at amortised cost | On-balance sheet | Credit risk | Loans and advances to banks | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | On-balance sheet | Credit risk | Reverse repurchase agreements - non trading
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	12,700	19,600
Financial assets at amortised cost | On-balance sheet | Credit risk | Reverse repurchase agreements - non trading | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	12,700	19,600
Financial assets at amortised cost | On-balance sheet | Credit risk | Reverse repurchase agreements - non trading | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | On-balance sheet | Credit risk | Other financial assets at amortised cost
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	500	1,200
Financial assets at amortised cost | On-balance sheet | Credit risk | Other financial assets at amortised cost | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	500	1,200
Financial assets at amortised cost | On-balance sheet | Credit risk | Other financial assets at amortised cost | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	37,700	43,100
Financial assets at amortised cost | Off-balance sheet | Credit risk | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	37,700	43,200
Financial assets at amortised cost | Off-balance sheet | Credit risk | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	(100)
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	37,300	42,100
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Loans secured on residential properties
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	16,000	13,300
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Corporate loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	7,700	15,300
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Finance leases
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	300	200
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Accrued interest and other adjustments
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Other unsecured
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	13,300	13,300
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Amounts due from fellow Banco Santander group subsidiaries and joint ventures
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	37,300	42,200
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Loans secured on residential properties
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	16,000	13,300
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Corporate loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	7,700	15,400
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Finance leases
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	300	200
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Accrued interest and other adjustments
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Other unsecured
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	13,300	13,300
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Gross amounts | Amounts due from fellow Banco Santander group subsidiaries and joint ventures
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	(100)
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Loans secured on residential properties
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Corporate loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	(100)
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Finance leases
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Accrued interest and other adjustments
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Other unsecured
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to customers | Accumulated impairment | Amounts due from fellow Banco Santander group subsidiaries and joint ventures
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to banks
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	400	1,000
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to banks | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	400	1,000
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loans and advances to banks | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Reverse repurchase agreements - non trading
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Reverse repurchase agreements - non trading | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Reverse repurchase agreements - non trading | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Other financial assets at amortised cost
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Other financial assets at amortised cost | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Off-balance sheet | Credit risk | Other financial assets at amortised cost | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Debt securities | Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	5,900	9,000
Debt securities | On-balance sheet | Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	5,900	9,000
Debt securities | On-balance sheet | Credit risk | Financial assets at FVOCI | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	5,900	9,000
Debt securities | On-balance sheet | Credit risk | Financial assets at FVOCI | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Debt securities | Off-balance sheet | Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Debt securities | Off-balance sheet | Credit risk | Financial assets at FVOCI | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Debt securities | Off-balance sheet | Credit risk | Financial assets at FVOCI | Accumulated impairment
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	£ 0	£ 0

Credit Risk - Disclosure of Dif

Credit Risk - Disclosure of Difference Between Maximum and Net Exposure to Credit Risk - IFRS 9 (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Collateral cash	£ (11,634)	£ (17,060)
Netting	(1,017)	(949)
Net exposure	319,319	328,792
Credit risk
Disclosure of credit risk exposure [line items]
Collateral cash	(100)	(200)
Collateral non-cash	(214,900)	(219,000)
Netting	(400)	(100)
Net exposure	106,800	111,300
Financial assets at fair value through profit loss | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	2,400	4,300
Collateral cash	0	0
Collateral non-cash	(700)	(1,800)
Netting	(600)	(800)
Net exposure	1,100	1,700
Derivative financial assets | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	1,700	3,500
Collateral cash	0	0
Collateral non-cash	(700)	(1,800)
Netting	(600)	(800)
Net exposure	400	900
Other financial assets at fair value through profit loss | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	700	800
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	£ 700	£ 800

Credit Risk - Disclosure of Equ

Credit Risk - Disclosure of Equivalent Credit Rating Grade used by Standard and Poors Ratings Services (Details)	12 Months Ended
	Dec. 31, 2021
Mid range | Santander UK risk grade 9
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.01%
Mid range | Santander UK risk grade 8
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.032%
Mid range | Santander UK risk grade 7
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.10%
Mid range | Santander UK risk grade 6
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.316%
Mid range | Santander UK risk grade 5
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	1.00%
Mid range | Santander UK risk grade 4
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	3.162%
Mid range | Santander UK risk grade 3
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	10.00%
Mid range | Santander UK risk grade 2
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	31.623%
Mid range | Santander UK risk grade 1
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	100.00%
Lower range | Santander UK risk grade 9
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.00%
Lower range | Santander UK risk grade 8
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.021%
Lower range | Santander UK risk grade 7
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.066%
Lower range | Santander UK risk grade 6
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.208%
Lower range | Santander UK risk grade 5
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.658%
Lower range | Santander UK risk grade 4
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	2.081%
Lower range | Santander UK risk grade 3
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	6.581%
Lower range | Santander UK risk grade 2
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	20.811%
Lower range | Santander UK risk grade 1
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	100.00%
Upper range | Santander UK risk grade 9
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.021%
Upper range | Santander UK risk grade 8
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.066%
Upper range | Santander UK risk grade 7
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.208%
Upper range | Santander UK risk grade 6
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.658%
Upper range | Santander UK risk grade 5
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	2.081%
Upper range | Santander UK risk grade 4
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	6.581%
Upper range | Santander UK risk grade 3
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	20.811%
Upper range | Santander UK risk grade 2
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	99.999%
Upper range | Santander UK risk grade 1
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	100.00%

Credit Risk - Disclosure of Cre

Credit Risk - Disclosure of Credit Rating of Financial Assets Subject to Credit Risk (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of internal credit grades [line items]
Loss allowance	£ (828)	£ (1,303)
Coverage	0.30%	0.40%
Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 322,200	£ 330,600
Loss allowance	£ (900)	£ (1,400)
Coverage	0.30%	0.40%
Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 900	£ 1,400
Internal grade 9 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 73,600	£ 70,700
Coverage	0.00%	0.00%
Internal grade 9 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Internal grade 8 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 42,700	£ 43,800
Coverage	0.00%	0.00%
Internal grade 8 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Internal grade 7 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 95,100	£ 87,700
Coverage	0.00%	0.00%
Internal grade 7 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Internal grade 6 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 56,000	£ 56,100
Coverage	0.00%	0.20%
Internal grade 6 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
Internal grade 5 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 17,400	£ 18,700
Coverage	1.70%	0.50%
Internal grade 5 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 300	£ 100
Internal grade 4 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 11,500	£ 29,000
Coverage	0.90%	0.70%
Internal grade 4 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
Internal grade 3 to 1 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 6,500	£ 8,700
Coverage	7.70%	11.50%
Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 500	£ 1,000
Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 20,300	£ 17,300
Coverage	0.00%	0.00%
Other | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	284,500	287,500
Loss allowance	£ (900)	£ (1,300)
Coverage	0.30%	0.50%
On-balance sheet | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 900	£ 1,300
On-balance sheet | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	228,100	235,000
Loss allowance	£ (900)	£ (1,300)
Coverage	0.40%	0.60%
On-balance sheet | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 177,800	£ 169,700
Loss allowance	£ (200)	£ (300)
Coverage	0.10%	0.20%
On-balance sheet | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 900	£ 1,300
On-balance sheet | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	200	300
On-balance sheet | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	50,500	43,500
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	213,500	212,200
Loss allowance	£ (900)	£ (1,300)
Coverage	0.40%	0.40%
On-balance sheet | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 900	£ 1,300
On-balance sheet | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	1,400	2,000
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	12,700	19,600
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	500	1,200
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	5,900	9,000
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 9 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 73,500	£ 70,300
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 9 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 9 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 19,400	£ 21,500
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 9 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 9,000	£ 7,900
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 9 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 9 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
On-balance sheet | Internal grade 9 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 50,500	£ 43,500
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 9 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 9 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 9,000	£ 8,000
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 9 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 9 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 9 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 9 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 9,700	£ 12,200
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 9 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 9 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 500	£ 1,200
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 9 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 9 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 3,600	£ 5,300
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 9 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 8 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 35,400	£ 35,000
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 8 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 8 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 33,300	£ 31,600
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 8 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 30,200	£ 24,800
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 8 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 8 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
On-balance sheet | Internal grade 8 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 8 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 8 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 33,000	£ 28,200
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 8 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 8 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 8 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 8 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 3,300
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 8 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 8 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 8 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 8 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 2,100	£ 3,400
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 8 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 7 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 88,100	£ 78,200
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 7 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 7 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 87,900	£ 78,000
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 7 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 80,500	£ 69,300
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 7 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 7 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
On-balance sheet | Internal grade 7 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 7 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 7 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 85,800	£ 75,800
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 7 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 7 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 1,000	£ 700
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 7 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 7 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 1,100	£ 1,500
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 7 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 7 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 7 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 7 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 200
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 7 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 6 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 49,200	£ 47,300
Coverage	0.00%	0.20%
On-balance sheet | Internal grade 6 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
On-balance sheet | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 49,200	£ 47,200
Coverage	0.00%	0.20%
On-balance sheet | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 43,100	£ 37,600
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 6 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
On-balance sheet | Internal grade 6 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
On-balance sheet | Internal grade 6 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 6 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 6 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 48,600	£ 44,800
Coverage	0.00%	0.20%
On-balance sheet | Internal grade 6 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
On-balance sheet | Internal grade 6 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 6 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 6 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 600	£ 2,400
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 6 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 6 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 6 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 6 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 6 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 5 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 12,900	£ 13,600
Coverage	2.30%	0.70%
On-balance sheet | Internal grade 5 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 300	£ 100
On-balance sheet | Internal grade 5 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 12,900	£ 13,600
Coverage	2.30%	0.70%
On-balance sheet | Internal grade 5 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 6,500	£ 5,700
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 5 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 300	£ 100
On-balance sheet | Internal grade 5 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
On-balance sheet | Internal grade 5 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 5 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 5 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 12,900	£ 13,600
Coverage	2.30%	0.70%
On-balance sheet | Internal grade 5 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 300	£ 100
On-balance sheet | Internal grade 5 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 5 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 5 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 5 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 5 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 5 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 5 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 5 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 4 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,200	£ 27,400
Coverage	1.00%	0.70%
On-balance sheet | Internal grade 4 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
On-balance sheet | Internal grade 4 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,200	£ 27,400
Coverage	1.00%	0.70%
On-balance sheet | Internal grade 4 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 4,700	£ 19,900
Coverage	2.10%	0.50%
On-balance sheet | Internal grade 4 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
On-balance sheet | Internal grade 4 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	100	100
On-balance sheet | Internal grade 4 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 4 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 4 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,200	£ 27,400
Coverage	1.00%	0.70%
On-balance sheet | Internal grade 4 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
On-balance sheet | Internal grade 4 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 4 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 4 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 4 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 4 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 4 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 4 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 4 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 3 to 1 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 6,000	£ 8,200
Coverage	8.30%	11.00%
On-balance sheet | Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 500	£ 900
On-balance sheet | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 6,000	£ 8,200
Coverage	8.30%	11.00%
On-balance sheet | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 3,200	£ 4,500
Coverage	3.10%	4.40%
On-balance sheet | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 500	£ 900
On-balance sheet | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	100	200
On-balance sheet | Internal grade 3 to 1 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 3 to 1 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 3 to 1 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 6,000	£ 8,200
Coverage	8.30%	11.00%
On-balance sheet | Internal grade 3 to 1 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 500	£ 900
On-balance sheet | Internal grade 3 to 1 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 3 to 1 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 3 to 1 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 3 to 1 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 3 to 1 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 3 to 1 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Internal grade 3 to 1 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Internal grade 3 to 1 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,100	£ 8,800
Coverage	0.00%	0.00%
On-balance sheet | Other | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Other | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,100	£ 8,800
Coverage	0.00%	0.00%
On-balance sheet | Other | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 800	£ 300
Coverage	0.00%	0.00%
On-balance sheet | Other | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Other | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
On-balance sheet | Other | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Other | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Other | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 8,900	£ 7,500
Coverage	0.00%	0.00%
On-balance sheet | Other | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Other | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 1,100
Coverage	0.00%	0.00%
On-balance sheet | Other | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Other | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 1,200	£ 200
Coverage	0.00%	0.00%
On-balance sheet | Other | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Other | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Other | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
On-balance sheet | Other | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
On-balance sheet | Other | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Off-balance sheet | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	37,700	43,100
Loss allowance	£ 0	£ (100)
Coverage	0.00%	0.20%
Off-balance sheet | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
Off-balance sheet | Internal grade 9 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 400
Coverage	0.00%	0.00%
Off-balance sheet | Internal grade 9 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Off-balance sheet | Internal grade 8 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 7,300	£ 8,800
Coverage	0.00%	0.00%
Off-balance sheet | Internal grade 8 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Off-balance sheet | Internal grade 7 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 7,000	£ 9,500
Coverage	0.00%	0.00%
Off-balance sheet | Internal grade 7 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Off-balance sheet | Internal grade 6 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 6,800	£ 8,800
Coverage	0.00%	0.00%
Off-balance sheet | Internal grade 6 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Off-balance sheet | Internal grade 5 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 4,500	£ 5,100
Coverage	0.00%	0.00%
Off-balance sheet | Internal grade 5 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Off-balance sheet | Internal grade 4 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 1,300	£ 1,600
Coverage	0.00%	0.00%
Off-balance sheet | Internal grade 4 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Off-balance sheet | Internal grade 3 to 1 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 500	£ 500
Coverage	0.00%	20.00%
Off-balance sheet | Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets		£ 100
Off-balance sheet | Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,200	£ 8,500
Coverage	0.00%	0.00%
Off-balance sheet | Other | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	165,100	157,800
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	50,500	43,500
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	194,900	193,300
Loss allowance	£ (100)	£ (200)
Coverage	0.10%	0.10%
Stage 1 | On-balance sheet | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
Stage 1 | On-balance sheet | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	1,400	2,000
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	12,700	19,600
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	500	1,200
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	5,900	9,000
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 9 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 9,000	£ 7,900
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 9 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 9 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 50,500	£ 43,500
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 9 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 9 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 9,000	£ 8,000
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 9 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 9 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 9 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 9 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 9,700	£ 12,200
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 9 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 9 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 500	£ 1,200
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 9 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 9 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 3,600	£ 5,300
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 9 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 8 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 30,000	£ 24,800
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 8 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 8 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 8 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 8 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 32,200	£ 28,100
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 8 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 8 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 8 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 8 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 3,300
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 8 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 8 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 8 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 8 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 2,100	£ 3,400
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 8 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 7 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 79,200	£ 69,000
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 7 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 7 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 7 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 7 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 84,300	£ 75,400
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 7 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 7 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 1,000	£ 700
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 7 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 7 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 1,100	£ 1,500
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 7 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 7 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 7 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 7 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 200
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 7 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 40,200	£ 36,200
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 6 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 6 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 6 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 6 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 45,500	£ 43,300
Coverage	0.00%	0.20%
Stage 1 | On-balance sheet | Internal grade 6 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
Stage 1 | On-balance sheet | Internal grade 6 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 6 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 6 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 600	£ 2,400
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 6 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 6 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 6 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 6 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 6 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 5 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 4,200	£ 4,000
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 5 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 5 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 5 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 5 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,100	£ 10,900
Coverage	1.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 5 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 0
Stage 1 | On-balance sheet | Internal grade 5 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 5 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 5 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 5 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 5 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 5 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 5 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 5 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 4 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 1,600	£ 15,000
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 4 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 4 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 4 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 4 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 5,000	£ 19,400
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 4 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 4 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 4 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 4 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 4 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 4 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 4 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 4 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 4 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 600
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 600	£ 1,100
Coverage	0.00%	9.10%
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Internal grade 3 to 1 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Other | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 800	£ 300
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Other | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Other | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Other | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Other | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 8,300	£ 7,300
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Other | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Other | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 1,100
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Other | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Other | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 1,200	£ 200
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Other | Reverse repurchase agreements - non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Other | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Other | Other financial assets at amortised cost | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | On-balance sheet | Other | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | On-balance sheet | Other | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Off-balance sheet | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	36,100	41,800
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | Off-balance sheet | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Off-balance sheet | Internal grade 9 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 400
Coverage	0.00%	0.00%
Stage 1 | Off-balance sheet | Internal grade 9 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Off-balance sheet | Internal grade 8 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 7,000	£ 8,800
Coverage	0.00%	0.00%
Stage 1 | Off-balance sheet | Internal grade 8 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Off-balance sheet | Internal grade 7 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 6,700	£ 9,500
Coverage	0.00%	0.00%
Stage 1 | Off-balance sheet | Internal grade 7 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Off-balance sheet | Internal grade 6 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 6,600	£ 8,600
Coverage	0.00%	0.00%
Stage 1 | Off-balance sheet | Internal grade 6 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Off-balance sheet | Internal grade 5 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 4,300	£ 4,700
Coverage	0.00%	0.00%
Stage 1 | Off-balance sheet | Internal grade 5 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Off-balance sheet | Internal grade 4 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 1,000	£ 1,100
Coverage	0.00%	0.00%
Stage 1 | Off-balance sheet | Internal grade 4 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Off-balance sheet | Internal grade 3 to 1 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 200
Coverage	0.00%	0.00%
Stage 1 | Off-balance sheet | Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Off-balance sheet | Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,200	£ 8,500
Coverage	0.00%	0.00%
Stage 1 | Off-balance sheet | Other | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	11,000	10,200
Loss allowance	£ (100)	£ (200)
Coverage	0.90%	2.00%
Stage 2 | On-balance sheet | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
Stage 2 | On-balance sheet | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	16,100	16,600
Loss allowance	£ (400)	£ (500)
Coverage	2.50%	3.00%
Stage 2 | On-balance sheet | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 400	£ 500
Stage 2 | On-balance sheet | Internal grade 9 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Internal grade 9 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Internal grade 9 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Internal grade 9 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Internal grade 8 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 0
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Internal grade 8 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Internal grade 8 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 800	£ 100
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Internal grade 8 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Internal grade 7 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 1,300	£ 300
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Internal grade 7 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Internal grade 7 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 1,500	£ 400
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Internal grade 7 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 2,900	£ 1,400
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Internal grade 6 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Internal grade 6 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 3,100	£ 1,500
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Internal grade 6 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Internal grade 5 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 2,300	£ 1,700
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Internal grade 5 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Internal grade 5 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 2,800	£ 2,700
Coverage	7.10%	3.70%
Stage 2 | On-balance sheet | Internal grade 5 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
Stage 2 | On-balance sheet | Internal grade 4 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 3,100	£ 4,900
Coverage	3.20%	2.00%
Stage 2 | On-balance sheet | Internal grade 4 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 100
Stage 2 | On-balance sheet | Internal grade 4 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 5,200	£ 8,000
Coverage	1.90%	2.50%
Stage 2 | On-balance sheet | Internal grade 4 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
Stage 2 | On-balance sheet | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 1,300	£ 2,100
Coverage	0.00%	4.80%
Stage 2 | On-balance sheet | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
Stage 2 | On-balance sheet | Internal grade 3 to 1 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 2,800	£ 4,200
Coverage	3.60%	4.80%
Stage 2 | On-balance sheet | Internal grade 3 to 1 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
Stage 2 | On-balance sheet | Other | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Other | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | On-balance sheet | Other | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 300	£ 200
Coverage	0.00%	0.00%
Stage 2 | On-balance sheet | Other | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | Off-balance sheet | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	1,500	1,200
Loss allowance	£ 0	£ (100)
Coverage	0.00%	8.30%
Stage 2 | Off-balance sheet | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
Stage 2 | Off-balance sheet | Internal grade 9 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 2 | Off-balance sheet | Internal grade 9 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | Off-balance sheet | Internal grade 8 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 300	£ 0
Coverage	0.00%	0.00%
Stage 2 | Off-balance sheet | Internal grade 8 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | Off-balance sheet | Internal grade 7 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 300	£ 0
Coverage	0.00%	0.00%
Stage 2 | Off-balance sheet | Internal grade 7 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | Off-balance sheet | Internal grade 6 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 200
Coverage	0.00%	0.00%
Stage 2 | Off-balance sheet | Internal grade 6 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | Off-balance sheet | Internal grade 5 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 400
Coverage	0.00%	0.00%
Stage 2 | Off-balance sheet | Internal grade 5 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | Off-balance sheet | Internal grade 4 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 300	£ 500
Coverage	0.00%	0.00%
Stage 2 | Off-balance sheet | Internal grade 4 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | Off-balance sheet | Internal grade 3 to 1 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 200
Coverage	0.00%	50.00%
Stage 2 | Off-balance sheet | Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets		£ 100
Stage 2 | Off-balance sheet | Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 2 | Off-balance sheet | Other | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	1,700	1,700
Loss allowance	£ (100)	£ (100)
Coverage	5.90%	5.90%
Stage 3 | On-balance sheet | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 100
Stage 3 | On-balance sheet | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	2,500	2,300
Loss allowance	£ (400)	£ (600)
Coverage	16.00%	26.10%
Stage 3 | On-balance sheet | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 400	£ 600
Stage 3 | On-balance sheet | Internal grade 9 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 9 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 9 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 9 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 8 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 8 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 8 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 8 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 7 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 7 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 7 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 7 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 6 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 6 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 6 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 5 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 5 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 5 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 5 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 4 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 4 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 4 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Internal grade 4 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 1,800	£ 1,800
Coverage	5.60%	5.60%
Stage 3 | On-balance sheet | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 100
Stage 3 | On-balance sheet | Internal grade 3 to 1 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 2,600	£ 2,900
Coverage	15.40%	20.70%
Stage 3 | On-balance sheet | Internal grade 3 to 1 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 400	£ 600
Stage 3 | On-balance sheet | Other | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Other | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | On-balance sheet | Other | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 300	£ 0
Coverage	0.00%	0.00%
Stage 3 | On-balance sheet | Other | Loans and advances to customers | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | Off-balance sheet | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	100	100
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Off-balance sheet | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | Off-balance sheet | Internal grade 9 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Off-balance sheet | Internal grade 9 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | Off-balance sheet | Internal grade 8 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Off-balance sheet | Internal grade 8 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | Off-balance sheet | Internal grade 7 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Off-balance sheet | Internal grade 7 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | Off-balance sheet | Internal grade 6 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Off-balance sheet | Internal grade 6 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | Off-balance sheet | Internal grade 5 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Off-balance sheet | Internal grade 5 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | Off-balance sheet | Internal grade 4 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Off-balance sheet | Internal grade 4 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | Off-balance sheet | Internal grade 3 to 1 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 100
Coverage	0.00%	0.00%
Stage 3 | Off-balance sheet | Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | Off-balance sheet | Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Off-balance sheet | Other | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0

Credit Risk - Disclosure of C_2

Credit Risk - Disclosure of Credit Performance (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 213,525	£ 212,178
Exposure	319,319	328,792
Loss allowance	828	1,303
Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	210,600	210,400
Gross write- offs	191	253
Loss allowance	866	1,377
Loans to customers | Undrawn Balances
Disclosure of credit risk exposure [line items]
Loans and advances to customers	37,800	43,200
Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure	191,200	190,400
Loans to customers | Stage 1 | Undrawn Balances
Disclosure of credit risk exposure [line items]
Exposure	36,200	41,800
Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	16,500	17,100
Loans to customers | Stage 2 | Undrawn Balances
Disclosure of credit risk exposure [line items]
Exposure	1,500	1,300
Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure	2,900	2,900
Loans to customers | Stage 3 | Undrawn Balances
Disclosure of credit risk exposure [line items]
Exposure	100	100
Retail Banking | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	185,600	178,500
Gross write- offs	108	155
Loss allowance	389	588
Retail Banking | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure	171,800	165,600
Retail Banking | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	11,700	11,000
Retail Banking | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure	2,100	1,900
Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	177,297	169,801
Homes | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	177,300	169,800
Gross write- offs	5	14
Loss allowance	191	280
Homes | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure	164,400	157,600
Homes | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	11,100	10,400
Homes | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure	1,800	1,800
Everyday Banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	8,311	8,650
Gross write- offs	103	141
Loss allowance	198	308
Everyday Banking | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	8,300	8,700
Gross write- offs	103	141
Loss allowance	198	308
Everyday Banking | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure	7,400	8,000
Everyday Banking | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	600	600
Everyday Banking | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure	300	100
Consumer Finance
Disclosure of credit risk exposure [line items]
Loans and advances to customers	4,984	8,024
Gross write- offs	25	25
Loss allowance	52	118
Consumer Finance | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	5,000	8,000
Gross write- offs	25	25
Loss allowance	52	118
Consumer Finance | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure	4,800	7,600
Consumer Finance | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	200	400
Consumer Finance | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure	0	0
Corporate & Commercial Banking | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	17,000	17,600
Gross write- offs	58	51
Loss allowance	423	603
Corporate & Commercial Banking | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure	11,800	11,100
Corporate & Commercial Banking | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	4,400	5,500
Corporate & Commercial Banking | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure	800	1,000
Corporate Centre | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	3,000	3,500
Gross write- offs	0	0
Loss allowance	2	35
Corporate Centre | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure	2,800	3,500
Corporate Centre | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	200	0
Corporate Centre | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure	£ 0	0
Corporate & Investment Banking | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers		2,800
Gross write- offs		22
Loss allowance		33
Corporate & Investment Banking | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure		2,600
Corporate & Investment Banking | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure		200
Corporate & Investment Banking | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure		£ 0
Corporate loans | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure ratio	90.79%	90.49%
Corporate loans | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure ratio	7.83%	8.12%
Corporate loans | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure ratio	1.43%	1.42%

Credit Risk - Disclosure of IFR

Credit Risk - Disclosure of IFRS 9 Credit Quality (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
Loss allowance	828	1,303
Provisions	366	468
Total ECL	£ 866	£ 1,377
Coverage	0.30%	0.40%
Retail mortgage offers in pipeline	£ 10,600	£ 7,700
On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	281,571	285,622
Loss allowance	£ 828	£ 1,302
Coverage	0.30%	0.50%
Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 37,748	£ 43,170
Provisions	£ 38	£ 75
Coverage	0.10%	0.20%
Customer loans | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 210,600	£ 210,400
Loans and advances to banks | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	1,400	2,000
Sovereign assets measured at amortized cost | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	13,200	20,800
Financial assets measured at fair value through other comprehensive income | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	5,900	9,000
Cash and balances at central banks | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	50,500	43,500
Retail Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	185,608	178,452
Loss allowance	£ 368	£ 550
Coverage	0.20%	0.30%
Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 29,371	£ 26,610
Provisions	£ 21	£ 38
Coverage	0.10%	0.10%
Homes | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 177,297	£ 169,801
Loss allowance	£ 186	£ 277
Coverage	0.10%	0.20%
Homes | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 15,950	£ 13,276
Provisions	£ 5	£ 3
Coverage	0.00%	0.00%
Everyday Banking
Disclosure of credit risk exposure [line items]
Loss allowance	£ 198	£ 308
Everyday Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	8,311	8,651
Loss allowance	£ 182	£ 273
Coverage	2.20%	3.20%
Everyday Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 13,421	£ 13,334
Provisions	£ 16	£ 35
Coverage	0.10%	0.30%
Consumer Finance
Disclosure of credit risk exposure [line items]
Loss allowance	£ 52	£ 118
Consumer Finance | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	4,984	8,024
Loss allowance	£ 52	£ 118
Coverage	1.00%	1.50%
Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 314	£ 237
Provisions	£ 0	£ 0
Coverage	0.00%	0.00%
Corporate & Commercial Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 16,997	£ 17,626
Loss allowance	£ 407	£ 577
Coverage	2.40%	3.30%
Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 7,694	£ 6,877
Provisions	£ 16	£ 26
Coverage	0.20%	0.40%
Corporate Centre | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 73,982	£ 78,735
Loss allowance	£ 1	£ 35
Coverage	0.00%	0.00%
Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 369	£ 585
Corporate & Investment Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure		2,785
Loss allowance		£ 22
Coverage		0.80%
Corporate & Investment Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure		£ 8,861
Provisions		£ 11
Coverage		0.10%
Stage 1
Disclosure of credit risk exposure [line items]
Exposure	298,285	£ 307,416
Total ECL	£ 133	£ 216
Coverage	0.00%	0.10%
Stage 1 | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 262,134	£ 265,619
Loss allowance	£ 115	£ 186
Coverage	0.00%	0.10%
Stage 1 | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 36,151	£ 41,797
Provisions	£ 18	£ 30
Coverage	0.00%	0.10%
Stage 1 | Retail Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 171,791	£ 165,570
Loss allowance	£ 53	£ 56
Coverage	0.00%	0.00%
Stage 1 | Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 29,123	£ 26,313
Provisions	£ 12	£ 18
Coverage	0.00%	0.10%
Stage 1 | Homes | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 164,381	£ 157,614
Loss allowance	£ 9	£ 15
Coverage	0.00%	0.00%
Stage 1 | Homes | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 15,851	£ 13,180
Provisions	£ 5	£ 2
Coverage	0.00%	0.00%
Stage 1 | Everyday Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 7,410	£ 7,956
Loss allowance	£ 44	£ 41
Coverage	0.60%	0.50%
Stage 1 | Everyday Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 13,272	£ 13,133
Provisions	£ 7	£ 16
Coverage	0.10%	0.10%
Stage 1 | Consumer Finance | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 4,760	£ 7,587
Loss allowance	£ 18	£ 44
Coverage	0.40%	0.60%
Stage 1 | Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 314	£ 237
Provisions	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | Corporate & Commercial Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 11,812	£ 11,167
Loss allowance	£ 44	£ 46
Coverage	0.40%	0.40%
Stage 1 | Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 6,391	£ 6,050
Provisions	£ 5	£ 8
Coverage	0.10%	0.10%
Stage 1 | Corporate Centre | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 73,771	£ 78,708
Loss allowance	£ 0	£ 35
Coverage	0.00%	0.00%
Stage 1 | Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 323	£ 567
Stage 1 | Corporate & Investment Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure		2,587
Loss allowance		£ 5
Coverage		0.20%
Stage 1 | Corporate & Investment Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure		£ 8,630
Provisions		£ 4
Coverage		0.00%
Stage 2
Disclosure of credit risk exposure [line items]
Exposure	18,013	£ 18,380
Total ECL	£ 330	£ 592
Coverage	1.80%	3.20%
Stage 2 | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 16,497	£ 17,107
Loss allowance	£ 314	£ 556
Coverage	1.90%	3.30%
Stage 2 | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 1,516	£ 1,273
Provisions	£ 16	£ 36
Coverage	1.10%	2.80%
Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 11,897	£ 11,261
Coverage	1.60%	2.90%
Stage 2 | Retail Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 11,693	£ 11,005
Loss allowance	£ 178	£ 313
Coverage	1.50%	2.80%
Stage 2 | Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 204	£ 256
Provisions	£ 8	£ 19
Coverage	3.90%	7.40%
Stage 2 | Homes | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 11,118	£ 10,388
Loss allowance	£ 88	£ 130
Coverage	0.80%	1.30%
Stage 2 | Homes | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 81	£ 82
Provisions	£ 0	£ 1
Coverage	0.00%	1.20%
Stage 2 | Everyday Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 575	£ 617
Loss allowance	£ 90	£ 183
Coverage	15.70%	29.70%
Stage 2 | Everyday Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 123	£ 174
Provisions	£ 8	£ 18
Coverage	6.50%	10.30%
Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 200	£ 379
Coverage	8.50%	9.80%
Stage 2 | Consumer Finance | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 200	£ 379
Loss allowance	£ 17	£ 37
Coverage	8.50%	9.80%
Stage 2 | Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
Provisions	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 5,661	£ 6,266
Coverage	2.20%	3.20%
Stage 2 | Corporate & Commercial Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 4,395	£ 5,498
Loss allowance	£ 119	£ 189
Coverage	2.70%	3.40%
Stage 2 | Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 1,266	£ 768
Provisions	£ 8	£ 10
Coverage	0.60%	1.30%
Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 255	£ 45
Coverage	0.00%	0.00%
Stage 2 | Corporate Centre | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 209	£ 27
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 2 | Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 46	£ 18
Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 429
Coverage	0.00%	5.60%
Stage 2 | Corporate & Investment Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure		£ 198
Loss allowance		£ 17
Coverage		8.60%
Stage 2 | Corporate & Investment Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure		£ 231
Provisions		£ 7
Coverage		3.00%
Stage 3
Disclosure of credit risk exposure [line items]
Exposure	£ 3,021	£ 2,996
Total ECL	£ 403	£ 569
Coverage	13.30%	19.00%
Stage 3 | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 2,940	£ 2,896
Loss allowance	£ 399	£ 560
Coverage	13.60%	19.30%
Stage 3 | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 81	£ 100
Provisions	£ 4	£ 9
Coverage	4.90%	9.00%
Stage 3 | Retail Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 2,124	£ 1,877
Loss allowance	£ 137	£ 181
Coverage	6.50%	9.60%
Stage 3 | Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 44	£ 41
Provisions	£ 1	£ 1
Coverage	2.30%	2.40%
Stage 3 | Homes | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 1,798	£ 1,799
Loss allowance	£ 89	£ 132
Coverage	4.90%	7.30%
Stage 3 | Homes | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 18	£ 14
Provisions	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Everyday Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 326	£ 78
Loss allowance	£ 48	£ 49
Coverage	14.70%	62.80%
Stage 3 | Everyday Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 26	£ 27
Provisions	£ 1	£ 1
Coverage	3.80%	3.70%
Stage 3 | Consumer Finance | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 24	£ 58
Loss allowance	£ 17	£ 37
Coverage	70.80%	63.80%
Stage 3 | Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
Provisions	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 826	£ 1,020
Stage 3 | Corporate & Commercial Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	790	961
Loss allowance	£ 244	£ 342
Coverage	30.90%	35.60%
Stage 3 | Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 37	£ 59
Provisions	£ 3	£ 8
Coverage	8.10%	13.60%
Stage 3 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 2	£ 0
Stage 3 | Corporate Centre | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	2	0
Loss allowance	£ 1	£ 0
Coverage	50.00%	0.00%
Stage 3 | Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
Stage 3 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure		0
Stage 3 | Corporate & Investment Banking | On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure		0
Loss allowance		£ 0
Coverage		0.00%
Stage 3 | Corporate & Investment Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure		£ 0
Provisions		£ 0
Coverage		0.00%

Credit Risk - Disclosure of Sta

Credit Risk - Disclosure of Stage 2 Exposures by Classification (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
Coverage	0.30%	0.40%
Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 18,013	£ 18,380
ECL	£ 330	£ 592
Coverage	1.80%	3.20%
Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 11,897	£ 11,261
ECL	£ 186	£ 332
Coverage	1.60%	2.90%
Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 200	£ 379
ECL	£ 17	£ 37
Coverage	8.50%	9.80%
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 5,661	£ 6,266
ECL	£ 127	£ 199
Coverage	2.20%	3.20%
Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 429
ECL	£ 0	£ 24
Coverage	0.00%	5.60%
Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 255	£ 45
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
PD deterioration | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 7,422	£ 10,000
ECL	£ 151	£ 299
Coverage	2.00%	3.00%
PD deterioration | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 5,644	£ 7,752
ECL	£ 125	£ 246
Coverage	2.20%	3.20%
PD deterioration | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 42	£ 88
ECL	£ 6	£ 13
Coverage	14.30%	14.80%
PD deterioration | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 1,522	£ 2,128
ECL	£ 20	£ 40
Coverage	1.30%	1.90%
PD deterioration | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
PD deterioration | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 214	£ 32
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Forbearance | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 947	£ 767
ECL	£ 14	£ 8
Coverage	1.50%	1.00%
Forbearance | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 664	£ 612
ECL	£ 4	£ 3
Coverage	0.60%	0.50%
Forbearance | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 11	£ 0
ECL	£ 2	£ 0
Coverage	18.20%	0.00%
Forbearance | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 272	£ 151
ECL	£ 8	£ 5
Coverage	2.90%	3.30%
Forbearance | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Forbearance | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 4
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Other | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 1,180	£ 2,493
ECL	£ 27	£ 112
Coverage	2.30%	4.50%
Other | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 603	£ 1,199
ECL	£ 5	£ 11
Coverage	0.80%	0.90%
Other | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 130	£ 248
ECL	£ 3	£ 11
Coverage	2.30%	4.40%
Other | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 445	£ 611
ECL	£ 19	£ 66
Coverage	4.30%	10.80%
Other | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 429
ECL	£ 0	£ 24
Coverage	0.00%	5.60%
Other | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 2	£ 6
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
30 DPD | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 1,114	£ 1,150
ECL	£ 40	£ 63
Coverage	3.60%	5.50%
30 DPD | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 745	£ 870
ECL	£ 33	£ 46
Coverage	4.40%	5.30%
30 DPD | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 17	£ 27
ECL	£ 5	£ 12
Coverage	29.40%	44.40%
30 DPD | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 313	£ 250
ECL	£ 2	£ 5
Coverage	0.60%	2.00%
30 DPD | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
30 DPD | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 39	£ 3
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Payment holiday | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 844
ECL	£ 0	£ 27
Coverage	0.00%	3.20%
Payment holiday | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 828
ECL	£ 0	£ 26
Coverage	0.00%	3.10%
Payment holiday | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 16
ECL	£ 0	£ 1
Coverage	0.00%	6.30%
Payment holiday | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Payment holiday | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Payment holiday | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Mortgages affordability | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 4,241	£ 0
ECL	£ 19	£ 0
Coverage	0.40%	0.00%
Mortgages affordability | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 4,241	£ 0
ECL	£ 19	£ 0
Coverage	0.40%	0.00%
Mortgages affordability | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Mortgages affordability | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Mortgages affordability | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Mortgages affordability | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
High risk corporate | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 3,109	£ 3,126
ECL	£ 79	£ 83
Coverage	2.50%	2.70%
High risk corporate | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
High risk corporate | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 1	£ 0
Coverage	0.00%	0.00%
High risk corporate | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 3,109	£ 3,126
ECL	£ 78	£ 83
Coverage	2.50%	2.70%
High risk corporate | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
High risk corporate | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%

Credit Risk - Disclosure of S_2

Credit Risk - Disclosure of Stage 2 Decomposition Cure and Not Cure Explanatory (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
Coverage	0.30%	0.40%
Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 18,013	£ 18,380
ECL	£ 330	£ 592
Coverage	1.80%	3.20%
Stage 2 not in cure period | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 13,351	£ 17,036
ECL	£ 286	£ 554
Coverage	2.10%	3.30%
Stage 2 in cure period (for transfer to Stage 1) | Stage 2
Disclosure of credit risk exposure [line items]
Exposure	£ 4,662	£ 1,344
ECL	£ 44	£ 38
Coverage	0.90%	2.80%

