Santander UK (STNDF) 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	001-14928
Entity Registrant Name	Santander UK 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
Title of 15(d) Security	7.95% Term Subordinated Securities due October 26, 2029
Entity Common Stock, Shares Outstanding	31,051,768,866
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	0001087711
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
2.100% Notes due 2023, issued by Santander UK plc
Document And Entity Information [Line Items]
Title of 12(b) Security	2.100% Notes due 2023, issued by Santander UK plc
Trading Symbol	SAN/23B
Security Exchange Name	NYSE
4.000% Notes due 2024, issued by Abbey National Treasury Services plc *
Document And Entity Information [Line Items]
Title of 12(b) Security	4.000% Notes due 2024, issued by Abbey National Treasury Services plc *
Trading Symbol	SAN/24
Security Exchange Name	NYSE
2.875% Notes due 2024, issued by Santander UK plc
Document And Entity Information [Line Items]
Title of 12(b) Security	2.875% Notes due 2024, issued by Santander UK plc
Trading Symbol	SAN/24D
Security Exchange Name	NYSE
10 3/8% Non-cumulative Preference Shares of nominal value of £1 each
Document And Entity Information [Line Items]
Entity Common Stock, Shares Outstanding	200,000,000
8 5/8% Non-cumulative Preference Shares of nominal value of £1 each
Document And Entity Information [Line Items]
Entity Common Stock, Shares Outstanding	125,000,000

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	£ 4,762	£ 5,031		£ 5,817
Interest expense and similar charges	(813)	(1,643)		(2,593)
Net interest income	3,949	3,388		3,224
Fee and commission income	697	680		1,038
Fee and commission expense	(411)	(361)		(414)
Net fee and commission income	286	319		624
Other operating income	264	145		187
Total operating income	4,499	3,852		4,035
Operating expenses before credit impairment write-backs/losses, provisions and charges	(2,510)	(2,390)		(2,439)
Credit impairment write-backs/ (losses)	233	(638)		(199)
Provisions for other liabilities and charges	(377)	(264)		(426)
Total operating credit impairment write-backs/losses, provisions and charges	(144)	(902)		(625)
Profit from continuing operations before tax	1,845	560		971
Tax on profit from continuing operations	(492)	(121)		(268)
Profit from continuing operations after tax	1,353	439		703
Profit/(loss) from discontinued operations after tax	31	32		30
Profit after tax	1,384	471		733
Attributable to:
Equity holders of the parent	1,365	452		714
Non-controlling interests	19	19		19
Profit after tax	£ 1,384	£ 471		£ 733
[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	£ 1,384	£ 471	[1]	£ 733	[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	(873)	971		(857)
Income statement transfers	358	(809)		1,013
Taxation	141	(52)		(41)
Other comprehensive income, cash flow hedges, total	(374)	110		115
Currency translation on foreign operations	0	0		(4)
Net other comprehensive (expense)/income that may be reclassified to profit or loss subsequently	(377)	115		111
Pension remeasurement:
Change in fair value	1,264	(505)		(522)
Taxation	(419)	133		131
Pension remeasurement, total	845	(372)		(391)
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	845	(375)		(449)
Total other comprehensive income/(expense) net of tax	468	(260)		(338)
Total comprehensive income	1,852	211		395
Attributable to:
Equity holders of the parent	1,833	194		374
Non-controlling interests	19	17		21
Total comprehensive income	£ 1,852	£ 211		£ 395
[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	£ 48,139	£ 41,250
Financial assets at fair value through profit or loss:
Derivative financial instruments	1,681	3,406
Other financial assets at fair value through profit or loss	185	208
Financial assets at amortised cost:
Loans and advances to customers	210,094	208,750
Loans and advances to banks	1,169	1,682
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	1,646
Property, plant and equipment	1,548	1,734
Current tax assets	347	264
Retirement benefit assets	1,572	495
Other assets	1,577	3,013
Total assets	287,098	292,332
Financial liabilities at fair value through profit or loss:
Derivative financial instruments	777	1,584
Other financial liabilities at fair value through profit or loss	803	1,434
Financial liabilities at amortised cost:
Deposits by customers	192,926	195,135
Deposits by banks	33,855	20,958
Repurchase agreements – non trading	11,718	15,848
Debt securities in issue	25,520	35,566
Subordinated liabilities	2,228	2,556
Other liabilities	2,189	2,337
Provisions	364	464
Deferred tax liabilities	579	111
Retirement benefit obligations	37	403
Total liabilities	270,996	276,396
Equity
Share capital	3,105	3,105
Share premium	5,620	5,620
Other equity instruments	2,191	2,191
Retained earnings	5,053	4,348
Other reserves	133	510
Total shareholders’ equity	16,102	15,774
Non-controlling interests	0	162
Total equity	16,102	15,936
Total liabilities and equity	£ 287,098	£ 292,332