Credit Risk - Disclosure of Rec

Credit Risk - Disclosure of Reconciliation of Exposures, ECL and Net Carrying Amounts (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
Loss allowance	828	1,303
Assets classified at FVTPL	222	325
Total assets	293,676	299,064	£ 288,488
Provisions	366	468
Retail Banking
Disclosure of credit risk exposure [line items]
Total assets	193,214	186,226	178,665
Everyday Banking
Disclosure of credit risk exposure [line items]
Loss allowance	198	308
Consumer Finance
Disclosure of credit risk exposure [line items]
Loss allowance	52	118
Total assets	8,873	11,143	10,748
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Total assets	16,997	17,626	18,391
Corporate Centre
Disclosure of credit risk exposure [line items]
Total assets	74,592	81,285	76,638
Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Total assets	0	2,784	£ 4,046
On-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	281,571	285,622
Loss allowance	828	1,302
Net carrying amount	280,743	284,320
Other items	3,736	3,111
Adjusted net carrying amount	284,479	287,431
Assets classified at FVTPL	2,396	4,285
Non-financial assets	6,801	7,348
Total assets	293,676	299,064
On-balance sheet | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	185,608	178,452
Loss allowance	368	550
Net carrying amount	185,240	177,902
On-balance sheet | Homes
Disclosure of credit risk exposure [line items]
Exposure	177,297	169,801
Loss allowance	186	277
Net carrying amount	177,111	169,524
On-balance sheet | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	8,311	8,651
Loss allowance	182	273
Net carrying amount	8,129	8,378
On-balance sheet | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	4,984	8,024
Loss allowance	52	118
Net carrying amount	4,932	7,906
On-balance sheet | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	16,997	17,626
Loss allowance	407	577
Net carrying amount	16,590	17,049
On-balance sheet | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	73,982	78,735
Loss allowance	1	35
Net carrying amount	73,981	78,700
On-balance sheet | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure		2,785
Loss allowance		22
Net carrying amount		2,763
Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposure	37,748	43,170
Provisions	38	75
Off-balance sheet | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	29,371	26,610
Provisions	21	38
Off-balance sheet | Homes
Disclosure of credit risk exposure [line items]
Exposure	15,950	13,276
Provisions	5	3
Off-balance sheet | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	13,421	13,334
Provisions	16	35
Off-balance sheet | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	314	237
Provisions	0	0
Off-balance sheet | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	7,694	6,877
Provisions	16	26
Off-balance sheet | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	369	585
Provisions	£ 1	0
Off-balance sheet | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure		8,861
Provisions		£ 11

Credit Risk - Disclosure of E_2

Credit Risk - Disclosure of ECL Reconciliation (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	£ 1,377
Ending balance	866	£ 1,377
Less: Recoveries net of collection costs	17	24		£ 40
Total ECL charge/(release) to the Income Statement	(233)	639	[1]	198	[1]
ECL
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	1,377	863
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	(43)	379
Change in economic scenarios	(170)	164
Changes to model	0	25
New lending and assets purchased	76	155
Redemptions, repayments and assets sold	(205)	(90)
Changes in risk parameters and other movements	22	134
Assets written off	(191)	(253)
Ending balance	866	1,377		863
Net movement in the period	(511)	514
ECL charge/(release) to the Income Statement	(320)	767
Less: Discount unwind	(11)	(14)
Less: Recoveries net of collection costs	87	(108)
ECL charge/(release) to the Income Statement from continued operations	(244)	645
Discontinued operations ECL adjustment	11	(6)
Total ECL charge/(release) to the Income Statement	(233)	639
Stage 1
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	216
Ending balance	133	216
Stage 2
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	592
Ending balance	330	592
Stage 3
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	569
Ending balance	403	569
Exposures
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	328,792	316,322
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	51,823	57,022
Redemptions, repayments and assets sold	(67,619)	(50,362)
Changes in risk parameters and other movements	6,620	6,205
Assets written off	(297)	(395)
Ending balance	319,319	328,792		316,322
Net movement in the period	(9,473)	12,470
Financial instruments not credit-impaired | Subject to 12-month ECL | Stage 1 ECL
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	216	147
Transfers from Stage 1 to Stage 2	(9)	(47)
Transfers from Stage 2 to Stage 1	167	110
Transfers to Stage 3	(3)	(8)
Transfers from Stage 3	2	2
Transfers of financial instruments	157	57
Net ECL remeasurement on stage transfer	(133)	(101)
Change in economic scenarios	(7)	15
Changes to model	0	0
New lending and assets purchased	31	40
Redemptions, repayments and assets sold	(70)	(30)
Changes in risk parameters and other movements	(61)	88
Assets written off	0	0
Ending balance	133	216		147
Net movement in the period	(83)	69
ECL charge/(release) to the Income Statement	(83)	69
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	(83)	69
Discontinued operations ECL adjustment	11	0
Total ECL charge/(release) to the Income Statement	(72)	69
Financial instruments not credit-impaired | Subject to 12-month ECL | Stage 1
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	307,416	301,599
Transfers from Stage 1 to Stage 2	(6,805)	(9,814)
Transfers from Stage 2 to Stage 1	5,883	3,178
Transfers to Stage 3	(572)	(385)
Transfers from Stage 3	14	12
Transfers of financial instruments	(1,480)	(7,009)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	50,863	55,546
Redemptions, repayments and assets sold	(63,659)	(47,671)
Changes in risk parameters and other movements	5,145	4,953
Assets written off	0	(2)
Ending balance	298,285	307,416		301,599
Net movement in the period	(9,131)	5,817
Financial instruments not credit-impaired | Subject to Lifetime ECL | Stage 2 ECL
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	592	348
Transfers from Stage 1 to Stage 2	9	47
Transfers from Stage 2 to Stage 1	(167)	(110)
Transfers to Stage 3	(20)	(61)
Transfers from Stage 3	62	21
Transfers of financial instruments	(116)	(103)
Net ECL remeasurement on stage transfer	26	239
Change in economic scenarios	(151)	139
Changes to model	0	0
New lending and assets purchased	26	64
Redemptions, repayments and assets sold	(67)	(42)
Changes in risk parameters and other movements	20	(53)
Assets written off	0	0
Ending balance	330	592		348
Net movement in the period	(262)	244
ECL charge/(release) to the Income Statement	(262)	244
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	(262)	244
Discontinued operations ECL adjustment	0	0
Total ECL charge/(release) to the Income Statement	(262)	244
Financial instruments not credit-impaired | Subject to Lifetime ECL | Stage 2
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	18,380	12,354
Transfers from Stage 1 to Stage 2	6,805	9,814
Transfers from Stage 2 to Stage 1	(5,883)	(3,178)
Transfers to Stage 3	(532)	(1,126)
Transfers from Stage 3	455	326
Transfers of financial instruments	845	5,836
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	936	1,372
Redemptions, repayments and assets sold	(3,441)	(2,250)
Changes in risk parameters and other movements	1,293	1,068
Assets written off	0	0
Ending balance	18,013	18,380		12,354
Net movement in the period	(367)	6,026
Financial instruments credit-impaired | Subject to Lifetime ECL | Stage 3 ECL
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	569	368
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	23	69
Transfers from Stage 3	(64)	(23)
Transfers of financial instruments	(41)	46
Net ECL remeasurement on stage transfer	64	241
Change in economic scenarios	(12)	10
Changes to model	0	25
New lending and assets purchased	19	51
Redemptions, repayments and assets sold	(68)	(18)
Changes in risk parameters and other movements	63	99
Assets written off	(191)	(253)
Ending balance	403	569		368
Net movement in the period	(166)	201
ECL charge/(release) to the Income Statement	25	454
Less: Discount unwind	(11)	(14)
Less: Recoveries net of collection costs	87	(108)
ECL charge/(release) to the Income Statement from continued operations	101	332
Discontinued operations ECL adjustment	0	(6)
Total ECL charge/(release) to the Income Statement	101	326
Financial instruments credit-impaired | Subject to Lifetime ECL | Stage 3
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	2,996	2,369
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	1,104	1,511
Transfers from Stage 3	(469)	(338)
Transfers of financial instruments	635	1,173
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	24	104
Redemptions, repayments and assets sold	(519)	(441)
Changes in risk parameters and other movements	182	184
Assets written off	(297)	(393)
Ending balance	3,021	2,996		£ 2,369
Net movement in the period	£ 25	£ 627
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Credit Risk - Disclosure of Cou

Credit Risk - Disclosure of Country Risk Exposure (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
Governments
Disclosure of credit risk exposure [line items]
Exposure	52,400	48,400
Banks
Disclosure of credit risk exposure [line items]
Exposure	4,900	7,600
Other
Disclosure of credit risk exposure [line items]
Exposure	15,600	23,300
Retail
Disclosure of credit risk exposure [line items]
Exposure	218,500	209,600
Corporate
Disclosure of credit risk exposure [line items]
Exposure	28,900	42,200
Total
Disclosure of credit risk exposure [line items]
Exposure	320,300	331,100
Eurozone | Netherlands
Disclosure of credit risk exposure [line items]
Exposure	200	600
Eurozone | Belgium
Disclosure of credit risk exposure [line items]
Exposure	700	900
Eurozone | Governments
Disclosure of credit risk exposure [line items]
Exposure	400	500
Eurozone | Governments | Ireland
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Governments | Italy
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Governments | Spain
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Governments | France
Disclosure of credit risk exposure [line items]
Exposure	100	100
Eurozone | Governments | Germany
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Governments | Luxembourg
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Governments | Other
Disclosure of credit risk exposure [line items]
Exposure	300	400
Eurozone | Banks
Disclosure of credit risk exposure [line items]
Exposure	1,600	2,400
Eurozone | Banks | Ireland
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Banks | Italy
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Banks | Spain
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Banks | France
Disclosure of credit risk exposure [line items]
Exposure	300	500
Eurozone | Banks | Germany
Disclosure of credit risk exposure [line items]
Exposure	500	700
Eurozone | Banks | Luxembourg
Disclosure of credit risk exposure [line items]
Exposure	0	100
Eurozone | Banks | Other
Disclosure of credit risk exposure [line items]
Exposure	800	1,100
Eurozone | Other
Disclosure of credit risk exposure [line items]
Exposure	5,600	7,600
Eurozone | Other | Ireland
Disclosure of credit risk exposure [line items]
Exposure	5,300	6,000
Eurozone | Other | Italy
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Other | Spain
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Other | France
Disclosure of credit risk exposure [line items]
Exposure	200	200
Eurozone | Other | Germany
Disclosure of credit risk exposure [line items]
Exposure	0	100
Eurozone | Other | Luxembourg
Disclosure of credit risk exposure [line items]
Exposure	100	1,300
Eurozone | Other | Other
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Retail
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Retail | Ireland
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Retail | Italy
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Retail | Spain
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Retail | France
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Retail | Germany
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Retail | Luxembourg
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Retail | Other
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Corporate
Disclosure of credit risk exposure [line items]
Exposure	100	800
Eurozone | Corporate | Ireland
Disclosure of credit risk exposure [line items]
Exposure	0	100
Eurozone | Corporate | Italy
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Corporate | Spain
Disclosure of credit risk exposure [line items]
Exposure	100	100
Eurozone | Corporate | France
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Corporate | Germany
Disclosure of credit risk exposure [line items]
Exposure	0	100
Eurozone | Corporate | Luxembourg
Disclosure of credit risk exposure [line items]
Exposure	0	100
Eurozone | Corporate | Other
Disclosure of credit risk exposure [line items]
Exposure	0	400
Eurozone | Total
Disclosure of credit risk exposure [line items]
Exposure	7,700	11,300
Eurozone | Total | Ireland
Disclosure of credit risk exposure [line items]
Exposure	5,300	6,100
Eurozone | Total | Italy
Disclosure of credit risk exposure [line items]
Exposure	0	0
Eurozone | Total | Spain
Disclosure of credit risk exposure [line items]
Exposure	100	100
Eurozone | Total | France
Disclosure of credit risk exposure [line items]
Exposure	600	800
Eurozone | Total | Germany
Disclosure of credit risk exposure [line items]
Exposure	500	900
Eurozone | Total | Luxembourg
Disclosure of credit risk exposure [line items]
Exposure	100	1,500
Eurozone | Total | Other
Disclosure of credit risk exposure [line items]
Exposure	1,100	1,900
Other countries | Switzerland
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Governments | Other
Disclosure of credit risk exposure [line items]
Exposure	300	300
Other countries | Governments | UK
Disclosure of credit risk exposure [line items]
Exposure	50,200	44,400
Other countries | Governments | US
Disclosure of credit risk exposure [line items]
Exposure	500	800
Other countries | Governments | Japan
Disclosure of credit risk exposure [line items]
Exposure	1,000	2,400
Other countries | Governments | Switzerland
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Governments | Denmark
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Banks | Other
Disclosure of credit risk exposure [line items]
Exposure	200	500
Other countries | Banks | UK
Disclosure of credit risk exposure [line items]
Exposure	2,100	2,800
Other countries | Banks | US
Disclosure of credit risk exposure [line items]
Exposure	800	900
Other countries | Banks | Japan
Disclosure of credit risk exposure [line items]
Exposure	200	1,000
Other countries | Banks | Switzerland
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Banks | Denmark
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Other | Other
Disclosure of credit risk exposure [line items]
Exposure	100	100
Other countries | Other | UK
Disclosure of credit risk exposure [line items]
Exposure	9,900	15,500
Other countries | Other | US
Disclosure of credit risk exposure [line items]
Exposure	0	100
Other countries | Other | Japan
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Other | Switzerland
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Other | Denmark
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Retail | Other
Disclosure of credit risk exposure [line items]
Exposure	700	300
Other countries | Retail | UK
Disclosure of credit risk exposure [line items]
Exposure	217,800	209,300
Other countries | Retail | US
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Retail | Japan
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Retail | Switzerland
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Retail | Denmark
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Corporate | Other
Disclosure of credit risk exposure [line items]
Exposure	100	700
Other countries | Corporate | UK
Disclosure of credit risk exposure [line items]
Exposure	28,700	40,400
Other countries | Corporate | US
Disclosure of credit risk exposure [line items]
Exposure	0	300
Other countries | Corporate | Japan
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Corporate | Switzerland
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Corporate | Denmark
Disclosure of credit risk exposure [line items]
Exposure	0	0
Other countries | Total | Other
Disclosure of credit risk exposure [line items]
Exposure	1,400	1,900
Other countries | Total | UK
Disclosure of credit risk exposure [line items]
Exposure	308,700	312,400
Other countries | Total | US
Disclosure of credit risk exposure [line items]
Exposure	1,300	2,100
Other countries | Total | Japan
Disclosure of credit risk exposure [line items]
Exposure	1,200	3,400
Other countries | Total | Denmark
Disclosure of credit risk exposure [line items]
Exposure	0	0
All countries excluding Eurozone countries | Governments
Disclosure of credit risk exposure [line items]
Exposure	52,000	47,900
All countries excluding Eurozone countries | Banks
Disclosure of credit risk exposure [line items]
Exposure	3,300	5,200
All countries excluding Eurozone countries | Other
Disclosure of credit risk exposure [line items]
Exposure	10,000	15,700
All countries excluding Eurozone countries | Retail
Disclosure of credit risk exposure [line items]
Exposure	218,500	209,600
All countries excluding Eurozone countries | Corporate
Disclosure of credit risk exposure [line items]
Exposure	28,800	41,400
All countries excluding Eurozone countries | Total
Disclosure of credit risk exposure [line items]
Exposure	£ 312,600	£ 319,800

Credit Risk - Disclosure of Bal

Credit Risk - Disclosure of Balances with Other Banco Santander Companies (Details) - Santander UK Group Holdings plc - GBP (£) £ in Billions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about financial instruments [line items]
Financial assets	£ 4.1	£ 4.1
Financial liabilities	2.8	4
Spain
Disclosure of detailed information about financial instruments [line items]
Financial assets	1	1.8
Financial liabilities	1.5	2.6
UK
Disclosure of detailed information about financial instruments [line items]
Financial assets	3.1	2.3
Financial liabilities	1.2	1.3
Uruguay
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	0.1	0.1
Banks
Disclosure of detailed information about financial instruments [line items]
Financial assets	1	1.8
Financial liabilities	1.5	2.6
Banks | Spain
Disclosure of detailed information about financial instruments [line items]
Financial assets	1	1.8
Financial liabilities	1.4	2.5
Banks | UK
Disclosure of detailed information about financial instruments [line items]
Financial assets	0	0
Financial liabilities	0	0
Banks | Uruguay
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	0.1	0.1
Other
Disclosure of detailed information about financial instruments [line items]
Financial assets	3.1	2.3
Financial liabilities	1.3	1.4
Other | Spain
Disclosure of detailed information about financial instruments [line items]
Financial assets	0	0
Financial liabilities	0.1	0.1
Other | UK
Disclosure of detailed information about financial instruments [line items]
Financial assets	3.1	2.3
Financial liabilities	1.2	1.3
Other | Uruguay
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	0	0
Corporate
Disclosure of detailed information about financial instruments [line items]
Financial assets	0	0
Financial liabilities	0	0
Corporate | Spain
Disclosure of detailed information about financial instruments [line items]
Financial assets	0	0
Financial liabilities	0	0
Corporate | UK
Disclosure of detailed information about financial instruments [line items]
Financial assets	0	0
Financial liabilities	0	0
Corporate | Uruguay
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	£ 0	£ 0

Credit Risk - Disclosure of E_3

Credit Risk - Disclosure of ECL Reconciliation by Segment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	£ 1,377
Ending balance	866	£ 1,377
Less: Recoveries net of collection costs	17	24		£ 40
Total ECL charge/(release) to the Income Statement	(233)	639	[1]	198	[1]
Retail Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Total ECL charge/(release) to the Income Statement	(98)	264		129
Consumer Finance
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Total ECL charge/(release) to the Income Statement	(33)	44		27
Corporate & Commercial Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Total ECL charge/(release) to the Income Statement	(91)	294		45
Corporate Centre
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Total ECL charge/(release) to the Income Statement	(11)	37		(3)
Corporate & Investment Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Total ECL charge/(release) to the Income Statement	0	0		0
Stage 1
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	216
Ending balance	133	216
Stage 1 | Subject to 12-month ECL | Financial instruments not credit-impaired
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	307,416	301,599
Transfers from Stage 1 to Stage 2	(6,805)	(9,814)
Transfers from Stage 2 to Stage 1	5,883	3,178
Transfers to Stage 3	(572)	(385)
Transfers from Stage 3	14	12
Transfers of financial instruments	(1,480)	(7,009)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	50,863	55,546
Redemptions, repayments and assets sold	(63,659)	(47,671)
Changes in risk parameters and other movements	5,145	4,953
Assets written off	0	(2)
Ending balance	298,285	307,416		301,599
Net movement in the period	(9,131)	5,817
Stage 1 | Subject to 12-month ECL | Financial instruments not credit-impaired | Retail Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	191,883	186,088
Transfers from Stage 1 to Stage 2	(5,653)	(5,087)
Transfers from Stage 2 to Stage 1	4,200	2,168
Transfers to Stage 3	(526)	(272)
Transfers from Stage 3	9	8
Transfers of financial instruments	(1,970)	(3,183)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	35,442	31,499
Redemptions, repayments and assets sold	(28,094)	(23,699)
Changes in risk parameters and other movements	3,653	1,178
Assets written off	0	0
Ending balance	200,914	191,883		186,088
Net movement in the period	9,031	5,795
Stage 1 | Subject to 12-month ECL | Financial instruments not credit-impaired | Homes
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	170,794	168,830
Transfers from Stage 1 to Stage 2	(5,439)	(4,686)
Transfers from Stage 2 to Stage 1	3,782	1,911
Transfers to Stage 3	(242)	(229)
Transfers from Stage 3	3	4
Transfers of financial instruments	(1,896)	(3,000)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	33,292	26,102
Redemptions, repayments and assets sold	(25,073)	(20,679)
Changes in risk parameters and other movements	3,115	(459)
Assets written off	0	0
Ending balance	180,232	170,794		168,830
Net movement in the period	9,438	1,964
Stage 1 | Subject to 12-month ECL | Financial instruments not credit-impaired | Everyday Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	21,089	17,258
Transfers from Stage 1 to Stage 2	(214)	(402)
Transfers from Stage 2 to Stage 1	418	257
Transfers to Stage 3	(284)	(42)
Transfers from Stage 3	5	4
Transfers of financial instruments	(75)	(183)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	2,150	5,398
Redemptions, repayments and assets sold	(3,023)	3,020
Changes in risk parameters and other movements	541	1,636
Assets written off	0	0
Ending balance	20,682	21,089		17,258
Net movement in the period	(407)	3,831
Stage 1 | Subject to 12-month ECL | Financial instruments not credit-impaired | Consumer Finance
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	7,824	7,315
Transfers from Stage 1 to Stage 2	(98)	(154)
Transfers from Stage 2 to Stage 1	105	375
Transfers to Stage 3	(8)	(33)
Transfers from Stage 3	5	0
Transfers of financial instruments	4	188
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	2,212	3,486
Redemptions, repayments and assets sold	(4,063)	(2,136)
Changes in risk parameters and other movements	(903)	(1,027)
Assets written off	0	(2)
Ending balance	5,074	7,824		7,315
Net movement in the period	(2,750)	509
Stage 1 | Subject to 12-month ECL | Financial instruments not credit-impaired | Corporate & Commercial Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	17,217	21,281
Transfers from Stage 1 to Stage 2	(914)	(4,443)
Transfers from Stage 2 to Stage 1	1,579	528
Transfers to Stage 3	(38)	(78)
Transfers from Stage 3	1	4
Transfers of financial instruments	628	(3,989)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	12,783	7,984
Redemptions, repayments and assets sold	(15,067)	(6,487)
Changes in risk parameters and other movements	2,642	(1,572)
Assets written off	0	0
Ending balance	18,203	17,217		21,281
Net movement in the period	986	(4,064)
Stage 1 | Subject to 12-month ECL | Financial instruments not credit-impaired | Corporate Centre
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	79,275	73,943
Transfers from Stage 1 to Stage 2	(141)	(87)
Transfers from Stage 2 to Stage 1	0	106
Transfers to Stage 3	0	(2)
Transfers from Stage 3	0	1
Transfers of financial instruments	(141)	18
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	425	11,457
Redemptions, repayments and assets sold	(5,326)	(10,344)
Changes in risk parameters and other movements	(139)	4,201
Assets written off	0	0
Ending balance	74,094	79,275		73,943
Net movement in the period	(5,181)	5,332
Stage 1 | Subject to 12-month ECL | Financial instruments not credit-impaired | Corporate & Investment Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	11,217	12,972
Transfers from Stage 1 to Stage 2		(43)
Transfers from Stage 2 to Stage 1		0
Transfers to Stage 3		0
Transfers from Stage 3		0
Transfers of financial instruments		(43)
Net ECL remeasurement on stage transfer		0
Change in economic scenarios		0
Changes to model		0
New lending and assets purchased		1,119
Redemptions, repayments and assets sold		(5,005)
Changes in risk parameters and other movements		2,174
Assets written off		0
Ending balance		11,217		12,972
Net movement in the period		(1,755)
Stage 2
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	592
Ending balance	330	592
Stage 2 | Subject to Lifetime ECL | Financial instruments not credit-impaired
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	18,380	12,354
Transfers from Stage 1 to Stage 2	6,805	9,814
Transfers from Stage 2 to Stage 1	(5,883)	(3,178)
Transfers to Stage 3	(532)	(1,126)
Transfers from Stage 3	455	326
Transfers of financial instruments	845	5,836
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	936	1,372
Redemptions, repayments and assets sold	(3,441)	(2,250)
Changes in risk parameters and other movements	1,293	1,068
Assets written off	0	0
Ending balance	18,013	18,380		12,354
Net movement in the period	(367)	6,026
Stage 2 | Subject to Lifetime ECL | Financial instruments not credit-impaired | Retail Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	11,261	8,872
Transfers from Stage 1 to Stage 2	5,653	5,087
Transfers from Stage 2 to Stage 1	(4,200)	(2,168)
Transfers to Stage 3	(488)	(520)
Transfers from Stage 3	364	323
Transfers of financial instruments	1,329	2,722
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	417	345
Redemptions, repayments and assets sold	(1,537)	(987)
Changes in risk parameters and other movements	427	309
Assets written off	0	0
Ending balance	11,897	11,261		8,872
Net movement in the period	636	2,389
Stage 2 | Subject to Lifetime ECL | Financial instruments not credit-impaired | Homes
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	10,470	8,224
Transfers from Stage 1 to Stage 2	5,439	4,686
Transfers from Stage 2 to Stage 1	(3,782)	(1,911)
Transfers to Stage 3	(451)	(491)
Transfers from Stage 3	353	311
Transfers of financial instruments	1,559	2,595
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	332	237
Redemptions, repayments and assets sold	(1,435)	(856)
Changes in risk parameters and other movements	273	270
Assets written off	0	0
Ending balance	11,199	10,470		8,224
Net movement in the period	729	2,246
Stage 2 | Subject to Lifetime ECL | Financial instruments not credit-impaired | Everyday Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	791	648
Transfers from Stage 1 to Stage 2	214	402
Transfers from Stage 2 to Stage 1	(418)	(257)
Transfers to Stage 3	(36)	(29)
Transfers from Stage 3	11	11
Transfers of financial instruments	(229)	127
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	84	107
Redemptions, repayments and assets sold	(101)	130
Changes in risk parameters and other movements	153	39
Assets written off	0	0
Ending balance	698	791		648
Net movement in the period	(93)	143
Stage 2 | Subject to Lifetime ECL | Financial instruments not credit-impaired | Consumer Finance
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	379	604
Transfers from Stage 1 to Stage 2	98	154
Transfers from Stage 2 to Stage 1	(105)	(375)
Transfers to Stage 3	(8)	(20)
Transfers from Stage 3	3	1
Transfers of financial instruments	(12)	(240)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	70	134
Redemptions, repayments and assets sold	(142)	(151)
Changes in risk parameters and other movements	(95)	32
Assets written off	0	0
Ending balance	200	379		604
Net movement in the period	(179)	(225)
Stage 2 | Subject to Lifetime ECL | Financial instruments not credit-impaired | Corporate & Commercial Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	6,266	2,385
Transfers from Stage 1 to Stage 2	914	4,443
Transfers from Stage 2 to Stage 1	(1,579)	(528)
Transfers to Stage 3	(37)	(543)
Transfers from Stage 3	88	1
Transfers of financial instruments	(614)	3,373
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	448	805
Redemptions, repayments and assets sold	(1,330)	(818)
Changes in risk parameters and other movements	891	521
Assets written off	0	0
Ending balance	5,661	6,266		2,385
Net movement in the period	(605)	3,881
Stage 2 | Subject to Lifetime ECL | Financial instruments not credit-impaired | Corporate Centre
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	45	97
Transfers from Stage 1 to Stage 2	141	87
Transfers from Stage 2 to Stage 1	0	(106)
Transfers to Stage 3	0	(3)
Transfers from Stage 3	0	1
Transfers of financial instruments	141	(21)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	2	45
Redemptions, repayments and assets sold	(27)	(7)
Changes in risk parameters and other movements	94	(69)
Assets written off	0	0
Ending balance	255	45		97
Net movement in the period	210	(52)
Stage 2 | Subject to Lifetime ECL | Financial instruments not credit-impaired | Corporate & Investment Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	429	397
Transfers from Stage 1 to Stage 2		43
Transfers from Stage 2 to Stage 1		0
Transfers to Stage 3		(40)
Transfers from Stage 3		0
Transfers of financial instruments		3
Net ECL remeasurement on stage transfer		0
Change in economic scenarios		0
Changes to model		0
New lending and assets purchased		43
Redemptions, repayments and assets sold		(287)
Changes in risk parameters and other movements		273
Assets written off		0
Ending balance		429		397
Net movement in the period		32
Stage 3
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	569
Ending balance	403	569
Stage 3 | Subject to Lifetime ECL | Financial instruments credit-impaired
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	2,996	2,369
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	1,104	1,511
Transfers from Stage 3	(469)	(338)
Transfers of financial instruments	635	1,173
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	24	104
Redemptions, repayments and assets sold	(519)	(441)
Changes in risk parameters and other movements	182	184
Assets written off	(297)	(393)
Ending balance	3,021	2,996		2,369
Net movement in the period	25	627
Stage 3 | Subject to Lifetime ECL | Financial instruments credit-impaired | Retail Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	1,918	1,859
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	1,014	792
Transfers from Stage 3	(373)	(331)
Transfers of financial instruments	641	461
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	9	5
Redemptions, repayments and assets sold	(361)	(314)
Changes in risk parameters and other movements	90	110
Assets written off	(129)	(203)
Ending balance	2,168	1,918		1,859
Net movement in the period	250	59
Stage 3 | Subject to Lifetime ECL | Financial instruments credit-impaired | Homes
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	1,813	1,734
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	693	720
Transfers from Stage 3	(356)	(315)
Transfers of financial instruments	337	405
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	1	1
Redemptions, repayments and assets sold	(332)	(297)
Changes in risk parameters and other movements	13	24
Assets written off	(16)	(54)
Ending balance	1,816	1,813		1,734
Net movement in the period	3	79
Stage 3 | Subject to Lifetime ECL | Financial instruments credit-impaired | Everyday Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	105	125
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	320	71
Transfers from Stage 3	(16)	(15)
Transfers of financial instruments	304	56
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	9	5
Redemptions, repayments and assets sold	(29)	19
Changes in risk parameters and other movements	77	87
Assets written off	(114)	149
Ending balance	352	105		125
Net movement in the period	247	(20)
Stage 3 | Subject to Lifetime ECL | Financial instruments credit-impaired | Consumer Finance
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	58	42
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	16	53
Transfers from Stage 3	(8)	(1)
Transfers of financial instruments	8	52
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	3	4
Redemptions, repayments and assets sold	(19)	(5)
Changes in risk parameters and other movements	11	(10)
Assets written off	(37)	(25)
Ending balance	24	58		42
Net movement in the period	(34)	16
Stage 3 | Subject to Lifetime ECL | Financial instruments credit-impaired | Corporate & Commercial Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	1,020	452
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	75	621
Transfers from Stage 3	(89)	(5)
Transfers of financial instruments	(14)	616
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	12	94
Redemptions, repayments and assets sold	(140)	(118)
Changes in risk parameters and other movements	55	97
Assets written off	(106)	(121)
Ending balance	827	1,020		452
Net movement in the period	(193)	568
Stage 3 | Subject to Lifetime ECL | Financial instruments credit-impaired | Corporate Centre
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	0	0
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	5
Transfers from Stage 3	0	(2)
Transfers of financial instruments	0	3
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	0	1
Redemptions, repayments and assets sold	1	(3)
Changes in risk parameters and other movements	1	1
Assets written off	0	(2)
Ending balance	2	0		0
Net movement in the period	2	0
Stage 3 | Subject to Lifetime ECL | Financial instruments credit-impaired | Corporate & Investment Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	0	15
Transfers from Stage 1 to Stage 2		0
Transfers from Stage 2 to Stage 1		0
Transfers to Stage 3		40
Transfers from Stage 3		0
Transfers of financial instruments		40
Net ECL remeasurement on stage transfer		0
Change in economic scenarios		0
Changes to model		0
New lending and assets purchased		0
Redemptions, repayments and assets sold		(1)
Changes in risk parameters and other movements		(12)
Assets written off		(42)
Ending balance		0		15
Net movement in the period		(15)
Exposures
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	328,792	316,322
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	51,823	57,022
Redemptions, repayments and assets sold	(67,619)	(50,362)
Changes in risk parameters and other movements	6,620	6,205
Assets written off	(297)	(395)
Ending balance	319,319	328,792		316,322
Net movement in the period	(9,473)	12,470
Exposures | Retail Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	205,062	196,819
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	35,868	31,849
Redemptions, repayments and assets sold	(29,992)	(25,000)
Changes in risk parameters and other movements	4,170	1,597
Assets written off	(129)	(203)
Ending balance	214,979	205,062		196,819
Net movement in the period	9,917	8,243
Exposures | Homes
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	183,077	178,788
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	33,625	26,340
Redemptions, repayments and assets sold	(26,840)	(21,832)
Changes in risk parameters and other movements	3,401	(165)
Assets written off	(16)	(54)
Ending balance	193,247	183,077		178,788
Net movement in the period	10,170	4,289
Exposures | Everyday Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	21,985	18,031
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	2,243	5,510
Redemptions, repayments and assets sold	(3,153)	3,169
Changes in risk parameters and other movements	771	1,762
Assets written off	(114)	149
Ending balance	21,732	21,985		18,031
Net movement in the period	(253)	3,954
Exposures | Consumer Finance
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	8,261	7,961
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	2,285	3,624
Redemptions, repayments and assets sold	(4,224)	(2,292)
Changes in risk parameters and other movements	(987)	(1,005)
Assets written off	(37)	(27)
Ending balance	5,298	8,261		7,961
Net movement in the period	(2,963)	300
Exposures | Corporate & Commercial Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	24,503	24,118
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model		0
New lending and assets purchased	13,243	8,883
Redemptions, repayments and assets sold	(16,537)	(7,423)
Changes in risk parameters and other movements	3,588	(954)
Assets written off	(106)	(121)
Ending balance	24,691	24,503		24,118
Net movement in the period	188	385
Exposures | Corporate Centre
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	79,320	74,040
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	427	11,503
Redemptions, repayments and assets sold	(5,352)	(10,354)
Changes in risk parameters and other movements	(44)	4,133
Assets written off	0	(2)
Ending balance	74,351	79,320		74,040
Net movement in the period	(4,969)	5,280
Exposures | Corporate & Investment Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	11,646	13,384
Transfers from Stage 1 to Stage 2		0
Transfers from Stage 2 to Stage 1		0
Transfers to Stage 3		0
Transfers from Stage 3		0
Transfers of financial instruments		0
Net ECL remeasurement on stage transfer		0
Change in economic scenarios		0
Changes to model		0
New lending and assets purchased		1,162
Redemptions, repayments and assets sold		(5,293)
Changes in risk parameters and other movements		2,435
Assets written off		(42)
Ending balance		11,646		13,384
Net movement in the period		(1,738)
Stage 1 ECL | Subject to 12-month ECL | Financial instruments not credit-impaired
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	216	147
Transfers from Stage 1 to Stage 2	(9)	(47)
Transfers from Stage 2 to Stage 1	167	110
Transfers to Stage 3	(3)	(8)
Transfers from Stage 3	2	2
Transfers of financial instruments	157	57
Net ECL remeasurement on stage transfer	(133)	(101)
Change in economic scenarios	(7)	15
Changes to model	0	0
New lending and assets purchased	31	40
Redemptions, repayments and assets sold	(70)	(30)
Changes in risk parameters and other movements	(61)	88
Assets written off	0	0
Ending balance	133	216		147
Net movement in the period	(83)	69
ECL charge/(release) to the Income Statement	(83)	69
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(72)	69
Stage 1 ECL | Subject to 12-month ECL | Financial instruments not credit-impaired | Retail Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	74	60
Transfers from Stage 1 to Stage 2	(4)	(7)
Transfers from Stage 2 to Stage 1	101	82
Transfers to Stage 3	(2)	(4)
Transfers from Stage 3	1	1
Transfers of financial instruments	96	72
Net ECL remeasurement on stage transfer	(95)	(80)
Change in economic scenarios	(7)	8
Changes to model	0	0
New lending and assets purchased	19	15
Redemptions, repayments and assets sold	(13)	(12)
Changes in risk parameters and other movements	(10)	12
Assets written off	1	(1)
Ending balance	65	74		60
Net movement in the period	(9)	14
ECL charge/(release) to the Income Statement	(10)	15
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(10)	15
Stage 1 ECL | Subject to 12-month ECL | Financial instruments not credit-impaired | Homes
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	17	14
Transfers from Stage 1 to Stage 2	(2)	(2)
Transfers from Stage 2 to Stage 1	21	17
Transfers to Stage 3	(2)	(3)
Transfers from Stage 3	0	0
Transfers of financial instruments	17	12
Net ECL remeasurement on stage transfer	(18)	(15)
Change in economic scenarios	(1)	7
Changes to model	0	0
New lending and assets purchased	6	4
Redemptions, repayments and assets sold	(3)	(4)
Changes in risk parameters and other movements	(4)	(1)
Assets written off	0	0
Ending balance	14	17		14
Net movement in the period	(3)	3
ECL charge/(release) to the Income Statement	(3)	3
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(3)	3
Stage 1 ECL | Subject to 12-month ECL | Financial instruments not credit-impaired | Everyday Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	57	46
Transfers from Stage 1 to Stage 2	(2)	(5)
Transfers from Stage 2 to Stage 1	81	65
Transfers to Stage 3	(1)	(1)
Transfers from Stage 3	1	1
Transfers of financial instruments	79	60
Net ECL remeasurement on stage transfer	(78)	(63)
Change in economic scenarios	(4)	0
Changes to model	0	0
New lending and assets purchased	13	11
Redemptions, repayments and assets sold	(11)	8
Changes in risk parameters and other movements	(6)	12
Assets written off	1	1
Ending balance	51	57		46
Net movement in the period	(6)	11
ECL charge/(release) to the Income Statement	(7)	12
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(7)	12
Stage 1 ECL | Subject to 12-month ECL | Financial instruments not credit-impaired | Consumer Finance
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	44	29
Transfers from Stage 1 to Stage 2	(1)	(1)
Transfers from Stage 2 to Stage 1	6	4
Transfers to Stage 3	0	(3)
Transfers from Stage 3	0	0
Transfers of financial instruments	5	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	6	14
Redemptions, repayments and assets sold	(19)	(4)
Changes in risk parameters and other movements	(18)	5
Assets written off	0	0
Ending balance	18	44		29
Net movement in the period	(26)	15
ECL charge/(release) to the Income Statement	(26)	15
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(26)	15
Stage 1 ECL | Subject to 12-month ECL | Financial instruments not credit-impaired | Corporate & Commercial Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	54	53
Transfers from Stage 1 to Stage 2	(4)	(37)
Transfers from Stage 2 to Stage 1	60	20
Transfers to Stage 3	0	(1)
Transfers from Stage 3	0	1
Transfers of financial instruments	56	(17)
Net ECL remeasurement on stage transfer	(39)	(18)
Change in economic scenarios	(2)	7
Changes to model	0
New lending and assets purchased	5	10
Redemptions, repayments and assets sold	(9)	(13)
Changes in risk parameters and other movements	(16)	32
Assets written off	0	0
Ending balance	49	54		53
Net movement in the period	(5)	1
ECL charge/(release) to the Income Statement	(5)	1
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(5)	1
Stage 1 ECL | Subject to 12-month ECL | Financial instruments not credit-impaired | Corporate Centre
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	35	1
Transfers from Stage 1 to Stage 2	0	(2)
Transfers from Stage 2 to Stage 1	0	4
Transfers to Stage 3	0	0
Transfers from Stage 3	0	1
Transfers of financial instruments	0	3
Net ECL remeasurement on stage transfer	0	(4)
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	1	1
Redemptions, repayments and assets sold	(18)	(1)
Changes in risk parameters and other movements	(17)	35
Assets written off	0	0
Ending balance	1	35		1
Net movement in the period	(34)	34
ECL charge/(release) to the Income Statement	(34)	34
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(34)	34
Stage 1 ECL | Subject to 12-month ECL | Financial instruments not credit-impaired | Corporate & Investment Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	9	4
Transfers from Stage 1 to Stage 2		0
Transfers from Stage 2 to Stage 1		0
Transfers to Stage 3		0
Transfers from Stage 3		0
Transfers of financial instruments		0
Net ECL remeasurement on stage transfer		0
Change in economic scenarios		0
Changes to model		0
New lending and assets purchased		1
Redemptions, repayments and assets sold		(1)
Changes in risk parameters and other movements		5
Assets written off		0
Ending balance		9		4
Net movement in the period		5
ECL charge/(release) to the Income Statement		5
Less: Discount unwind		0
Less: Recoveries net of collection costs		0
Total ECL charge/(release) to the Income Statement		5
Stage 2 ECL | Subject to Lifetime ECL | Financial instruments not credit-impaired
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	592	348
Transfers from Stage 1 to Stage 2	9	47
Transfers from Stage 2 to Stage 1	(167)	(110)
Transfers to Stage 3	(20)	(61)
Transfers from Stage 3	62	21
Transfers of financial instruments	(116)	(103)
Net ECL remeasurement on stage transfer	26	239
Change in economic scenarios	(151)	139
Changes to model	0	0
New lending and assets purchased	26	64
Redemptions, repayments and assets sold	(67)	(42)
Changes in risk parameters and other movements	20	(53)
Assets written off	0	0
Ending balance	330	592		348
Net movement in the period	(262)	244
ECL charge/(release) to the Income Statement	(262)	244
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(262)	244
Stage 2 ECL | Subject to Lifetime ECL | Financial instruments not credit-impaired | Retail Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	332	231
Transfers from Stage 1 to Stage 2	4	7
Transfers from Stage 2 to Stage 1	(101)	(82)
Transfers to Stage 3	(16)	(22)
Transfers from Stage 3	21	20
Transfers of financial instruments	(92)	(77)
Net ECL remeasurement on stage transfer	48	145
Change in economic scenarios	(85)	81
Changes to model	0	0
New lending and assets purchased	14	30
Redemptions, repayments and assets sold	(22)	(25)
Changes in risk parameters and other movements	(8)	(54)
Assets written off	(1)	1
Ending balance	186	332		231
Net movement in the period	(146)	101
ECL charge/(release) to the Income Statement	(145)	100
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(145)	100
Stage 2 ECL | Subject to Lifetime ECL | Financial instruments not credit-impaired | Homes
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	131	101
Transfers from Stage 1 to Stage 2	2	2
Transfers from Stage 2 to Stage 1	(21)	(17)
Transfers to Stage 3	(4)	(11)
Transfers from Stage 3	15	14
Transfers of financial instruments	(8)	(12)
Net ECL remeasurement on stage transfer	10	50
Change in economic scenarios	(67)	13
Changes to model	0	0
New lending and assets purchased	2	5
Redemptions, repayments and assets sold	(6)	(7)
Changes in risk parameters and other movements	26	(19)
Assets written off	0	0
Ending balance	88	131		101
Net movement in the period	(43)	30
ECL charge/(release) to the Income Statement	(43)	30
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(43)	30
Stage 2 ECL | Subject to Lifetime ECL | Financial instruments not credit-impaired | Everyday Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	201	130
Transfers from Stage 1 to Stage 2	2	5
Transfers from Stage 2 to Stage 1	(81)	(65)
Transfers to Stage 3	(10)	(11)
Transfers from Stage 3	5	5
Transfers of financial instruments	(84)	(66)
Net ECL remeasurement on stage transfer	39	95
Change in economic scenarios	(19)	68
Changes to model	0	0
New lending and assets purchased	12	25
Redemptions, repayments and assets sold	(16)	19
Changes in risk parameters and other movements	(34)	(33)
Assets written off	(1)	(1)
Ending balance	98	201		130
Net movement in the period	(103)	71
ECL charge/(release) to the Income Statement	(102)	70
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(102)	70
Stage 2 ECL | Subject to Lifetime ECL | Financial instruments not credit-impaired | Consumer Finance
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	37	28
Transfers from Stage 1 to Stage 2	1	1
Transfers from Stage 2 to Stage 1	(6)	(4)
Transfers to Stage 3	(2)	(5)
Transfers from Stage 3	2	1
Transfers of financial instruments	(5)	(7)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	(2)	0
Changes to model	0	0
New lending and assets purchased	4	6
Redemptions, repayments and assets sold	(6)	3
Changes in risk parameters and other movements	(12)	8
Assets written off	1	(1)
Ending balance	17	37		28
Net movement in the period	(20)	9
ECL charge/(release) to the Income Statement	(21)	10
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(21)	10
Stage 2 ECL | Subject to Lifetime ECL | Financial instruments not credit-impaired | Corporate & Commercial Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	199	51
Transfers from Stage 1 to Stage 2	4	37
Transfers from Stage 2 to Stage 1	(60)	(20)
Transfers to Stage 3	(3)	(21)
Transfers from Stage 3	40	0
Transfers of financial instruments	(19)	(4)
Net ECL remeasurement on stage transfer	(22)	92
Change in economic scenarios	(62)	44
Changes to model	0
New lending and assets purchased	8	28
Redemptions, repayments and assets sold	(17)	(18)
Changes in risk parameters and other movements	40	6
Assets written off	0	0
Ending balance	127	199		51
Net movement in the period	(72)	148
ECL charge/(release) to the Income Statement	(72)	148
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(72)	148
Stage 2 ECL | Subject to Lifetime ECL | Financial instruments not credit-impaired | Corporate Centre
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	0	1
Transfers from Stage 1 to Stage 2	0	2
Transfers from Stage 2 to Stage 1	0	(4)
Transfers to Stage 3	0	(1)
Transfers from Stage 3	0	0
Transfers of financial instruments	0	(3)
Net ECL remeasurement on stage transfer	0	3
Change in economic scenarios	0	6
Changes to model	0	0
New lending and assets purchased	0	0
Redemptions, repayments and assets sold	0	(1)
Changes in risk parameters and other movements	0	(6)
Assets written off	0	0
Ending balance	0	0		1
Net movement in the period	0	(1)
ECL charge/(release) to the Income Statement	0	(1)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	0	(1)
Stage 2 ECL | Subject to Lifetime ECL | Financial instruments not credit-impaired | Corporate & Investment Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	24	37
Transfers from Stage 1 to Stage 2		0
Transfers from Stage 2 to Stage 1		0
Transfers to Stage 3		(13)
Transfers from Stage 3		0
Transfers of financial instruments		(13)
Net ECL remeasurement on stage transfer		0
Change in economic scenarios		8
Changes to model		0
New lending and assets purchased		0
Redemptions, repayments and assets sold		(1)
Changes in risk parameters and other movements		(7)
Assets written off		0
Ending balance		24		37
Net movement in the period		(13)
ECL charge/(release) to the Income Statement		(13)
Less: Discount unwind		0
Less: Recoveries net of collection costs		0
Total ECL charge/(release) to the Income Statement		(13)
Stage 3 ECL | Subject to Lifetime ECL | Financial instruments credit-impaired
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	569	368
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	23	69
Transfers from Stage 3	(64)	(23)
Transfers of financial instruments	(41)	46
Net ECL remeasurement on stage transfer	64	241
Change in economic scenarios	(12)	10
Changes to model	0	25
New lending and assets purchased	19	51
Redemptions, repayments and assets sold	(68)	(18)
Changes in risk parameters and other movements	63	99
Assets written off	(191)	(253)
Ending balance	403	569		368
Net movement in the period	(166)	201
ECL charge/(release) to the Income Statement	25	454
Less: Discount unwind	(11)	(14)
Less: Recoveries net of collection costs	87	(108)
Total ECL charge/(release) to the Income Statement	101	326
Stage 3 ECL | Subject to Lifetime ECL | Financial instruments credit-impaired | Retail Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	182	170
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	18	26
Transfers from Stage 3	(22)	(21)
Transfers of financial instruments	(4)	5
Net ECL remeasurement on stage transfer	33	42
Change in economic scenarios	(12)	9
Changes to model	0	25
New lending and assets purchased	4	4
Redemptions, repayments and assets sold	(21)	(20)
Changes in risk parameters and other movements	64	102
Assets written off	(108)	(155)
Ending balance	138	182		170
Net movement in the period	(44)	12
ECL charge/(release) to the Income Statement	64	167
Less: Discount unwind	(7)	(7)
Less: Recoveries net of collection costs	0	(11)
Total ECL charge/(release) to the Income Statement	57	149
Stage 3 ECL | Subject to Lifetime ECL | Financial instruments credit-impaired | Homes
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	132	103
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	6	14
Transfers from Stage 3	(15)	(14)
Transfers of financial instruments	(9)	0
Net ECL remeasurement on stage transfer	9	16
Change in economic scenarios	(12)	10
Changes to model	0	25
New lending and assets purchased	0	0
Redemptions, repayments and assets sold	(16)	(15)
Changes in risk parameters and other movements	(10)	7
Assets written off	(5)	(14)
Ending balance	89	132		103
Net movement in the period	(43)	29
ECL charge/(release) to the Income Statement	(38)	43
Less: Discount unwind	(2)	(2)
Less: Recoveries net of collection costs	(1)	(1)
Total ECL charge/(release) to the Income Statement	(41)	40
Stage 3 ECL | Subject to Lifetime ECL | Financial instruments credit-impaired | Everyday Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	50	67
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	11	12
Transfers from Stage 3	(6)	(6)
Transfers of financial instruments	5	6
Net ECL remeasurement on stage transfer	23	25
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	4	4
Redemptions, repayments and assets sold	(5)	5
Changes in risk parameters and other movements	74	94
Assets written off	(102)	141
Ending balance	49	50		67
Net movement in the period	(1)	(17)
ECL charge/(release) to the Income Statement	101	124
Less: Discount unwind	(4)	(4)
Less: Recoveries net of collection costs	(51)	(52)
Total ECL charge/(release) to the Income Statement	46	68
Stage 3 ECL | Subject to Lifetime ECL | Financial instruments credit-impaired | Consumer Finance
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	37	31
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	2	8
Transfers from Stage 3	(2)	(1)
Transfers of financial instruments	0	7
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	2	2
Redemptions, repayments and assets sold	(3)	29
Changes in risk parameters and other movements	6	(8)
Assets written off	(25)	(24)
Ending balance	17	37		31
Net movement in the period	(20)	6
ECL charge/(release) to the Income Statement	5	30
Less: Discount unwind	0	6
Less: Recoveries net of collection costs	9	(17)
Total ECL charge/(release) to the Income Statement	14	19
Stage 3 ECL | Subject to Lifetime ECL | Financial instruments credit-impaired | Corporate & Commercial Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	350	158
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	3	22
Transfers from Stage 3	(40)	(1)
Transfers of financial instruments	(37)	21
Net ECL remeasurement on stage transfer	31	198
Change in economic scenarios	(1)	0
Changes to model	0
New lending and assets purchased	13	44
Redemptions, repayments and assets sold	(43)	(25)
Changes in risk parameters and other movements	(7)	5
Assets written off	(59)	(51)
Ending balance	247	350		158
Net movement in the period	(103)	192
ECL charge/(release) to the Income Statement	(44)	243
Less: Discount unwind	(4)	(5)
Less: Recoveries net of collection costs	34	(93)
Total ECL charge/(release) to the Income Statement	(14)	145
Stage 3 ECL | Subject to Lifetime ECL | Financial instruments credit-impaired | Corporate Centre
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	0	0
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	1
Transfers from Stage 3	0	(1)
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	1
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	0	0
Redemptions, repayments and assets sold	1	(1)
Changes in risk parameters and other movements	0	0
Assets written off	0	0
Ending balance	1	0		0
Net movement in the period	1	0
ECL charge/(release) to the Income Statement	1	0
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	22	3
Total ECL charge/(release) to the Income Statement	23	3
Stage 3 ECL | Subject to Lifetime ECL | Financial instruments credit-impaired | Corporate & Investment Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	0	9
Transfers from Stage 1 to Stage 2		0
Transfers from Stage 2 to Stage 1		0
Transfers to Stage 3		13
Transfers from Stage 3		0
Transfers of financial instruments		13
Net ECL remeasurement on stage transfer		0
Change in economic scenarios		0
Changes to model		0
New lending and assets purchased		0
Redemptions, repayments and assets sold		0
Changes in risk parameters and other movements		0
Assets written off		(22)
Ending balance		0		9
Net movement in the period		(9)
ECL charge/(release) to the Income Statement		13
Less: Discount unwind		0
Less: Recoveries net of collection costs		2
Total ECL charge/(release) to the Income Statement		15
ECL
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	1,377	863
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	(43)	379
Change in economic scenarios	(170)	164
Changes to model	0	25
New lending and assets purchased	76	155
Redemptions, repayments and assets sold	(205)	(90)
Changes in risk parameters and other movements	22	134
Assets written off	(191)	(253)
Ending balance	866	1,377		863
Net movement in the period	(511)	514
ECL charge/(release) to the Income Statement	(320)	767
Less: Discount unwind	(11)	(14)
Less: Recoveries net of collection costs	87	(108)
Total ECL charge/(release) to the Income Statement	(233)	639
ECL | Retail Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	588	461
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	(14)	107
Change in economic scenarios	(104)	98
Changes to model	0	25
New lending and assets purchased	37	49
Redemptions, repayments and assets sold	(56)	(57)
Changes in risk parameters and other movements	46	60
Assets written off	(108)	(155)
Ending balance	389	588		461
Net movement in the period	(199)	127
ECL charge/(release) to the Income Statement	(91)	282
Less: Discount unwind	(7)	(7)
Less: Recoveries net of collection costs	0	(11)
Total ECL charge/(release) to the Income Statement	(98)	264
ECL | Homes
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	280	218
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	1	51
Change in economic scenarios	(80)	30
Changes to model	0	25
New lending and assets purchased	8	9
Redemptions, repayments and assets sold	(25)	(26)
Changes in risk parameters and other movements	12	(13)
Assets written off	(5)	(14)
Ending balance	191	280		218
Net movement in the period	(89)	62
ECL charge/(release) to the Income Statement	(84)	76
Less: Discount unwind	(2)	(2)
Less: Recoveries net of collection costs	(1)	(1)
Total ECL charge/(release) to the Income Statement	(87)	73
ECL | Everyday Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	308	243
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	(16)	57
Change in economic scenarios	(23)	68
Changes to model	0	0
New lending and assets purchased	29	40
Redemptions, repayments and assets sold	(32)	32
Changes in risk parameters and other movements	34	73
Assets written off	(102)	141
Ending balance	198	308		243
Net movement in the period	(110)	65
ECL charge/(release) to the Income Statement	(8)	206
Less: Discount unwind	(4)	(4)
Less: Recoveries net of collection costs	(51)	(52)
Total ECL charge/(release) to the Income Statement	(63)	150
ECL | Consumer Finance
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	118	88
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	(2)	0
Changes to model	0	0
New lending and assets purchased	12	22
Redemptions, repayments and assets sold	(28)	28
Changes in risk parameters and other movements	(24)	5
Assets written off	(24)	(25)
Ending balance	52	118		88
Net movement in the period	(66)	30
ECL charge/(release) to the Income Statement	(42)	55
Less: Discount unwind	0	6
Less: Recoveries net of collection costs	9	(17)
Total ECL charge/(release) to the Income Statement	(33)	44
ECL | Corporate & Commercial Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	603	262
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	(30)	272
Change in economic scenarios	(65)	51
Changes to model	0
New lending and assets purchased	26	82
Redemptions, repayments and assets sold	(69)	(56)
Changes in risk parameters and other movements	17	43
Assets written off	(59)	(51)
Ending balance	423	603		262
Net movement in the period	(180)	341
ECL charge/(release) to the Income Statement	(121)	392
Less: Discount unwind	(4)	(5)
Less: Recoveries net of collection costs	34	(93)
Total ECL charge/(release) to the Income Statement	(91)	294
ECL | Corporate Centre
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	35	2
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	6
Changes to model	0	0
New lending and assets purchased	1	1
Redemptions, repayments and assets sold	(17)	(3)
Changes in risk parameters and other movements	(17)	29
Assets written off	0	0
Ending balance	2	35		2
Net movement in the period	(33)	33
ECL charge/(release) to the Income Statement	(33)	33
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	22	3
Total ECL charge/(release) to the Income Statement	(11)	36
ECL | Corporate & Investment Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	£ 33	50
Transfers from Stage 1 to Stage 2		0
Transfers from Stage 2 to Stage 1		0
Transfers to Stage 3		0
Transfers from Stage 3		0
Transfers of financial instruments		0
Net ECL remeasurement on stage transfer		0
Change in economic scenarios		8
Changes to model		0
New lending and assets purchased		1
Redemptions, repayments and assets sold		(2)
Changes in risk parameters and other movements		(2)
Assets written off		(22)
Ending balance		33		£ 50
Net movement in the period		(17)
ECL charge/(release) to the Income Statement		5
Less: Discount unwind		0
Less: Recoveries net of collection costs		2
Total ECL charge/(release) to the Income Statement		£ 7
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Credit Risk - Disclosure of Hom