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	£ 1,384	£ 471	[1]	£ 733	[1]
Non-cash items included in profit:
– Depreciation and amortisation	501	562		543
– Provisions for other liabilities and charges	381	273		441
– Impairment losses	(228)	672		239
– Corporation tax charge	504	134		279
– Other non-cash items	(147)	(267)		(439)
– Pension charge/(credit) for defined benefit pension schemes	38	38		35
Non-cash items included in profit	1,049	1,412		1,098
Net change in operating assets and liabilities:
– Cash and balances at central banks	(64)	(147)		(71)
– Derivative assets	1,725	(90)		1,943
– Other financial assets at fair value through profit or loss	1,007	1,603		1,664
– Loans and advances to banks and customers	(971)	(2,654)		170
– Reverse repurchase agreements - non trading	7,024	3,924		(5,044)
– Other assets	324	(340)		247
– Deposits by banks and customers	10,735	19,977		641
– Repurchase agreements - non trading	(7,550)	(2,958)		5,943
– Derivative liabilities	(807)	136		79
– Other financial liabilities at fair value through profit or loss	(1,109)	(1,618)		(959)
– Debt securities in issue	(329)	(223)		(529)
– Other liabilities	(603)	(921)		(514)
Net change in operating assets and liabilities	9,382	16,689		3,570
Corporation taxes paid	(427)	(159)		(292)
Effects of exchange rate differences	(542)	410		(1,079)
Net cash flows from operating activities	10,846	18,823		4,030
Cash flows from investing activities
Purchase of property, plant and equipment and intangible assets	(613)	(373)		(505)
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	3,077	6,636		2,890
Cash flows from financing activities
Issue of other equity instruments	210	0		500
Issue of debt securities and subordinated notes	2,878	5,614		4,145
Issuance costs of debt securities and subordinated notes	(6)	(13)		(15)
Repayment of debt securities and subordinated notes	(11,914)	(12,037)		(7,969)
Repurchase of preference shares	0	0		14
Disposal of non-controlling interests	(181)	0		0
Repurchase of other equity instruments	(210)	0		(304)
Dividends paid on ordinary shares	(1,358)	(129)		(315)
Dividends paid on preference shares and other equity instruments	147	148		142
Dividends paid on non-controlling interests	0	(15)		(12)
Principal elements of lease payments	(25)	(45)		(54)
Net cash flows from financing activities	(10,753)	(6,773)		(4,180)
Change in cash and cash equivalents	3,170	18,686		2,740
Cash and cash equivalents at beginning of the year	47,682	28,951		26,264
Effects of exchange rate changes on cash and cash equivalents	(18)	45		(53)
Cash and cash equivalents at end of the year	50,834	47,682		28,951
Cash and cash equivalents consist of:
Cash and balances at central banks	48,139	41,250		21,180
Less: regulatory minimum cash balances	(918)	(854)		(707)
Cash and bank balances at central banks less regulatory minimum cash balances	47,221	40,396		20,473
Other cash equivalents: Loans and advances to banks - Non trading	1,074	1,435		1,995
Other cash equivalents: Reverse repurchase agreements	2,539	5,851		6,483
Cash and cash equivalents at the end of the year	£ 50,834	£ 47,682		£ 28,951
[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	Share premium	Other equity instruments	Fair value	Cash flow hedging	Currency translation	Retained earnings	Non-controlling interests
Beginning balance at Dec. 31, 2018	£ 15,909		£ 15,758	£ 3,119	£ 5,620	£ 1,991	£ 23	£ 256	£ 5	£ 4,744	£ 151
Profit for the year	733	[1]	714							714	19
Other comprehensive (expense)/income, net of tax:
– Fair value reserve (debt instruments)	0
– Cash flow hedges	115		115					115
– Pension remeasurement	(391)		(393)							(393)	2
– Own credit adjustment	(58)		(58)							(58)
– Currency translation on foreign operations	(4)		(4)						(4)
Total comprehensive income	395		374				0	115	(4)	263	21
Issue of other equity instruments	500		500			500
Repurchase of other equity instruments	(318)		(318)	(14)		(300)				(4)
Dividends on ordinary shares	(315)		(315)							(315)
Dividends on preference shares and other equity instruments	(142)		(142)							(142)
Dividends on non-controlling interests	(12)										(12)
Ending balance at Dec. 31, 2019	16,017		15,857	3,105	5,620	2,191	23	371	1	4,546	160
Profit for the year	471	[1]	452							452	19
Other comprehensive (expense)/income, net of tax:
– Fair value reserve (debt instruments)	5		5				5
– Cash flow hedges	110		110					110
– Pension remeasurement	(372)		(370)							(370)	(2)
– Own credit adjustment	(3)		(3)							(3)
Total comprehensive income	211		194				5	110	0	79	17
Dividends on ordinary shares	(129)		(129)							(129)
Dividends on preference shares and other equity instruments	(148)		(148)							(148)
Dividends on non-controlling interests	(15)										(15)
Ending balance at Dec. 31, 2020	15,936		15,774	3,105	5,620	2,191	28	481	1	4,348	162
Profit for the year	1,384		1,365							1,365	19
Other comprehensive (expense)/income, net of tax:
– Fair value reserve (debt instruments)	(3)		(3)				(3)
– Cash flow hedges	(374)		(374)					(374)
– Pension remeasurement	845		845							845
– Own credit adjustment	0
Total comprehensive income	1,852		1,833				(3)	(374)	0	2,210	19
Issue of other equity instruments	210		210			210
Repurchase of other equity instruments	(210)		(210)			(210)
Disposal of non-controlling interests	(181)										(181)
Dividends on ordinary shares	(1,358)		(1,358)							(1,358)
Dividends on preference shares and other equity instruments	(147)		(147)							(147)
Dividends on non-controlling interests	0
Tax on non-controlling interests and other equity instruments	0
Ending balance at Dec. 31, 2021	£ 16,102		£ 16,102	£ 3,105	£ 5,620	£ 2,191	£ 25	£ 107	£ 1	£ 5,053	£ 0
[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 – 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 1.45% (2020: 1.45%). Loss allowances decreased to £865m (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. 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. 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. 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. 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 monitor the performance of all forborne loans. A loan moves from a lifetime ECL to a 12-month ECL once the criteria to exit forbearance have been met, as set out below. Exit from forbearance or cure For an account in Stage 3 to exit forbearance, all the following conditions must be met: – The account has been classed as Stage 3 for at least one year since the end of the latest forbearance strategy – The account is not deemed unlikely to pay – The account is no longer in arrears, and the customer has no other material debts with us which are more than 90 days in arrears. If all the conditions are met, the account is re-classed as Stage 2 forbearance until the Stage 2 forbearance exit conditions set out below are also met. For an account in Stage 2 to exit forbearance, all the following conditions must be met: – The account has been classed as Stage 2 for at least two years since the end of the latest forbearance strategy – The account has been performing, i.e. the customer is no longer in financial difficulty – Meaningful capital and interest repayments have been made for at least 50% of the two year period – The account is no longer in arrears, and the customer has no other material debts with us which are more than 30 days in arrears. Other forms of debt management and modifications When a customer is not showing

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 Net Interest Margin (NIM) sensitivity to +25bps was £89m and to ‑25bps was £(94)m (2020: £116m and £(23)m) Economic Value of Equity (EVE) sensitivity to +25bps was £89m and to ‑25bps was £(125)m (2020: £190m and £(369)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. 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. 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. 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) 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 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 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. 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. We have 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. 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%) Wholesale funding with maturity <1 year £10.2bn (2020: £21.1bn) RFB DoLSub LCR eligible liquidity pool of £51.4bn (2020: £51.5bn) 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. Under 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. Risk appetite 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. 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 % (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. 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 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 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%. 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. Our immediate parent 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 our immediate parent 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. The Company 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 – Together with our immediate parent, Santander UK Group Holdings plc, 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. – 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 (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 12.3 — 5.8 — — 6.5 — — – privately placed 0.6 — 0.1 — 0.5 — — — 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 4.1 — — — — — 1.9 2.2 Total wholesale funding 67.4 32.1 5.9 — 0.5 24.8 1.9 2.2 Repos 11.7 — — 11.7 — — — — Foreign exchange and hedge accounting 1.1 — 0.1 — — 0.7 0.3 — Other 2.1 1.8 — — 0.3 — — — Balance sheet total 82.3 33.9 6.0 11.7 0.8 25.5 2.2 2.2 2020 Deposits by banks — — — — — — — — Certificates of deposit and commercial paper 5.7 — — — — 5.7 — — Senior unsecured – public benchmark 15.4 — 7.8 — — 7.6 — – privately placed 1.1 — 0.1 — 0.9 0.1 — — 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 4.4 — — — — — 2.2 2.2 Total wholesale funding 65.3 18.0 7.9 — 1.4 33.6 2.2 2.2 Repos 15.8 — — 15.8 — — — — Foreign exchange and hedge accounting 2.5 — 0.2 — — 2.0 0.3 — Other 3.0 3.0 — — — — — — Balance sheet total 86.6 21.0 8.1 15.8 1.4 35.6 2.5 2.2 (1) This is included in our balance sheet total of £192,926m (2020: £195,135m). (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 £1,956m (2020: £1,956m) Perpetual Capital Securities. 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 Downstreamed from Santander UK Group Holdings plc to Santander UK plc (1) Senior unsecured – public benchmark 0.8 — 0.4 — — 1.2 3.0 4.0 1.8 10.0 – privately placed — — — — — — — — 0.1 0.1 Subordinated liabilities and equity (incl. AT1) — — 0.8 — — 0.8 — 1.6 0.3 2.7 0.8 — 1.2 — — 2.0 3.0 5.6 2.2 12.8 Other 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 40.7 10.6 67.4 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 7.0 3.4 22.3 3.1 3.2 2.8 0.2 0.9 10.2 5.9 40.7 10.6 67.4 2020 Total at 31 December 2020 2.2 5.6 8.0 4.1 1.2 21.1 7.9 28.2 8.1 65.3 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 9.6 3.7 26.6 (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 % % % % % % % % Downstreamed from Santander UK Group Holdings plc to Santander UK plc Senior unsecured – public benchmark 9 59 32 — 10 62 28 — – privately placed — — — 100 — — — 100 Subordinated liabilities and equity (incl. AT1) 73 27 — — 73 27 — — 22 52 25 1 24 53 22 1 Other 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 66 18 15 1 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 Downstreamed from Santander UK Group Holdings plc to Santander UK plc Senior unsecured – public benchmark — 2.2 0.6 — 2.8 1.4 Subordinated debt and equity (inc. AT1) 0.2 — — — 0.2 — 0.2 2.2 0.6 — 3.0 1.4 Other 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 20.5 2.2 0.6 — 23.3 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 1,580 918 45,641 — — 46,559 48,139 Financial assets at FVTPL: – Derivative financial instruments — — — — — — — 1,681 1,681 1,681 – Other financial assets at FVTPL — — — — — — — 185 185 185 Financial assets at amortised cost: – Loans and advances to customers 15,713 3,720 100 19,533 80,624 74,890 18,893 16,154 190,561 210,094 – Loans and advances to banks — — 478 478 — — — 691 691 1,169 – Repurchase agreements – non trading — — — — — — — 12,683 12,683 12,683 – Other financial assets at amortised cost — — — — — 506 — — 506 506 Financial assets at FVOCI — — 4,363 4,363 — 1,488 — — 1,488 5,851 Interests in other entities — — — — — — — 201 201 201 Intangible assets — — — — — — — 1,545 1,545 1,545 Property, plant and equipment — — — — — — 1,548 — 1,548 1,548 Current tax assets — — — — — — — 347 347 347 Retirement benefit assets — — — — — — — 1,572 1,572 1,572 Other assets — — — — — — — 1,577 1,577 1,577 Total assets 15,713 3,720 6,521 25,954 81,542 122,525 20,441 36,636 261,144 287,098 2020 Cash and balances at central banks (1)(2) — — 985 985 854 39,411 — — 40,265 41,250 Financial assets at FVTPL: — – Derivative financial instruments — — — — — — — 3,406 3,406 3,406 – Other financial assets at FVTPL — — — — — — — 208 208 208 Financial assets at amortised cost: — – Loans and advances to customers 23,669 7,469 184 31,322 61,292 74,758 19,801 21,577 177,428 208,750 – Loans and advances to banks — — 804 804 — — — 878 878 1,682 – 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 — — 5,581 5,581 — 3,369 — — 3,369 8,950 Interests in other entities — — — — — — — 172 172 172 Intangible assets — — — — — — — 1,646 1,646 1,646 Property, plant and equipment — — — — — — 1,734 — 1,734 1,734 Current tax assets — — — — — — — 264 264 264 Retirement benefit assets — — — — — — — 495 495 495 Other assets — — — — — — — 3,013 3,013 3,013 Total assets 23,669 7,469 8,202 39,340 62,146 118,053 21,535 51,258 252,992 292,332 (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