Credit Risk - Disclosure of Homes by Borrower Profile (Details) - Credit risk - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 177,297	£ 169,801
Percentage of residential mortgage loans	100.00%	100.00%
New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 32,013	£ 24,953
Percentage of residential mortgage loans	100.00%	100.00%
Home movers | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 75,879	£ 72,439
Percentage of residential mortgage loans	43.00%	42.00%
Home movers | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 13,537	£ 10,116
Percentage of residential mortgage loans	43.00%	41.00%
Remortgagers | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 51,336	£ 51,796
Percentage of residential mortgage loans	29.00%	31.00%
Remortgagers | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 8,031	£ 6,861
Percentage of residential mortgage loans	25.00%	27.00%
First-time buyers | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 35,189	£ 33,958
Percentage of residential mortgage loans	20.00%	20.00%
First-time buyers | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 6,206	£ 5,354
Percentage of residential mortgage loans	19.00%	21.00%
Buy-To-Let | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 14,893	£ 11,608
Percentage of residential mortgage loans	8.00%	7.00%
Buy-To-Let | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 4,239	£ 2,622
Percentage of residential mortgage loans	13.00%	11.00%

Credit Risk - Homes Credit Risk

Credit Risk - Homes Credit Risk Review, Additional Information (Details) £ in Millions	12 Months Ended
	Dec. 31, 2021GBP (£)mortgage_loan	Dec. 31, 2020GBP (£)mortgage_loan
Disclosure of credit risk exposure [line items]
Advances and flexible mortgage drawdowns	£ 1,400	£ 1,200
Part of loans in negative equity, uncollateralized	£ 75	£ 107
Average LTV of mortgage total new lending, in London	60.00%	60.00%
Internal remortgages
Disclosure of credit risk exposure [line items]
Internal remortgages	£ 30,500	£ 31,700
Greater than £2.0m | Credit risk
Disclosure of credit risk exposure [line items]
Number of individual mortgage loans | mortgage_loan	131	98
New business number of individual mortgage loans | mortgage_loan	52	38

Credit Risk - Disclosure of Int

Credit Risk - Disclosure of Interest Rate Profile of Mortgage Assets Stock (Details) - Stock - Credit risk - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 177,297	£ 169,801
Percentage of residential mortgage loans	100.00%	100.00%
Fixed rate
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 149,517	£ 136,045
Percentage of residential mortgage loans	84.00%	80.00%
Variable rate
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 17,124	£ 21,152
Percentage of residential mortgage loans	10.00%	13.00%
Standard Variable Rate (SVR)
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 7,876	£ 10,682
Percentage of residential mortgage loans	4.00%	6.00%
Follow on Rate (FoR)
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 2,780	£ 1,922
Percentage of residential mortgage loans	2.00%	1.00%

Credit Risk - Disclosure of Geo

Credit Risk - Disclosure of Geographic Distribution of Mortgage Assets Stock (Details) - Credit risk - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 177,297	£ 169,801
New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	32,013	24,953
London | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	45,300	42,600
London | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	8,300	6,100
Midlands and East Anglia | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	24,100	22,900
Midlands and East Anglia | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	4,700	3,700
North | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	23,500	23,100
North | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	3,800	3,300
Northern Ireland | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	3,000	3,100
Northern Ireland | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	300	200
Scotland | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	6,600	6,700
Scotland | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	1,000	800
South East excluding London | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	56,400	53,600
South East excluding London | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	10,500	8,300
South West, Wales and other | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	18,400	17,800
South West, Wales and other | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 3,400	£ 2,600

Credit Risk - Disclosure of Ave

Credit Risk - Disclosure of Average Loan Size for New Business (Details) - GBP (£) £ in Thousands	Dec. 31, 2021	Dec. 31, 2020
South East including London
Disclosure of credit risk exposure [line items]
New business residential mortgage loans average size	£ 306	£ 284
Rest of the UK
Disclosure of credit risk exposure [line items]
New business residential mortgage loans average size	175	166
UK
Disclosure of credit risk exposure [line items]
New business residential mortgage loans average size	£ 234	£ 218

Credit Risk - Disclosure of Mor

Credit Risk - Disclosure of Mortgage Assets Stock of Larger Loans (Details) - Credit risk - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 101,701	£ 96,178
UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	177,297	169,801
Less than £0.25m | South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	45,108	45,553
Less than £0.25m | UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	105,147	105,493
£0.25m to £0.50m | South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	39,367	36,241
£0.25m to £0.50m | UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	52,495	47,903
£0.50m to £1.0m | South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	14,036	12,214
£0.50m to £1.0m | UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	16,221	14,076
£1.0m to £2.0m | South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	2,872	1,934
£1.0m to £2.0m | UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	3,103	2,085
Greater than £2.0m | South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	318	236
Greater than £2.0m | UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 331	£ 244

Credit Risk - Disclosure of LTV

Credit Risk - Disclosure of LTV Distribution of Mortgage Assets Stock (Details) - Credit risk - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	£ 177,297	£ 169,801
Collateral value of residential properties, stock	177,222	169,694
Loan-to-value, stage 3	1,798	1,799
Collateral value of residential properties, stage 3	1,786	1,783
Loan-to-value, new business	32,013	24,953
Collateral value of residential properties, new business	32,012	24,953
Collateral against loans in negative equity	455	629
ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	191	280
Loan-to-value, stage 3	89	132
Up to 50%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	80,058	74,620
Loan-to-value, stage 3	944	858
Loan-to-value, new business	4,997	4,180
Up to 50% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	25	28
Loan-to-value, stage 3	9	11
>50-75%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	79,027	69,771
Loan-to-value, stage 3	614	633
Loan-to-value, new business	15,831	10,088
>50-75% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	63	90
Loan-to-value, stage 3	28	36
>75-85%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	14,035	18,508
Loan-to-value, stage 3	106	125
Loan-to-value, new business	6,896	5,858
>75-85% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	26	41
Loan-to-value, stage 3	12	19
>85-100%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	3,646	6,165
Loan-to-value, stage 3	69	93
Loan-to-value, new business	4,239	4,781
>85-100% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	26	44
Loan-to-value, stage 3	14	22
>100%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	531	737
Loan-to-value, stage 3	65	90
Loan-to-value, new business	50	46
>100% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	51	77
Loan-to-value, stage 3	£ 26	£ 44
Simple Average LTV
Disclosure of credit risk exposure [line items]
Percentage of loan to value, stock	41.00%	42.00%
Percentage of loan to value, stage 3	38.00%	41.00%
Percentage of loan to value, new business	64.00%	64.00%

Credit Risk - Disclosure of C_3

Credit Risk - Disclosure of Credit Performance by Segment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 213,525	£ 212,178
Loss allowance	828	1,303
Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	177,297	169,801
Everyday Banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	8,311	8,650
Loss allowance	£ 198	£ 308
Stage 3 ratio	4.23%	1.24%
Gross write- offs	£ 103	£ 141
Everyday Banking | Business banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	3,532	3,855
Loss allowance	£ 22	£ 9
Stage 3 ratio	7.20%	0.10%
Gross write- offs	£ 6	£ 12
Everyday Banking | Personal loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,000	2,038
Loss allowance	47	80
Everyday Banking | Credit cards
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,341	2,349
Loss allowance	89	158
Everyday Banking | Overdrafts
Disclosure of credit risk exposure [line items]
Loans and advances to customers	438	408
Loss allowance	40	61
Everyday Banking | Other unsecured
Disclosure of credit risk exposure [line items]
Loans and advances to customers	4,779	4,795
Loss allowance	£ 176	£ 299
Stage 3 ratio	2.03%	2.09%
Gross write- offs	£ 97	£ 129
Everyday Banking | Undrawn Balances
Disclosure of credit risk exposure [line items]
Stage 3 undrawn exposures	26	27
Everyday Banking | Undrawn Balances | Business banking
Disclosure of credit risk exposure [line items]
Stage 3 undrawn exposures	0	0
Everyday Banking | Undrawn Balances | Other unsecured
Disclosure of credit risk exposure [line items]
Stage 3 undrawn exposures	26	27
Consumer Finance
Disclosure of credit risk exposure [line items]
Loans and advances to customers	4,984	8,024
Loss allowance	£ 52	£ 118
Stage 3 ratio	0.49%	0.72%
Gross write- offs	£ 25	£ 25
Consumer Finance | Undrawn Balances
Disclosure of credit risk exposure [line items]
Stage 3 undrawn exposures	0	0
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	24,536	24,683
Loss allowances	423	603
Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	65,394	60,692
Loss allowances	2	35
Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		12,389
Loss allowances		33
Credit risk | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	177,297	169,801
Loss allowance	£ 191	£ 280
Stage 1 ratio	92.72%	92.82%
Stage 2 ratio	6.27%	6.12%
Stage 3 ratio	1.02%	1.07%
SME and mid corporate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	£ 14,529	£ 14,446
Loss allowances	378	478
Commercial Real Estate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,497	5,152
Loss allowances	43	125
Social Housing | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,510	5,085
Loss allowances	2	0
Social Housing | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,858	3,817
Loss allowances	1	0
Sovereign and Supranational | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	58,466	53,250
Loss allowances	0	0
Structured Products | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,875	2,482
Loss allowances	0	35
Financial Institutions | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,403	712
Loss allowances	0	0
Financial Institutions | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,479
Loss allowances		0
Legacy Portfolios in run–off | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	50	156
Loss allowances	1	0
Derivatives | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Loss allowances	0	0
Crown Dependencies | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	742	275
Loss allowances	0	0
Large Corporate | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		10,910
Loss allowances		33
Stage 1 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	164,381	157,614
Stage 1 | Everyday Banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	7,410	7,954
Stage 1 | Everyday Banking | Business banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	3,076	3,845
Stage 1 | Everyday Banking | Personal loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	1,910	1,881
Stage 1 | Everyday Banking | Credit cards
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,125	1,975
Stage 1 | Everyday Banking | Overdrafts
Disclosure of credit risk exposure [line items]
Loans and advances to customers	299	253
Stage 1 | Everyday Banking | Other unsecured
Disclosure of credit risk exposure [line items]
Loans and advances to customers	4,334	4,109
Stage 1 | Consumer Finance
Disclosure of credit risk exposure [line items]
Loans and advances to customers	4,760	7,587
Stage 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	18,049	17,396
Stage 1 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	65,137	60,647
Stage 1 | Credit risk | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	164,381	157,614
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	11,118	10,388
Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	575	618
Stage 2 | Everyday Banking | Business banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	201	6
Stage 2 | Everyday Banking | Personal loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	73	139
Stage 2 | Everyday Banking | Credit cards
Disclosure of credit risk exposure [line items]
Loans and advances to customers	181	335
Stage 2 | Everyday Banking | Overdrafts
Disclosure of credit risk exposure [line items]
Loans and advances to customers	120	138
Stage 2 | Everyday Banking | Other unsecured
Disclosure of credit risk exposure [line items]
Loans and advances to customers	374	612
Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Loans and advances to customers	200	379
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,661	6,267
Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	255	45
Stage 2 | Credit risk | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	11,118	10,388
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 1,798	£ 1,799
Stage 3 ratio	1.02%	1.07%
Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 326	£ 78
Stage 3 | Everyday Banking | Business banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	255	4
Stage 3 | Everyday Banking | Personal loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	17	18
Stage 3 | Everyday Banking | Credit cards
Disclosure of credit risk exposure [line items]
Loans and advances to customers	35	39
Stage 3 | Everyday Banking | Overdrafts
Disclosure of credit risk exposure [line items]
Loans and advances to customers	19	17
Stage 3 | Everyday Banking | Other unsecured
Disclosure of credit risk exposure [line items]
Loans and advances to customers	71	74
Stage 3 | Consumer Finance
Disclosure of credit risk exposure [line items]
Loans and advances to customers	24	58
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	826	1,020
Stage 3 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2	0
Stage 3 | Credit risk | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	1,798	1,799
Fully performing | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	20,465	20,047
Fully performing | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	65,392	60,623
Fully performing | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		10,877
Fully performing | SME and mid corporate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	11,131	10,844
Fully performing | Commercial Real Estate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,989	4,191
Fully performing | Social Housing | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,345	5,012
Fully performing | Social Housing | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,858	3,748
Fully performing | Sovereign and Supranational | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	58,466	53,250
Fully performing | Structured Products | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,875	2,482
Fully performing | Financial Institutions | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,403	712
Fully performing | Financial Institutions | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,479
Fully performing | Legacy Portfolios in run–off | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	48	156
Fully performing | Derivatives | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Fully performing | Crown Dependencies | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	742	275
Fully performing | Large Corporate | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		9,398
Enhanced monitoring | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	724	573
Enhanced monitoring | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	69
Enhanced monitoring | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		252
Enhanced monitoring | SME and mid corporate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	531	340
Enhanced monitoring | Commercial Real Estate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	193	233
Enhanced monitoring | Social Housing | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Enhanced monitoring | Social Housing | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	69
Enhanced monitoring | Sovereign and Supranational | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Enhanced monitoring | Structured Products | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Enhanced monitoring | Financial Institutions | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Enhanced monitoring | Financial Institutions | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		0
Enhanced monitoring | Legacy Portfolios in run–off | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Enhanced monitoring | Derivatives | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Enhanced monitoring | Crown Dependencies | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Enhanced monitoring | Large Corporate | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		252
Proactive management | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,521	3,043
Proactive management | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Proactive management | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,260
Proactive management | SME and mid corporate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,144	2,409
Proactive management | Commercial Real Estate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	212	561
Proactive management | Social Housing | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	165	73
Proactive management | Social Housing | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Proactive management | Sovereign and Supranational | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Proactive management | Structured Products | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Proactive management | Financial Institutions | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Proactive management | Financial Institutions | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		0
Proactive management | Legacy Portfolios in run–off | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Proactive management | Derivatives | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Proactive management | Crown Dependencies | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Proactive management | Large Corporate | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,260
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	826	1,020
Stage 3 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2	0
Stage 3 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		0
Stage 3 | SME and mid corporate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	723	853
Stage 3 | Commercial Real Estate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	103	167
Stage 3 | Social Housing | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Stage 3 | Social Housing | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Stage 3 | Sovereign and Supranational | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Stage 3 | Structured Products | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Stage 3 | Financial Institutions | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Stage 3 | Financial Institutions | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		0
Stage 3 | Legacy Portfolios in run–off | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2	0
Stage 3 | Derivatives | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Stage 3 | Crown Dependencies | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	£ 0	0
Stage 3 | Large Corporate | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		£ 0

Credit Risk - Disclosure of Loa

Credit Risk - Disclosure of Loan Modification by Segment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Homes
Disclosure of credit risk exposure [line items]
Amortised cost before modification	£ 424	£ 305
Net modification loss	9	7
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	152	114
Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	22	26
Net modification loss	9	12
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	6	4
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	243	201
Net modification loss	(5)	(5)
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	29	40
Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification		23
Net modification loss		1
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year		0
Business banking | Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	0	0
Net modification loss	0	0
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	0	0
Credit cards | Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	13	18
Net modification loss	5	8
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	4	2
Overdrafts | Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	9	8
Net modification loss	4	4
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	£ 2	£ 2

Credit Risk - Disclosure of For

Credit Risk - Disclosure of Forbearance Balances by Segment (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Capitalisation	£ 605	£ 628
Term extension	519	476
Interest-only	346	396
Concessionary interest rate	115	28
Forbearance	1,585	1,528
Loss allowances	£ 38	£ 42
Loans capitalisation forbearance Percentage	0.30%	0.40%
Loans term extension forbearance percentage	0.30%	0.30%
Loans interest only forbearance percentage	0.20%	0.20%
Loans concessionary interest rate forbearance percentage	0.10%	0.00%
Loans forbearance percentage	0.90%	0.90%
Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	£ 56	£ 63
Consumer Finance
Disclosure of credit risk exposure [line items]
Forbearance	0	9
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Capitalisation	204	180
Term extension	150	141
Interest-only	239	175
Forbearance	£ 593	£ 496
Proportion of portfolio	2.40%	2.00%
Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Capitalisation		£ 0
Term extension		23
Interest-only		0
Forbearance		£ 23
Proportion of portfolio		0.20%
Stage 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Forbearance	£ 20	£ 13
Stage 1 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Forbearance		0
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Capitalisation	388	409
Term extension	444	393
Interest-only	273	310
Concessionary interest rate	4	0
Forbearance	1,109	1,112
Loss allowances	12	13
Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	10	15
Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Forbearance	0	4
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Forbearance	303	179
Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Forbearance		23
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Capitalisation	217	219
Term extension	75	83
Interest-only	73	86
Concessionary interest rate	111	28
Forbearance	476	416
Loss allowances	26	29
Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	46	48
Stage 3 | Consumer Finance
Disclosure of credit risk exposure [line items]
Forbearance	0	5
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Forbearance	270	304
Stage 3 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Forbearance		0
Business banking | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	2	4
Business banking | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	0	0
Business banking | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	2	4
Personal loans | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	1	0
Personal loans | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	0	0
Personal loans | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	1	0
Credit cards | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	38	43
Credit cards | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	7	10
Credit cards | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	31	33
Overdrafts | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	15	16
Overdrafts | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	3	5
Overdrafts | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	12	11
Total other unsecured | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	54	59
Total other unsecured | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	10	15
Total other unsecured | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	£ 44	£ 44

Credit Risk - Disclosure of Oth

Credit Risk - Disclosure of Other Loan Modification by Segment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Homes
Disclosure of credit risk exposure [line items]
Amortised cost before modification	£ 424	£ 305
Net modification loss	9	7
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	152	114
Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	22	26
Net modification loss	9	12
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	6	4
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	243	201
Net modification loss	(5)	(5)
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	29	40
Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification		23
Net modification loss		1
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year		0
Other loans | Homes
Disclosure of credit risk exposure [line items]
Amortised cost before modification	658	37,085
Net modification loss	0	0
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	8	99
Other loans | Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	9	300
Net modification loss	0	0
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	1	6
Other loans | Consumer Finance
Disclosure of credit risk exposure [line items]
Amortised cost before modification	54	403
Net modification loss	0	6
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	226	403
Business banking | Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	0	0
Net modification loss	0	0
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	0	0
Other unsecured | Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	9	300
Net modification loss	0	0
Gross carrying amount of financial assets for which the ECL allowance has changed to 12-month measurement during the year	£ 1	£ 6

Credit Risk - Disclosure of H_2

Credit Risk - Disclosure of Homes Portfolios of Particular Interest by Credit Performance (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 213,525	£ 212,178
PIPs	£ 2	£ 10
Simple average LTV (indexed)	41.00%	42.00%
Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 177,297	£ 169,801
Interest-only
Disclosure of credit risk exposure [line items]
PIPs	£ 1	£ 5
Simple average LTV (indexed)	44.00%	44.00%
Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 40,906	£ 38,722
Part interest-only, part repayment
Disclosure of credit risk exposure [line items]
PIPs	£ 1	£ 2
Simple average LTV (indexed)	43.00%	44.00%
Mortgage loan including interest-only part	£ 10,270	£ 10,037
Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	13,865	13,498
Flexible
Disclosure of credit risk exposure [line items]
PIPs	£ 0	£ 1
Simple average LTV (indexed)	23.00%	26.00%
Flexible | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 8,549	£ 9,953
LTV >100%
Disclosure of credit risk exposure [line items]
PIPs	£ 1	£ 4
Simple average LTV (indexed)	116.00%	117.00%
LTV >100% | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 531	£ 737
Buy-to-let
Disclosure of credit risk exposure [line items]
PIPs	£ 0	£ 0
Simple average LTV (indexed)	59.00%	59.00%
Buy-to-let | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 14,893	£ 11,608
Other portfolio
Disclosure of credit risk exposure [line items]
PIPs	£ 0	£ 2
Simple average LTV (indexed)	41.00%	43.00%
Other portfolio | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 118,874	£ 113,378
Stage 1 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	164,381	157,614
Stage 1 | Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	36,459	33,609
Stage 1 | Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	12,614	12,118
Stage 1 | Flexible | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	7,509	8,731
Stage 1 | LTV >100% | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	357	426
Stage 1 | Buy-to-let | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	14,363	11,180
Stage 1 | Other portfolio | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	111,947	108,003
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	11,118	10,388
Stage 2 | Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	3,630	4,230
Stage 2 | Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	1,024	1,132
Stage 2 | Flexible | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	796	989
Stage 2 | LTV >100% | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	109	221
Stage 2 | Buy-to-let | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	489	393
Stage 2 | Other portfolio | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	6,225	4,763
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 1,798	£ 1,799
Stage 3 ratio	1.02%	1.07%
Stage 3 | Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 817	£ 883
Stage 3 ratio	2.02%	2.30%
Stage 3 | Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 227	£ 248
Stage 3 ratio	1.64%	1.84%
Stage 3 | Flexible | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 244	£ 233
Stage 3 ratio	3.06%	2.48%
Stage 3 | LTV >100% | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 65	£ 90
Stage 3 ratio	12.29%	12.25%
Stage 3 | Buy-to-let | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 41	£ 35
Stage 3 ratio	0.27%	0.30%
Stage 3 | Other portfolio | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 702	£ 612
Stage 3 ratio	0.59%	0.54%

Credit Risk - Disclosure of Ful

Credit Risk - Disclosure of Full Interest-Only New Business in the Year (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [abstract]
Full interest-only loans	£ 6,339	£ 4,267

Credit Risk - Disclosure of Det

Credit Risk - Disclosure of Detailed Information of Interest Only Loan Maturity Analysis (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	£ 40,906	£ 38,722
Term expired
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	393	374
Within 2 years
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	1,902	1,736
Between 2-5 years
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	3,825	3,722
Between 5-15 years
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	19,784	20,490
Greater than 15 years
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	15,002	12,400
Weighted average LTV
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	2,608	2,721
Weighted average LTV | Term expired
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	13	13
Weighted average LTV | Within 2 years
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	106	131
Weighted average LTV | Between 2-5 years
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	113	154
Weighted average LTV | Between 5-15 years
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	1,020	1,405
Weighted average LTV | Greater than 15 years
Disclosure of credit risk exposure [line items]
Carrying amount of interest-only loans	£ 1,356	£ 1,018

Credit Risk - Disclosure of H_3

Credit Risk - Disclosure of Homes Portfolios of Particular Interest by Forbearance Balances (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Forbearance	£ 1,585	£ 1,528
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	1,109	1,112
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	476	416
Interest-only | Homes
Disclosure of credit risk exposure [line items]
Forbearance	419	285
Interest-only | Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	280	184
Interest-only | Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	139	101
Flexible | Homes
Disclosure of credit risk exposure [line items]
Forbearance	35	48
Flexible | Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	24	34
Flexible | Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	11	14
LTV >100% | Homes
Disclosure of credit risk exposure [line items]
Forbearance	13	10
LTV >100% | Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	3	3
LTV >100% | Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	10	7
Buy-to-let | Homes
Disclosure of credit risk exposure [line items]
Forbearance	11	9
Buy-to-let | Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	8	6
Buy-to-let | Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	£ 3	£ 3