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 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 RWAs. Key metrics CET1 capital ratio of 16.1% (2020: 15.4%) Total qualifying regulatory capital of £14.8bn (2020: £15.2bn) 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 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 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 and total capital 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. 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). 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. MREL recapitalisation To date, we have down streamed £9.7bn of senior unsecured bonds from Santander UK Group Holdings plc as Internal MREL compliant, secondary non-preferential debt to Santander UK plc as the ring-fenced bank. Key capital ratios 2021 2020 % % CET1 capital ratio 16.1 15.4 AT1 2.9 2.7 Grandfathered Tier 1 0.2 0.4 Tier 2 2.7 2.7 Total capital ratio 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: 0.16%). 2021 compared to 2020 CET1 capital ratio increased 70bps to 16.1%, largely due to lower RWAs and retained profit. CET1 capital ratio includes a benefit of circa 20bps 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 70bps to 21.9%, 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 10,820 11,057 AT1 capital 2,119 2,281 Tier 1 capital 12,939 13,338 Tier 2 capital 1,816 1,909 Total regulatory capital (1) 14,755 15,247 (1) Capital resources include a transitional IFRS 9 benefit at 31 December 2021 of £21m(2020: £73m). 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 £bn £bn Total RWAs 67.1 71.9

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 plc (the Company) and the Santander UK 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 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 an operating company undertaking banking and financial services transactions. 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 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 ceases when the software is capable of op

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) 3,356 233 401 — (41) 3,949 Non-interest income 205 178 109 — 58 550 Total operating income 3,561 411 510 — 17 4,499 Operating expenses before credit impairment write-backs, provisions and charges (1,701) (163) (365) — (281) (2,510) Credit impairment write-backs 98 33 91 — 11 233 Provisions for other liabilities and charges (185) 4 (34) — (162) (377) Total operating credit impairment write-backs, provisions and charges (87) 37 57 — (151) (144) Profit/(loss) from continuing operations before tax 1,773 285 202 — (415) 1,845 Revenue from external customers 4,010 489 553 — (553) 4,499 Inter-segment revenue (449) (78) (43) — 570 — Total operating income 3,561 411 510 — 17 4,499 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 — 5 79 Total fee and commission income 570 10 112 — 5 697 Fee and commission expense (380) — (22) — (9) (411) Net fee and commission income/(expense) 190 10 90 — (4) 286 Customer loans 183,023 4,984 16,997 — 2,284 207,288 Total assets (3) 190,629 8,873 16,997 — 70,599 287,098 Customer deposits 156,991 — 25,597 — 3,627 186,215 Total liabilities 157,622 1,173 25,613 — 86,588 270,996 Average number of full-time equivalent staff 16,149 670 2,281 528 76 19,704 (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) 2,753 264 363 — 8 3,388 Non-interest income 245 127 94 — (2) 464 Total operating income/(expense) 2,998 391 457 — 6 3,852 Operating expenses before credit impairment losses, provisions and charges (1,792) (166) (324) — (108) (2,390) Credit impairment losses (264) (44) (294) — (36) (638) Provisions for other liabilities and charges (157) (8) (6) — (93) (264) Total operating credit impairment losses, provisions and charges (421) (52) (300) — (129) (902) Profit/(loss) from continuing operations before tax 785 173 (167) — (231) 560 Revenue from external customers 3,669 501 549 — (867) 3,852 Inter-segment revenue (671) (110) (92) — 873 — Total operating income/(expense) 2,998 391 457 — 6 3,852 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 — 2 65 Total fee and commission income 576 10 92 — 2 680 Fee and commission expense (335) — (22) — (4) (361) Net fee and commission income 241 10 70 — (2) 319 Customer loans 175,380 8,025 17,626 2,784 3,196 207,011 Total assets (3) 183,154 11,143 17,626 2,784 77,625 292,332 Customer deposits 152,167 — 24,985 6,506 2,049 185,707 Total liabilities 152,687 2,397 25,011 6,517 89,784 276,396 Average number of full-time equivalent staff 18,198 640 2,405 716 39 21,998 2019 Net interest income 2,581 246 422 — (25) 3,224 Non-interest income 531 155 109 — 16 811 Total operating income 3,112 401 531 — (9) 4,035 Operating expenses before credit impairment losses, provisions and charges (1,860) (179) (334) — (66) (2,439) Credit impairment (losses)/write-backs (129) (27) (45) — 2 (199) Provisions for other liabilities and charges (273) (8) (24) — (121) (426) Total operating credit impairment losses, provisions and (charges)/releases (402) (35) (69) — (119) (625) Profit/(loss) from continuing operations before tax 850 187 128 — (194) 971 Revenue from external customers 3,748 525 633 — (871) 4,035 Inter-segment revenue (636) (124) (102) — 862 — Total operating income 3,112 401 531 — (9) 4,035 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 — 18 129 Total fee and commission income 899 13 108 — 18 1,038 Fee and commission expense (372) — (24) — (18) (414) Net fee and commission income 527 13 84 — 0 624 Customer loans 171,078 7,684 18,391 4,041 3,814 205,008 Total assets (3) 178,665 10,748 18,391 4,046 69,852 281,702 Customer deposits 142,735 — 20,546 6,102 2,332 171,715 Total liabilities 143,570 2,748 20,572 6,233 92,562 265,685 Average number of full-time equivalent staff 19,669 612 2,464 804 21 23,570 (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) 4,619 4,745 5,130 Loans and advances to banks 52 49 137 Reverse repurchase agreements – non trading 35 118 244 Other 56 119 306 Total interest and similar income (1) 4,762 5,031 5,817 Interest expense and similar charges: Deposits by customers (430) (1,011) (1,540) Deposits by banks (25) (28) (102) Repurchase agreements – non trading (3) (43) (126) Debt securities in issue (252) (440) (678) Subordinated liabilities (92) (111) (137) Other (11) (10) (10) Total interest expense and similar charges (2) (813) (1,643) (2,593) Net interest income 3,949 3,388 3,224 (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) 79 65 129 Total fee and commission income 697 680 1,038 Total fee and commission expense (411) (361) (414) Net fee and commission income 286 319 624 (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 (24) (77) (142) Net gains on financial instruments mandatorily at fair value through profit or loss (2) 46 70 Hedge ineffectiveness 13 20 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 13 112 264 145 187 (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 £242m income (2020: £751m 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 £358m expense (2020: £809m income, 2019: £1,013m 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 745 788 801 Performance-related payments 183 97 159 Social security costs 112 101 111 Pensions costs: – defined contribution plans 64 66 66 – defined benefit plans (2) 38 38 35 Other share-based payments — — — Other personnel costs 41 33 40 1,183 1,123 1,212 Other administration expenses 826 706 684 Depreciation, amortisation and impairment 501 561 543 Total 2,510 2,390 2,439 (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 77 — — 156 77 – deferred 8 9 15 11 23 20 Shares award – not deferred 11 3 — — 11 3 – deferred 8 8 14 11 22 19 Total discretionary bonus 183 97 29 22 212 119 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 19,704 (2020: 21,998, 2019: 23,570). 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 £19m (2020: £58m,2019: £60m) on right-of-use assets with a net book value of £118m at 31 December 2021 (2020: £100m, 2019: £152m). '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. For the Company, in 2021 impairment associated with the closure of branches and head office sites as part of the transformation programme was £63m (2020: £0m).