Credit Risk - Disclosure of Seg

Credit Risk - Disclosure of Segments Exposure by Credit Rating (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	£ 24,536	£ 24,683
Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	18,049	17,396
Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,661	6,267
Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	826	1,020
Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	14,529	14,446
Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,497	5,152
Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,510	5,085
Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	65,394	60,692
Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	65,137	60,647
Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	255	45
Corporate Centre | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2	0
Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,858	3,817
Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	58,466	53,250
Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,875	2,482
Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,403	712
Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	50	156
Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	742	275
Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		12,389
Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,479
Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		10,910
Internal grade 9 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	52	112
Internal grade 9 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	52	112
Internal grade 9 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 9 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 9 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 9 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 9 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	52	112
Internal grade 9 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	58,489	52,534
Internal grade 9 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	58,489	52,534
Internal grade 9 | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 9 | Corporate Centre | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 9 | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	2
Internal grade 9 | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	57,415	50,867
Internal grade 9 | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	573	1,168
Internal grade 9 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	501	497
Internal grade 9 | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 9 | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 9 | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 9 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		541
Internal grade 9 | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		367
Internal grade 9 | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		174
Internal grade 8 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,577	3,099
Internal grade 8 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,889	3,060
Internal grade 8 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	688	39
Internal grade 8 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 8 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	592	468
Internal grade 8 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 8 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,985	2,631
Internal grade 8 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,939	5,628
Internal grade 8 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,732	5,583
Internal grade 8 | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	207	45
Internal grade 8 | Corporate Centre | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 8 | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,290	2,001
Internal grade 8 | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,051	2,383
Internal grade 8 | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,064	1,044
Internal grade 8 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	534	200
Internal grade 8 | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 8 | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 8 | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 8 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		2,270
Internal grade 8 | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		444
Internal grade 8 | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,826
Internal grade 7 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,480	3,687
Internal grade 7 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,168	3,626
Internal grade 7 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	312	61
Internal grade 7 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 7 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	954	1,288
Internal grade 7 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	55	65
Internal grade 7 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,471	2,334
Internal grade 7 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,126	2,052
Internal grade 7 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,082	2,052
Internal grade 7 | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	44	0
Internal grade 7 | Corporate Centre | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 7 | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,568	1,814
Internal grade 7 | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 7 | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	197	229
Internal grade 7 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	361	9
Internal grade 7 | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 7 | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 7 | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 7 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		3,906
Internal grade 7 | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		639
Internal grade 7 | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		3,267
Internal grade 6 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,081	2,854
Internal grade 6 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,750	2,589
Internal grade 6 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	331	265
Internal grade 6 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 6 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,060	2,640
Internal grade 6 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	21	214
Internal grade 6 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 6 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	54	47
Internal grade 6 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	54	47
Internal grade 6 | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 6 | Corporate Centre | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 6 | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 6 | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 6 | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	41	41
Internal grade 6 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	7	6
Internal grade 6 | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	6	0
Internal grade 6 | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 6 | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 6 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		3,905
Internal grade 6 | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		23
Internal grade 6 | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		3,882
Internal grade 5 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,338	3,516
Internal grade 5 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,796	2,776
Internal grade 5 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	542	740
Internal grade 5 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,166	2,820
Internal grade 5 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,172	696
Internal grade 5 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 5 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,529
Internal grade 5 | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		6
Internal grade 5 | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,523
Internal grade 4 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,625	7,204
Internal grade 4 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,389	4,027
Internal grade 4 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,236	3,177
Internal grade 4 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,559	3,518
Internal grade 4 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,064	3,684
Internal grade 4 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2	2
Internal grade 4 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate Centre | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 4 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		157
Internal grade 4 | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		0
Internal grade 4 | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		157
Internal grade 3 to 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,646	3,274
Internal grade 3 to 1 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	428	454
Internal grade 3 to 1 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,392	1,800
Internal grade 3 to 1 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	826	1,020
Internal grade 3 to 1 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,465	2,790
Internal grade 3 to 1 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	181	484
Internal grade 3 to 1 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Internal grade 3 to 1 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		81
Internal grade 3 to 1 | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		0
Internal grade 3 to 1 | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		81
Other | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	737	937
Other | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	577	752
Other | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	160	185
Other | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Other | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	733	922
Other | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4	9
Other | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	6
Other | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	786	431
Other | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	780	431
Other | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4	0
Other | Corporate Centre | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2	0
Other | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Other | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Other | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Other | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Other | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	44	156
Other | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Other | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	£ 742	275
Other | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		0
Other | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		0
Other | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		£ 0

Credit Risk - Disclosure of S_3

Credit Risk - Disclosure of Segments Exposure by Geographical Distribution (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	£ 24,536	£ 24,683
Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	14,529	14,446
Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,497	5,152
Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,510	5,085
Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	65,394	60,692
Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,858	3,817
Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	58,466	53,250
Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,875	2,482
Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,403	712
Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	50	156
Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	742	275
Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		12,389
Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,479
Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		10,910
UK | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	24,493	24,635
UK | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	14,486	14,399
UK | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,497	5,151
UK | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,510	5,085
UK | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	59,314	52,773
UK | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,858	3,817
UK | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	54,651	46,912
UK | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,219	1,683
UK | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	536	301
UK | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	50	60
UK | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
UK | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
UK | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		10,493
UK | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		655
UK | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		9,838
Europe | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	43	47
Europe | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	43	47
Europe | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Europe | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Europe | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,178	2,680
Europe | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Europe | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	950	1,516
Europe | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	656	799
Europe | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	572	365
Europe | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Europe | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Europe | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Europe | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,491
Europe | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		439
Europe | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,052
US | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
US | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
US | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
US | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
US | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	550	855
US | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
US | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	469	849
US | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
US | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	81	6
US | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
US | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
US | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
US | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		131
US | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		131
US | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		0
Rest of World | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	1
Rest of World | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Rest of World | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	1
Rest of World | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Rest of World | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,352	4,384
Rest of World | Corporate Centre | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Rest of World | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,396	3,973
Rest of World | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Rest of World | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	214	40
Rest of World | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	96
Rest of World | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Rest of World | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	£ 742	275
Rest of World | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		274
Rest of World | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		254
Rest of World | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		£ 20

Credit Risk - Disclosure of S_4

Credit Risk - Disclosure of Segment by Exposure by Gross and Net Credit Exposure (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Exposure	£ 319,319	£ 328,792
Stage 3
Disclosure of credit risk exposure [line items]
Exposure	3,021	2,996
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	826	1,020
Collateral	439	391
Net exposure	387	629
Stage 3 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Exposure	723	853
Collateral	354	286
Net exposure	369	567
Stage 3 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Exposure	103	167
Collateral	85	105
Net exposure	18	62
Stage 3 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	2	0
Collateral	0	0
Net exposure	2	0
Stage 3 | Corporate Centre | Legacy Portfolios in run–off
Disclosure of credit risk exposure [line items]
Exposure	2	0
Collateral	0	0
Net exposure	2	0
Stage 3 | Corporate Centre | Crown Dependencies
Disclosure of credit risk exposure [line items]
Exposure	0	0
Collateral	0	0
Net exposure	£ 0	0
Stage 3 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposure		0
Collateral		0
Net exposure		0
Stage 3 | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Exposure		0
Collateral		0
Net exposure		£ 0

Market Risk - Summary of Detail

Market Risk - Summary of Detailed Information about VaR (Details)	12 Months Ended
	Dec. 31, 2021trading_day
Disclosure Of Detailed Information About VaR [Line Items]
VaR, confidence level	99.00%
VaR, losses greater than VaR estimate, percentage of trading days	1.00%
VaR, number of trading days between expected losses	100 days
Minimum
Disclosure Of Detailed Information About VaR [Line Items]
VaR, number of expected Losses per year, in days	2
Maximum
Disclosure Of Detailed Information About VaR [Line Items]
VaR, number of expected Losses per year, in days	3

Market Risk - Additional Inform

Market Risk - Additional Information (Details)	Dec. 31, 2021
Disclosure Of Market Risk Exposure [Abstract]
VaR, losses greater than VaR estimate, percentage of trading days	1.00%

Liquidity Risk - Summary of Rec

Liquidity Risk - Summary of Reconciliation of Wholesale Funding to Balance Sheet (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Deposits by banks	£ 33,862	£ 20,973
Deposits by customers	192,914	193,088
Repurchase agreements - non trading	11,718	15,848
Debt securities in issue	31,580	43,679
Subordinated liabilities	2,228	2,556
Other equity interest	2,191	2,241
Liquidity risk
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	82,600	87,000
Deposits by banks	33,900	21,000
Deposits by customers	0	0
Repurchase agreements - non trading	11,700	15,800
Financial liabilities designated at fair value	800	1,400
Debt securities in issue	31,600	43,700
Subordinated liabilities	2,200	2,600
Other equity instruments and non-controlling interests	2,400	2,500
Liquidity risk | Repos
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	11,700	15,800
Deposits by banks	0	0
Deposits by customers	0	0
Repurchase agreements - non trading	11,700	15,800
Financial liabilities designated at fair value	0	0
Debt securities in issue	0	0
Subordinated liabilities	0	0
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Foreign exchange and hedge accounting
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	1,000	2,500
Deposits by banks	0	0
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	800	2,100
Subordinated liabilities	200	400
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Other
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	2,100	3,000
Deposits by banks	1,800	3,000
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	300	0
Debt securities in issue	0	0
Subordinated liabilities	0	0
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Wholesale funding
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	67,800	65,700
Deposits by banks	32,100	18,000
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	500	1,400
Debt securities in issue	30,800	41,600
Subordinated liabilities	2,000	2,200
Other equity instruments and non-controlling interests	2,400	2,500
Liquidity risk | Wholesale funding | Deposits by banks
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	200	0
Deposits by banks	200	0
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	0	0
Subordinated liabilities	0	0
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Wholesale funding | Certificates of deposit and commercial paper
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	5,100	5,700
Deposits by banks	0	0
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	5,100	5,700
Subordinated liabilities	0	0
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Wholesale funding | Senior unsecured – public benchmark
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	12,400	15,500
Deposits by banks	0	0
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	12,400	15,500
Subordinated liabilities	0	0
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Wholesale funding | Senior unsecured – privately placed
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	600	1,100
Deposits by banks	0	0
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	500	900
Debt securities in issue	100	200
Subordinated liabilities	0	0
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Wholesale funding | Covered bonds
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	12,500	17,900
Deposits by banks	0	0
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	12,500	17,900
Subordinated liabilities	0	0
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Wholesale funding | Securitisation and structured issuance
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	700	2,800
Deposits by banks	0	0
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	500
Debt securities in issue	700	2,300
Subordinated liabilities	0	0
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Wholesale funding | Term Funding Scheme
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	0	6,300
Deposits by banks	0	6,300
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	0	0
Subordinated liabilities	0	0
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Wholesale funding | TFSME
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	31,900	11,700
Deposits by banks	31,900	11,700
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	0	0
Subordinated liabilities	0	0
Other equity instruments and non-controlling interests	0	0
Liquidity risk | Wholesale funding | Subordinated liabilities and equity
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	4,400	4,700
Deposits by banks	0	0
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	0	0
Subordinated liabilities	2,000	2,200
Other equity instruments and non-controlling interests	2,400	2,500
Liquidity risk | Non-cumulative callable preference shares
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Other equity interest	0	0
Liquidity risk | Step-up callable perpetual reserve capital instruments
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Other equity interest	235	235
Liquidity risk | Perpetual Capital Securities
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Other equity interest	£ 2,191	£ 2,241

Liquidity Risk - Summary of Sou

Liquidity Risk - Summary of Sources of Wholesale Funding by Maturity (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	£ 67,800	£ 65,700
Deposits by banks	33,862	20,973
Subordinated liabilities	2,228	2,556
Of which secured	45,100	38,700
Of which unsecured	22,700	27,000
Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	10,100
Senior unsecured – privately placed	100
Subordinated liabilities and equity (incl. AT1)	3,000
Wholesale fund amount	£ 13,200
Unsecured debt issued	95.00%
Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	£ 2,300
Senior unsecured – privately placed	500
Wholesale fund amount	54,600
Deposits by banks	200
Certificates of deposit and commercial paper	5,100
Covered bonds	12,500
Securitisation and structured issuance	700
Term Funding Scheme (TFS)	0
TFSME	31,900
Subordinated liabilities	1,400
Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
≤ 1 month
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	3,100	2,200
Of which secured	200	400
Of which unsecured	2,900	1,800
≤ 1 month | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	800
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	0
Wholesale fund amount	800
≤ 1 month | Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	600
Senior unsecured – privately placed	0
Wholesale fund amount	2,300
Deposits by banks	200
Certificates of deposit and commercial paper	1,300
Covered bonds	0
Securitisation and structured issuance	200
Term Funding Scheme (TFS)	0
TFSME	0
Subordinated liabilities	0
≤ 1 month | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>1 and ≤ 3 months
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	3,200	5,600
Of which secured	0	1,600
Of which unsecured	3,200	4,000
>1 and ≤ 3 months | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	0
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	0
Wholesale fund amount	0
>1 and ≤ 3 months | Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	0
Senior unsecured – privately placed	0
Wholesale fund amount	3,200
Deposits by banks	0
Certificates of deposit and commercial paper	3,000
Covered bonds	0
Securitisation and structured issuance	0
Term Funding Scheme (TFS)	0
TFSME	0
Subordinated liabilities	200
>1 and ≤ 3 months | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>3 and ≤ 6 months
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	2,800	8,000
Of which secured	900	5,200
Of which unsecured	1,900	2,800
>3 and ≤ 6 months | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	400
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	800
Wholesale fund amount	1,200
>3 and ≤ 6 months | Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	0
Senior unsecured – privately placed	0
Wholesale fund amount	1,600
Deposits by banks	0
Certificates of deposit and commercial paper	700
Covered bonds	800
Securitisation and structured issuance	100
Term Funding Scheme (TFS)	0
TFSME	0
Subordinated liabilities	0
>3 and ≤ 6 months | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>6 and ≤ 9 months
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	200	4,100
Of which secured	100	3,000
Of which unsecured	100	1,100
>6 and ≤ 9 months | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	0
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	0
Wholesale fund amount	0
>6 and ≤ 9 months | Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	0
Senior unsecured – privately placed	0
Wholesale fund amount	200
Deposits by banks	0
Certificates of deposit and commercial paper	100
Covered bonds	0
Securitisation and structured issuance	100
Term Funding Scheme (TFS)	0
TFSME	0
Subordinated liabilities	0
>6 and ≤ 9 months | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>9 and ≤ 12 months
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	900	1,200
Of which secured	900	200
Of which unsecured	0	1,000
>9 and ≤ 12 months | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	0
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	0
Wholesale fund amount	0
>9 and ≤ 12 months | Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	0
Senior unsecured – privately placed	0
Wholesale fund amount	900
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	900
Securitisation and structured issuance	0
Term Funding Scheme (TFS)	0
TFSME	0
Subordinated liabilities	0
>9 and ≤ 12 months | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
Sub-total ≤ 1 year
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	10,200	21,100
Of which secured	2,100	10,400
Of which unsecured	8,100	10,700
Sub-total ≤ 1 year | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	1,200
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	800
Wholesale fund amount	2,000
Sub-total ≤ 1 year | Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	600
Senior unsecured – privately placed	0
Wholesale fund amount	8,200
Deposits by banks	200
Certificates of deposit and commercial paper	5,100
Covered bonds	1,700
Securitisation and structured issuance	400
Term Funding Scheme (TFS)	0
TFSME	0
Subordinated liabilities	200
Sub-total ≤ 1 year | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>1 and ≤ 2 years
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	5,900	7,900
Of which secured	2,100	5,300
Of which unsecured	3,800	2,600
>1 and ≤ 2 years | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	3,000
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	0
Wholesale fund amount	3,000
>1 and ≤ 2 years | Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	300
Senior unsecured – privately placed	0
Wholesale fund amount	2,900
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	1,900
Securitisation and structured issuance	200
Term Funding Scheme (TFS)	0
TFSME	0
Subordinated liabilities	500
>1 and ≤ 2 years | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>2 and ≤ 5 years
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	41,100	28,300
Of which secured	33,700	18,600
Of which unsecured	7,400	9,700
>2 and ≤ 5 years | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	4,100
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	1,900
Wholesale fund amount	6,000
>2 and ≤ 5 years | Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	1,100
Senior unsecured – privately placed	300
Wholesale fund amount	35,100
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	5,600
Securitisation and structured issuance	100
Term Funding Scheme (TFS)	0
TFSME	28,000
Subordinated liabilities	0
>2 and ≤ 5 years | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>5 years
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	10,600	8,400
Of which secured	7,200	4,400
Of which unsecured	3,400	£ 4,000
>5 years | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	1,800
Senior unsecured – privately placed	100
Subordinated liabilities and equity (incl. AT1)	300
Wholesale fund amount	2,200
>5 years | Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	300
Senior unsecured – privately placed	200
Wholesale fund amount	8,400
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	3,300
Securitisation and structured issuance	0
Term Funding Scheme (TFS)	0
TFSME	3,900
Subordinated liabilities	700
>5 years | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	£ 0

Liquidity Risk - Summary of Who

Liquidity Risk - Summary of Wholesale Funding by Currency (Details) - Liquidity risk	Dec. 31, 2021	Dec. 31, 2020
Sterling
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	67.00%	57.00%
Sterling | Santander UK Group Holdings plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	24.00%	27.00%
Sterling | Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	10.00%	11.00%
Sterling | Santander UK Group Holdings plc | Senior unsecured – privately placed
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Sterling | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	75.00%	75.00%
Sterling | Santander UK plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	77.00%	63.00%
Sterling | Santander UK plc | Senior unsecured – public benchmark
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	14.00%	10.00%
Sterling | Santander UK plc | Senior unsecured – privately placed
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	92.00%	41.00%
Sterling | Santander UK plc | Deposits by banks
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	32.00%	0.00%
Sterling | Santander UK plc | Certificates of deposit and commercial paper
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	45.00%	51.00%
Sterling | Santander UK plc | Covered bonds
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	44.00%	48.00%
Sterling | Santander UK plc | Securitisation and structured issuance
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	74.00%	77.00%
Sterling | Santander UK plc | Term Funding Scheme
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	100.00%
Sterling | Santander UK plc | TFSME
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	100.00%	100.00%
Sterling | Santander UK plc | Subordinated liabilities
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	57.00%	63.00%
Sterling | Other group entities | Securitisation and structured issuance
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	100.00%
US Dollar
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	18.00%	24.00%
US Dollar | Santander UK Group Holdings plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	51.00%	51.00%
US Dollar | Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	59.00%	61.00%
US Dollar | Santander UK Group Holdings plc | Senior unsecured – privately placed
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
US Dollar | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	25.00%	25.00%
US Dollar | Santander UK plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	10.00%	18.00%
US Dollar | Santander UK plc | Senior unsecured – public benchmark
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	46.00%	73.00%
US Dollar | Santander UK plc | Senior unsecured – privately placed
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	37.00%
US Dollar | Santander UK plc | Deposits by banks
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	68.00%	0.00%
US Dollar | Santander UK plc | Certificates of deposit and commercial paper
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	53.00%	44.00%
US Dollar | Santander UK plc | Covered bonds
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	8.00%	5.00%
US Dollar | Santander UK plc | Securitisation and structured issuance
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	26.00%	23.00%
US Dollar | Santander UK plc | Term Funding Scheme
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
US Dollar | Santander UK plc | TFSME
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
US Dollar | Santander UK plc | Subordinated liabilities
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	43.00%	37.00%
US Dollar | Other group entities | Securitisation and structured issuance
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Euro
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	15.00%	19.00%
Euro | Santander UK Group Holdings plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	24.00%	21.00%
Euro | Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	31.00%	28.00%
Euro | Santander UK Group Holdings plc | Senior unsecured – privately placed
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Euro | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Euro | Santander UK plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	13.00%	19.00%
Euro | Santander UK plc | Senior unsecured – public benchmark
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	40.00%	17.00%
Euro | Santander UK plc | Senior unsecured – privately placed
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	6.00%	10.00%
Euro | Santander UK plc | Deposits by banks
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Euro | Santander UK plc | Certificates of deposit and commercial paper
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	2.00%	4.00%
Euro | Santander UK plc | Covered bonds
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	48.00%	46.00%
Euro | Santander UK plc | Securitisation and structured issuance
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Euro | Santander UK plc | Term Funding Scheme
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Euro | Santander UK plc | TFSME
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Euro | Santander UK plc | Subordinated liabilities
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Euro | Other group entities | Securitisation and structured issuance
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other | Santander UK Group Holdings plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	1.00%	1.00%
Other | Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other | Santander UK Group Holdings plc | Senior unsecured – privately placed
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	100.00%	100.00%
Other | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other | Santander UK plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other | Santander UK plc | Senior unsecured – public benchmark
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other | Santander UK plc | Senior unsecured – privately placed
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	2.00%	12.00%
Other | Santander UK plc | Deposits by banks
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other | Santander UK plc | Certificates of deposit and commercial paper
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	1.00%
Other | Santander UK plc | Covered bonds
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	1.00%
Other | Santander UK plc | Securitisation and structured issuance
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other | Santander UK plc | Term Funding Scheme
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other | Santander UK plc | TFSME
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other | Santander UK plc | Subordinated liabilities
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%
Other | Other group entities | Securitisation and structured issuance
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0.00%	0.00%

Liquidity Risk - Summary of Ext

Liquidity Risk - Summary of External Term Issuance, Sterling Equivalent (Details) - Liquidity risk - GBP (£) £ in Billions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about borrowings [line items]
Borrowings	£ 23.6	£ 17.1
Santander UK Group Holdings plc
Disclosure of detailed information about borrowings [line items]
Borrowings	3.3	1.4
Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	2.8	1.4
Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure of detailed information about borrowings [line items]
Borrowings	0.5	0
Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	20.3	15.7
Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0	1
Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0	0
Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	0	3
Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0.1	0
Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	20.2	11.7
Other group entities | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0	£ 0
Sterling
Disclosure of detailed information about borrowings [line items]
Borrowings	20.8
Sterling | Santander UK Group Holdings plc
Disclosure of detailed information about borrowings [line items]
Borrowings	0.5
Sterling | Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Sterling | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure of detailed information about borrowings [line items]
Borrowings	0.5
Sterling | Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	20.3
Sterling | Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Sterling | Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Sterling | Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Sterling | Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0.1
Sterling | Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	20.2
Sterling | Other group entities | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar
Disclosure of detailed information about borrowings [line items]
Borrowings	2.2
US Dollar | Santander UK Group Holdings plc
Disclosure of detailed information about borrowings [line items]
Borrowings	2.2
US Dollar | Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	2.2
US Dollar | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Other group entities | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro
Disclosure of detailed information about borrowings [line items]
Borrowings	0.6
Euro | Santander UK Group Holdings plc
Disclosure of detailed information about borrowings [line items]
Borrowings	0.6
Euro | Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0.6
Euro | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Other group entities | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Santander UK Group Holdings plc
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Other group entities | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	£ 0

Liquidity Risk - Summary of Bal

Liquidity Risk - Summary of Balance Sheet Encumbered and Unencumbered Assets Explanatory (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	£ 50,494	£ 43,537	£ 26,395
Financial assets at fair value through profit or loss:
Derivative financial instruments	1,720	3,451
Other financial assets at fair value through profit or loss	676	834
Financial assets at amortised cost:
Loans and advances to customers	213,525	212,178
Loans and advances to banks	1,420	2,004
Reverse repurchase agreements – non trading	12,683	19,599
Other financial assets at amortised cost	506	1,163
Financial assets at fair value through other comprehensive income	5,851	8,950
Interests in other entities	201	172
Intangible assets	1,545	1,649
Property, plant and equipment	1,555	1,740
Current tax assets	351	271	186
Net defined benefit asset	1,573	496
Other assets	1,576	3,020
Total assets	293,676	299,064	£ 288,488
Liquidity risk
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	50,494	43,537
Financial assets at fair value through profit or loss:
Derivative financial instruments	1,720	3,451
Other financial assets at fair value through profit or loss	676	834
Financial assets at amortised cost:
Loans and advances to customers	213,525	212,178
Loans and advances to banks	1,420	2,004
Reverse repurchase agreements – non trading	12,683	19,599
Other financial assets at amortised cost	506	1,163
Financial assets at fair value through other comprehensive income	5,851	8,950
Interests in other entities	201	172
Intangible assets	1,545	1,649
Property, plant and equipment	1,555	1,740
Current tax assets	351	271
Net defined benefit asset	1,573	496
Other assets	1,576	3,020
Total assets	293,676	299,064
Liquidity risk | Total
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	48,914	42,552
Financial assets at fair value through profit or loss:
Derivative financial instruments	1,720	3,451
Other financial assets at fair value through profit or loss	676	834
Financial assets at amortised cost:
Loans and advances to customers	194,008	180,891
Loans and advances to banks	942	1,200
Reverse repurchase agreements – non trading	12,683	19,599
Other financial assets at amortised cost	506	515
Financial assets at fair value through other comprehensive income	1,417	3,273
Interests in other entities	201	172
Intangible assets	1,545	1,649
Property, plant and equipment	1,555	1,740
Current tax assets	351	271
Net defined benefit asset	1,573	496
Other assets	1,576	3,020
Total assets	267,667	259,663
Liquidity risk | Assets positioned at central banks
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	935	871
Financial assets at fair value through profit or loss:
Derivative financial instruments	0	0
Other financial assets at fair value through profit or loss	0	0
Financial assets at amortised cost:
Loans and advances to customers	80,623	61,292
Loans and advances to banks	0	0
Reverse repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at fair value through other comprehensive income	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Net defined benefit asset	0	0
Other assets	0	0
Total assets	81,558	62,163
Liquidity risk | Readily available
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	47,979	41,681
Financial assets at fair value through profit or loss:
Derivative financial instruments	0	0
Other financial assets at fair value through profit or loss	0	0
Financial assets at amortised cost:
Loans and advances to customers	74,890	77,833
Loans and advances to banks	0	0
Reverse repurchase agreements – non trading	0	0
Other financial assets at amortised cost	506	515
Financial assets at fair value through other comprehensive income	1,417	3,273
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Net defined benefit asset	0	0
Other assets	0	0
Total assets	124,792	123,302
Liquidity risk | Other available assets
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	0	0
Financial assets at fair value through profit or loss:
Derivative financial instruments	0	0
Other financial assets at fair value through profit or loss	0	0
Financial assets at amortised cost:
Loans and advances to customers	18,893	19,801
Loans and advances to banks	0	0
Reverse repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at fair value through other comprehensive income	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	1,555	1,740
Current tax assets	0	0
Net defined benefit asset	0	0
Other assets	0	0
Total assets	20,448	21,541
Liquidity risk | Cannot be encumbered
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	0	0
Financial assets at fair value through profit or loss:
Derivative financial instruments	1,720	3,451
Other financial assets at fair value through profit or loss	676	834
Financial assets at amortised cost:
Loans and advances to customers	19,602	21,965
Loans and advances to banks	942	1,200
Reverse repurchase agreements – non trading	12,683	19,599
Other financial assets at amortised cost	0	0
Financial assets at fair value through other comprehensive income	0	0
Interests in other entities	201	172
Intangible assets	1,545	1,649
Property, plant and equipment	0	0
Current tax assets	351	271
Net defined benefit asset	1,573	496
Other assets	1,576	3,020
Total assets	40,869	52,657
Total | Liquidity risk
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	1,580	985
Financial assets at fair value through profit or loss:
Derivative financial instruments	0	0
Other financial assets at fair value through profit or loss	0	0
Financial assets at amortised cost:
Loans and advances to customers	19,517	31,287
Loans and advances to banks	478	804
Reverse repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	648
Financial assets at fair value through other comprehensive income	4,434	5,677
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Net defined benefit asset	0	0
Other assets	0	0
Total assets	26,009	39,401
Covered bonds | Liquidity risk
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	0	0
Financial assets at fair value through profit or loss:
Derivative financial instruments	0	0
Other financial assets at fair value through profit or loss	0	0
Financial assets at amortised cost:
Loans and advances to customers	15,713	23,669
Loans and advances to banks	0	0
Reverse repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at fair value through other comprehensive income	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Net defined benefit asset	0	0
Other assets	0	0
Total assets	15,713	23,669
Securitis- ations | Liquidity risk
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	0	0
Financial assets at fair value through profit or loss:
Derivative financial instruments	0	0
Other financial assets at fair value through profit or loss	0	0
Financial assets at amortised cost:
Loans and advances to customers	3,720	7,469
Loans and advances to banks	0	0
Reverse repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at fair value through other comprehensive income	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Net defined benefit asset	0	0
Other assets	0	0
Total assets	3,720	7,469
Other | Liquidity risk
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	1,580	985
Financial assets at fair value through profit or loss:
Derivative financial instruments	0	0
Other financial assets at fair value through profit or loss	0	0
Financial assets at amortised cost:
Loans and advances to customers	84	149
Loans and advances to banks	478	804
Reverse repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	648
Financial assets at fair value through other comprehensive income	4,434	5,677
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Net defined benefit asset	0	0
Other assets	0	0
Total assets	£ 6,576	£ 8,263

Capital Risk - Additional Infor

Capital Risk - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Capital Risk Exposure [Abstract]
Possible occurence of adverse economic stress	20 years
Possible occurence of very severe economic stress	100 years

Capital Risk - Summary of Regul

Capital Risk - Summary of Regulatory Capital Resources (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	£ 10,848	£ 11,059
AT1 capital	2,306	2,472
Tier 1 capital	13,154	13,531
Tier 2 capital	1,573	1,857
Total regulatory capital	14,727	15,388
– Additional value adjustments
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	(25)	(21)
– Goodwill (net of tax)
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	(1,130)	(1,150)
– Other intangibles
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	(195)	(199)
– Fair value reserves related to gains or losses on cash flow hedges
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	(110)	(486)
– Negative amounts resulting from the calculation of regulatory expected loss amounts
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	(585)	(368)
– Gains or losses on liabilities valued at fair value resulting from changes in own credit standing
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	0	(6)
– Deferred tax assets that rely on future profitability excluding timing differences
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	(2)	(9)
– Defined benefit pension fund assets
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	(1,061)	(364)
– Dividend accrual
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	(17)	(18)
– IFRS 9 Transitional Adjustment
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	21	73
– Deductions for non-controlling interests
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	0	(162)
CET1 capital before regulatory adjustments
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	13,952	13,769
– Capital instruments
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	7,060	7,060
AT1 capital	2,191	2,241
Tier 2 capital	2,263	2,076
– Retained earnings
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	6,754	6,030
– Accumulated other reserves and non-controlling interests
Disclosure Of Regulatory Capital Resources [Line Items]
CET1 capital	138	679
– Amount of qualifying items subject to phase out from AT1
Disclosure Of Regulatory Capital Resources [Line Items]
AT1 capital	163	324
– Regulatory deductions for instruments issued by subsidiary undertakings
Disclosure Of Regulatory Capital Resources [Line Items]
AT1 capital	(48)	(93)
Tier 2 capital	(725)	(571)
– Amount of qualifying items subject to phase out from Tier 2
Disclosure Of Regulatory Capital Resources [Line Items]
Tier 2 capital	£ 35	£ 352

Accounting Policies - Summary o

Accounting Policies - Summary of Useful Lives or Depreciation Rates Used for Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2021
Other intangible | Minimum
Disclosure of detailed information about intangible assets [line items]
Useful life measured as period of time, intangible assets other than goodwill	3 years
Other intangible | Maximum
Disclosure of detailed information about intangible assets [line items]
Useful life measured as period of time, intangible assets other than goodwill	7 years
Computer software | Minimum
Disclosure of detailed information about intangible assets [line items]
Useful life measured as period of time, intangible assets other than goodwill	3 years
Computer software | Maximum
Disclosure of detailed information about intangible assets [line items]
Useful life measured as period of time, intangible assets other than goodwill	7 years

Accounting Policies - Summary_2

Accounting Policies - Summary of Useful Lives or Depreciation Rates Used for Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2021
Minimum | Office fixtures and equipment
Disclosure of detailed information about property, plant and equipment [line items]
Useful lives or depreciation rates, property, plant and equipment	3 years
Minimum | Computer software
Disclosure of detailed information about property, plant and equipment [line items]
Useful lives or depreciation rates, property, plant and equipment	3 years
Maximum | Owner-occupied properties
Disclosure of detailed information about property, plant and equipment [line items]
Useful lives or depreciation rates, property, plant and equipment	50 years
Maximum | Office fixtures and equipment
Disclosure of detailed information about property, plant and equipment [line items]
Useful lives or depreciation rates, property, plant and equipment	15 years
Maximum | Computer software
Disclosure of detailed information about property, plant and equipment [line items]
Useful lives or depreciation rates, property, plant and equipment	7 years

Accounting Policies - Additiona

Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021area
Disclosure of detailed information about financial instruments [line items]
Climate change objective, number of main focus areas	3
Climate change, period covered for ECL calculations	5 years
180 Days | Unsecured Debt
Disclosure of detailed information about financial instruments [line items]
Written off period for past due	180 days

Segments - Additional Informati

Segments - Additional Information (Details) £ in Millions	12 Months Ended
	Dec. 31, 2021GBP (£)business_unit
Retail Banking
Disclosure of operating segments [line items]
Number of business units | business_unit	2
Corporate & Commercial Banking | Minimum
Disclosure of operating segments [line items]
Customers, annual turnover	£ 2
Corporate & Commercial Banking | Maximum
Disclosure of operating segments [line items]
Customers, annual turnover	500
Corporate & Investment Banking
Disclosure of operating segments [line items]
Customers, annual turnover	£ 500

Segments - Summary of Results b

Segments - Summary of Results by Segment (Details) £ in Millions	12 Months Ended
	Dec. 31, 2021GBP (£)employee	Dec. 31, 2020GBP (£)employee		Dec. 31, 2019GBP (£)employee
Disclosure of operating segments [line items]
Net interest income/(expense)	£ 3,997	£ 3,381	[1]	£ 3,227	[1]
Non-interest income	547	454		805
Total operating income/(expense)	4,544	3,835		4,032
Operating expenses before credit impairment write-backs/losses, provisions and charges	(2,540)	(2,425)	[1]	(2,466)	[1]
Credit impairment write-backs	233	(639)	[1]	(198)	[1]
Provisions for other liabilities and charges	(379)	(263)	[1]	(428)	[1]
Total operating credit impairment write-backs/losses, provisions and charges	(146)	(902)	[1]	(626)	[1]
Profit from continuing operations before tax	1,858	508	[1]	940	[1]
Revenue from external customers	4,544	3,835		4,032
Inter-segment revenue	4,544	3,835	[1]	4,032	[1]
Revenue from external customers includes the following fee and commission income disaggregated by income type
Current account and debit card fees	478	484		754
Insurance, protection and investments	67	65		69
Credit cards	73	66		86
Non-banking and other fees	76	66		134
Total fee and commission income	694	681	[1]	1,043	[1]
Fee and commission expense	(414)	(363)	[1]	(416)	[1]
Net fee and commission income/(expense)	280	318		627
Customer loans	210,616	210,369		205,298
Total assets	293,676	299,064		288,488
Customer deposits	192,176	191,732		177,821
Total liabilities	£ 277,298	£ 282,819		£ 272,147
Average number of full-time equivalent staff | employee	19,844	22,139		23,706
Elimination of intersegment amounts
Disclosure of operating segments [line items]
Inter-segment revenue	£ 0	£ 0		£ 0
Retail Banking
Disclosure of operating segments [line items]
Net interest income/(expense)	3,374	2,758		2,581
Non-interest income	201	245		531
Total operating income/(expense)	3,575	3,003		3,112
Operating expenses before credit impairment write-backs/losses, provisions and charges	(1,703)	(1,792)		(1,860)
Credit impairment write-backs	98	(264)		(129)
Provisions for other liabilities and charges	(187)	(160)		(273)
Total operating credit impairment write-backs/losses, provisions and charges	(89)	(424)		(402)
Profit from continuing operations before tax	1,783	787		850
Revenue from external customers	4,061	3,685		3,748
Revenue from external customers includes the following fee and commission income disaggregated by income type
Current account and debit card fees	428	442		711
Insurance, protection and investments	67	65		69
Credit cards	73	66		86
Non-banking and other fees	2	3		33
Total fee and commission income	570	576		899
Fee and commission expense	(384)	(337)		(372)
Net fee and commission income/(expense)	186	239		527
Customer loans	185,608	178,451		171,078
Total assets	193,214	186,226		178,665
Customer deposits	156,991	152,167		142,735
Total liabilities	£ 157,622	£ 152,687		£ 143,570
Average number of full-time equivalent staff | employee	16,149	18,198		19,669
Retail Banking | Elimination of intersegment amounts
Disclosure of operating segments [line items]
Inter-segment revenue	£ (486)	£ (682)		£ (636)
Consumer Finance
Disclosure of operating segments [line items]
Net interest income/(expense)	233	264		246
Non-interest income	178	127		155
Total operating income/(expense)	411	391		401
Operating expenses before credit impairment write-backs/losses, provisions and charges	(163)	(166)		(179)
Credit impairment write-backs	33	(44)		(27)
Provisions for other liabilities and charges	4	(8)		(8)
Total operating credit impairment write-backs/losses, provisions and charges	37	(52)		(35)
Profit from continuing operations before tax	285	173		187
Revenue from external customers	489	501		525
Revenue from external customers includes the following fee and commission income disaggregated by income type
Current account and debit card fees	0	0		0
Insurance, protection and investments	0	0		0
Credit cards	0	0		0
Non-banking and other fees	10	10		13
Total fee and commission income	10	10		13
Fee and commission expense	0	0		0
Net fee and commission income/(expense)	10	10		13
Customer loans	4,984	8,025		7,684
Total assets	8,873	11,143		10,748
Customer deposits	0	0		0
Total liabilities	£ 1,173	£ 2,397		£ 2,748
Average number of full-time equivalent staff | employee	670	640		612
Consumer Finance | Elimination of intersegment amounts
Disclosure of operating segments [line items]
Inter-segment revenue	£ (78)	£ (110)		£ (124)
Corporate & Commercial Banking
Disclosure of operating segments [line items]
Net interest income/(expense)	401	363		422
Non-interest income	109	94		109
Total operating income/(expense)	510	457		531
Operating expenses before credit impairment write-backs/losses, provisions and charges	(365)	(324)		(334)
Credit impairment write-backs	91	(294)		(45)
Provisions for other liabilities and charges	(34)	(6)		(24)
Total operating credit impairment write-backs/losses, provisions and charges	57	(300)		(69)
Profit from continuing operations before tax	202	(167)		128
Revenue from external customers	553	549		633
Revenue from external customers includes the following fee and commission income disaggregated by income type
Current account and debit card fees	50	42		43
Insurance, protection and investments	0	0		0
Credit cards	0	0		0
Non-banking and other fees	62	50		65
Total fee and commission income	112	92		108
Fee and commission expense	(22)	(22)		(24)
Net fee and commission income/(expense)	90	70		84
Customer loans	16,997	17,626		18,391
Total assets	16,997	17,626		18,391
Customer deposits	25,597	24,985		20,546
Total liabilities	£ 25,613	£ 25,011		£ 20,572
Average number of full-time equivalent staff | employee	2,281	2,405		2,464
Corporate & Commercial Banking | Elimination of intersegment amounts
Disclosure of operating segments [line items]
Inter-segment revenue	£ (43)	£ (92)		£ (102)
Corporate & Investment Banking
Disclosure of operating segments [line items]
Net interest income/(expense)	0	0		0
Non-interest income	0	0		0
Total operating income/(expense)	0	0		0
Operating expenses before credit impairment write-backs/losses, provisions and charges	0	0		0
Credit impairment write-backs	0	0		0
Provisions for other liabilities and charges	0	0		0
Total operating credit impairment write-backs/losses, provisions and charges	0	0		0
Profit from continuing operations before tax	0	0		0
Revenue from external customers	0	0		0
Revenue from external customers includes the following fee and commission income disaggregated by income type
Current account and debit card fees	0	0		0
Insurance, protection and investments	0	0		0
Credit cards	0	0		0
Non-banking and other fees	0	0		0
Total fee and commission income	0	0		0
Fee and commission expense	0	0		0
Net fee and commission income/(expense)	0	0		0
Customer loans	0	2,784		4,041
Total assets	0	2,784		4,046
Customer deposits	0	6,506		6,102
Total liabilities	£ 0	£ 6,517		£ 6,233
Average number of full-time equivalent staff | employee	528	716		804
Corporate & Investment Banking | Elimination of intersegment amounts
Disclosure of operating segments [line items]
Inter-segment revenue	£ 0	£ 0		£ 0
Corporate Centre
Disclosure of operating segments [line items]
Net interest income/(expense)	(11)	(4)		(22)
Non-interest income	59	(12)		10
Total operating income/(expense)	48	(16)		(12)
Operating expenses before credit impairment write-backs/losses, provisions and charges	(309)	(143)		(93)
Credit impairment write-backs	11	(37)		3
Provisions for other liabilities and charges	(162)	(89)		(123)
Total operating credit impairment write-backs/losses, provisions and charges	(151)	(126)		(120)
Profit from continuing operations before tax	(412)	(285)		(225)
Revenue from external customers	(559)	(900)		(874)
Revenue from external customers includes the following fee and commission income disaggregated by income type
Current account and debit card fees	0	0		0
Insurance, protection and investments	0	0		0
Credit cards	0	0		0
Non-banking and other fees	2	3		23
Total fee and commission income	2	3		23
Fee and commission expense	(8)	(4)		(20)
Net fee and commission income/(expense)	(6)	(1)		3
Customer loans	3,027	3,483		4,104
Total assets	74,592	81,285		76,638
Customer deposits	9,588	8,074		8,438
Total liabilities	£ 92,890	£ 96,207		£ 99,024
Average number of full-time equivalent staff | employee	216	180		157
Corporate Centre | Elimination of intersegment amounts
Disclosure of operating segments [line items]
Inter-segment revenue	£ 607	£ 884		£ 862
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Net Interest Income (Details)