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 11.2 10.0 8.0 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 0.9 1.4 1.3 Total audit fees (1) 12.1 11.4 9.3 Non-audit fees: Audit-related assurance services 0.8 0.8 0.8 Other assurance services 0.1 0.3 0.2 Other non-audit services 0.2 0.0 0.2 Total non-audit fees 1.1 1.1 1.2 (1) 2021 audit fees included £1.2m (2020: £0.8m, 2019: £0.1m) which related to the prior year. 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, £0.4m (2020: £0.4m, 2019: £0.6m) accords with the definition of 'Audit Fees' per US Securities and Exchange Commission (SEC) guidance, £0.7m (2020: £0.7m, 2019: £0.4m) 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) 665 217 Recoveries of loans and advances, net of collection costs (17) (24) (40) Off-balance sheet exposures (See Note 29) (30) (3) 22 (233) 638 199 Provisions for other liabilities and charges (excluding off-balance sheet credit exposures) (See Note 29) 386 258 420 Provisions for residual value and voluntary termination (9) 6 6 377 264 426 144 902 625 (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]
Disclosure of income tax [text block]	9. TAXATION Group 2021 2020 (1) 2019 (1) £m £m £m Current tax: UK corporation tax on profit for the year 401 107 254 Adjustments in respect of prior years (24) (24) (25) Total current tax 377 83 229 Deferred tax: Charge for the year 100 34 46 Adjustments in respect of prior years 15 4 (7) Total deferred tax 115 38 39 Tax on profit from continuing operations 492 121 268 (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 26.7% (2020: 21.6%, 2019: 27.6%). 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 1,845 560 971 Tax calculated at a tax rate of 19% (2020: 19%, 2019: 19%) 351 106 184 Bank surcharge on profits 104 27 62 Non-deductible preference dividends paid 9 8 8 Non-deductible UK Bank Levy 14 19 24 Non-deductible conduct remediation, fines and penalties 6 (4) 44 Other non-deductible costs and non-taxable income 37 25 31 Effect of change in tax rate on deferred tax provision 9 6 (14) Tax relief on dividends in respect of other equity instruments (40) (40) (39) Adjustment to prior year provisions 2 (26) (32) Tax on profit from continuing operations 492 121 268 (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 £23m and reduce the deferred tax liability by £90m. Current tax assets and liabilities Movements in current tax assets and liabilities during the year were as follows: Group 2021 2020 £m £m Assets 264 200 Liabilities — — At 1 January 264 200 Income statement charge (including discontinued operations) (389) (96) Other comprehensive income credit 33 1 Corporate income tax paid 427 159 Other movements 12 — 347 264 Assets 347 264 Liabilities — — At 31 December 347 264 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 Tax losses carried forward Accelerated tax depreciation Other temporary differences Total £m £m £m £m £m £m £m £m At 1 January 2021 (65) (26) (99) (11) 15 38 37 (111) Income statement (charge)/credit (58) (67) — — (7) 40 (23) (115) Transfers/reclassifications — 4 (16) 1 — (10) (19) (40) Credited/(charged) to other comprehensive income — (419) 108 (2) — — — (313) At 31 December 2021 (123) (508) (7) (12) 8 68 (5) (579) At 1 January 2020 (52) (96) (58) (8) 13 17 35 (149) Income statement (charge)/credit (13) (63) — — 2 21 15 (38) Transfers/reclassifications — — 12 (1) — — (13) (2) Credited/(charged) to other comprehensive income — 133 (53) (2) — — — 78 At 31 December 2020 (65) (26) (99) (11) 15 38 37 (111)