Net Interest Income (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Interest and similar income:
Loans and advances to customers	£ 4,685	£ 4,772		£ 5,137
Loans and advances to banks	54	62		182
Reverse repurchase agreements – non trading	35	118		244
Other	56	119		309
Total interest and similar income	4,830	5,071	[1]	5,872	[1]
Interest expense and similar charges:
Deposits by customers	(331)	(884)		(1,331)
Deposits by banks	(23)	(28)		(103)
Repurchase agreements – non trading	(3)	(43)		(126)
Debt securities in issue	(372)	(614)		(938)
Subordinated liabilities	(92)	(111)		(137)
Other	(12)	(10)		(10)
Total interest expense and similar charges	(833)	(1,690)	[1]	(2,645)	[1]
Net interest income	3,997	3,381	[1]	£ 3,227	[1]
Interest income on financial assets at fair value through other comprehensive income	22	38
Interest expense on derivatives hedging debt issuances	317	451
Interest expense on lease liabilities	£ 3	£ 3
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Net Fee and Commission Income_2

Net Fee and Commission Income (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Net Fee And Commission Income [Line Items]
Fee and commission income	£ 694	£ 681	[1]	£ 1,043	[1]
Fee and commission expense	(414)	(363)	[1]	(416)	[1]
Net fee and commission income	280	318	[1]	627	[1]
Current account and debit card fees
Net Fee And Commission Income [Line Items]
Fee and commission income	478	484		754
Insurance, protection and investments
Net Fee And Commission Income [Line Items]
Fee and commission income	67	65		69
Credit cards
Net Fee And Commission Income [Line Items]
Fee and commission income	73	66		86
Non-banking and other fees
Net Fee And Commission Income [Line Items]
Fee and commission income	£ 76	£ 66		£ 134
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Other Operating Income - Summar

Other Operating Income - Summary of Net Trading and Other Income (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Net Trading And Other Income [Abstract]
Net losses on financial instruments designated at fair value through profit or loss	£ (68)	£ (26)		£ (102)
Net gains on financial instruments mandatorily at fair value through profit or loss	50	64		95
Hedge ineffectiveness	8	19		8
Net profit on sale of financial assets at fair value through other comprehensive income	6	17		15
Income from operating lease assets	136	126		124
Other	135	(64)		38
Other operating income (expense)	£ 267	£ 136	[1]	£ 178	[1]
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Other Operating Income - Additi

Other Operating Income - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Subordinated Liabilities [Line Items]
Fair value (losses)/gains on net trading and funding of other items by trading book	£ (15)	£ 89	£ (42)
Gains (losses) on equity derivatives trading desk	15	(88)	43
Net gain on equity index-linked deposits and the related economic hedges	0	1	1
Exchange rate differences recognised	215	(719)	1,102
Principally offset from cash flow hedge reserve	(357)	803	(1,021)
Loss on repurchase of debt securities and subordinated liabilities	1	£ 24	0
Gains on disposals of UK head office site	£ 73
Vocalink Holdings Limited
Disclosure Of Subordinated Liabilities [Line Items]
Gain on sale of shares			£ 15

Operating Expenses Before Cre_4

Operating Expenses Before Credit Impairment Losses, Provisions and Charges - Summary of Operating Expenses Before Credit Impairment Losses, Provisions and Charges (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Staff costs:
Wages and salaries	£ 759	£ 802		£ 815
Performance-related payments	184	99		160
Social security costs	113	102		112
Pension costs, defined contribution plans	65	67		67
Pension costs, defined benefit plans	38	38		35
Other share-based payments	1	4		7
Other personnel costs	42	34		41
Total employee benefits expense	1,202	1,146		1,237
Other administration expenses	831	710		684
Depreciation, amortisation and impairment	507	569		545
Total operating expenses before impairment losses, provisions and charges	2,540	2,425	[1]	2,466	[1]
Past service curtailment costs	£ 5	£ 0		£ 0
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Operating Expenses Before Cre_5

Operating Expenses Before Credit Impairment Losses, Provisions and Charges - Summary of Deferred Performance Awards (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Deferred Performance Awards [Line Items]
Cash	£ 23	£ 20
Shares	22	19
Expenses charged in the year
Disclosure Of Deferred Performance Awards [Line Items]
Cash	8	9
Shares	8	8
Deferred performance awards	16
Expenses charged in the year | Arising from awards in current year
Disclosure Of Deferred Performance Awards [Line Items]
Cash	3
Shares	3
Deferred performance awards	6
Expenses charged in the year | Arising from awards in prior year
Disclosure Of Deferred Performance Awards [Line Items]
Cash	5
Shares	5
Deferred performance awards	10
Expenses deferred to future periods
Disclosure Of Deferred Performance Awards [Line Items]
Cash	15	11
Shares	14	£ 11
Deferred performance awards	29
Expenses deferred to future periods | Arising from awards in current year
Disclosure Of Deferred Performance Awards [Line Items]
Cash	9
Shares	8
Deferred performance awards	17
Expenses deferred to future periods | Arising from awards in prior year
Disclosure Of Deferred Performance Awards [Line Items]
Cash	6
Shares	6
Deferred performance awards	£ 12

Operating Expenses Before Cre_6

Operating Expenses Before Credit Impairment Losses, Provisions and Charges - Summary of Amount of Bonus Awarded to Employees (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Amount Of Bonus Awarded To Employees [Line Items]
Cash award – not deferred	£ 156	£ 79
Cash award - deferred	23	20
Shares award – not deferred	12	3
Share award - deferred	22	19
Total discretionary bonus	213	121
Expenses charged in the year
Disclosure Of Amount Of Bonus Awarded To Employees [Line Items]
Cash award – not deferred	156	79
Cash award - deferred	8	9
Shares award – not deferred	12	3
Share award - deferred	8	8
Total discretionary bonus	184	99
Expenses deferred to future periods
Disclosure Of Amount Of Bonus Awarded To Employees [Line Items]
Cash award – not deferred	0	0
Cash award - deferred	15	11
Shares award – not deferred	0	0
Share award - deferred	14	11
Total discretionary bonus	£ 29	£ 22

Operating Expenses Before Cre_7

Operating Expenses Before Credit Impairment Losses, Provisions and Charges - Additional Information (Details) £ in Millions	12 Months Ended
	Dec. 31, 2021GBP (£)employee	Dec. 31, 2020GBP (£)employee	Dec. 31, 2019GBP (£)employee
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Average number of full-time equivalent staff | employee	19,844	22,139	23,706
Property, plant and equipment	£ 1,555	£ 1,740
Expense relating to short-term leases	23	10	£ 13
Accumulated depreciation
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Property, plant and equipment	(1,932)	(2,275)	(2,137)
Impairment loss recognised in profit or loss	(97)	(24)
Accumulated depreciation | Branch and head office site closures
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Impairment loss recognised in profit or loss	88	0
Operating lease assets
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Depreciation, property, plant and equipment	81	92	103
Property, plant and equipment	595	542	574
Depreciation for lease assets	20	59	61
Operating lease assets	£ 119	£ 103	£ 153

Audit and Other Services - Summ

Audit and Other Services - Summary of Audit and Other Services (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Audit fees:
Fees payable to the Company's auditor and its associates for the audit of the Santander UK group's annual accounts	£ 12.1	£ 10.5	£ 8.5
Audit of the Santander UK group’s subsidiaries	1.2	1.8	1.9
Total audit fees	13.3	12.3	10.4
Non-audit fees:
Audit-related assurance services	1.7	1.7	1.7
Other assurance services	0.5	0.5	0.4
Other non-audit services	0.2	0	0.2
Total non-audit fees	2.4	2.2	2.3
Prior year audit services
Non-audit fees:
Auditors fee	£ 1.2	£ 0.8	£ 0.3

Audit and Other Services - Addi

Audit and Other Services - Additional Information (Details) - GBP (£) £ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Audit Fees And Non Audit Fees [Line Items]
Audit fees payable for statutory audit	£ 13,300	£ 12,300	£ 10,400
Non-audit fees - Audit fees per US Securities and Exchange Commission guidance	1,200	1,200	1,600
Non-audit fees - Audit related fees per US Securities and Exchange Commission guidance	1,200	1,000	500
Non-audit fees - All other fees per US Securities and Exchange Commission guidance	0	0	200
Incremental work, audit of Banco Santander
Disclosure Of Audit Fees And Non Audit Fees [Line Items]
Audit fees payable for statutory audit	1,400	1,500	1,500
Santander UK Group Holdings plc
Disclosure Of Audit Fees And Non Audit Fees [Line Items]
Audit fees payable for statutory audit	500	500	500
Corporate and Other Borrowers
Disclosure Of Audit Fees And Non Audit Fees [Line Items]
Audit fees payable for statutory audit	£ 27	£ 24	£ 0

Credit Impairment Losses and _3

Credit Impairment Losses and Provisions - Summary of Impairment Losses and Provisions (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Disclosure Of Credit Impairment Loss And Provisions [Abstract]
Loans and advances to customers	£ (186)	£ 666		£ 216
Recoveries of loans and advances, net of collection costs	(17)	(24)		(40)
Off-balance sheet exposures (See Note 29)	(30)	(3)		22
Impairment loss on financial assets	(233)	639	[1]	198	[1]
Provisions for other liabilities and charges (excluding off-balance sheet credit exposures) (See Note 29)	388	257		422
Provisions for residual value and voluntary termination	(9)	6		6
Provisions for other liabilities and charges	379	263	[1]	428	[1]
Total operating credit impairment loss/(release), provisions and charges	£ 146	£ 902	[1]	£ 626	[1]
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Credit Impairment Losses and _4

Credit Impairment Losses and Provisions - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Credit Impairment Loss And Provisions [Abstract]
Impairment losses on loans and advances to banks	£ 0	£ 0
Impairment losses on non-trading reverse repurchase agreements	0	0
Impairment losses on other financial assets at amortised cost	0	0
Impairment losses on financial assets at FVOCI	£ 0	£ 0

Taxation - Disclosure of Income

Taxation - Disclosure of Income Tax and Deferred Taxes Explanatory (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Current tax:
UK corporation tax on profit for the year	£ 400	£ 92		£ 244
Adjustments in respect of prior years	(30)	(27)		(30)
Total current tax	370	65		214
Deferred tax:
Charge for the year	101	35		51
Adjustments in respect of prior years	14	1		(4)
Total deferred tax	115	36		47
Tax on profit from continuing operations	£ 485	£ 101	[1]	£ 261	[1]
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Taxation - Additional Informati

Taxation - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2016
Income Tax Expense Benefits [Line Items]
Bank corporation tax surcharge	8.00%			8.00%
Increase in applicable tax rate		2.00%
Unrecognised capital losses carried forward	£ 0	£ 0
At 1 April 2023
Income Tax Expense Benefits [Line Items]
Applicable tax rate (percentage)	25.00%
Increase in applicable tax rate	6.00%
Bank Surcharge, Q1 2022
Income Tax Expense Benefits [Line Items]
Bank corporation tax surcharge	3.00%
Bank Surcharge, Q1 2022 | Bank Surcharge, Q1 2022
Income Tax Expense Benefits [Line Items]
Expected decrease in tax expense	£ 22
Expected decrease in deferred tax liaiblity	£ 89
Banking entities
Income Tax Expense Benefits [Line Items]
Applicable tax rate (percentage)	27.00%	27.00%	27.00%
Non-banking entities
Income Tax Expense Benefits [Line Items]
Applicable tax rate (percentage)	19.00%	19.00%	19.00%
Deferred tax assets
Income Tax Expense Benefits [Line Items]
Recognised capital losses carried forward	£ 5	£ 12

Taxation - Schedule of Tax on P

Taxation - Schedule of Tax on Profit Before Tax Differs from Theoretical Amount that Arise Using Basic Corporation Tax Rate (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Major components of tax expense (income) [abstract]
Effective tax rate (percentage)	26.10%	19.90%		27.80%
Profit from continuing operations before tax	£ 1,858	£ 508	[1]	£ 940	[1]
Tax calculated at a tax rate of 19% (2020: 19%, 2019: 19%)	353	97		179
Bank surcharge on profits	106	23		60
Non-deductible preference dividends paid	9	8		8
Non-deductible UK Bank Levy	14	20		24
Non-deductible conduct remediation, fines and penalties	6	(4)		44
Other non-deductible costs and non-taxable income	33	23		29
Effect of change in tax rate on deferred tax provision	8	6		(10)
Tax relief on dividends in respect of other equity instruments	(40)	(40)		(39)
Adjustment to prior year provisions	(4)	(32)		(34)
Tax on profit from continuing operations	£ 485	£ 101	[1]	£ 261	[1]
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Taxation - Disclosure of Moveme

Taxation - Disclosure of Movements in Current Tax Assets and Liabilities (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Major components of tax expense (income) [abstract]
Assets	£ 271	£ 186
Liabilities	0	0
Beginning balance	271	186
Income statement charge (including discontinued operations)	(382)	(78)
Other comprehensive income credit	33	1
Corporate income tax paid	418	161	£ 309
Other movements	11	1
Ending balance	351	271	186
Assets	351	271	186
Liabilities	£ 0	£ 0	£ 0

Taxation - Disclosure of Deferr

Taxation - Disclosure of Deferred Tax Assets and Liabilities Including Movement in Deferred Tax Account (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	£ (107)	£ (145)
Income statement (charge)/credit	(115)	(36)
Transfers/reclassifications	(39)	(3)
Credited/(charged) to other comprehensive income	(312)	77
Ending balance	(573)	(107)
Fair value of financial instruments
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(65)	(52)
Income statement (charge)/credit	(58)	(13)
Transfers/reclassifications	0	0
Credited/(charged) to other comprehensive income	0	0
Ending balance	(123)	(65)
Pension remeasurement
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(27)	(98)
Income statement (charge)/credit	(67)	(62)
Transfers/reclassifications	5	0
Credited/(charged) to other comprehensive income	(419)	133
Ending balance	(508)	(27)
Cash flow hedges
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(100)	(58)
Income statement (charge)/credit	0	0
Transfers/reclassifications	(16)	12
Credited/(charged) to other comprehensive income	109	(54)
Ending balance	(7)	(100)
Fair value reserve
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(10)	(8)
Income statement (charge)/credit	(1)	0
Transfers/reclassifications	1	0
Credited/(charged) to other comprehensive income	(2)	(2)
Ending balance	(12)	(10)
Tax losses carried forward
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	15	13
Income statement (charge)/credit	(7)	2
Transfers/reclassifications	0	0
Credited/(charged) to other comprehensive income	0	0
Ending balance	8	15
Accelerated tax depreciation
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	39	18
Income statement (charge)/credit	39	21
Transfers/reclassifications	(10)	0
Credited/(charged) to other comprehensive income	0	0
Ending balance	68	39
Other temporary differences
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	41	40
Income statement (charge)/credit	(21)	16
Transfers/reclassifications	(19)	(15)
Credited/(charged) to other comprehensive income	0	0
Ending balance	£ 1	£ 41

Dividends on Ordinary Shares _2

Dividends on Ordinary Shares - Disclosure of Dividends on Ordinary Shares Declared and Paid (Details) - GBP (£) £ / shares in Units, £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividend per share	£ 19.06	£ 1.46	£ 3.71
Dividends	£ 1,346	£ 103	£ 262
First interim
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividend per share	£ 4.05	£ 1.46	£ 1.95
Dividends	£ 286	£ 103	£ 138
Second interim
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividend per share	£ 15.01	£ 0	£ 1.76
Dividends	£ 1,060	£ 0	£ 124

Dividends on Ordinary Shares _3

Dividends on Ordinary Shares - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Dividends On Ordinary Shares [Abstract]
Dividends declared and paid	£ 1,346	£ 103

Derivative Financial Instrume_3

Derivative Financial Instruments - Notional Amounts of Transactions Outstanding (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about hedges
Notional amount	£ 163,361	£ 198,391
Fair value assets	1,720	3,451
Fair value liabilities	1,019	1,920
Cash collateral received subject to enforceable master netting arrangement or similar agreement not set off against financial assets	12,941	21,310
Collateral cash	11,634	17,060
Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	38,505	57,414
Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	124,856	140,977
Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	81,241	94,537
Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	43,615	46,440
Exchange rate contracts
Disclosure of detailed information about hedges
Notional amount	34,579	43,274
Exchange rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	11,750	15,465
Exchange rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	590	789
Exchange rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	22,239	27,020
Interest rate contracts
Disclosure of detailed information about hedges
Notional amount	127,597	153,785
Interest rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	25,617	40,630
Interest rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	80,651	93,748
Interest rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	21,329	19,407
Equity and credit contracts
Disclosure of detailed information about hedges
Notional amount	1,185	1,332
Equity and credit contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	1,138	1,319
Equity derivative contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	0
Equity derivative contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	47	13
Derivative assets
Disclosure of detailed information about hedges
Cash collateral received subject to enforceable master netting arrangement or similar agreement not set off against financial assets	189	330
Derivative liabilities
Disclosure of detailed information about hedges
Collateral cash	202	651
Fair value
Disclosure of detailed information about hedges
Fair value assets	1,720	3,451
Fair value liabilities	1,019	1,920
Fair value | Derivatives held for trading:
Disclosure of detailed information about hedges
Fair value assets	814	1,445
Fair value liabilities	948	1,351
Fair value | Derivatives held for hedging
Disclosure of detailed information about hedges
Fair value assets	2,127	3,760
Fair value liabilities	1,292	2,323
Fair value | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Fair value assets	947	1,309
Fair value liabilities	737	1,891
Fair value | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Fair value assets	1,180	2,451
Fair value liabilities	555	432
Fair value | Exchange rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Fair value assets	159	395
Fair value liabilities	183	431
Fair value | Exchange rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Fair value assets	39	84
Fair value liabilities	0	6
Fair value | Exchange rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Fair value assets	996	1,978
Fair value liabilities	338	409
Fair value | Interest rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Fair value assets	489	926
Fair value liabilities	708	837
Fair value | Interest rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Fair value assets	908	1,225
Fair value liabilities	737	1,885
Fair value | Interest rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Fair value assets	177	467
Fair value liabilities	216	23
Fair value | Equity and credit contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Fair value assets	166	124
Fair value liabilities	57	83
Fair value | Equity derivative contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Fair value assets	0
Fair value liabilities	0
Fair value | Equity derivative contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Fair value assets	7	6
Fair value liabilities	1	0
Fair value | Derivative netting
Disclosure of detailed information about hedges
Fair value assets	(1,221)	(1,754)
Fair value liabilities	£ (1,221)	£ (1,754)

Derivative Financial Instrume_4

Derivative Financial Instruments - Analysis of the Notional and Fair Values of Derivatives by Trading and Settlement Method (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	£ 163,361	£ 198,391
Exchange rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	34,579	43,274
Interest rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	127,597	153,785
Equity and credit contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	1,185	1,332
Traded on recognised exchanges
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	0	0
Asset	0	0
Liability	0	0
Traded on recognised exchanges | Exchange rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	0	0
Asset	0	0
Liability	0	0
Traded on recognised exchanges | Interest rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	0	0
Asset	0	0
Liability	0	0
Traded on recognised exchanges | Equity and credit contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	0	0
Asset	0	0
Liability	0	0
Settled by central counterparties
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	117,560	144,343
Settled by central counterparties | Exchange rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	0	0
Settled by central counterparties | Interest rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	117,560	144,343
Settled by central counterparties | Equity and credit contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	0	0
Not settled by central counterparties
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	45,801	54,048
Not settled by central counterparties | Exchange rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	34,579	43,274
Not settled by central counterparties | Interest rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	10,037	9,442
Not settled by central counterparties | Equity and credit contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	1,185	1,332
Traded over the counter
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Asset	1,720	3,451
Liability	1,019	1,920
Traded over the counter | Exchange rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Asset	1,193	2,457
Liability	522	846
Traded over the counter | Interest rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Asset	353	864
Liability	441	991
Traded over the counter | Equity and credit contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Asset	174	130
Liability	£ 56	£ 83

Derivative Financial Instrume_5

Derivative Financial Instruments - Summary of Maturity Profile and Average Price/Rate of Hedging Instruments Used in Hedging Strategies (Details) £ in Millions	Dec. 31, 2021GBP (£)	Dec. 31, 2020GBP (£)
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 163,361	£ 198,391
Interest rate contracts
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	127,597	153,785
Interest rate contracts | Interest rate risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	80,421	93,475
Interest rate contracts | Interest rate risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	15,031	12,450
Interest rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	230	273
Interest rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	2,973	6,591
Interest rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	3,325	366
Exchange rate contracts
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	34,579	43,274
Exchange rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	590	789
Exchange rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	7,704	11,457
Exchange rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	14,535	15,563
Equity derivative contracts | Equity risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	47	13
≤1 month | Interest rate contracts | Interest rate risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 3,121	£ 2,429
≤1 month | Interest rate contracts | Interest rate risk | Fair value hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0059	0.0069
≤1 month | Interest rate contracts | Interest rate risk | Fair value hedges | Euro
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0051	0.0118
≤1 month | Interest rate contracts | Interest rate risk | Fair value hedges | US Dollar
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0191	0.0187
≤1 month | Interest rate contracts | Interest rate risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 1,010	£ 0
≤1 month | Interest rate contracts | Interest rate risk | Cash flow hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0197	0
≤1 month | Interest rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
≤1 month | Interest rate contracts | Interest rate/FX risk | Fair value hedges | Euro
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0	0
≤1 month | Interest rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 732
≤1 month | Interest rate contracts | Interest rate/FX risk | Cash flow hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0226	0.0201
≤1 month | Interest rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
≤1 month | Exchange rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
Average GBP - EUR exchange rate	0	0
≤1 month | Exchange rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 620	£ 732
Average GBP - EUR exchange rate	1.28	0
Average GBP - USD exchange rate	0	1.46
≤1 month | Exchange rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 2,703	£ 1,439
Average GBP - EUR exchange rate	1.17	0
Average GBP - USD exchange rate	1.34	1.29
Average GBP - JPY exchange rate	0	0
≤1 month | Equity derivative contracts | Equity risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
>1 and ≤ 3 months | Interest rate contracts | Interest rate risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 6,223	£ 7,617
>1 and ≤ 3 months | Interest rate contracts | Interest rate risk | Fair value hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0042	0.0065
>1 and ≤ 3 months | Interest rate contracts | Interest rate risk | Fair value hedges | Euro
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0174	0.0023
>1 and ≤ 3 months | Interest rate contracts | Interest rate risk | Fair value hedges | US Dollar
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0096	0.0172
>1 and ≤ 3 months | Interest rate contracts | Interest rate risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 481	£ 897
>1 and ≤ 3 months | Interest rate contracts | Interest rate risk | Cash flow hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0044	0.0046
>1 and ≤ 3 months | Interest rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
>1 and ≤ 3 months | Interest rate contracts | Interest rate/FX risk | Fair value hedges | Euro
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0	0
>1 and ≤ 3 months | Interest rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
>1 and ≤ 3 months | Interest rate contracts | Interest rate/FX risk | Cash flow hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0	0
>1 and ≤ 3 months | Interest rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
>1 and ≤ 3 months | Exchange rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
Average GBP - EUR exchange rate	0	0
>1 and ≤ 3 months | Exchange rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
Average GBP - EUR exchange rate	0	0
Average GBP - USD exchange rate	0	0
>1 and ≤ 3 months | Exchange rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 936	£ 2,015
Average GBP - EUR exchange rate	0	0
Average GBP - USD exchange rate	1.34	1.32
Average GBP - JPY exchange rate	142.91	137.98
>1 and ≤ 3 months | Equity derivative contracts | Equity risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
>3 and ≤12 months | Interest rate contracts | Interest rate risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 21,442	£ 27,791
>3 and ≤12 months | Interest rate contracts | Interest rate risk | Fair value hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0009	0.0082
>3 and ≤12 months | Interest rate contracts | Interest rate risk | Fair value hedges | Euro
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0108	0.0302
>3 and ≤12 months | Interest rate contracts | Interest rate risk | Fair value hedges | US Dollar
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0144	0.0289
>3 and ≤12 months | Interest rate contracts | Interest rate risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 871	£ 2,528
>3 and ≤12 months | Interest rate contracts | Interest rate risk | Cash flow hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0008	0.0057
>3 and ≤12 months | Interest rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
>3 and ≤12 months | Interest rate contracts | Interest rate/FX risk | Fair value hedges | Euro
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0329	0.0464
>3 and ≤12 months | Interest rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 882
>3 and ≤12 months | Interest rate contracts | Interest rate/FX risk | Cash flow hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0117	0.0318
>3 and ≤12 months | Interest rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 0	£ 0
>3 and ≤12 months | Exchange rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 107	£ 132
Average GBP - EUR exchange rate	1.21	1.14
>3 and ≤12 months | Exchange rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 840	£ 2,583
Average GBP - EUR exchange rate	1.39	1.35
Average GBP - USD exchange rate	0	0
>3 and ≤12 months | Exchange rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 2,057	£ 3,877
Average GBP - EUR exchange rate	1.18	0
Average GBP - USD exchange rate	1.33	1.32
Average GBP - JPY exchange rate	148.86	135.61
>3 and ≤12 months | Equity derivative contracts | Equity risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 2	£ 0
>1 and ≤5 years | Interest rate contracts | Interest rate risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 44,644	£ 47,749
>1 and ≤5 years | Interest rate contracts | Interest rate risk | Fair value hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0088	0.0073
>1 and ≤5 years | Interest rate contracts | Interest rate risk | Fair value hedges | Euro
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0081	0.0098
>1 and ≤5 years | Interest rate contracts | Interest rate risk | Fair value hedges | US Dollar
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0276	0.0249
>1 and ≤5 years | Interest rate contracts | Interest rate risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 7,532	£ 7,964
>1 and ≤5 years | Interest rate contracts | Interest rate risk | Cash flow hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0139	0.0145
>1 and ≤5 years | Interest rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 193	£ 236
>1 and ≤5 years | Interest rate contracts | Interest rate/FX risk | Fair value hedges | Euro
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0203	0.0178
>1 and ≤5 years | Interest rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 2,049	£ 4,062
>1 and ≤5 years | Interest rate contracts | Interest rate/FX risk | Cash flow hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0272	0.0248
>1 and ≤5 years | Interest rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 2,438	£ 366
>1 and ≤5 years | Exchange rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 381	£ 461
Average GBP - EUR exchange rate	1.16	1.17
>1 and ≤5 years | Exchange rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 4,765	£ 6,550
Average GBP - EUR exchange rate	1.20	1.25
Average GBP - USD exchange rate	1.61	1.61
>1 and ≤5 years | Exchange rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 6,715	£ 7,113
Average GBP - EUR exchange rate	1.16	1.16
Average GBP - USD exchange rate	1.34	1.30
Average GBP - JPY exchange rate	0	132.27
>1 and ≤5 years | Equity derivative contracts | Equity risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 41	£ 12
>5 years | Interest rate contracts | Interest rate risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 4,991	£ 7,889
>5 years | Interest rate contracts | Interest rate risk | Fair value hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0313	0.0361
>5 years | Interest rate contracts | Interest rate risk | Fair value hedges | Euro
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0261	0.0234
>5 years | Interest rate contracts | Interest rate risk | Fair value hedges | US Dollar
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0405	0.0416
>5 years | Interest rate contracts | Interest rate risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 5,137	£ 1,061
>5 years | Interest rate contracts | Interest rate risk | Cash flow hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0097	0.0133
>5 years | Interest rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 37	£ 37
>5 years | Interest rate contracts | Interest rate/FX risk | Fair value hedges | Euro
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0262	0.0356
>5 years | Interest rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 924	£ 915
>5 years | Interest rate contracts | Interest rate/FX risk | Cash flow hedges | Sterling
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0341	0.0339
>5 years | Interest rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 887	£ 0
>5 years | Exchange rate contracts | Interest rate/FX risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 102	£ 196
Average GBP - EUR exchange rate	1.17	1.17
>5 years | Exchange rate contracts | Interest rate/FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 1,479	£ 1,592
Average GBP - EUR exchange rate	1.20	1.20
Average GBP - USD exchange rate	1.38	1.38
>5 years | Exchange rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 2,124	£ 1,119
Average GBP - EUR exchange rate	1.17	1.18
Average GBP - USD exchange rate	1.39	0
Average GBP - JPY exchange rate	0	0
>5 years | Equity derivative contracts | Equity risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 4	£ 1

Derivative Financial Instrume_6

Derivative Financial Instruments - Summary of Net Gains or Losses Arising from Fair Value and Cash Flow Hedges Included in Net Trading and Other Income (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about hedges
Hedge ineffectiveness	£ 8	£ 19	£ 8
Fair Value and Cash Flow Hedges
Disclosure of detailed information about hedges
Gains/(losses) on hedging instruments	846	(299)	(360)
(Losses)/gains on hedged items attributable to hedged risks	(804)	364	414
Fair value hedging ineffectiveness	42	65	54
Cash flow hedging ineffectiveness	(34)	(46)	(46)
Hedge ineffectiveness	£ 8	£ 19	£ 8

Derivative Financial Instrume_7

Derivative Financial Instruments - Summary of Information About Hedging Ineffectiveness by Risk Category (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair value hedges
Disclosure of detailed information about hedges
Change in FV of hedging instruments	£ 846	£ (299)
Change in FV of hedged items	(804)	364
Recognised in income statement	42	65
Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	868	(358)
Change in FV of hedged items	(838)	384
Recognised in income statement	30	26
Fair value hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(22)	59
Change in FV of hedged items	34	(20)
Recognised in income statement	12	39
Cash flow hedges
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(909)	927
Change in FV of hedged items	875	(974)
Recognised in OCI	875	(973)
Recognised in income statement	(34)	(46)
Reclassified from reserves to income	(359)	803
Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(312)	185
Recognised in OCI	306	(179)
Recognised in income statement	(6)	6
Reclassified from reserves to income	70	33
Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(54)	(42)
Recognised in OCI	54	38
Recognised in income statement	0	(4)
Reclassified from reserves to income	(158)	2
Cash flow hedges | Equity risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(1)	2
Recognised in OCI	1	(2)
Recognised in income statement	0	0
Reclassified from reserves to income	2	(5)
Cash flow hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(542)	782
Recognised in OCI	514	(830)
Recognised in income statement	(28)	(48)
Reclassified from reserves to income	£ (273)	£ 773

Derivative Financial Instrume_8

Derivative Financial Instruments - Additional Information (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of nature and extent of risks arising from financial instruments [abstract]
Ceased cash flow hedge accounting	£ 14	£ 57

Derivative Financial Instrume_9

Derivative Financial Instruments - Summary of Reconciliation by Risk Category of Components of Equity and Analysis of Other Comprehensive Income Items Resulting from Hedge Accounting (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about hedges
Beginning Balance	£ 649	£ 479
Effective portion of changes in fair value:	(875)	973
Income statement transfers:	359	(803)
Ending Balance	133	649
Interest rate risk
Disclosure of detailed information about hedges
Effective portion of changes in fair value:	(306)	179
Income statement transfers:	(70)	(33)
Foreign currency risk
Disclosure of detailed information about hedges
Effective portion of changes in fair value:	(54)	(38)
Income statement transfers:	158	(2)
Equity risk
Disclosure of detailed information about hedges
Effective portion of changes in fair value:	(1)	2
Income statement transfers:	(2)	5
Interest rate/FX risk
Disclosure of detailed information about hedges
Effective portion of changes in fair value:	(514)	830
Income statement transfers:	£ 273	£ (773)

Derivative Financial Instrum_10

Derivative Financial Instruments - Summary of Details of Hedged Exposures by Hedging Strategies (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of detailed information about hedges
Cash flow hedge reserve	£ 133	£ 649	£ 479
Fair value hedges
Disclosure of detailed information about hedges
Carrying value of assets	67,053	58,019
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	(293)	(649)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks assets	(38)	1,051
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	206	437
Change in value to calculate hedge ineffectiveness	(804)	364
Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	(838)	384
Fair value hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	34	(20)
Cash flow hedges
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	875	(974)
Cash flow hedge reserve	133	649
Balances on cash flow hedge reserve for discontinued hedges	80	(1)
Deposits by customers | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of liabilities	0	(4,305)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	0	(15)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks liabilities	0	(10)
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	0	(10)
Change in value to calculate hedge ineffectiveness	14	(13)
Deposits by customers | Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	4	(7)
Cash flow hedge reserve	0	0
Balances on cash flow hedge reserve for discontinued hedges	0	0
Debt securities in issue | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of liabilities	(4,373)	(8,889)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	(188)	(518)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks liabilities	(115)	(137)
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	(230)	(305)
Change in value to calculate hedge ineffectiveness	325	(120)
Debt securities in issue | Fair value hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Carrying value of liabilities	(423)	(621)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	(55)	(94)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks liabilities	0	0
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	(47)	(76)
Change in value to calculate hedge ineffectiveness	55	(34)
Debt securities in issue | Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	90	(13)
Cash flow hedge reserve	67	(46)
Balances on cash flow hedge reserve for discontinued hedges	6	0
Subordinated liabilities | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of liabilities	(293)	(636)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	(75)	(185)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks liabilities	(8)	(41)
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	(70)	(166)
Change in value to calculate hedge ineffectiveness	49	(27)
Subordinated liabilities | Fair value hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Carrying value of liabilities	(2)	(3)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	2	3
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks liabilities	0	0
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	2	3
Change in value to calculate hedge ineffectiveness	(1)	(1)
Deposits by banks | Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	(1)	7
Cash flow hedge reserve	1	(2)
Balances on cash flow hedge reserve for discontinued hedges	0	0
Repurchase agreements – non trading | Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	0	1
Cash flow hedge reserve	0	(1)
Balances on cash flow hedge reserve for discontinued hedges	0	0
Repurchase agreements – non trading | Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	6	(15)
Cash flow hedge reserve	0	0
Balances on cash flow hedge reserve for discontinued hedges	0	0
Other liabilities | Cash flow hedges | Equity risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	1	(2)
Cash flow hedge reserve	3	6
Balances on cash flow hedge reserve for discontinued hedges	0	0
Loans and advances to customers | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of assets	58,455	54,118
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item assets	0	0
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks assets	88	1,202
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	500	904
Change in value to calculate hedge ineffectiveness	(1,096)	332
Loans and advances to customers | Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	236	(183)
Cash flow hedge reserve	(135)	165
Balances on cash flow hedge reserve for discontinued hedges	(2)	1
Other financial assets at amortised cost | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of assets	160	772
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item assets	0	0
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks assets	2	36
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	3	13
Change in value to calculate hedge ineffectiveness	(12)	121
Reverse repurchase agreements – non trading | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of assets	9,570	12,149
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item assets	0	0
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks assets	(5)	1
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	0	0
Change in value to calculate hedge ineffectiveness	(6)	3
Other financial assets at FVOCI | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of assets	3,728	5,129
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item assets	23	155
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks assets	0	0
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	47	74
Change in value to calculate hedge ineffectiveness	(112)	88
Other financial assets at FVOCI | Fair value hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Carrying value of assets	227	299
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item assets	0	5
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks assets	0	0
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	1	0
Change in value to calculate hedge ineffectiveness	(20)	15
Cash and balances at central banks | Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	71	(2)
Cash flow hedge reserve	(80)	1
Balances on cash flow hedge reserve for discontinued hedges	0	0
Reverse repurchase agreements - non trading | Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	0	(2)
Cash flow hedge reserve	0	1
Balances on cash flow hedge reserve for discontinued hedges	0	0
Other financial assets at FVOCI | Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	(194)	40
Cash flow hedge reserve	(1)	6
Balances on cash flow hedge reserve for discontinued hedges	0	0
Not applicable – highly probable forecast transactions | Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	148	33
Cash flow hedge reserve	1	3
Balances on cash flow hedge reserve for discontinued hedges	0	0
Debt securities in issue/loans and advances to customers | Debt securities in issue/loans and advances to customers | Cash flow hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	503	(701)
Cash flow hedge reserve	144	322
Balances on cash flow hedge reserve for discontinued hedges	(4)	(2)
Subordinated liabilities/loans and advances to customers | Subordinated liabilities/loans and advances to customers | Cash flow hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	11	(130)
Cash flow hedge reserve	133	194
Balances on cash flow hedge reserve for discontinued hedges	£ 80	£ 0

Other Financial Assets at Fai_5

Other Financial Assets at Fair Value Through Profit or Loss - Summary of Other Financial Assets at Fair Value Through Profit or Loss (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Other Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	£ 676	£ 834
Loans and advances to customers
Disclosure Of Other Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	514	592
Loans and advances to customers | Loans to housing associations
Disclosure Of Other Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	12	13
Loans and advances to customers | Other loans
Disclosure Of Other Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	502	579
Debt securities
Disclosure Of Other Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	112	112
Equity securities
Disclosure Of Other Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	£ 50	£ 130

Other Financial Assets at Fai_6

Other Financial Assets at Fair Value Through Profit or Loss - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financial assets at fair value through profit or loss [abstract]
Financial assets designated at FVTPL	£ 454	£ 508
Financial assets mandatorily at FVTPL	222	325
Net (loss)/gain attributable to changes in credit risk for loans and advances at fair value through profit or loss	0	0	£ 0
Cumulative net loss attributable to changes in credit risk for loans and advances at fair value through profit or loss	£ (2)	£ (2)

Loans and Advances to Custome_3

Loans and Advances to Customers - Summary of Net Loans and Advances to Customers (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Net Loans And Advances To Customers [Abstract]
Loans secured on residential properties	£ 178,039	£ 170,089
Corporate loans	19,282	23,613
Finance leases	3,916	6,554
Secured advances	0	0
Other unsecured loans	9,405	10,169
Accrued interest and other adjustments	656	861
Amounts due from fellow Banco Santander subsidiaries and joint ventures	3,080	2,249
Loans and advances to customers	214,378	213,535
Credit impairment loss allowances on loans and advances to customers	(828)	(1,303)
RV and voluntary termination provisions on finance leases	(25)	(54)
Net loans and advances to customers	£ 213,525	£ 212,178

Loans and Advances to Custome_4

Loans and Advances to Customers - Summary of Finance Lease and Hire Purchase Contract Receivables (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	£ 4,383	£ 7,210
Unearned finance income	(467)	(656)
Net investment	3,916	6,554
No later than one year
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	1,906	3,468
Unearned finance income	(5)	(297)
Net investment	1,901	3,171
Later than one year and not later than two years
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	1,324	1,829
Unearned finance income	(201)	(173)
Net investment	1,123	1,656
Later than two years and not later than three years
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	772	1,099
Unearned finance income	(141)	(106)
Net investment	631	993
Later than three years and not later than four years
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	343	575
Unearned finance income	(82)	(55)
Net investment	261	520
Later than four years and not later than five years
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	38	231
Unearned finance income	(38)	(25)
Net investment	0	206
Later than five years
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	0	8
Unearned finance income	0	0
Net investment	£ 0	£ 8

Loans and Advances to Custome_5

Loans and Advances to Customers - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net Loans And Advances To Customers [Abstract]
Unguaranteed residual value of leases	£ 1,510	£ 3,552
Contingent rent income	0	0	£ 0
Finance income on the net investment in finance leases	£ 243	£ 308	£ 299

Loans and Advances to Custome_6

Loans and Advances to Customers - Disclosure of Maturity Analysis of Operating Lease Payments (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	£ 134	£ 101
No later than one year
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	31	17
Later than one year and not later than two years
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	27	17
Later than two years and not later than three years
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	22	16
Later than three years and not later than four years
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	15	11
Later than four years and not later than five years
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	11	10
Later than five years
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	£ 28	£ 30

Securitisations and Covered B_3

Securitisations and Covered Bonds - Analysis of Securitisations and Covered Bonds (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	£ 20,199	£ 33,432
External notes in issue	13,519	21,615
Notes issued to Santander UK plc/subsidiaries as collateral	1,585	4,549
Notional amount	163,361	198,391
Securitisation programmes
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	4,486	9,762
External notes in issue	759	2,330
Notes issued to Santander UK plc/subsidiaries as collateral	1,585	4,549
Securitisation programmes | Mortgage-backed master trust structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	4,448	8,113
External notes in issue	718	1,119
Notes issued to Santander UK plc/subsidiaries as collateral	1,585	4,091
Securitisation programmes | Other asset-backed securitisation structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	38	1,649
External notes in issue	41	1,211
Notes issued to Santander UK plc/subsidiaries as collateral	0	458
Holmes | Securitisation programmes | Mortgage-backed master trust structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	2,294	3,073
External notes in issue	430	829
Notes issued to Santander UK plc/subsidiaries as collateral	183	334
Fosse | Securitisation programmes | Mortgage-backed master trust structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	2,154	2,258
External notes in issue	288	290
Notes issued to Santander UK plc/subsidiaries as collateral	1,402	1,402
Langton | Securitisation programmes | Mortgage-backed master trust structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	0	2,782
External notes in issue	0	0
Notes issued to Santander UK plc/subsidiaries as collateral	0	2,355
Motor | Securitisation programmes | Other asset-backed securitisation structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	38	189
External notes in issue	41	104
Notes issued to Santander UK plc/subsidiaries as collateral	0	97
Auto ABS UK Loans | Securitisation programmes | Other asset-backed securitisation structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	0	1,460
External notes in issue	0	1,107
Notes issued to Santander UK plc/subsidiaries as collateral	0	361
Euro 35bn Global Covered Bond Programme | Covered bond programmes
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	15,713	23,670
External notes in issue	12,760	19,285
Notes issued to Santander UK plc/subsidiaries as collateral	£ 0	£ 0

Securitisations and Covered B_4

Securitisations and Covered Bonds - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Jul. 30, 2021	Dec. 31, 2020
PSA Finance UK Limited | Santander Consumer (UK)
Disclosure Of Gross Asset Securitised [Line Items]
Proportion of ownership interest in subsidiary sold		50.00%
Holmes
Disclosure Of Gross Asset Securitised [Line Items]
Beneficial interest in residential mortgage loans	£ 500		£ 1,000
Cash deposits	60		186
Fosse
Disclosure Of Gross Asset Securitised [Line Items]
Beneficial interest in residential mortgage loans	1,600		1,700
Cash deposits	0		0
Langton
Disclosure Of Gross Asset Securitised [Line Items]
Gain or loss on covered bonds programme redemption	0
Beneficial interest in residential mortgage loans	£ 0		£ 2,400

Securitisations and Covered B_5

Securitisations and Covered Bonds - Summary of Issuances and Redemptions of Securitisation and Covered Bond Programme (Details) - GBP (£) £ in Billions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Internal issuances
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	£ 0	£ 0
Internal and external redemptions	2.8	0.4
Internal issuances | Mortgage-backed master trust structures: | Holmes
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0
Internal and external redemptions	0.2	0.3
Internal issuances | Mortgage-backed master trust structures: | Langton
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0
Internal and external redemptions	2.4	0
Internal issuances | Other asset-backed securitisation structures: | Motor
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0
Internal and external redemptions	0.1	0.1
Internal issuances | Other asset-backed securitisation structures: | Auto ABS UK Loans
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0
Internal and external redemptions	0.1	0
Internal issuances | Covered bond programmes
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0
Internal and external redemptions	0	0
External issuances
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	3.3
Internal and external redemptions	7.1	3.9
External issuances | Mortgage-backed master trust structures: | Holmes
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0
Internal and external redemptions	0.4	0.9
External issuances | Mortgage-backed master trust structures: | Langton
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0
Internal and external redemptions	0	0
External issuances | Other asset-backed securitisation structures: | Motor
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0
Internal and external redemptions	0.1	0.2
External issuances | Other asset-backed securitisation structures: | Auto ABS UK Loans
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0.3
Internal and external redemptions	0.1	0.1
External issuances | Covered bond programmes
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	3
Internal and external redemptions	£ 6.5	£ 2.7

Transfers of Financial Assets_3

Transfers of Financial Assets Not Qualifying for Derecognition (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of continuing involvement in derecognised financial assets [line items]
Carrying amount of financial assets not derecognised in their entirety	£ 6,549	£ 9,495
Carrying amount of associated financial liabilities	(2,673)	(4,422)
Sale and repurchase agreements
Disclosure of continuing involvement in derecognised financial assets [line items]
Carrying amount of financial assets not derecognised in their entirety	171	1,597
Carrying amount of associated financial liabilities	(172)	(1,340)
Securities lending agreements
Disclosure of continuing involvement in derecognised financial assets [line items]
Carrying amount of financial assets not derecognised in their entirety	1,892	918
Carrying amount of associated financial liabilities	(1,742)	(752)
Securitisations (See Notes 14 and 26)
Disclosure of continuing involvement in derecognised financial assets [line items]
Carrying amount of financial assets not derecognised in their entirety	4,486	6,980
Carrying amount of associated financial liabilities	£ (759)	£ (2,330)

Reverse Repurchase Agreements_3

Reverse Repurchase Agreements - Non Trading (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Reserve Repurchase Agreements Non-Trading [Line Items]
Reverse repurchase agreements – non trading	£ 12,683	£ 19,599
Agreements with banks
Disclosure Of Reserve Repurchase Agreements Non-Trading [Line Items]
Reverse repurchase agreements – non trading	447	1,258
Agreements with customers
Disclosure Of Reserve Repurchase Agreements Non-Trading [Line Items]
Reverse repurchase agreements – non trading	£ 12,236	£ 18,341

Other Financial Assets at Amo_4

Other Financial Assets at Amortised Cost (Details) - Other financial assets - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at amortised cost	£ 506	£ 1,163
Asset backed securities
Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at amortised cost	443	491
Debt securities
Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at amortised cost	£ 63	£ 672

Financial Assets at Fair Valu_3

Financial Assets at Fair Value Through Other Comprehensive Income (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Financial Assets At Fair Value Through Other Comprehensive Income [Line Items]
Financial assets at fair value through other comprehensive income	£ 5,851	£ 8,950
Debt securities
Disclosure Of Financial Assets At Fair Value Through Other Comprehensive Income [Line Items]
Financial assets at fair value through other comprehensive income	5,833	8,929
Loans and advances to customers
Disclosure Of Financial Assets At Fair Value Through Other Comprehensive Income [Line Items]
Financial assets at fair value through other comprehensive income	£ 18	£ 21

Interests in Other Entities - S

Interests in Other Entities - Schedule of Interests in Other Entities (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Investments accounted for using equity method [abstract]
Joint Ventures	£ 201	£ 172
Total	£ 201	£ 172

Interests In Other Entities - I

Interests In Other Entities - Interests in Subsidiaries - Additional Information (Details) - GBP (£) £ in Millions	Jul. 30, 2021	Jul. 29, 2021	Dec. 31, 2021	Dec. 31, 2020
Disclosure of subsidiaries [line items]
Ownership interest in share capital			100.00%
PSA Finance UK Limited
Disclosure of subsidiaries [line items]
Ownership interest in share capital		50.00%		50.00%
PSA Finance UK Limited | Santander Consumer (UK)
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary sold	50.00%
Assets derecognised at disposal	£ 3,200
Liabilities derecognised at disposal	2,900
PSA Finance UK Limited | Santander Consumer (UK) | Non-controlling interests
Disclosure of subsidiaries [line items]
Non-controlling interest derecognised at disposal	£ 150

Interests in Other Entities -_3

Interests in Other Entities - Schedule of Subsidiaries With Significant Non-Controlling Interests (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Disclosure of subsidiaries [line items]
Profit attributable to non-controlling interests	£ 36	£ 36	[1]	£ 37	[1]
Accumulated non-controlling interests of the subsidiary	235	397
Total assets	293,676	299,064		288,488
Total liabilities	277,298	282,819		272,147
Profit after tax	1,405	438	[1]	709	[1]
Total comprehensive income for the year	1,870	186		£ 373
Subsidiaries with material non-controlling interests
Disclosure of subsidiaries [line items]
Profit attributable to non-controlling interests	0	19
Accumulated non-controlling interests of the subsidiary	0	162
Dividends paid to non-controlling interests	0	15
Total assets	0	3,451
Total liabilities	0	3,127
Profit after tax	0	38
Total comprehensive income for the year	£ 0	£ 33
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Interests in Other Entities -_4

Interests in Other Entities - Interests in Joint Ventures - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of joint ventures [line items]
Carrying value of interest in joint venture	£ 201	£ 172
Joint ventures
Disclosure of joint ventures [line items]
Profit after tax	22	20
Carrying value of interest in joint venture	201	172
Commitments and contingent liabilities	£ 0	£ 0

Interests in Other Entities -_5

Interests in Other Entities - Interests in Unconsolidated Structured Entities - Additional Information (Details) £ in Millions	12 Months Ended
	Dec. 31, 2021GBP (£)	Dec. 31, 2020GBP (£)
Disclosure of information about unconsolidated subsidiaries [line items]
Number of credit protection vehicles	3	3
Senior credit linked notes issued	£ 1,184	£ 2,160
Junior credit linked notes issued	£ 619	678
Santander (UK) Common Investment Fund
Disclosure of information about unconsolidated subsidiaries [line items]
Name of subsidiary	The Santander (UK) Common Investment Fund
Defined benefit assets and obligations	£ 14,100	£ 13,553

Intangible Assets - Schedule of

Intangible Assets - Schedule of Goodwill (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Goodwill [Line Items]
Carrying value	£ 1,203	£ 1,203
Cost
Disclosure Of Goodwill [Line Items]
Carrying value	1,285	1,285
Accumulated impairment
Disclosure Of Goodwill [Line Items]
Carrying value	£ (82)	£ (82)

Intangible Assets - Additional

Intangible Assets - Additional Information (Details) - GBP (£)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about intangible assets [abstract]
Goodwill impairment recognised	£ 0	£ 0
Computer software	83,000,000	99,000,000
Internally generated computer software	31,000,000	68,000,000
Impairment charge	£ 27,000,000	£ 30,000,000

Intangible Assets - Schedule _2

Intangible Assets - Schedule of Goodwill for Cash Generating Units (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of information for cash-generating units [line items]
Goodwill	£ 1,203	£ 1,203
Personal Financial Services
Disclosure of information for cash-generating units [line items]
Goodwill	£ 1,169	£ 1,169
Discount rate	13.60%	13.60%
Growth rate beyond initial cash flow projections	1.60%	1.60%
Private Banking
Disclosure of information for cash-generating units [line items]
Goodwill	£ 30	£ 30
Discount rate	16.30%	8.90%
Growth rate beyond initial cash flow projections	1.60%	1.60%
Other
Disclosure of information for cash-generating units [line items]
Goodwill	£ 4	£ 4
Discount rate	13.60%	13.60%
Growth rate beyond initial cash flow projections	1.60%	1.60%

Intangible Assets - Reasonably

Intangible Assets - Reasonably Possible Changes in Key Assumptions (Details) - Personal Financial Services - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Goodwill [Line Items]
Value in use estimate, increase (decrease) in cash flows	5.00%	5.00%
Increase (decrease) in discount rate applied to cash flow projections	1.00%	1.00%
Value in use estimate, impairment increase sensitivity for cash flows adjustment	£ 0	£ 0
Value in use estimate, impairment increase sensitivity for discount rate adjustment	£ 276	£ 0

Intangible Assets - Sensitivity

Intangible Assets - Sensitivity of VIU Changes to Current Assumptions (Details) - Personal Financial Services - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Goodwill [Line Items]
Carrying value	£ 8,433	£ 6,758
Value in use	9,100	8,602
Headroom	£ 667	£ 1,844
Increase in post tax discount rate	0.68%	2.39%
Decrease in cash flows	7.00%	22.00%

Intangible Assets - Schedule _3

Intangible Assets - Schedule of Other Intangibles (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about intangible assets [line items]
Beginning balance	£ 446	£ 573
Additions	83	101
Disposals	(1)	0
Charge	(159)	(198)
Impairment	(27)	(30)
Ending balance	342	446
Cost
Disclosure of detailed information about intangible assets [line items]
Beginning balance	1,317	1,263
Additions	83	101
Disposals	(54)	(47)
Charge	0	0
Impairment	0	0
Ending balance	1,346	1,317
Accumulated amortisation / impairment
Disclosure of detailed information about intangible assets [line items]
Beginning balance	(871)	(690)
Additions	0	0
Disposals	53	47
Charge	(159)	(198)
Impairment	(27)	(30)
Ending balance	£ (1,004)	£ (871)

Property, Plant and Equipment -

Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	£ 1,740
Property, plant and equipment at end of period	1,555	£ 1,740
Accelerated depreciation expense	9	9
Construction in progress	106	55
Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	4,015	4,108
Additions	504	282
Disposals	(1,032)	(375)
Property, plant and equipment at end of period	3,487	4,015
Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(2,275)	(2,137)
Additions	(221)	(318)
Disposals	661	204
Impairment during the year	97	24
Property, plant and equipment at end of period	(1,932)	(2,275)
Property
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	784
Property, plant and equipment at end of period	646	784
Property | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	1,275	1,275
Additions	126	61
Disposals	(420)	(61)
Property, plant and equipment at end of period	981	1,275
Property | Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(491)	(457)
Additions	(32)	(56)
Disposals	234	46
Impairment during the year	46	24
Property, plant and equipment at end of period	(335)	(491)
Office fixtures and equipment
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	309
Property, plant and equipment at end of period	193	309
Office fixtures and equipment | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	1,362	1,442
Additions	28	24
Disposals	(334)	(104)
Property, plant and equipment at end of period	1,056	1,362
Office fixtures and equipment | Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(1,053)	(1,022)
Additions	(87)	(111)
Disposals	305	80
Impairment during the year	28	0
Property, plant and equipment at end of period	(863)	(1,053)
Computer software
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	2
Property, plant and equipment at end of period	2	2
Computer software | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	436	439
Additions	1	2
Disposals	0	(5)
Property, plant and equipment at end of period	437	436
Computer software | Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(434)	(434)
Additions	(1)	0
Disposals	0	0
Impairment during the year	0	0
Property, plant and equipment at end of period	(435)	(434)
Operating lease assets
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	542
Property, plant and equipment at end of period	595	542
Operating lease assets | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	720	738
Additions	284	185
Disposals	(249)	(203)
Property, plant and equipment at end of period	755	720
Operating lease assets | Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(178)	(164)
Additions	(81)	(92)
Disposals	99	78
Impairment during the year	0	0
Property, plant and equipment at end of period	(160)	(178)
Right-of-use assets
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	103
Property, plant and equipment at end of period	119	103
Right-of-use assets | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	222	214
Additions	65	10
Disposals	(29)	(2)
Property, plant and equipment at end of period	258	222
Right-of-use assets | Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(119)	(60)
Additions	(20)	(59)
Disposals	23	0
Impairment during the year	23	0
Property, plant and equipment at end of period	£ (139)	£ (119)

Property, Plant and Equipment_2

Property, Plant and Equipment - Additional Information (Details) - Head Office, Milton Keynes £ in Millions	Dec. 31, 2021GBP (£)
Disclosure of detailed information about property, plant and equipment [line items]
Planned investment	£ 200
Expenditures	£ 57

Other Financial Liabilities a_5

Other Financial Liabilities at Fair Value Through Profit or Loss - Summary of Other Financial Liabilities at Fair Value Through Profit or Loss (Details) £ in Millions	Dec. 31, 2021USD ($)	Dec. 31, 2021GBP (£)	Dec. 31, 2020USD ($)	Dec. 31, 2020GBP (£)
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Other financial liabilities at fair value through profit or loss		£ 803		£ 1,434
Notional amount		163,361		198,391
– US$30bn Euro Medium Term Note Programme
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Other financial liabilities at fair value through profit or loss		5		102
Notional amount | $	$ 30,000,000,000		$ 30,000,000,000
Structured Notes Programmes
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Other financial liabilities at fair value through profit or loss		413		805
Eurobonds
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Other financial liabilities at fair value through profit or loss		142		150
Structured deposits
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Other financial liabilities at fair value through profit or loss		223		375
Collateral and associated financial guarantees
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Other financial liabilities at fair value through profit or loss		£ 20		£ 2

Other Financial Liabilities a_6

Other Financial Liabilities at Fair Value Through Profit or Loss - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of financial liabilities [abstract]
Increase (decrease) in fair value of financial liability, attributable to changes in credit risk of liability	£ (12)	£ (3)	£ (77)
Accumulated increase (decrease) in fair value of financial liability, attributable to changes in credit risk of liability	(10)	(3)
Difference between carrying amount of financial liability and amount contractually required to pay at maturity to holder of obligation	£ 0	£ 11

Deposits by Customers (Details)

Deposits by Customers (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	£ 192,914	£ 193,088
Demand and time deposits
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	191,764	191,774
Amounts due to fellow Banco Santander subsidiaries and joint ventures
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	1,150	1,314
Equity Index Linked Deposits
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	549	577
Capital amount guaranteed or protected	549	577
Capital amount of return guaranteed	£ 2	£ 2

Deposits by Banks (Details)

Deposits by Banks (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	£ 33,862	£ 20,973
Drawdown from TFS	0	6,300
Drawdown from TFSME	31,900	11,700
Items in the course of transmission
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	414	375
Deposits held as collateral
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	941	2,071
Other deposits
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	£ 32,507	£ 18,527

Repurchase Agreements - Non T_3

Repurchase Agreements - Non Trading (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Repurchase Agreements [Line Items]
Repurchase agreements - non trading	£ 11,718	£ 15,848
Agreements with banks
Disclosure Of Repurchase Agreements [Line Items]
Repurchase agreements - non trading	4,145	6,358
Agreements with customers
Disclosure Of Repurchase Agreements [Line Items]
Repurchase agreements - non trading	£ 7,573	£ 9,490

Debt Securities in Issue - Summ

Debt Securities in Issue - Summary of Debt Securities in Issue (Details) £ in Millions	Dec. 31, 2021GBP (£)	Dec. 31, 2021EUR (€)	Dec. 31, 2021USD ($)	Dec. 31, 2020GBP (£)	Dec. 31, 2020EUR (€)	Dec. 31, 2020USD ($)
Debt Securities In Issue [Line Items]
Notional amount	£ 163,361			£ 198,391
Debt securities	31,580			43,679
Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities	12,911			16,325
Euro 35bn Global Covered Bond Programme
Debt Securities In Issue [Line Items]
Notional amount | €		€ 35,000,000,000			€ 35,000,000,000
Debt securities	12,760			19,285
US$20bn Commercial Paper Programmes
Debt Securities In Issue [Line Items]
Notional amount | $			$ 20,000,000,000			$ 20,000,000,000
Debt securities	2,704			2,824
Certificates of deposit
Debt Securities In Issue [Line Items]
Debt securities	2,387			2,858
Credit linked notes
Debt Securities In Issue [Line Items]
Credit linked notes	59			57
Securitisation programmes
Debt Securities In Issue [Line Items]
Debt securities	759			2,330
– US$30bn Euro Medium Term Note Programme | Medium-term notes
Debt Securities In Issue [Line Items]
Notional amount | $			$ 30,000,000,000			30,000,000,000
Debt securities	1,405			1,694
– Euro 30bn Euro Medium Term Note Programme | Medium-term notes
Debt Securities In Issue [Line Items]
Notional amount | €		€ 30,000,000,000			30,000,000,000
Debt securities	4,304			4,292
– Euro 30bn Euro Medium Term Note Programme | Medium-term notes | Euro 750m Senior Unsecured Notes
Debt Securities In Issue [Line Items]
Debt securities				673
– US SEC-registered Debt Programme – Santander UK Group Holdings plc | Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities	5,978			5,616
– US SEC-registered Debt Programme – Santander UK Group Holdings plc | Medium-term notes | US Dollar One Billion Senior Unsecured Notes
Debt Securities In Issue [Line Items]
Debt securities				734
– US SEC-registered Debt Programme – Santander UK plc | Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities	£ 1,224			£ 4,723
Euro 750m Senior Unsecured Notes | Medium-term notes
Debt Securities In Issue [Line Items]
Notional amount | €					€ 750,000,000
US Dollar One Billion Senior Unsecured Notes | Medium-term notes
Debt Securities In Issue [Line Items]
Notional amount | $						$ 1,000,000,000

Subordinated Liabilities - Sche

Subordinated Liabilities - Schedule of Subordinated Liabilities (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Subordinated liabilities [abstract]
£325m Sterling preference shares	£ 344	£ 344
Undated subordinated liabilities	240	557
Dated subordinated liabilities	1,644	1,655
Subordinated liabilities	2,228	2,556
325m Sterling Preference Shares, Notional amount	£ 325	£ 325

Subordinated Liabilities - Addi

Subordinated Liabilities - Additional Information (Details) - GBP (£)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2021
Disclosure Of Subordinated Liabilities [Line Items]
Loss on repurchase of debt securities and subordinated liabilities	£ 1,000,000	£ 24,000,000	£ 0
Defaults of principal, interest or other breaches with respect to subordinated liabilities	0	0
Repayment or purchase of subordinated liabilities before stated maturity allowed	£ 0	£ 0
Par value per share (in GBP per share)	£ 1	£ 1		£ 1
10.375% non-cumulative non-redeemable sterling preference shares
Disclosure Of Subordinated Liabilities [Line Items]
Par value per share (in GBP per share)	£ 1
7.125% 30 Year Step-up perpetual callable subordinated notes
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	7.125%	7.125%
7.125% 30 Year Step-up perpetual callable subordinated notes | Santander UK plc
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	7.125%
10.0625% Exchangeable capital securities
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	10.0625%	10.0625%
10.0625% Exchangeable capital securities | Santander UK plc
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	10.0625%
10.375% exchangeable subordinated capital securities
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	10.375%

Subordinated Liabilities - Summ

Subordinated Liabilities - Summary of Undated Subordinated Liabilities (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Subordinated Liabilities [Line Items]
Undated subordinated liabilities	£ 240	£ 557
10.0625% Exchangeable capital securities
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	10.0625%	10.0625%
First call date	n/a	n/a
Undated subordinated liabilities	£ 205	£ 205
7.125% 30 Year Step-up perpetual callable subordinated notes
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	7.125%	7.125%
Notes maturity, year	30 years	30 years
First call date	2030	2030
Undated subordinated liabilities	£ 35	£ 352

Subordinated Liabilities - Su_2

Subordinated Liabilities - Summary of Dated Subordinated Liabilities (Details) £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2021GBP (£)	Dec. 31, 2020GBP (£)
Disclosure Of Subordinated Liabilities [Line Items]
Dated subordinated liabilities			£ 1,644	£ 1,655
5% Subordinated notes (US$1,500m)
Disclosure Of Subordinated Liabilities [Line Items]
Borrowings maturity	2023	2023
Dated subordinated liabilities			£ 548	£ 542
Interest rate	5.00%	5.00%	5.00%	5.00%
Notional amount | $	$ 1,500	$ 1,500
4.75% Subordinated notes (US$1,000m)
Disclosure Of Subordinated Liabilities [Line Items]
Borrowings maturity	2025	2025
Dated subordinated liabilities			£ 541	£ 536
Interest rate	4.75%	4.75%	4.75%	4.75%
Notional amount | $	$ 1,000	$ 1,000
7.95% Subordinated notes (US$1,000m)
Disclosure Of Subordinated Liabilities [Line Items]
Borrowings maturity	2029	2029
Dated subordinated liabilities			£ 221	£ 242
Interest rate	7.95%	7.95%	7.95%	7.95%
Notional amount | $	$ 1,000	$ 1,000
6.50% Subordinated notes
Disclosure Of Subordinated Liabilities [Line Items]
Borrowings maturity	2030	2030
Dated subordinated liabilities			£ 28	£ 31
Interest rate	6.50%	6.50%	6.50%	6.50%
5.875% Subordinated notes
Disclosure Of Subordinated Liabilities [Line Items]
Borrowings maturity	2031	2031
Dated subordinated liabilities			£ 9	£ 10
Interest rate	5.875%	5.875%	5.875%	5.875%
5.625% Subordinated notes (US$500m)
Disclosure Of Subordinated Liabilities [Line Items]
Borrowings maturity	2045	2045
Dated subordinated liabilities			£ 297	£ 294
Interest rate	5.625%	5.625%	5.625%	5.625%
Notional amount | $	$ 500	$ 500

Other Liabilities (Details)

Other Liabilities (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Subclassifications of assets, liabilities and equities [abstract]
Lease liabilities	£ 134	£ 100
Other	2,064	2,243
Other liabilities	£ 2,198	£ 2,343

Provisions - Summary of Provisi

Provisions - Summary of Provisions Reconciliation (Details) £ in Millions	12 Months Ended
	Dec. 31, 2021GBP (£)
Disclosure of other provisions [line items]
Beginning balance	£ 468
Additional provisions	392
Provisions released	(34)
Utilisation and other	(473)
Recharge	13
Ending balance	366
Customer remediation
Disclosure of other provisions [line items]
Beginning balance	69
Additional provisions	25
Provisions released	0
Utilisation and other	(50)
Recharge	0
Ending balance	44
Customer remediation | Other
Disclosure of other provisions [line items]
Beginning balance	61
Customer remediation | Conduct remediation
Disclosure of other provisions [line items]
Beginning balance	8
Litigation and other regulatory
Disclosure of other provisions [line items]
Beginning balance	198
Additional provisions	72
Provisions released	0
Utilisation and other	(104)
Recharge	0
Ending balance	166
Litigation and other regulatory | Other
Disclosure of other provisions [line items]
Beginning balance	121
Litigation and other regulatory | Conduct remediation
Disclosure of other provisions [line items]
Beginning balance	76
Bank Levy
Disclosure of other provisions [line items]
Beginning balance	38
Additional provisions	53
Provisions released	0
Utilisation and other	(103)
Recharge	13
Ending balance	1
Property
Disclosure of other provisions [line items]
Beginning balance	45
Additional provisions	52
Provisions released	(2)
Utilisation and other	(21)
Recharge	0
Ending balance	74
ECL on undrawn facilities and guarantees
Disclosure of other provisions [line items]
Beginning balance	75
Additional provisions	0
Provisions released	(30)
Utilisation and other	(7)
Recharge	0
Ending balance	38
Restructuring
Disclosure of other provisions [line items]
Beginning balance	39
Additional provisions	81
Provisions released	0
Utilisation and other	(91)
Recharge	0
Ending balance	29
Restructuring | Other
Disclosure of other provisions [line items]
Beginning balance	39
Other
Disclosure of other provisions [line items]
Beginning balance	4
Additional provisions	109
Provisions released	(2)
Utilisation and other	(97)
Recharge	0
Ending balance	£ 14

Provisions - Additional Informa

Provisions - Additional Information (Details) - GBP (£) £ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2020
Future expected provision number
Provisions	£ 366	£ 366	£ 468
Additional provisions		392
No later than one year
Future expected provision number
Provisions	182	182	340
PPI
Future expected provision number
Provisions	0	0	59
Discount plans
Future expected provision number
Additional provisions	16
Consumer Credit Act Compliance
Future expected provision number
Provisions	6	6	£ 47
PPI, current stock and estimated future claim
Future expected provision number
Additional provisions		21
Legal provision
Future expected provision number
Additional provisions		29
Restructuring
Future expected provision number
Additional provisions		£ 22
Regulatory related UK Bank Levy
Future expected provision number
Bank Levy Rate		0.10%	0.14%
Property
Future expected provision number
Provisions	74	£ 74	£ 45
Additional provisions		52
Off-balance sheet ECL, transfer of CIB
Future expected provision number
Provisions	7	7
Restructuring
Future expected provision number
Provisions	£ 29	29	£ 39
Additional provisions		81
Provisions for costs related to transformation programs		76
Operational risk provisions
Future expected provision number
Additional provisions		£ 94

Retirement Benefit Plans - Summ

Retirement Benefit Plans - Summary of Retirement Benefit Plans (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Assets/(liabilities)
Total net assets	£ 1,536	£ 93
Unfunded pension and post-retirement medical benefits
Assets/(liabilities)
Surplus (deficit) in plan	(37)	(42)
Surplus | Funded defined benefit pension scheme
Assets/(liabilities)
Surplus (deficit) in plan	1,573	496
Deficit | Funded defined benefit pension scheme
Assets/(liabilities)
Surplus (deficit) in plan	£ 0	£ (361)

Retirement Benefit Plans - Su_2

Retirement Benefit Plans - Summary of Remeasurement Losses/(Gains) Recognised in Other Comprehensive Income (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of net defined benefit liability (asset) [abstract]
Pension remeasurement	£ (1,263)	£ 505	£ 523

Retirement Benefit Plans - Addi

Retirement Benefit Plans - Additional Information (Details) £ in Millions	Oct. 26, 2018GBP (£)	Dec. 31, 2021GBP (£)	Dec. 31, 2021GBP (£)directorsection	Dec. 31, 2020GBP (£)director	Dec. 31, 2019GBP (£)	Mar. 31, 2021	Aug. 31, 2019GBP (£)	Mar. 01, 2015
Disclosure of defined benefit plans [line items]
Defined contribution expense			£ 65	£ 67	£ 67
Number of legally segregated sections | section			7
Percentage of employee covered defined benefit pension schemes		11.00%	11.00%	11.00%
Number of directors selected | director			5	5
Number of directors nominated | director			5	5
Actuarial valuation deficit							£ 1,136
Decrease in GMP allowance			£ 5	£ 5	5
GMP allowance included in scheme liabilities		£ 45	45	50	45
Past service curtailment costs			5	0	0
Contribution to scheme based on agreement		£ 241	£ 241	236
Forward curve term			30 years
Increase (decrease) in net defined benefit liability (asset)			£ 46	£ 35	£ 19
Percentage of pension pay increase		3.20%	3.20%	2.90%	2.90%			1.00%
Percentage improvements in membership profile retirement benefits plan			0.15%
Improvements to life expectancy of female employees			1.25%
Improvements to life expectancy of male employees			1.25%
Average duration of defined benefit obligation			18.3 years	19.4 years
Percentage of the SMA section pensioner liabilities insured		100.00%	100.00%
Percentage of the SPI section pensioner liabilities insured		50.00%	50.00%
Liabilities at fair value		£ 1,822	£ 1,822	£ 3,354
Longevity swap
Disclosure of defined benefit plans [line items]
Percentage of pensioner liabilities covered by longevity swap						85.00%
Liabilities at fair value		8	£ 8
Minimum
Disclosure of defined benefit plans [line items]
Period over which the forward rate is used for computing retirement benefits			15 years
Maximum
Disclosure of defined benefit plans [line items]
Period over which the forward rate is used for computing retirement benefits			30 years
Actuarial assumption of expected rates of inflation
Disclosure of defined benefit plans [line items]
Increase (decrease) in net defined benefit liability (asset)				64
Santander UK plc
Disclosure of defined benefit plans [line items]
Number of trustee directors | director			3
Deficit Repair Contributions
Disclosure of defined benefit plans [line items]
Contribution to scheme based on agreement		194	£ 194	187
Deficit Group Section Contributions Plan | Santander UK Group
Disclosure of defined benefit plans [line items]
Contributions to defined benefit plans			£ 187
Maturity date for contribution			31 March 2026
Monthly additional contributions to defined benefit plans		1
Equity collar
Disclosure of defined benefit plans [line items]
Gross notional value		1,259	£ 1,259	1,076
Currency futures
Disclosure of defined benefit plans [line items]
Gross notional value		£ 2,296	2,296	2,378
Present value of defined benefit obligations
Disclosure of defined benefit plans [line items]
Estimated increase in liabilities in relation to judgment on GMP equalisation	£ 40
Past service curtailment costs			£ (5)	£ 0
Santander CF Trustee Limited
Disclosure of defined benefit plans [line items]
Number of trustee directors | director			5
Santander (UK) Group Pension Scheme Trustees Limited
Disclosure of defined benefit plans [line items]
Number of trustee directors | director			2

Retirement Benefit Plans - Tota

Retirement Benefit Plans - Total Defined Benefit Plan Amount Charged to Income Statement (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of net defined benefit liability (asset) [abstract]
Net interest income	£ (5)	£ (10)	£ (24)
Current service cost	38	36	34
Past service and GMP costs	0	1	1
Past service curtailment costs	5	0	0
Administration costs	8	8	8
Total	£ 46	£ 35	£ 19

Retirement Benefit Plans - Su_3

Retirement Benefit Plans - Summary of Amounts Recognised in Other Comprehensive Income (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of net defined benefit liability (asset) [abstract]
Return on plan assets (excluding amounts included in net interest expense)	£ (452)	£ (1,328)	£ (873)
Actuarial (gains)/losses arising from changes in demographic assumptions	(17)	34	42
Actuarial gains arising from experience adjustments	(19)	(141)	(40)
Actuarial (gains)/losses arising from changes in financial assumptions	(775)	1,940	1,394
Pension remeasurement	£ (1,263)	£ 505	£ 523

Retirement Benefit Plans - Disc

Retirement Benefit Plans - Disclosure of Movements in Present Value of Defined Benefit Obligations (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	£ (93)
Current service cost paid by Santander UK plc	38	£ 36	£ 34
Interest cost	(5)	(10)	(24)
Past service curtailment costs	5	0	0
Remeasurement due to actuarial movements arising from:
– Changes in demographic assumptions	(17)	34	42
– Experience adjustments	(19)	(141)	(40)
– Changes in financial assumptions	(775)	1,940	1,394
Ending balance	(1,536)	(93)
Present value of defined benefit obligations
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	(13,894)	(12,165)
Current service cost paid by Santander UK plc	(29)	(24)
Current service cost paid by other subsidiaries	(9)	(12)
Interest cost	(188)	(253)
Employer salary sacrifice contributions	(9)	(2)
Past service cost	0	(1)
Past service curtailment costs	(5)	0
Remeasurement due to actuarial movements arising from:
– Changes in demographic assumptions	17	(34)
– Experience adjustments	19	141
– Changes in financial assumptions	775	(1,940)
Benefits paid	398	396
Derecognition of pension scheme liabilities arising from the sale of PSA	41	0
Ending balance	£ (12,884)	£ (13,894)	£ (12,165)

Retirement Benefit Plans - Di_2

Retirement Benefit Plans - Disclosure of Movements in Fair Value of Scheme Assets (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	£ (93)
Interest cost	(5)	£ (10)	£ (24)
Return on plan assets (excluding amounts included in net interest expense)	(452)	(1,328)	(873)
Ending balance	(1,536)	(93)
Fair value of scheme assets
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	13,987	12,555
Interest cost	193	263
Contributions paid by employer and scheme members	247	245
Administration costs paid	(8)	(8)
Return on plan assets (excluding amounts included in net interest expense)	452	1,328
Benefits paid	(398)	(396)
Derecognition of pension scheme liabilities arising from the sale of PSA	(53)	0
Ending balance	£ 14,420	£ 13,987	£ 12,555

Retirement Benefit Plans - Su_4

Retirement Benefit Plans - Summary of Composition and Fair Value of Plan Assets (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of net defined benefit liability (asset) [line items]
UK equities	£ 38	£ 40
Overseas equities	2,466	2,275
Corporate bonds	1,919	1,578
Government fixed interest bonds	2,788	1,618
Government index-linked bonds	9,159	6,695
Property	1,409	1,454
Derivatives	(83)	312
Cash	2,290	1,161
Repurchase agreements	(6,582)	(2,198)
Infrastructure	390	406
Annuities	298	317
Longevity swap	(8)	0
Other	336	329
Total	£ 14,420	£ 13,987
UK equities, percentage	0.00%	0.00%
Overseas equities, percentage	17.00%	16.00%
Corporate bonds, percentage	13.00%	11.00%
Government fixed interest bonds, percentage	19.00%	12.00%
Government index-linked bonds, percentage	64.00%	48.00%
Property, percentage	10.00%	10.00%
Derivatives, percentage	(1.00%)	2.00%
Cash, percentage	16.00%	8.00%
Repurchase agreements, percentage	(45.00%)	(15.00%)
Infrastructure, percentage	3.00%	3.00%
Annuities, percentage	2.00%	2.00%
Longevity swap, percentage	0.00%	0.00%
Other, percentage	2.00%	3.00%
Total, percentage	100.00%	100.00%
Quoted prices in active markets
Disclosure of net defined benefit liability (asset) [line items]
UK equities	£ 38	£ 40
Overseas equities	1,401	1,271
Corporate bonds	1,607	1,121
Government fixed interest bonds	2,788	1,618
Government index-linked bonds	9,159	6,695
Property	0	0
Derivatives	0	0
Cash	0	0
Repurchase agreements	0	0
Infrastructure	0	0
Annuities	0	0
Longevity swap	0	0
Other	0	0
Total	£ 14,993	£ 10,745
UK equities, percentage	0.00%	0.00%
Overseas equities, percentage	10.00%	9.00%
Corporate bonds, percentage	11.00%	8.00%
Government fixed interest bonds, percentage	19.00%	12.00%
Government index-linked bonds, percentage	64.00%	48.00%
Property, percentage	0.00%	0.00%
Derivatives, percentage	0.00%	0.00%
Cash, percentage	0.00%	0.00%
Repurchase agreements, percentage	0.00%	0.00%
Infrastructure, percentage	0.00%	0.00%
Annuities, percentage	0.00%	0.00%
Longevity swap, percentage	0.00%	0.00%
Other, percentage	0.00%	0.00%
Total, percentage	104.00%	77.00%
Prices not quoted in active markets
Disclosure of net defined benefit liability (asset) [line items]
UK equities	£ 0	£ 0
Overseas equities	1,065	1,004
Corporate bonds	312	457
Government fixed interest bonds	0	0
Government index-linked bonds	0	0
Property	1,409	1,454
Derivatives	(83)	312
Cash	2,290	1,161
Repurchase agreements	(6,582)	(2,198)
Infrastructure	390	406
Annuities	298	317
Longevity swap	(8)	0
Other	336	329
Total	£ (573)	£ 3,242
UK equities, percentage	0.00%	0.00%
Overseas equities, percentage	7.00%	7.00%
Corporate bonds, percentage	2.00%	3.00%
Government fixed interest bonds, percentage	0.00%	0.00%
Government index-linked bonds, percentage	0.00%	0.00%
Property, percentage	10.00%	10.00%
Derivatives, percentage	(1.00%)	2.00%
Cash, percentage	16.00%	8.00%
Repurchase agreements, percentage	(45.00%)	(15.00%)
Infrastructure, percentage	3.00%	3.00%
Annuities, percentage	2.00%	2.00%
Longevity swap, percentage	0.00%	0.00%
Other, percentage	2.00%	3.00%
Total, percentage	(4.00%)	23.00%