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 0.90 0.42 0.53 281 129 164 – second interim 3.47 — 0.49 1,077 — 151 4.37 0.42 1.02 1,358 129 315 In 2021, an interim dividend of £1,358m (2020: £129m ) was paid on the Company's ordinary shares in issue related to 2021 profit and an assessment of capital surpluses. Dividends were paid in line with our dividend policy following review and approval by the Santander UK Board.

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 11,036 159 168 14,951 395 418 Interest rate contracts 25,148 463 485 40,160 888 542 Equity and credit contracts 1,056 161 54 1,140 123 55 Total derivatives held for trading 37,240 783 707 56,251 1,406 1,015 Derivatives held for hedging Designated as fair value hedges: Exchange rate contracts 590 39 — 789 84 6 Interest rate contracts 80,514 904 737 93,748 1,225 1,885 81,104 943 737 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 21,466 180 216 19,407 467 23 43,705 1,176 554 46,427 2,445 432 Total derivatives held for hedging 124,809 2,119 1,291 140,964 3,754 2,323 Derivative netting (1) (1,221) (1,221) (1,754) (1,754) Total derivatives 162,049 1,681 777 197,215 3,406 1,584 (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 — — 33,865 33,865 — 1,194 — 507 Interest rate contracts — 117,559 9,569 127,128 — 326 — 216 Equity and credit contracts — — 1,056 1,056 — 161 — 54 — 117,559 44,490 162,049 — 1,681 — 777 2020 Exchange rate contracts — — 42,760 42,760 — 2,457 — 833 Interest rate contracts — 144,343 8,972 153,315 — 826 — 696 Equity and credit contracts — — 1,140 1,140 — 123 — 55 — 144,343 52,872 197,215 — 3,406 — 1,584 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. 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. 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 44,507 4,991 80,284 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 7,669 5,137 15,168 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 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) — — 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 — 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 852 (299) (360) (Losses)/gains on hedged items attributable to hedged risks (800) 365 414 Fair value hedging ineffectiveness 52 66 54 Cash flow hedging ineffectiveness (39) (46) (46) 13 20 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 874 (834) 40 (358) 385 27 Interest rate/FX risk (22) 34 12 59 (20) 39 852 (800) 52 (299) 365 66 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 (317) 305 (12) 73 185 (179) 6 33 FX risk Net interest income/other operating income (54) 54 — (158) (42) 38 (4) 2 Interest rate/FX risk Net interest income/other operating income (541) 514 (27) (273) 782 (830) (48) 773 (912) 873 (39) (358) 925 (971) (46) 808 In 2021, cash flow hedge accounting of £14m (2020: £4m) 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 644 481 Effective portion of changes in fair value: – Interest rate risk (305) 179 – Foreign currency risk (54) (38) – Equity risk — — – Interest rate/foreign currency risk (514) 830 (873) 971 Income statement transfers – Interest rate risk (73) (33) – Foreign currency risk 158 (2) – Equity risk — — – Interest rate/foreign currency risk 273 (773) 358 (808) Balances at 31 December 129 644 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 — 80 491 (1,092) 54,118 — 1,189 892 334 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 (1,665) (46) — (44) 104 (7,309) (158) (10) (77) (73) Deposits by banks — — — — — — — — — — Debt securities in issue (2,567) (140) (114) (185) 235 (5,885) (375) (137) (239) (61) 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) 67,194 (291) (45) 198 (800) 58,019 (649) 1,038 424 365 Group 2021 2020 Change in value to calculate hedge ineffectiveness Cash flow hedge reserve Balances on cash flow hedge reserve for discontinued hedges Change in value to calculate hedge ineffectiveness Cash flow hedge reserve 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 235 (135) (2) (183) 165 1 Cash and balances at central banks 71 (79) — (2) 1 — Reverse repurchase agreements – non trading — — — (2) 1 — Deposits by banks (1) 1 — 7 (2) — Debt securities in issue — — — — — — Repurchase agreements – non trading — — — 1 (1) — FX risk: Other financial assets at FVOCI (195) (1) — 40 6 — Not applicable – highly probable forecast transactions 149 1 — 33 3 — Deposits by customers 9 9 10 (5) 14 — Deposits by banks — — — — — — Debt securities in issue 85 57 (4) (15) (60) — Repurchase agreements – non trading 6 — — (15) — — Equity risk: Other liabilities — — — — — — Interest rate/FX risk: Debt securities in issue/loans and advances to customers 410 105 (4) (569) 236 (2) Deposits by customers 93 38 — (132) 87 — Subordinated liabilities/loans and advances to customers 11 133 80 (130) 194 — 873 129 80 (972) 644 (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 62 86 74 99 Debt securities 111 109 185 208 For the Santander UK group, other financial assets at FVTPL comprised £12m (2020: £13m) of financial assets designated at FVTPL and £173m (2020: £195m) of financial assets mandatorily held at FVTPL. Loans and advances to customers principally represented other loans, being a portfolio of roll-up mortgages. 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 174,712 166,714 Corporate loans 19,282 23,613 Finance leases 3,916 6,554 Secured advances — — Other unsecured loans 9,404 9,933 Accrued interest and other adjustments 452 861 Amounts due from fellow Banco Santander subsidiaries and joint ventures 3,175 2,425 Amounts due from Santander UK Group Holdings plc 6 7 Amounts due from subsidiaries — — Loans and advances to customers 210,947 210,107 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 210,094 208,750 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 (200) 1,124 1,829 (173) 1,656 Later than two years and not later than three years 771 (141) 630 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 4,382 (466) 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 £m No later than one year 31 17 Later than one year and not later than two years 27 16 Later than two years and not later than three years 21 15 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 29 133 98