Retirement Benefit Plans - Su_5

Retirement Benefit Plans - Summary of Principal Actuarial Assumptions Used for Defined Benefit Schemes (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 01, 2015
Disclosure of net defined benefit liability (asset) [abstract]
Discount rate for scheme liabilities	1.90%	1.30%	2.10%
General price inflation	3.40%	3.00%	3.00%
General salary increase	1.00%	1.00%	1.00%
Expected rate of pension increase	3.20%	2.90%	2.90%	1.00%
Longevity at 60 for current pensioners, on the valuation date:
Males	27 years 6 months	27 years 6 months	27 years 3 months 18 days
Females	30 years 1 month 6 days	30 years	29 years 9 months 18 days
Longevity at 60 for future pensioners currently aged 40, on the valuation date:
Males	29 years	29 years	28 years 10 months 24 days
Females	31 years 7 months 6 days	31 years 6 months	31 years 3 months 18 days

Retirement Benefit Plans - Su_6

Retirement Benefit Plans - Summary of Actuarial Assumption Sensitivities (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Actuarial assumption of discount rates
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Description of changes in methods and assumptions	25 bps increase
Increase (decrease) in defined benefit obligation	£ (571)	£ (662)
Percentage of reasonably possible increase in actuarial assumption	0.25%
Actuarial assumption of expected rates of inflation
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Description of changes in methods and assumptions	25 bps increase
Increase (decrease) in defined benefit obligation	£ 392	480
Percentage of reasonably possible increase in actuarial assumption	0.25%
Actuarial assumption of expected rates of inflation | Previously stated
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Increase (decrease) in defined benefit obligation		365
Actuarial assumption of mortality rates
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Description of changes in methods and assumptions	Each additional year of longevity assumed
Increase (decrease) in defined benefit obligation	£ 478	£ 515

Retirement Benefit Plans - Di_3

Retirement Benefit Plans - Disclosure of Benefits Expected To Be Paid (Details) £ in Millions	Dec. 31, 2021GBP (£)
No later than one year
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	£ 387
Later than one year and not later than two years
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	335
Later than two years and not later than three years
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	356
Later than three years and not later than four years
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	381
Later than four years and not later than five years
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	401
Five years ending 2031
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	£ 2,240

Contingent Liabilities and Co_4

Contingent Liabilities and Commitments - Summary of Contingent Liabilities and Commitments (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of contingent liabilities [line items]
Guarantees and formal standby facilities, credit lines and other commitments	£ 37,748	£ 43,170
Contingent liability for guarantees
Disclosure of contingent liabilities [line items]
Guarantees given to third parties	363	939
Loan commitments
Disclosure of contingent liabilities [line items]
Formal standby facilities, credit lines and other commitments	£ 37,385	£ 42,231

Contingent Liabilities and Co_5

Contingent Liabilities and Commitments - Additional Information (Details) £ in Millions	Nov. 02, 2015	Dec. 31, 2021EUR (€)shares	Dec. 31, 2020GBP (£)	Dec. 31, 2021GBP (£)	Dec. 31, 2021EUR (€)	Sep. 30, 2020shares	Jul. 31, 2020GBP (£)
Disclosure of contingent liabilities [line items]
Capital support arrangements, risk-weighted exposures of regulated entities				0.00%	0.00%
Provisions			£ 468	£ 366
Lease arrangements, potential final payment to HMRC				50
Decrease in convertible preferred stock fair value			10
Minimum
Disclosure of contingent liabilities [line items]
Losses on litigation settlements | €		€ 1,000,000,000
Maximum
Disclosure of contingent liabilities [line items]
Santander UK liability under indemnity cap | €					€ 39,850,000
AXA France
Disclosure of contingent liabilities [line items]
Amount claimed by other party				636
UK&I Banks
Disclosure of contingent liabilities [line items]
Preferred stock issued, threshold value | €		€ 0
Genworth Financial International Holdings Inc
Disclosure of contingent liabilities [line items]
Amount awarded to other party							£ 624
Visa Europe Ltd
Disclosure of contingent liabilities [line items]
Visa Europe Ltd sale to Visa Inc	100.00%
Santander Equity Investment Limited
Disclosure of contingent liabilities [line items]
Convertible preferred stock, sold | shares		5,211
Santander Equity Investment Limited | Visa Europe Ltd
Disclosure of contingent liabilities [line items]
Convertible preferred stock, issued | shares						5,211
Number of shares issued upon conversion of convertible preferred stock | shares						82,000,000
Compliance with Consumer Credit Act
Disclosure of contingent liabilities [line items]
Provisions			£ 47	£ 6

Share Capital (Details)

Share Capital (Details) - GBP (£) £ / shares in Units, £ in Millions	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Disclosure of classes of share capital [abstract]
Ordinary shares, price per share (in GBP per share)	£ 1	£ 1	£ 1
Number of shares issued and fully paid (in shares)	7,060,000,000	7,060,000,000	7,060,000,000
Issued capital	£ 7,060	£ 7,060	£ 7,060

Other Equity Instruments - Summ

Other Equity Instruments - Summary of Other Equity Instruments (Details)	1 Months Ended	12 Months Ended
	Mar. 31, 2021GBP (£)	Dec. 31, 2021GBP (£)	Dec. 31, 2020GBP (£)
Disclosure Of Other Equity Instruments [Line Items]
Other equity instruments		£ 2,191,000,000	£ 2,241,000,000
£500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities		£ 500,000,000	£ 500,000,000
Interest rate		0.0675	0.0675
Other equity interest maturity period		2024-06	2024-06
Other equity instruments		£ 496,000,000	£ 496,000,000
£750m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities		£ 750,000,000	£ 750,000,000
Interest rate		0.07375	0.07375
Other equity interest maturity period		2022-06	2022-06
Other equity instruments		£ 745,000,000	£ 745,000,000
£500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities		£ 500,000,000	£ 500,000,000
Interest rate	0.0533	0.0533	0.0533
Other equity instruments		£ 0	£ 500,000,000
£500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities		£ 500,000,000	£ 500,000,000
Interest rate		0.0630	0.0630
Other equity interest maturity period		2025-03	2025-03
Other equity instruments		£ 500,000,000	£ 500,000,000
£450m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities	£ 450,000,000	£ 450,000,000	£ 450,000,000
Interest rate	0.0425	0.0425	0.0425
Other equity interest maturity period		2026-03	2026-03
Other equity instruments		£ 450,000,000	£ 0

Other Equity Instruments - Addi

Other Equity Instruments - Additional Information (Details)	1 Months Ended	12 Months Ended
	Mar. 31, 2021GBP (£)	Dec. 31, 2021GBP (£)	Dec. 31, 2020GBP (£)
£500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Distribution rate resets, period		5 years
Common equity tier 1 capital ratio minimum		7.00%
Interest rate		0.0675	0.0675
Capital securities issued		£ 500,000,000	£ 500,000,000
£750m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Interest rate		0.07375	0.07375
Capital securities issued		£ 750,000,000	£ 750,000,000
£500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Interest rate		0.0630	0.0630
Capital securities issued		£ 500,000,000	£ 500,000,000
£450m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Interest rate	0.0425	0.0425	0.0425
Capital securities issued	£ 450,000,000	£ 450,000,000	£ 450,000,000
£100m of the £750m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities issued		£ 100,000,000
£500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Interest rate	0.0533	0.0533	0.0533
Capital securities issued		£ 500,000,000	£ 500,000,000
Capital securities purchased and redeemed	£ 500,000,000

Non-Controlling Interests - Sch

Non-Controlling Interests - Schedule of Amounts Attributable to Non-Controlling Interests (Details)	12 Months Ended
	Dec. 31, 2021GBP (£)	Dec. 31, 2020GBP (£)
Disclosure Of Noncontrolling Interests [Line Items]
Notional amount	£ 163,361,000,000	£ 198,391,000,000
Non-controlling interests	235,000,000	397,000,000
£300m Step-up Callable Perpetual Reserve Capital Instruments
Disclosure Of Noncontrolling Interests [Line Items]
Notional amount	£ 300,000,000	£ 300,000,000
Initial interest rate	0.07037	0.07037
First call date	2026-02	2026-02
Non-controlling interests	£ 235,000,000	£ 235,000,000
PSA Finance UK Limited
Disclosure Of Noncontrolling Interests [Line Items]
Non-controlling interests	£ 0	£ 162,000,000

Non-Controlling Interests - Add

Non-Controlling Interests - Additional Information (Details) - GBP (£) £ in Millions	Jul. 30, 2021	Dec. 31, 2021
PSA Finance UK Limited | Santander Consumer (UK)
Disclosure Of Noncontrolling Interests [Line Items]
Proportion of ownership interest in subsidiary sold	50.00%
Assets derecognised at disposal	£ 3,200
Liabilities derecognised at disposal	2,900
£300m Step-up Callable Perpetual Reserve Capital Instruments
Disclosure Of Noncontrolling Interests [Line Items]
Reserve Capital Instruments bear interest rate reset period		5 years
£300m Fixed rate Perpetual at One Capital Securities
Disclosure Of Noncontrolling Interests [Line Items]
Step up callable perpetual reserve capital instruments bear interest rate gilt rate benchmark period		5 years
Non-controlling interests | PSA Finance UK Limited | Santander Consumer (UK)
Disclosure Of Noncontrolling Interests [Line Items]
Non-controlling interest derecognised at disposal	£ 150

Notes to Cash Flows - Summary o

Notes to Cash Flows - Summary of Changes in Liabilities Arising from Financing Activities (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	£ 48,576	£ 56,078
Proceeds from issue of debt securities	2,847	5,586
Repayment of debt securities	(13,724)	(12,348)
Repayment of subordinated liabilities	(4)	(939)
Issue of other equity instruments	450	0
Repurchase of other equity instruments	(500)	0
Payment of lease liability	(25)	(46)
Dividends paid	(1,506)	(282)
Liability-related other changes	(418)	(245)
Non-cash changes:
Unrealised foreign exchange	(916)	353
Other changes	1,353	419
Ending Balance	36,133	48,576
Santander UK Group Holdings plc
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	12,450	12,340
Proceeds from issue of debt securities	2,788	1,409
Repayment of debt securities	(1,814)	(969)
Repayment of subordinated liabilities	0	(281)
Issue of other equity instruments	450	0
Repurchase of other equity instruments	(500)	0
Dividends paid	(1,489)	(250)
Liability-related other changes	(28)	(3)
Non-cash changes:
Unrealised foreign exchange	(116)	(45)
Other changes	1,498	249
Ending Balance	13,239	12,450
Debt securities in issue
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	43,679	50,171
Proceeds from issue of debt securities	2,847	5,586
Repayment of debt securities	(13,724)	(12,348)
Liability-related other changes	(473)	(243)
Non-cash changes:
Unrealised foreign exchange	(930)	359
Other changes	181	154
Ending Balance	31,580	43,679
Debt securities in issue | Santander UK Group Holdings plc
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	9,379	8,957
Proceeds from issue of debt securities	2,788	1,409
Repayment of debt securities	(1,814)	(969)
Liability-related other changes	(28)	(3)
Non-cash changes:
Unrealised foreign exchange	(124)	(17)
Other changes	9	2
Ending Balance	10,210	9,379
Subordinated liabilities
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	2,556	3,528
Repayment of subordinated liabilities	(4)	(939)
Liability-related other changes	(4)	(10)
Non-cash changes:
Unrealised foreign exchange	14	(6)
Other changes	(334)	(17)
Ending Balance	2,228	2,556
Subordinated liabilities | Santander UK Group Holdings plc
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	830	1,142
Repayment of subordinated liabilities		(281)
Non-cash changes:
Unrealised foreign exchange	8	(28)
Other changes		(3)
Ending Balance	838	830
Other equity instruments
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	2,241	2,241
Issue of other equity instruments	450
Repurchase of other equity instruments	(500)
Non-cash changes:
Ending Balance	2,191	2,241
Other equity instruments | Santander UK Group Holdings plc
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	2,241	2,241
Issue of other equity instruments	450
Repurchase of other equity instruments	(500)
Non-cash changes:
Ending Balance	2,191	2,241
Lease liabilities
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	100	138
Payment of lease liability	(25)	(46)
Liability-related other changes	59	8
Non-cash changes:
Ending Balance	134	100
Dividends paid
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	0	0
Dividends paid	(1,506)	(282)
Non-cash changes:
Other changes	1,506	282
Ending Balance	0	0
Dividends paid | Santander UK Group Holdings plc
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	0	0
Dividends paid	(1,489)	(250)
Non-cash changes:
Other changes	1,489	250
Ending Balance	£ 0	£ 0

Notes to Cash Flows - Additiona

Notes to Cash Flows - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disclosure Of Cash Flows Explanatory Notes [Line Items]
Disposal of non-controlling interests	£ 181
Principal elements of lease payments	25	£ 46	£ 55
Cash outflow for leases	28	49
Interest received	4,873	5,176	5,856
Interest paid	1,085	1,900	2,587
Dividends received	0	0	0
Cash and cash equivalents restated	£ 53,367	50,206	34,367	£ 31,204
Increase (decrease) due to corrections of prior period errors
Disclosure Of Cash Flows Explanatory Notes [Line Items]
Cash and cash equivalents restated		2,100	1,134
Change in operating liabilities
Disclosure Of Cash Flows Explanatory Notes [Line Items]
Change in operating liabilities		£ 46	£ 55

Assets Charged as Security fo_3

Assets Charged as Security for Liabilities and Collateral Accepted as Security for Assets - Financial Assets Charged as Security Under On-Balance Sheet and Off-Balance (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	£ 1,585	£ 4,549
On-balance sheet:
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	67,878	62,942
On-balance sheet: | Cash and balances at central banks
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	1,580	985
On-balance sheet: | Loans and advances to banks
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	478	804
On-balance sheet: | Loans and advances to customers | Securitisations and covered bonds
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	19,432	31,138
On-balance sheet: | Loans and advances to customers | Other
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	41,953	23,690
On-balance sheet: | Other financial assets at amortised cost
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	0	648
On-balance sheet: | Financial assets at FVOCI
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	4,435	5,677
Off-balance sheet
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	£ 14,449	£ 24,701

Assets Charged as Security fo_4

Assets Charged as Security for Liabilities and Collateral Accepted as Security for Assets - Additional Information (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	£ 1,585	£ 4,549
Gross assets charged as security for liabilities	20,199	33,432
Notes issued under securitisation and covered bond programmes retained internally	13,519	21,615
Securities lending
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	46,007	30,135
Collateral accepted as security for assets	3,678	5,071
Internally retained | Securitisations and covered bonds
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued under securitisation and covered bond programmes retained internally	1,855	4,530
Third party bilateral secured funding transactions | Securitisations and covered bonds
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	500	1,114
Purchase and resale agreements
Disclosure Of Assets Pledged As Security [Line Items]
Collateral accepted as security for assets	14,562	25,972
Fellow subsidiaries | Sale and repurchase agreements
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	15,368	25,874
Fellow subsidiaries | Loans and advances to customers securitisations and covered bonds
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	639	1,392
Santander UK plc | Internally retained | Securitisations and covered bonds
Disclosure Of Assets Pledged As Security [Line Items]
Internally retained securitisation and covered bond issuances available for creating collateral	767	2,294
Derivatives | Cash
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	2,159	1,888
Collateral accepted as security for assets	£ 941	£ 2,071

Assets Charged as Security fo_5

Assets Charged as Security for Liabilities and Collateral Accepted as Security for Assets - Schedule of Collateral Held as Security for Assets (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
On-balance sheet:
Disclosure Of Assets Pledged As Security [Line Items]
Total on-balance sheet/ off-balance sheet	£ 941	£ 2,071
On-balance sheet: | Deposits by banks
Disclosure Of Assets Pledged As Security [Line Items]
Total on-balance sheet/ off-balance sheet	941	2,071
Off-balance sheet
Disclosure Of Assets Pledged As Security [Line Items]
Total on-balance sheet/ off-balance sheet	£ 18,240	£ 31,043

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details)	12 Months Ended		168 Months Ended
	Dec. 31, 2021GBP (£)shares	Dec. 31, 2020GBP (£)shares	Dec. 31, 2021GBP (£)invitation
Disclosure of terms and conditions of share-based payment arrangement [line items]
Liabilities arising from share-based payment transactions	£ 3,700,000	£ 500,000	£ 3,700,000
Liabilities arising from share-based payment transactions, vested liabilities	400,000	0	£ 400,000
Number of sharesave schemes launched | invitation			14
Employee saving on share based compensation	£ 500,000		£ 500,000
Price determination period for options	3 days
Expiration term of vested options	6 months
Weighted average grant-date fair value (GBP per share)	£ 0.20	£ 0.21	0.20
Number of shares outstanding | shares	3,618,796	3,254,900
Maximum discount applicable	20.00%
Actual discount applied	10.00%
Material Risk Takers
Disclosure of terms and conditions of share-based payment arrangement [line items]
Additional retention period for deferred bonus awards	1 year
Share Incentive Plans
Disclosure of terms and conditions of share-based payment arrangement [line items]
Maximum investment value per tax year	£ 1,800		1,800
Percentage of maximum salary that can be invested	10.00%
Transformation Incentive Plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Liabilities arising from share-based payment transactions	£ 1,000,000		1,000,000
Value of awards granted	£ 6,000,000
Shares | Material Risk Takers
Disclosure of terms and conditions of share-based payment arrangement [line items]
Annual bonus percentage	50.00%
Cash | Material Risk Takers
Disclosure of terms and conditions of share-based payment arrangement [line items]
Annual bonus percentage	50.00%
Minimum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Employee saving on share based compensation	£ 5		5
Terms of options	3 years
Maximum
Disclosure of terms and conditions of share-based payment arrangement [line items]
Employee saving on share based compensation	£ 500		£ 500
Terms of options	5 years
Variable pay of less than 500,000 | Material Risk Takers
Disclosure of terms and conditions of share-based payment arrangement [line items]
Percentage of defer annual bonus	40.00%
Variable pay at or above 500,000 | Material Risk Takers
Disclosure of terms and conditions of share-based payment arrangement [line items]
Percentage of defer annual bonus	60.00%
Period one | Material Risk Takers
Disclosure of terms and conditions of share-based payment arrangement [line items]
Deferral period from anniversary of initial award	4 years
Period two | Material Risk Takers
Disclosure of terms and conditions of share-based payment arrangement [line items]
Deferral period from anniversary of initial award	5 years
Period three | Material Risk Takers
Disclosure of terms and conditions of share-based payment arrangement [line items]
Deferral period from anniversary of initial award	7 years
Minimum | Share Incentive Plans
Disclosure of terms and conditions of share-based payment arrangement [line items]
Minimum retention period to sell shares free of income tax	5 years

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Movement in Share Options (Details) number in Thousands	12 Months Ended
	Dec. 31, 2021£ / shares	Dec. 31, 2020£ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average share price (GBP per share)	£ 2.65	£ 2.92
Sharesave Schemes
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of options outstanding beginning balance	21,162	23,373
Number of options granted	9,414	11,642
Number of options exercised	(48)	(860)
Number of options forfeited/expired	(4,535)	(12,993)
Number of options outstanding ending balance	25,993	21,162
Number of options exercisable	1,321	1,805
Weighted average exercise price outstanding beginning balance	£ 2.32	£ 3.03
Weighted average exercise price granted	2.43	1.65
Weighted average exercise price exercised	1.86	2.75
Weighted average exercise price forfeited/expired	2.95	2.96
Weighted average exercise price outstanding ending balance	2.25	2.32
Weighted average exercise price exercisable	£ 2.75	£ 3.59

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Range of Exercise Prices and Weighted Average Remaining Contractual Life of the Options Outstanding (Details) - Sharesave Schemes - £ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Weighted average exercise price (in GBP per share)	£ 2.25	£ 2.32	£ 3.03
£1 to £2
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Weighted average remaining contractual life	3 years	4 years
Weighted average exercise price (in GBP per share)	£ 1.65	£ 1.65
£2 to £3
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Weighted average remaining contractual life	3 years	2 years
Weighted average exercise price (in GBP per share)	£ 2.81	£ 2.81
£3 to £4
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Weighted average remaining contractual life	1 year	1 year
Weighted average exercise price (in GBP per share)	£ 3.38	£ 3.38
£4 to £5
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Weighted average remaining contractual life	1 year	1 year
Weighted average exercise price (in GBP per share)	£ 4.02	£ 4.02
Minimum | £1 to £2
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Range of exercise prices	1
Minimum | £2 to £3
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Range of exercise prices	2
Minimum | £3 to £4
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Range of exercise prices	3
Minimum | £4 to £5
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Range of exercise prices	4
Maximum | £1 to £2
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Range of exercise prices	2
Maximum | £2 to £3
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Range of exercise prices	3
Maximum | £3 to £4
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Range of exercise prices	4
Maximum | £4 to £5
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Range of exercise prices	£ 5

Transactions with Directors a_4

Transactions with Directors and Other Key Management Personnel - Summary of Remuneration of the Directors and Other Key Management Personnel (Details)	12 Months Ended
	Dec. 31, 2021GBP (£)individual	Dec. 31, 2020GBP (£)individual	Dec. 31, 2019GBP (£)individual
Disclosure Of Directors And Key Management Remuneration [Line Items]
Salaries and fees	£ 3,835,797	£ 3,906,401	£ 5,045,302
Performance-related payments	5,195,722	748,495	3,896,382
Other fixed remuneration (pension and other allowances & non-cash benefits)	806,103	1,047,986	1,386,439
Expenses	3,705	2,579	42,526
Total remuneration	9,841,327	5,705,461	10,370,649
Short-term employee benefits	23,392,657	17,886,869	23,238,187
Post-employment benefits	913,842	2,107,544	3,674,772
Total compensation	24,306,499	£ 19,994,413	26,912,959
Number of previously employed individuals for buy-out of deferred performance related payment | individual		2
Termination payment	£ 0	£ 0	£ 1,076,435
Number key management persons who receives termination benefit | individual			1
Director
Disclosure Of Directors And Key Management Remuneration [Line Items]
Number of previously employed individuals for buy-out of deferred performance related payment | individual		1
Deferred performance related payments of shares		£ 1,293,678
Deferred performance related payments of shares vested		£ 242,605
Key Management Personnel
Disclosure Of Directors And Key Management Remuneration [Line Items]
Number of previously employed individuals for buy-out of deferred performance related payment | individual	1	1
Deferred performance related payments of shares	£ 107,225	£ 924,133
Deferred performance related payments of shares vested	£ 25,413	£ 60,500

Transactions with Directors a_5

Transactions with Directors and Other Key Management Personnel - Additional Information (Details)	12 Months Ended
	Dec. 31, 2021GBP (£)director	Dec. 31, 2020GBP (£)director	Dec. 31, 2019GBP (£)
Disclosure Of Directors And Key Management Remuneration [Line Items]
Remuneration excluding pension contribution | £	£ 4,638,290	£ 2,200,138
Remuneration excluding pension contribution performance | £	2,913,000	748,495
Accrued defined benefit pension related to the highest paid director | £	£ 22,119	21,309
Directors with a deferred pension benefit accruing under a defined benefit scheme	1
Ex gratia pensions paid to former Directors | £	£ 370,668	£ 366,248	£ 335,202
Directors who held any interest in the shares	0	0
Directors who exercised or were granted any rights to subscribe for shares	0	0
Directors who exercised share options over shares in Banco Santander	0	0
Number of loan made to directors	2	4
Loans made to directors | £	£ 15,430	£ 13,994
Number of Directors undertook sharedealing transactions	0	0
Other key management personnel
Disclosure Of Directors And Key Management Remuneration [Line Items]
Number of loan made to key management personnel	2	5
Loans made to key management personnel | £	£ 11,678	£ 1,811,171

Transactions with Directors a_6

Transactions with Directors and Other Key Management Personnel - Summary of Transactions with Directors, Other Key Management Personnel (Details) - Key Management Personnel £ in Thousands	12 Months Ended
	Dec. 31, 2021GBP (£)loansdeposits	Dec. 31, 2020GBP (£)loansdeposits
Disclosure Of Directors And Key Management Remuneration [Line Items]
Number of secured loans, unsecured loans and overdrafts, beginning balance | loans	9	18
Number of secured loans, unsecured loans and overdrafts, net movements | loans	(5)	(9)
Number of secured loans, unsecured loans and overdrafts, ending balance | loans	4	9
Beginning balance	£ 1,825	£ 4,920
Net movements	(1,798)	(3,095)
Ending balance	£ 27	£ 1,825
Number of deposit, bank and instant access accounts and investments, beginning balance | deposits	16	32
Number of deposit, bank and instant access accounts and investments, net movements | deposits	0	(16)
Number of deposit, bank and instant access accounts and investments, ending balance | deposits	16	16
Beginning balance	£ 8,063	£ 11,975
Net movements	(1,636)	(3,912)
Ending balance	£ 6,427	£ 8,063

Related Party Disclosures - Sum

Related Party Disclosures - Summary of Transactions With Related Parties (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	£ (291)	£ (203)	£ (237)
Interest, fees and other expenses paid	189	306	492
Amounts owed by related parties	4,144	4,128
Amounts owed to related parties	(2,777)	(3,995)
Ultimate parent
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	(210)	(120)	(150)
Interest, fees and other expenses paid	34	158	334
Amounts owed by related parties	1,049	1,857
Amounts owed to related parties	(1,392)	(2,463)
Fellow subsidiaries
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	(47)	(54)	(58)
Interest, fees and other expenses paid	151	148	158
Amounts owed by related parties	20	37
Amounts owed to related parties	(467)	(498)
Associates & joint ventures
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	(34)	(29)	(29)
Interest, fees and other expenses paid	4	0	£ 0
Amounts owed by related parties	3,075	2,234
Amounts owed to related parties	£ (918)	£ (1,034)

Related Party Disclosures - Add

Related Party Disclosures - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Jul. 30, 2021
Santander Consumer (UK) | PSA Finance UK Limited
Disclosure of transactions between related parties [line items]
Proportion of ownership interest in subsidiary sold			50.00%
Volvo Car Financial Services UK Limited
Disclosure of transactions between related parties [line items]
Proportion of ownership interest in joint venture		50.00%
Volvo Car Financial Services UK Limited | Santander Consumer (UK)
Disclosure of transactions between related parties [line items]
Amout of dealer lending transferred	£ 390

Financial Instruments - Analysi

Financial Instruments - Analysis of Fair Value of Financial Instruments Carried at Amortised (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to customers	£ 213,525	£ 212,178
Loans and advances to banks	1,420	2,004
Reverse repurchase agreements - non trading	12,683	19,599
Deposits by customers	192,914	193,088
Deposits by banks	33,862	20,973
Repurchase agreements - non trading	11,718	15,848
Debt securities in issue	31,580	43,679
Subordinated liabilities	2,228	2,556
Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Total financial liabilities	272,302	276,144
Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	228,134	234,944
Deposits by customers | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by customers	192,914	193,088
Deposits by banks | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by banks	33,862	20,973
Repurchase agreements – non trading | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Repurchase agreements - non trading	11,718	15,848
Debt securities in issue | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Debt securities in issue	31,580	43,679
Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	2,228	2,556
Loans and advances to customers | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to customers	213,525	212,178
Loans and advances to banks | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to banks	1,420	2,004
Reverse repurchase agreements - non trading | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Reverse repurchase agreements - non trading	12,683	19,599
Other financial assets at amortised cost | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Other financial assets at amortised cost	506	1,163
Level 1 | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Total financial liabilities	5,089	0
Level 1 | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	164	799
Level 1 | Deposits by customers | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by customers	0	0
Level 1 | Deposits by banks | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by banks	0	0
Level 1 | Repurchase agreements – non trading | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Repurchase agreements - non trading	0	0
Level 1 | Debt securities in issue | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Debt securities in issue	4,070	0
Level 1 | Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	1,019	0
Level 1 | Loans and advances to customers | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to customers	0	0
Level 1 | Loans and advances to banks | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to banks	0	0
Level 1 | Reverse repurchase agreements - non trading | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Reverse repurchase agreements - non trading	0	0
Level 1 | Other financial assets at amortised cost | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Other financial assets at amortised cost	164	799
Level 2 | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Total financial liabilities	74,146	83,252
Level 2 | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	14,221	21,779
Level 2 | Deposits by customers | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by customers	52	109
Level 2 | Deposits by banks | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by banks	33,780	20,966
Level 2 | Repurchase agreements – non trading | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Repurchase agreements - non trading	11,718	15,847
Level 2 | Debt securities in issue | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Debt securities in issue	27,084	43,500
Level 2 | Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	1,512	2,830
Level 2 | Loans and advances to customers | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to customers	0	0
Level 2 | Loans and advances to banks | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to banks	1,420	2,004
Level 2 | Reverse repurchase agreements - non trading | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Reverse repurchase agreements - non trading	12,453	19,382
Level 2 | Other financial assets at amortised cost | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Other financial assets at amortised cost	348	393
Level 3 | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Total financial liabilities	194,425	194,787
Level 3 | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	216,505	214,956
Level 3 | Deposits by customers | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by customers	192,887	193,102
Level 3 | Deposits by banks | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by banks	82	16
Level 3 | Repurchase agreements – non trading | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Repurchase agreements - non trading	0	0
Level 3 | Debt securities in issue | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Debt securities in issue	1,218	1,430
Level 3 | Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	238	239
Level 3 | Loans and advances to customers | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to customers	216,279	214,730
Level 3 | Loans and advances to banks | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to banks	0	0
Level 3 | Reverse repurchase agreements - non trading | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Reverse repurchase agreements - non trading	226	226
Level 3 | Other financial assets at amortised cost | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Other financial assets at amortised cost	0	0
Fair value | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Total financial liabilities	273,660	278,039
Fair value | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	230,890	237,534
Fair value | Deposits by customers | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by customers	192,939	193,211
Fair value | Deposits by banks | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by banks	33,862	20,982
Fair value | Repurchase agreements – non trading | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Repurchase agreements - non trading	11,718	15,847
Fair value | Debt securities in issue | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Debt securities in issue	32,372	44,930
Fair value | Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	2,769	3,069
Fair value | Loans and advances to customers | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to customers	216,279	214,730
Fair value | Loans and advances to banks | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to banks	1,420	2,004
Fair value | Reverse repurchase agreements - non trading | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Reverse repurchase agreements - non trading	12,679	19,608
Fair value | Other financial assets at amortised cost | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Other financial assets at amortised cost	£ 512	£ 1,192

Financial Instruments - Fair Va

Financial Instruments - Fair Values of Financial Instruments Measured at Fair Value on a Recurring Basis (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 8,247	£ 13,235
Liabilities at fair value	1,822	3,354
Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	1,019	1,920
Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	803	1,434
Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	1,720	3,451
Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	676	834
Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	5,851	8,950
Level 1
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	5,833	8,584
Liabilities at fair value	0	0
Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Level 1 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	83
Level 1 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	5,833	8,501
Level 2
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	2,105	4,300
Liabilities at fair value	1,784	3,314
Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	987	1,888
Level 2 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	797	1,426
Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	1,664	3,376
Level 2 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	441	496
Level 2 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	428
Level 3
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	309	351
Liabilities at fair value	38	40
Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	32	32
Level 3 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	6	8
Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	56	75
Level 3 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	235	255
Level 3 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	18	21
Exchange rate contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 521	846
Valuation technique	A
Exchange rate contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 1,194	2,457
Valuation technique	A
Exchange rate contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Exchange rate contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Exchange rate contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	521	846
Exchange rate contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	1,193	2,455
Exchange rate contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Exchange rate contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	1	2
Interest rate contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 1,661	2,745
Valuation technique	A & C
Interest rate contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 1,574	2,618
Valuation technique	A & C
Interest rate contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Interest rate contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Interest rate contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	1,659	2,742
Interest rate contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	1,574	2,604
Interest rate contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	2	3
Interest rate contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	14
Equity and credit contracts
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	45	51
Equity and credit contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 58	83
Valuation technique	B & D
Equity and credit contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 173	130
Valuation technique	B & D
Equity and credit contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Equity and credit contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Equity and credit contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	28	54
Equity and credit contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	118	71
Equity and credit contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	30	29
Equity and credit contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	55	59
Netting | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	(1,221)	(1,754)
Netting | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	(1,221)	(1,754)
Netting | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Netting | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Netting | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	(1,221)	(1,754)
Netting | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	(1,221)	(1,754)
Netting | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Netting | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Loans and advances to customers | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 514	592
Valuation technique	A
Loans and advances to customers | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 18	21
Valuation technique	D
Loans and advances to customers | Level 1 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 0	0
Loans and advances to customers | Level 1 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Loans and advances to customers | Level 2 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	440	493
Loans and advances to customers | Level 2 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Loans and advances to customers | Level 3 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	74	99
Loans and advances to customers | Level 3 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	18	21
Debt securities | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 112	112
Valuation technique	A, B & D
Debt securities | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 5,833	8,929
Valuation technique	D
Debt securities | Level 1 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 0	0
Debt securities | Level 1 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	5,833	8,501
Debt securities | Level 2 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	1	3
Debt securities | Level 2 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	428
Debt securities | Level 3 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	111	109
Debt securities | Level 3 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Equity securities | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 50	130
Valuation technique	B
Equity securities | Level 1 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 0	83
Equity securities | Level 2 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Equity securities | Level 3 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	50	47
Reverse repurchase agreements - non trading | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 0	0
Valuation technique	A
Reverse repurchase agreements - non trading | Level 1 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 0	0
Reverse repurchase agreements - non trading | Level 2 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Reverse repurchase agreements - non trading | Level 3 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Debt securities in issue | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 560	1,057
Valuation technique	A
Debt securities in issue | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Debt securities in issue | Level 2 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	555	1,051
Debt securities in issue | Level 3 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	5	6
Structured deposits | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 223	375
Valuation technique	A
Structured deposits | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Structured deposits | Level 2 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	223	375
Structured deposits | Level 3 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Repurchase agreements – non trading | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Valuation technique	A
Repurchase agreements – non trading | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Repurchase agreements – non trading | Level 2 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Repurchase agreements – non trading | Level 3 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Collateral and associated financial guarantees | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 20	2
Valuation technique	D
Collateral and associated financial guarantees | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Collateral and associated financial guarantees | Level 2 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	19	0
Collateral and associated financial guarantees | Level 3 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 1	£ 2

Financial Instruments - Additio

Financial Instruments - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Assets
Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period	£ 0
Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period	0
Transfers into Level 3 of fair value hierarchy, assets	0
Transfers out of Level 3 of fair value hierarchy, assets	0	£ 81
Liabilities
Transfers out of Level 1 into Level 2 of fair value hierarchy, liabilities held at end of reporting period	0
Transfers out of Level 2 into Level 1 of fair value hierarchy, liabilities held at end of reporting period	0
Transfers into Level 3 of fair value hierarchy, liabilities	0
Transfers out of Level 3 of fair value hierarchy, liabilities	0
Exposure to wrong-way risk	£ 0	£ 0

Financial Instruments - Summary

Financial Instruments - Summary of Fair Value Adjustment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of financial assets [line items]
Fair value adjustments	£ 40	£ 51
Bid-offer and trade specific adjustments
Disclosure of financial assets [line items]
Fair value adjustments	(9)	(8)
Uncertainty
Disclosure of financial assets [line items]
Fair value adjustments	40	45
Credit risk adjustment
Disclosure of financial assets [line items]
Fair value adjustments	6	11
Funding fair value adjustment
Disclosure of financial assets [line items]
Fair value adjustments	3	3
Risk related adjustments
Disclosure of financial assets [line items]
Fair value adjustments	40	51
Model-related
Disclosure of financial assets [line items]
Fair value adjustments	0	0
Day One profit
Disclosure of financial assets [line items]
Fair value adjustments	£ 0	£ 0

Financial Instruments - Analy_2

Financial Instruments - Analysis of Financial Instruments Valued Using Internal Models Based on Information Other Than Market Data (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	£ 676	£ 834
Financial assets at fair value through other comprehensive income	5,851	8,950
Total net assets	271	311
Financial asset liabilities	(1)	27	£ 34
Total income/(expense)	(1)	27	34
Loans and advances to customers
Disclosure Of Financial Assets And Liabilities [Line Items]
Financial assets at fair value through other comprehensive income	18	21
Level 3
Disclosure Of Financial Assets And Liabilities [Line Items]
Financial assets and liabilities	267	296
Financial asset liabilities	(5)	23	26
Other Level 3 | Level 3
Disclosure Of Financial Assets And Liabilities [Line Items]
Other Level 3 assets	11	24
Other Level 3 liabilities	(7)	(9)
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	2	7	15
Derivative liabilities and other Level 3 liabilities, fair value movements recognised in profit/(loss)	2	(3)	(7)
Reversionary property interests | Equity and credit contracts
Disclosure Of Financial Assets And Liabilities [Line Items]
Derivative assets	45	51
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	0	3	2
Reversionary property interests | Debt securities in issue
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	91	107
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	5	6	(17)
Roll-up mortgage portfolio | Loans and advances to customers
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	48	56
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	(5)	6	0
Other loans | Loans and advances to customers
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	26	43
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	(2)	3	1
Other loans | Loans and advances to customers | Financial assets at FVOCI
Disclosure Of Financial Assets And Liabilities [Line Items]
Financial assets at fair value through other comprehensive income	18	21
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	(3)	(4)	(2)
Unlisted equity shares | Equity securities
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	50	47
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	1	12	42
Credit linked notes | Debt securities in issue
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	20	2
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	(5)	(16)	7
Property options and forwards | Equity securities
Disclosure Of Financial Assets And Liabilities [Line Items]
Derivative liabilities	(30)	(29)
Derivative liabilities and other Level 3 liabilities, fair value movements recognised in profit/(loss)	(1)	(3)	0
Credit protection guarantee | Financial guarantees
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL liabilities	(1)	(2)
Derivative liabilities and other Level 3 liabilities, fair value movements recognised in profit/(loss)	£ 5	£ 16	£ (7)