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 Subsidiaries — — Joint Ventures 201 172 0 201 172 The Santander UK group consists of a parent company, Santander UK 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. 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 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 1,269 (66) 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 Accumulated Net book value Cost £m £m £m At 1 January 2021 1,304 (861) 443 Additions 84 — 84 Disposals (54) 53 (1) Charge — (158) (158) Impairment — (26) (26) At 31 December 2021 1,334 (992) 342 At 1 January 2020 1,249 (686) 563 Additions 102 — 102 Disposals (47) 47 — Charge — (197) (197) Impairment — (25) (25) At 31 December 2020 1,304 (861) 443 Other intangibles which consist of computer software, include computer software under development of £83m ( 2020 : £99m ), of which £31m is internally generated ( 2020 : £68m ). For the Company, all computer software is externally generated. The impairment charge of £26m (2020: £25m ) 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 1,272 1,375 436 720 218 4,021 Additions 126 26 — 284 65 501 Disposals (420) (352) (2) (249) (29) (1,052) At 31 December 2021 978 1,049 434 755 254 3,470 Accumulated depreciation: At 1 January 2021 489 1,068 434 178 118 2,287 Charge for the year (1) 32 86 1 81 19 219 Impairment during the year 46 28 — — 23 97 Disposals (233) (325) (1) (99) (23) (681) At 31 December 2021 334 857 434 160 137 1,922 Net book value 644 192 — 595 117 1,548 Cost: At 1 January 2020 1,270 1,436 439 738 212 4,095 Additions 61 43 2 185 8 299 Disposals (59) (104) (5) (203) (2) (373) At 31 December 2020 1,272 1,375 436 720 218 4,021 Accumulated depreciation: At 1 January 2020 454 1,016 434 164 60 2,128 Charge for the year (1) 55 111 — 92 58 316 Impairment during the year 24 — — — — 24 Disposals (44) (59) — (78) — (181) At 31 December 2020 489 1,068 434 178 118 2,287 Net book value 783 307 2 542 100 1,734 (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 ( 2020: £11m lower) than the carrying value.

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) 185,843 185,879 Amounts due to other Santander UK Group Holdings plc subsidiaries 59 59 Amounts due to Santander UK Group Holdings plc (2) 5,874 7,883 Amounts due to fellow Banco Santander subsidiaries and joint ventures 1,150 1,314 192,926 195,135 (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. (2) Includes downstreamed funding from our immediate parent company Santander UK Group Holdings plc.

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 931 2,063 Other deposits (1) 32,507 18,519 Amounts due to Santander UK subsidiaries 3 1 33,855 20,958 (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) 1,261 1,061 – US SEC-registered Debt Programme – Santander UK plc (2) 4,185 5,457 6,851 8,212 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 25,520 35,566 (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. (2) Restated for 2020 to reclassify £734m previously disclosed as US$1bn Senior Unsecured Notes to US SEC-registered Debt Programme - Santander UK plc 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.

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 132 97 Other 2,057 2,240 2,189 2,337