Financial Instruments - Assets

Financial Instruments - Assets and Liabilities Reconciliation of Fair Value Measurements in Level 3 of the Fair Value Hierarchy (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of fair value measurement of assets [line items]
Beginning balance	£ 299,064	£ 288,488
Beginning balance	(282,819)	(272,147)
Transfers in	0
Transfers in	0
Transfers out	0	(81)
Transfers out	0
Ending Balance	293,676	299,064
Ending Balance	(277,298)	(282,819)
Level 3 | Other financial assets at FVTPL
Disclosure of fair value measurement of assets [line items]
Beginning balance	255	505
Fair value movements	(6)	11
Foreign exchange and other movements	2	(9)
Transfers in	0	1
Transfers out	0	(81)
Netting	23	(42)
Additions	0	0
Sales	(16)	(19)
Settlements	(23)	(111)
Ending Balance	235	255
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year	(4)	2
Level 3 | Financial assets at FVOCI
Disclosure of fair value measurement of assets [line items]
Beginning balance	21	56
Fair value movements	(3)	(4)
Foreign exchange and other movements	0	0
Transfers in	0	0
Transfers out	0	0
Netting	0	0
Additions	0	0
Sales	0	(19)
Settlements	0	(12)
Ending Balance	18	21
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year	(3)	(4)
Level 3 | Assets held for sale
Disclosure of fair value measurement of assets [line items]
Beginning balance	0	0
Fair value movements	0	0
Foreign exchange and other movements	0	0
Transfers in	0	0
Transfers out	0	0
Netting	0	0
Additions	0	0
Sales	0	0
Settlements	0	0
Ending Balance	0	0
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year	0	0
Level 3 | Financial assets at fair value
Disclosure of fair value measurement of assets [line items]
Beginning balance	351	645
Fair value movements	(7)	17
Foreign exchange and other movements	2	(9)
Transfers in	0	2
Transfers out	0	(81)
Netting	23	(42)
Additions	0	9
Sales	(16)	(38)
Settlements	(44)	(152)
Ending Balance	309	351
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year	(5)	8
Level 3 | Derivatives
Disclosure of fair value measurement of assets [line items]
Beginning balance	75	84
Fair value movements	2	10
Foreign exchange and other movements	0	0
Transfers in	0	1
Transfers out	0	0
Netting	0	0
Additions	0	9
Sales	0	0
Settlements	(21)	(29)
Ending Balance	56	75
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year	2	10
Derivatives | Level 3
Disclosure of fair value measurement of assets [line items]
Beginning balance	(32)	(35)
Fair value movements	0	(7)
Foreign exchange and other movements	0	0
Transfers in	0	0
Transfers out	0	0
Netting	0	0
Additions	0	0
Sales	0	0
Settlements	0	10
Ending Balance	(32)	(32)
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year	0	(7)
Other financial liabilities at FVTPL | Level 3
Disclosure of fair value measurement of assets [line items]
Beginning balance	(8)	(61)
Fair value movements	6	17
Foreign exchange and other movements	1	8
Transfers in	0	0
Transfers out	0	28
Netting	(5)	0
Additions	0	(2)
Sales	0	0
Settlements	0	2
Ending Balance	(6)	(8)
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year	7	25
Liabilities held for sale | Level 3
Disclosure of fair value measurement of assets [line items]
Beginning balance	0	0
Fair value movements	0	0
Foreign exchange and other movements	0	0
Transfers in	0	0
Transfers out	0	0
Netting	0	0
Additions	0	0
Sales	0	0
Settlements	0	0
Ending Balance	0	0
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year	0	0
Financial liabilities at fair value | Level 3
Disclosure of fair value measurement of assets [line items]
Beginning balance	(40)	(96)
Fair value movements	6	10
Foreign exchange and other movements	1	8
Transfers in	0	0
Transfers out	0	28
Netting	(5)	0
Additions	0	(2)
Sales	0	0
Settlements	0	12
Ending Balance	(38)	(40)
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year	£ 7	£ 18

Financial Instruments - Effects

Financial Instruments - Effects of Changes in Significant Unobservable Assumptions to Reasonably Possible Alternatives (Level 3) (Details) £ in Millions	12 Months Ended
	Dec. 31, 2021GBP (£)index	Dec. 31, 2020GBP (£)index
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 8,247	£ 13,235
Liabilities at fair value	(1,822)	(3,354)
Equity and credit contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 45	£ 51
Assumption description	HPI Forward growth rate	HPI Forward growth rate
Shift	1.00%	1.00%
Favourable changes	£ 6	£ 8
Unfavourable changes	£ (6)	£ (8)
Equity and credit contracts | Reversionary property derivatives
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Shift	10.00%	10.00%
Favourable changes	£ 6	£ 7
Unfavourable changes	(6)	(7)
Equity contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Liabilities at fair value	£ (30)	£ (29)
Assumption description	HPI Forward growth rate	HPI Forward growth rate
Shift	1.00%	1.00%
Favourable changes	£ 2	£ 2
Unfavourable changes	£ (2)	£ (2)
Equity contracts | Property options and forwards
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Shift	10.00%	10.00%
Favourable changes	£ 3	£ 3
Unfavourable changes	£ (3)	£ (3)
Weighted average | Equity and credit contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	2.56%	2.57%
Weighted average | Equity and credit contracts | Reversionary property derivatives
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
HPI spot rate index level | index	483	445
Weighted average | Equity contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	2.39%	2.42%
Weighted average | Equity contracts | Property options and forwards
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
HPI spot rate index level | index	469	433
Minimum | Equity and credit contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	0.00%	0.00%
Minimum | Equity contracts | Property options and forwards
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	0.00%	0.00%
Maximum | Equity and credit contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	5.00%	5.00%
Maximum | Equity contracts | Property options and forwards
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	5.00%	5.00%
Other financial assets at FVTPL | Loans and advances to customers | Roll-up mortgage portfolio
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 48	£ 56
Assumption description	HPI Forward growth rate	HPI Forward growth rate
Shift	1.00%	1.00%
Favourable changes	£ 2	£ 2
Unfavourable changes	(2)	(2)
Other financial assets at FVTPL | Loans and advances to customers | Other loans
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 26	£ 43
Assumption description	Credit spreads	Credit spreads
Shift	20.00%	20.00%
Favourable changes	£ 0	£ 0
Unfavourable changes	0	0
Other financial assets at FVTPL | Debt securities in issue
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 91	£ 107
Assumption description	HPI Forward growth rate	HPI Forward growth rate
Shift	1.00%	1.00%
Favourable changes	£ 1	£ 1
Unfavourable changes	£ (1)	£ (1)
Other financial assets at FVTPL | Debt securities in issue | Reversionary property securities
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Shift	10.00%	10.00%
Favourable changes	£ 4	£ 5
Unfavourable changes	(4)	(5)
Other financial assets at FVTPL | Equity securities | Unlisted equity shares
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 50	£ 47
Assumption description	Contingent litigation risk	Contingent litigation risk
Shift	20.00%	20.00%
Favourable changes	£ 7	£ 8
Unfavourable changes	£ (7)	£ (8)
Other financial assets at FVTPL | Weighted average | Loans and advances to customers | Roll-up mortgage portfolio
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	2.68%	2.69%
Other financial assets at FVTPL | Weighted average | Loans and advances to customers | Other loans
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	0.50%	0.44%
Other financial assets at FVTPL | Weighted average | Debt securities in issue
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	2.56%	2.57%
Other financial assets at FVTPL | Weighted average | Debt securities in issue | Reversionary property securities
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
HPI spot rate index level | index	483	445
Other financial assets at FVTPL | Weighted average | Equity securities | Unlisted equity shares
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	45.00%	49.00%
Other financial assets at FVTPL | Minimum | Loans and advances to customers | Roll-up mortgage portfolio
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	0.00%	0.00%
Other financial assets at FVTPL | Minimum | Loans and advances to customers | Other loans
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	0.07%	0.07%
Other financial assets at FVTPL | Minimum | Debt securities in issue
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	0.00%	0.00%
Other financial assets at FVTPL | Minimum | Equity securities | Unlisted equity shares
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	0.00%	0.00%
Other financial assets at FVTPL | Maximum | Loans and advances to customers | Roll-up mortgage portfolio
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	5.00%	5.00%
Other financial assets at FVTPL | Maximum | Loans and advances to customers | Other loans
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	1.44%	1.55%
Other financial assets at FVTPL | Maximum | Debt securities in issue
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	5.00%	5.00%
Other financial assets at FVTPL | Maximum | Equity securities | Unlisted equity shares
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	100.00%	100.00%
Financial assets at FVOCI
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 5,851	£ 8,950
Financial assets at FVOCI | Loans and advances to customers
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	18	21
Financial assets at FVOCI | Loans and advances to customers | Other loans
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 18	£ 21
Assumption description	Credit spreads	Credit spreads
Shift	20.00%	20.00%
Favourable changes	£ 0	£ 0
Unfavourable changes	£ 0	£ 0
Financial assets at FVOCI | Weighted average | Loans and advances to customers | Other loans
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	0.04%	0.32%
Financial assets at FVOCI | Minimum | Loans and advances to customers | Other loans
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	0.15%	0.15%
Financial assets at FVOCI | Maximum | Loans and advances to customers | Other loans
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	0.19%	0.53%

Financial Instruments - Maturit

Financial Instruments - Maturities of Undiscounted Cash Flows for Financial Liabilities and Off Balance Sheet Commitments (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Other financial liabilities at fair value through profit or loss	£ 803	£ 1,434
Deposits by customers	192,914	193,088
Deposits by banks	33,862	20,973
Repurchase agreements - non trading	11,718	15,848
Debt securities in issue	31,580	43,679
Subordinated liabilities	2,228	2,556
Lease liabilities	134	100
Undiscounted Cash Flow
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	1,066	1,988
Other financial liabilities at fair value through profit or loss	803	1,437
Deposits by customers	192,964	193,193
Deposits by banks	33,963	21,106
Repurchase agreements - non trading	11,718	15,850
Debt securities in issue	32,574	44,991
Subordinated liabilities	3,697	4,061
Lease liabilities	143	112
Total financial liabilities	276,928	282,738
Off-balance sheet commitments given	37,748	43,170
Undiscounted Cash Flow | On demand
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	0	0
Other financial liabilities at fair value through profit or loss	0	0
Deposits by customers	180,907	179,499
Deposits by banks	1,386	2,426
Repurchase agreements - non trading	0	0
Debt securities in issue	0	0
Subordinated liabilities	0	0
Lease liabilities	0	0
Total financial liabilities	182,293	181,925
Off-balance sheet commitments given	20,545	21,055
Undiscounted Cash Flow | Not later than 3 months
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	96	320
Other financial liabilities at fair value through profit or loss	6	1
Deposits by customers	3,706	4,251
Deposits by banks	536	1,894
Repurchase agreements - non trading	11,419	15,350
Debt securities in issue	5,011	5,759
Subordinated liabilities	32	30
Lease liabilities	0	0
Total financial liabilities	20,806	27,605
Off-balance sheet commitments given	5,359	4,493
Undiscounted Cash Flow | Later than 3 months and not later than 1 year
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	61	134
Other financial liabilities at fair value through profit or loss	8	107
Deposits by customers	5,690	5,994
Deposits by banks	57	2,535
Repurchase agreements - non trading	299	500
Debt securities in issue	2,752	11,042
Subordinated liabilities	98	92
Lease liabilities	32	18
Total financial liabilities	8,997	20,422
Off-balance sheet commitments given	5,747	4,983
Undiscounted Cash Flow | Later than 1 year and not later than 5 years
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	392	584
Other financial liabilities at fair value through profit or loss	553	570
Deposits by customers	1,920	2,767
Deposits by banks	31,984	14,044
Repurchase agreements - non trading	0	0
Debt securities in issue	16,754	19,269
Subordinated liabilities	1,547	1,221
Lease liabilities	79	57
Total financial liabilities	53,229	38,512
Off-balance sheet commitments given	5,523	11,493
Undiscounted Cash Flow | Later than five years
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	517	950
Other financial liabilities at fair value through profit or loss	236	759
Deposits by customers	741	682
Deposits by banks	0	207
Repurchase agreements - non trading	0	0
Debt securities in issue	8,057	8,921
Subordinated liabilities	2,020	2,718
Lease liabilities	32	37
Total financial liabilities	11,603	14,274
Off-balance sheet commitments given	£ 574	£ 1,146

Offsetting Financial Assets a_3

Offsetting Financial Assets and Liabilities (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	£ 22,068	£ 38,724
Amounts offset, Assets	(4,343)	(9,312)
Net amounts reported on the balance sheet, Assets	17,725	29,412
Financial instruments, Assets	(1,017)	(949)
Financial collateral, Assets	(12,941)	(21,310)
Net amount, Assets	3,767	7,153
Assets not subject to enforceable netting arrangements, Assets	211,624	207,820
Balance sheet total, Assets	229,349	237,232
Gross amounts, Liabilities	18,797	29,152
Amounts offset, Liabilities	(4,343)	(9,312)
Net amounts reported on the balance sheet, Liabilities	14,454	19,840
Financial instruments, Liabilities	(1,017)	(949)
Financial collateral, Liabilities	(11,634)	(17,060)
Net amount, Liabilities	1,803	1,831
Assets not subject to enforceable netting arrangements, Liabilities	225,059	211,989
Balance sheet total, Liabilities	239,513	231,829
Derivative financial assets
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	2,870	5,116
Amounts offset, Assets	(1,221)	(1,754)
Net amounts reported on the balance sheet, Assets	1,649	3,362
Financial instruments, Assets	(582)	(820)
Financial collateral, Assets	(693)	(1,840)
Net amount, Assets	374	702
Assets not subject to enforceable netting arrangements, Assets	72	89
Balance sheet total, Assets	1,721	3,451
Amortised cost
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	14,882	26,084
Amounts offset, Assets	(2,199)	(6,485)
Net amounts reported on the balance sheet, Assets	12,683	19,599
Financial instruments, Assets	(435)	(129)
Financial collateral, Assets	(12,248)	(19,470)
Net amount, Assets	0	0
Assets not subject to enforceable netting arrangements, Assets	0	0
Balance sheet total, Assets	12,683	19,599
Gross amounts, Liabilities	13,917	22,333
Amounts offset, Liabilities	(2,199)	(6,485)
Net amounts reported on the balance sheet, Liabilities	11,718	15,848
Financial instruments, Liabilities	(435)	(129)
Financial collateral, Liabilities	(11,283)	(15,719)
Net amount, Liabilities	0	0
Assets not subject to enforceable netting arrangements, Liabilities	0	0
Balance sheet total, Liabilities	11,718	15,848
Fair value
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	0	0
Amounts offset, Assets	0	0
Net amounts reported on the balance sheet, Assets	0	0
Financial instruments, Assets	0	0
Financial collateral, Assets	0	0
Net amount, Assets	0	0
Assets not subject to enforceable netting arrangements, Assets	0	0
Balance sheet total, Assets	0	0
Gross amounts, Liabilities	0	0
Amounts offset, Liabilities	0	0
Net amounts reported on the balance sheet, Liabilities	0	0
Financial instruments, Liabilities	0	0
Financial collateral, Liabilities	0	0
Net amount, Liabilities	0	0
Assets not subject to enforceable netting arrangements, Liabilities	0	0
Balance sheet total, Liabilities	0	0
Loans and advances to customers
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	4,316	7,524
Amounts offset, Assets	(923)	(1,073)
Net amounts reported on the balance sheet, Assets	3,393	6,451
Financial instruments, Assets	0	0
Financial collateral, Assets	0	0
Net amount, Assets	3,393	6,451
Assets not subject to enforceable netting arrangements, Assets	211,552	207,731
Balance sheet total, Assets	214,945	214,182
Derivative financial liabilities
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Liabilities	2,197	3,597
Amounts offset, Liabilities	(1,221)	(1,754)
Net amounts reported on the balance sheet, Liabilities	976	1,843
Financial instruments, Liabilities	(582)	(820)
Financial collateral, Liabilities	(351)	(839)
Net amount, Liabilities	43	184
Assets not subject to enforceable netting arrangements, Liabilities	43	77
Balance sheet total, Liabilities	1,019	1,920
Deposits by customers and banks
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Liabilities	2,683	3,222
Amounts offset, Liabilities	(923)	(1,073)
Net amounts reported on the balance sheet, Liabilities	1,760	2,149
Financial instruments, Liabilities	0	0
Financial collateral, Liabilities	0	(502)
Net amount, Liabilities	1,760	1,647
Assets not subject to enforceable netting arrangements, Liabilities	225,016	211,912
Balance sheet total, Liabilities	£ 226,776	£ 214,061

Interest Rate Benchmark Refor_3

Interest Rate Benchmark Reform - Amounts Affected by IBOR Reform (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assets
Derivative financial instruments	£ 1,720	£ 3,451
Other financial assets at fair value through profit or loss	676	834
Financial assets at amortised cost	506	1,163
Financial assets at fair value through comprehensive income	5,851	8,950
Total assets	293,676	299,064	£ 288,488
Liabilities
Derivative financial instruments	1,019	1,920
Other financial liabilities at fair value through profit or loss	803	1,434
Total liabilities	277,298	282,819	£ 272,147
GBP LIBOR
Assets
Derivative financial instruments	0	33,857
Other financial assets at fair value through profit or loss	8	968
Financial assets at amortised cost	1,373	15,062
Financial assets at fair value through comprehensive income		428
Total assets	1,381	50,315
Liabilities
Derivative financial instruments	338	35,312
Other financial liabilities at fair value through profit or loss	0	1,128
Financial liabilities at amortised cost	34	2,354
Total liabilities	372	38,794
Off-balance sheet commitments given	338	11,405
USD LIBOR
Assets
Derivative financial instruments	1,648	4,844
Other financial assets at fair value through profit or loss	0	22
Financial assets at amortised cost	81	1,191
Financial assets at fair value through comprehensive income		0
Total assets	1,729	6,057
Liabilities
Derivative financial instruments	1,975	5,381
Other financial liabilities at fair value through profit or loss	5	69
Financial liabilities at amortised cost	2,401	3,515
Total liabilities	4,381	8,965
Off-balance sheet commitments given	59	2,126
Other
Assets
Derivative financial instruments	0	2,149
Other financial assets at fair value through profit or loss	0	0
Financial assets at amortised cost	1	90
Financial assets at fair value through comprehensive income		0
Total assets	1	2,239
Liabilities
Derivative financial instruments	0	88
Other financial liabilities at fair value through profit or loss	0	0
Financial liabilities at amortised cost	0	0
Total liabilities	0	88
Off-balance sheet commitments given	0	573
Total
Assets
Derivative financial instruments	1,648	40,850
Other financial assets at fair value through profit or loss	8	990
Financial assets at amortised cost	1,455	16,343
Financial assets at fair value through comprehensive income		428
Total assets	3,111	58,611
Liabilities
Derivative financial instruments	2,313	40,781
Other financial liabilities at fair value through profit or loss	5	1,197
Financial liabilities at amortised cost	2,435	5,869
Total liabilities	4,753	47,847
Off-balance sheet commitments given	£ 397	£ 14,104

Interest Rate Benchmark Refor_4

Interest Rate Benchmark Reform - Derivatives Directly Affected by IBOR Reform Uncertainties (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
GBP LIBOR
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	47,421
GBP LIBOR | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	23,030
USD LIBOR
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	2,746	6,196
USD LIBOR | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	2,746	2,724
Other
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	778
Other | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	720
Total
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	2,746	54,395
Total | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	2,746	26,474
Cash flow hedges | GBP LIBOR
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	15,198
Cash flow hedges | GBP LIBOR | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	10,553
Cash flow hedges | USD LIBOR
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	2,586	5,119
Cash flow hedges | USD LIBOR | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	2,586	2,562
Cash flow hedges | Other
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	0
Cash flow hedges | Other | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	0
Cash flow hedges | Total
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	2,586	20,317
Cash flow hedges | Total | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	2,586	13,115
Fair value hedges | GBP LIBOR
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	32,223
Fair value hedges | GBP LIBOR | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	12,477
Fair value hedges | USD LIBOR
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	160	1,077
Fair value hedges | USD LIBOR | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	160	162
Fair value hedges | Other
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	778
Fair value hedges | Other | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	0	720
Fair value hedges | Total
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	160	34,078
Fair value hedges | Total | Maturing after cessation date
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	160	13,359

Discontinued Operations - Discl

Discontinued Operations - Disclosure of Financial Performance Relating to Discontinued Operations (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Disclosure of analysis of single amount of discontinued operations [line items]
Net interest income	£ 3,997	£ 3,381	[1]	£ 3,227	[1]
Net fee and commission income	280	318	[1]	627	[1]
Other operating income	267	136	[1]	178	[1]
Total operating income	4,544	3,835	[1]	4,032	[1]
Operating expenses before credit impairment write-backs/losses, provisions and charges	(2,540)	(2,425)	[1]	(2,466)	[1]
Credit impairment write-backs/ (losses)	233	(639)	[1]	(198)	[1]
Provisions for other liabilities and charges	(379)	(263)	[1]	(428)	[1]
Total operating credit impairment write-backs/losses, provisions and charges	(146)	(902)	[1]	(626)	[1]
Profit from discontinued operations before tax	44	44		41
Tax on profit from discontinued operations	(12)	(13)		(11)
Profit from discontinued operations after tax	32	31	[1]	30	[1]
Discontinued operations
Disclosure of analysis of single amount of discontinued operations [line items]
Net interest income	33	55		68
Net fee and commission income	34	65		62
Other operating income	2	2		8
Total operating income	69	122		138
Operating expenses before credit impairment write-backs/losses, provisions and charges	(32)	(62)		(60)
Credit impairment write-backs/ (losses)	11	(6)		(22)
Provisions for other liabilities and charges	(4)	(10)		(15)
Total operating credit impairment write-backs/losses, provisions and charges	£ 7	£ (16)		£ (37)
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Details) - GBP (£) £ in Millions	Oct. 11, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of analysis of single amount of discontinued operations [line items]
Total assets		£ 293,676	£ 299,064	£ 288,488
Total liabilities		277,298	282,819	272,147
Gain (loss) recognised on measurement to fair value less costs to sell or on disposal of assets or disposal groups constituting discontinued operation		0	0
Cash flows from (used in) operating activities, discontinued operations		3,612	1,815	(1,033)
Cash flows from (used in) investing activities, discontinued operations		0	0	0
Cash flows from (used in) financing activities, discontinued operations		0	0	0
Transfer within Santander UK
Disclosure of analysis of single amount of discontinued operations [line items]
Total liabilities		1,000
Banco Santander London Branch | CIB business transfer to SLB
Disclosure of analysis of single amount of discontinued operations [line items]
Total assets	£ 1,900
Total liabilities	2,100
Increase (decrease) in cash and cash equivalents, discontinued operations	£ 200
Corporate & Investment Banking
Disclosure of analysis of single amount of discontinued operations [line items]
Total assets		0	2,784	4,046
Total liabilities		£ 0	£ 6,517	£ 6,233

Events After the Balance Shee_3

Events After the Balance Sheet Date (Details)	12 Months Ended
	Dec. 31, 2021
Disclosure of non-adjusting events after reporting period [abstract]
Description of nature of non-adjusting event after reporting period	There have been no significant events between 31 December 2021 and the date of approval of these financial statements which would require a change to or additional disclosure in the financial statements.

Operating Expenses Before Cre_8

Operating Expenses Before Credit Impairment Losses, Provisions and Charges - Parent (Details) £ in Millions	12 Months Ended
	Dec. 31, 2021GBP (£)employee	Dec. 31, 2020GBP (£)employee	Dec. 31, 2019GBP (£)
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Wages and salaries	£ 759	£ 802	£ 815
Santander UK Group Holdings plc
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Wages and salaries	£ 6	£ 7
Number of full-time staff | employee	0	0

Other Financial Assets at Fai_7

Other Financial Assets at Fair Value Through Profit or Loss - Parent - Summary of Other Financial Assets at Fair Value Through Profit or Loss (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Financial Assets Designated As Measured At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	£ 676	£ 834
Debt securities
Disclosure Of Financial Assets Designated As Measured At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	112	112
Santander UK Group Holdings plc
Disclosure Of Financial Assets Designated As Measured At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	4,190	1,425
Santander UK Group Holdings plc | Debt securities
Disclosure Of Financial Assets Designated As Measured At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	£ 4,190	£ 1,425

Other Financial Assets at Fai_8

Other Financial Assets at Fair Value Through Profit or Loss - Parent - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Financial Assets Designated As Measured At Fair Value Through Profit Or Loss [Line Items]
Financial assets designated at FVTPL	£ 454	£ 508
Santander UK Group Holdings plc
Disclosure Of Financial Assets Designated As Measured At Fair Value Through Profit Or Loss [Line Items]
Financial assets designated at FVTPL	4,190	1,425
Debt securities issued during period for MREL requirements	£ 2,765	£ 1,425

Loans and Advances to Banks -_2

Loans and Advances to Banks - Parent (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Santander UK Group Holdings plc
Net Loans And Advances To Banks [Line Items]
Impairment loss	£ 0	£ 0

Other Financial Assets at Amo_5

Other Financial Assets at Amortised Cost - Parent (Details)	12 Months Ended
	Dec. 31, 2021
Santander UK Group Holdings plc | Later than ten years
Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Investments maturity period	10 years

Interests in Other Entities -_6

Interests in Other Entities - Parent - Summary of Interest in Other Entities - Parent (Details) - Santander UK Group Holdings plc - GBP (£)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of subsidiaries [line items]
Interests in other entities	£ 13,590,000,000	£ 13,585,000,000
£500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure of subsidiaries [line items]
Capital securities	500,000,000	500,000,000
Interests in other entities	495,000,000	495,000,000
£750m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure of subsidiaries [line items]
Capital securities	750,000,000	750,000,000
Interests in other entities	750,000,000	750,000,000
£500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure of subsidiaries [line items]
Capital securities	500,000,000	500,000,000
Interests in other entities	210,000,000	210,000,000
£500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure of subsidiaries [line items]
Capital securities	500,000,000	500,000,000
Interests in other entities	500,000,000	500,000,000
Interests in ordinary shares of subsidiaries | Fellow subsidiaries
Disclosure of subsidiaries [line items]
Interests in other entities	£ 11,635,000,000	£ 11,630,000,000

Interests in Other Entities -_7

Interests in Other Entities - Parent - Disclosure of Movements in Company's Interests in Subsidiaries - Parent (Details) - Santander UK Group Holdings plc - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of subsidiaries [line items]
Investments in subsidiaries	£ 11,635	£ 11,630
Cost
Disclosure of subsidiaries [line items]
Investments in subsidiaries	11,645	11,645
Accumulated impairment
Disclosure of subsidiaries [line items]
Investments in subsidiaries	£ (10)	£ (15)

Interests in Other Entities -_8

Interests in Other Entities - Parent - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019	[1]
Disclosure of subsidiaries [line items]
Ownership interest in share capital	100.00%
Impairment loss on investment	£ (233)	£ 639	[1]	£ 198
Santander UK plc
Disclosure of subsidiaries [line items]
Impairment loss on investment	0	0
Santander Financial Services plc
Disclosure of subsidiaries [line items]
Impairment loss on investment	£ 0	£ 0
Santander UK Group Holdings plc
Disclosure of subsidiaries [line items]
Ownership interest in share capital	100.00%
[1]	Adjusted to reflect the presentation of discontinued operations as set out in Note 43.

Interests in Other Entities - D

Interests in Other Entities - Disclosure of Key Assumptions in VIU Calculation (Details) - Santander UK Group Holdings plc - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure of subsidiaries [line items]
Carrying value	£ 11,635	£ 11,630
Santander UK plc
Disclosure of subsidiaries [line items]
Carrying value	£ 11,267	£ 11,267
Discount rate	13.60%	14.00%
Growth rate beyond initial cash flow projections	1.60%	1.60%
Santander Financial Services plc
Disclosure of subsidiaries [line items]
Carrying value	£ 337	£ 337
Discount rate	15.60%	13.70%
Growth rate beyond initial cash flow projections	1.60%	1.60%
Other
Disclosure of subsidiaries [line items]
Carrying value	£ 31	£ 26
Discount rate
Growth rate beyond initial cash flow projections

Interests in Other Entities -_9

Interests in Other Entities - Disclosure of Key Assumptions in Calculating VIU for Investments (Details) - Santander UK Group Holdings plc - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Santander UK plc
Disclosure of subsidiaries [line items]
Decrease in cash flows projections	5.00%	5.00%
Increase in discount rate	1.00%	1.00%
Decrease in GDP growth rate	(0.10%)	(0.10%)
Value in use estimate, impairment increase sensitivity for cash flows adjustment	£ 0	£ 109
Value in use estimate, impairment increase sensitivity for discount rate adjustment	381	637
Value in use estimate, impairment increase sensitivity for GDP growth rate adjustment	£ 0	£ 0
Santander Financial Services plc
Disclosure of subsidiaries [line items]
Decrease in cash flows projections	5.00%	5.00%
Increase in discount rate	1.00%	1.00%
Value in use estimate, impairment increase sensitivity for cash flows adjustment	£ 0	£ 0
Value in use estimate, impairment increase sensitivity for discount rate adjustment	£ 0	£ 5

Interests in Other Entities _10

Interests in Other Entities - Disclosure of Sensitivity of VIU Changes to Current Assumptions to Achieve Nil Headroom (Details) - Santander UK Group Holdings plc - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of subsidiaries [line items]
Carrying value	£ 11,635	£ 11,630
Santander UK plc
Disclosure of subsidiaries [line items]
Carrying value	11,267	11,267
Value in use	12,147	11,745
Headroom	£ 880	£ 478
Increase in post tax discount rate	0.67%	0.40%
Decrease in cash flows	7.00%	4.00%
Value in use estimate, increase (decrease) in cash flows	5.00%	5.00%
Increase (decrease) in discount rate applied to cash flow projections	1.00%	1.00%
Decrease in GDP growth rate	0.10%	0.10%
Santander Financial Services plc
Disclosure of subsidiaries [line items]
Carrying value	£ 337	£ 337
Value in use	376	363
Headroom	£ 39	£ 26
Increase in post tax discount rate	1.45%	0.82%
Decrease in cash flows	10.00%	7.00%
Value in use estimate, increase (decrease) in cash flows	5.00%	5.00%
Increase (decrease) in discount rate applied to cash flow projections	1.00%	1.00%

Other Financial Liabilities a_7

Other Financial Liabilities at Fair Value Through Profit or Loss - Parent - Summary of Other Financial Liabilities at Fair Value Through Profit or Loss (Details) - Santander UK Group Holdings plc - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Financial liabilities designated at fair value	£ 4,190	£ 1,425
Medium-term notes
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Financial liabilities designated at fair value	£ 4,190	£ 1,425

Other Financial Liabilities a_8

Other Financial Liabilities at Fair Value Through Profit or Loss - Parent - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Accumulated increase (decrease) in fair value of financial liability, attributable to changes in credit risk of liability	£ (10)	£ (3)
Difference between carrying amount of financial liability and amount contractually required to pay at maturity to holder of obligation	0	(11)
Santander UK Group Holdings plc
Disclosure Of Other Financial Liabilities At Fair Value Through Profit Or Loss [Line Items]
Financial liabilities designated at fair value	4,190	1,425
Debt securities issued during period for MREL requirements	2,765	1,425
Accumulated increase (decrease) in fair value of financial liability, attributable to changes in credit risk of liability	0	0
Difference between carrying amount of financial liability and amount contractually required to pay at maturity to holder of obligation	£ 26	£ (21)

Debt Securities in Issue - Pa_3

Debt Securities in Issue - Parent - Summary of Debt Securities in Issue (Details) £ in Millions	Dec. 31, 2021GBP (£)	Dec. 31, 2021EUR (€)	Dec. 31, 2020GBP (£)	Dec. 31, 2020EUR (€)
Debt Securities In Issue [Line Items]
Notional amount	£ 163,361		£ 198,391
Debt securities in issue	31,580		43,679
Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities in issue	12,911		16,325
– Euro 30bn Euro Medium Term Note Programme | Medium-term notes
Debt Securities In Issue [Line Items]
Notional amount | €		€ 30,000,000,000		€ 30,000,000,000
Debt securities in issue	4,304		4,292
– US SEC-registered Debt Programme – Santander UK Group Holdings plc | Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities in issue	5,978		5,616
Santander UK Group Holdings plc
Debt Securities In Issue [Line Items]
Debt securities in issue	6,013		7,970
Santander UK Group Holdings plc | Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities in issue	6,013		7,970
Santander UK Group Holdings plc | – Euro 30bn Euro Medium Term Note Programme | Medium-term notes
Debt Securities In Issue [Line Items]
Notional amount | €		€ 30,000,000,000		€ 30,000,000,000
Debt securities in issue	3,028		3,161
Santander UK Group Holdings plc | – US SEC-registered Debt Programme – Santander UK Group Holdings plc | Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities in issue	£ 2,985		£ 4,809

Debt Securities in Issue - Pa_4

Debt Securities in Issue - Parent - Additional Information (Details) £ in Millions	Dec. 31, 2021EUR (€)	Dec. 31, 2021GBP (£)	Dec. 31, 2020EUR (€)	Dec. 31, 2020GBP (£)
Debt Securities In Issue [Line Items]
Notional amount | £		£ 163,361		£ 198,391
– Euro 30bn Euro Medium Term Note Programme | Medium-term notes
Debt Securities In Issue [Line Items]
Notional amount	€ 30,000,000,000		€ 30,000,000,000
– Euro 30bn Euro Medium Term Note Programme | Medium-term notes | Santander UK Group Holdings plc
Debt Securities In Issue [Line Items]
Notional amount	€ 30,000,000,000		€ 30,000,000,000

Subordinated Liabilities - Pa_3

Subordinated Liabilities - Parent (Details) £ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2021GBP (£)	Dec. 31, 2020GBP (£)
Disclosure Of Subordinated Liabilities [Line Items]
Subordinated liabilities			£ 2,228	£ 2,556
Santander UK Group Holdings plc
Disclosure Of Subordinated Liabilities [Line Items]
Subordinated liabilities			838	830
Santander UK Group Holdings plc | 4.75% Subordinated notes (US$1,000m)
Disclosure Of Subordinated Liabilities [Line Items]
Borrowings maturity	2025	2025
Subordinated liabilities			£ 541	£ 536
Interest rate	4.75%	4.75%	4.75%	4.75%
Notional amount | $	$ 1,000,000,000	$ 1,000,000,000
Santander UK Group Holdings plc | 5.625% Subordinated notes (US$500m)
Disclosure Of Subordinated Liabilities [Line Items]
Borrowings maturity	2045	2045
Subordinated liabilities			£ 297	£ 294
Interest rate	5.625%	5.625%	5.625%	5.625%
Notional amount | $	$ 500,000,000	$ 500,000,000

Notes to Cash Flows - Parent -

Notes to Cash Flows - Parent - Summary of Changes in Liabilities Arising from Financing Activities (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	£ 48,576	£ 56,078
Proceeds from issue of debt securities	2,847	5,586
Repayment of debt securities	(13,724)	(12,348)
Repayment of subordinated liabilities	(4)	(939)
Issue of other equity instruments	450	0
Repurchase of other equity instruments	(500)	0
Payment of lease liability	(25)	(46)
Dividends paid	(1,506)	(282)
Liability-related other changes	(418)	(245)
Non-cash changes:
Unrealised foreign exchange	(916)	353
Other changes	1,353	419
Ending Balance	36,133	48,576
Debt securities in issue
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	43,679	50,171
Proceeds from issue of debt securities	2,847	5,586
Repayment of debt securities	(13,724)	(12,348)
Liability-related other changes	(473)	(243)
Non-cash changes:
Unrealised foreign exchange	(930)	359
Other changes	181	154
Ending Balance	31,580	43,679
Subordinated liabilities
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	2,556	3,528
Repayment of subordinated liabilities	(4)	(939)
Liability-related other changes	(4)	(10)
Non-cash changes:
Unrealised foreign exchange	14	(6)
Other changes	(334)	(17)
Ending Balance	2,228	2,556
Other equity instruments
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	2,241	2,241
Issue of other equity instruments	450
Repurchase of other equity instruments	(500)
Non-cash changes:
Ending Balance	2,191	2,241
Lease liabilities
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	100	138
Payment of lease liability	(25)	(46)
Liability-related other changes	59	8
Non-cash changes:
Ending Balance	134	100
Dividends paid
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	0	0
Dividends paid	(1,506)	(282)
Non-cash changes:
Other changes	1,506	282
Ending Balance	0	0
Santander UK Group Holdings plc
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	12,450	12,340
Proceeds from issue of debt securities	2,788	1,409
Repayment of debt securities	(1,814)	(969)
Repayment of subordinated liabilities	0	(281)
Issue of other equity instruments	450	0
Repurchase of other equity instruments	(500)	0
Dividends paid	(1,489)	(250)
Liability-related other changes	(28)	(3)
Non-cash changes:
Unrealised foreign exchange	(116)	(45)
Other changes	1,498	249
Ending Balance	13,239	12,450
Santander UK Group Holdings plc | Debt securities in issue
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	9,379	8,957
Proceeds from issue of debt securities	2,788	1,409
Repayment of debt securities	(1,814)	(969)
Liability-related other changes	(28)	(3)
Non-cash changes:
Unrealised foreign exchange	(124)	(17)
Other changes	9	2
Ending Balance	10,210	9,379
Santander UK Group Holdings plc | Subordinated liabilities
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	830	1,142
Repayment of subordinated liabilities		(281)
Non-cash changes:
Unrealised foreign exchange	8	(28)
Other changes		(3)
Ending Balance	838	830
Santander UK Group Holdings plc | Other equity instruments
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	2,241	2,241
Issue of other equity instruments	450
Repurchase of other equity instruments	(500)
Non-cash changes:
Ending Balance	2,191	2,241
Santander UK Group Holdings plc | Dividends paid
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	0	0
Dividends paid	(1,489)	(250)
Non-cash changes:
Other changes	1,489	250
Ending Balance	£ 0	£ 0

Notes to Cash Flows - Parent _2

Notes to Cash Flows - Parent - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Cash Flows Explanatory Notes [Line Items]
Interest received	£ 4,873	£ 5,176	£ 5,856
Interest paid	1,085	1,900	2,587
Dividends received	0	0	0
Purchase of financial assets at amortised cost and financial assets at FVOCI	1,256	3,015	5,013
Net change in operating assets and liabilities	11,449	14,788	4,334
Santander UK Group Holdings plc
Disclosure Of Cash Flows Explanatory Notes [Line Items]
Interest received	245	314
Interest paid	240	317
Dividends received	1,497	260
Purchase of financial assets at amortised cost and financial assets at FVOCI	2,774	1,424	0
Net change in operating assets and liabilities	£ 1,937	975
Santander UK Group Holdings plc | Net change in operating assets and liabilities
Disclosure Of Cash Flows Explanatory Notes [Line Items]
Net change in operating assets and liabilities		£ 1,424	£ 0

Interest Rate Benchmark Refor_5

Interest Rate Benchmark Reform - Parent (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Total liabilities	£ 277,298	£ 282,819	£ 272,147
USD LIBOR
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Total liabilities	4,381	8,965
Santander UK Group Holdings plc
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Total liabilities	11,048	10,233
Santander UK Group Holdings plc | USD LIBOR
Disclosure of expected impact of initial application of new standards or interpretations [line items]
Total liabilities	£ 2,217	£ 2,196