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 34 45 75 39 4 464 Additional provisions (See Note 8) 25 72 52 52 — 80 109 390 Provisions released (See Note 8) — — — (2) (30) — (2) (34) Utilisation and other (50) (104) (98) (21) (7) (91) (98) (469) Recharge (1) — — 13 — — — — 13 At 31 December 2021 44 166 1 74 38 28 13 364 (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 £180m (2020: £323m). 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 1,572 495 Funded defined benefit pension scheme - deficit — (361) Unfunded pension and post-retirement medical benefits (37) (42) Total net assets 1,535 92 Remeasurement losses/(gains) recognised in other comprehensive income during the year were as follows: Group 2021 2020 2019 £m £m £m Pension remeasurement (1,264) 505 522 An expense of £64m (2020: £66m) 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 main differences between the assumptions used for assessing the defined benefit liabilities for the funding valuation and those used for IAS 19 is that the financial and demographic assumptions used for the funding valuation are generally more prudent than those used for the IAS 19 valuation. The total amount charged to the income statement was as follows: Group 2021 2020 2019 £m £m £m Net interest income (5) (10) (23) 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 20 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) (454) (1,328) (855) Actuarial (gains)/losses arising from changes in demographic assumptions (17) 34 42 Actuarial gains arising from experience adjustments (19) (141) (42) Actuarial (gains)/losses arising from changes in financial assumptions (774) 1,940 1,377 Pension remeasurement (1,264) 505 522 Movements in the present value of defined benefit scheme obligations were as follows: Group 2021 2020 £m £m At 1 January (13,887) (12,158) Current service cost paid by Santander UK plc (29) (24) Current service cost paid by subsidiaries (9) (12) Current service cost paid by fellow Banco Santander subsidiaries — — 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 774 (1,940) Benefits paid 398 396 Derecognition of pension scheme liabilities arising from the sale of PSA 41 — At 31 December (12,878) (13,887) Movements in the fair value of the schemes’ assets were as follows: Group 2021 2020 £m £m At 1 January 13,979 12,547 Interest income 193 263 Contributions paid by employer and scheme members 246 245 Contributions paid by fellow Banco Santander subsidiaries — — Administration costs paid (8) (8) Return on plan assets (excluding amounts included in net interest expense) 454 1,328 Benefits paid (398) (396) Derecognition of pension scheme assets arising from the sale of PSA (53) — At 31 December 14,413 13,979 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 — — 291 2 291 2 D Longevity swap — — (8) 0 (8) 0 D Other — — 336 2 336 2 C 14,993 104 (580) (4) 14,413 100 2020 UK equities 40 0 — — 40 0 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 — — 309 2 309 2 D Longevity swap — 0 0 0 0 D Other — — 329 3 329 3 C 10,745 77 3,234 23 13,979 100 (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 2021 2020 Assumption Change in pension obligation at period end from £m £m Discount rate 25 bps increase (571) (662) General price inflation (1) 25 bps increase 392 365 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 37,346 42,221 37,709 43,160 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. Liquidity support arrangements Under 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. Any potential losses, claims or expenses suffered or incurred by Santander Financial Services plc in respect of these matters have been fully indemnified by Santander UK plc, as part of the ring-fencing transfer scheme between Santander UK plc, Santander Financial Services plc and Banco Santander SA. 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. The convertible preferred stock is now held by Santander Equity Investments Limited (SEIL), outside the ring-fenced bank. 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). In June 2020, the Supreme Court issued a judgement finding that MIFs restricted competition. 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, Santander UK plc (and/or, where relevant, its subsidiaries) has 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 Total Issued and fully paid share capital No. £m £m At 31 December 2020, 1 January 2021 and 31 December 2021 31,051,768,866 3,105 3,105 Group 2021 2020 Share premium £m £m At 1 January and 31 December 5,620 5,620

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 750 750 - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 5.18 n/a — 210 - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 6.30 March 2025 500 500 - £210m Fixed Rate Reset Perpetual AT1 Capital Securities 4.25 March 2026 210 — 2,191 2,191 AT1 securities The AT1 securities issued by the Company were subscribed by its immediate parent company, Santander UK Group Holdings plc. 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. In March 2021, Santander UK plc purchased and redeemed the remaining £210m of the original £500m 5.18% Fixed Rate Reset Perpetual AT1 Capital Securities and issued £210m 4.25% Fixed Rate Reset Perpetual AT1 Capital Securities, which were fully subscribed by the Company’s immediate parent company, Santander UK Group Holdings plc.

Non-Controlling Interests

Non-Controlling Interests	12 Months Ended
	Dec. 31, 2021
Disclosure Of Noncontrolling Interests [Abstract]
Non-Controlling Interests	34. NON-CONTROLLING INTERESTS 2021 2020 £m £m PSA Finance UK Limited — 162 — 162 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 35,566 2,556 2,191 97 — 40,410 41,129 3,528 2,191 137 — 46,985 Proceeds from issue of debt securities 2,872 — — — — 2,872 5,602 — — — — 5,602 Repayment of debt securities (11,910) — — — — (11,910) (11,378) — — — — (11,378) Repayment of subordinated liabilities — (4) — — — (4) — (659) — — — (659) Issue of other equity instruments — — 450 — — 450 — — — — — — Repurchase of other equity instruments — — (500) — — (500) — — — — — — Payment of lease liability — — — (25) — (25) — — — (45) — (45) Dividends paid — — — — (1,494) (1,494) — — — — (292) (292) Liability-related other changes (447) (4) — 60 — (391) (250) (10) — 5 — (255) Non-cash changes: – Unrealised foreign exchange (806) 6 — — — (800) 376 22 — — — 398 – Other changes 245 (326) 50 — 1,494 1,463 87 (325) — — 292 54 At 31 December 25,520 2,228 2,191 132 — 30,071 35,566 2,556 2,191 97 — 40,410 (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 consolidated 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 £45m for 2020 (2019: £54m) 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: £48m). Net cash flows from operating activities includes interest received of £4,806m (2020: £5,139m, 2019: £5,801m), interest paid of £1,064m (2020: £1,857m, 2019: £2,538m) and dividends received of £nil (2020: £nil, 2019: £nil). Restatements in the consolidated cash flow Reverse repurchase agreements with a contractual maturity of greater than 3 months and repurchase agreements were previously included in cash and cash equivalents. In 2021, such agreements are no longer included in cash and cash equivalents, and line items have been added in the cash flow statement within ‘net change in operating assets and liabilities’ for ‘reverse repurchase agreements - non trading’ and ‘repurchase agreements - non trading’. As a result, cash and cash equivalents for 2020 and 2019 have been restated by £2,100m and £1,134m respectively. Footnotes to the Company 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 £43m for 2020 (2019: £53m) have been reclassified from 'Other liabilities' within operating activities to 'Principal elements of lease payments' within financing activities. Total cash outflow for leases was £25m (2020: £46m). Net cash flows from operating activities includes interest received of £4,945m (2020: £5,313m, 2019: £6,032m), interest paid of £1,490m (2020: £2,542m,2019: £3,206m) and dividends received of £230m (2020: £nil, 2019: £nil). Restatements in the Company cash flow Reverse repurchase agreements with a contractual maturity of greater than 3 months and repurchase agreements were previously included in cash and cash equivalents. In 2021, such agreements are no longer included in cash and cash equivalents, and line items have been added in the cash flow statement within ‘net change in operating assets and liabilities’ for ‘reverse repurchase agreements - non trading’ and ‘repurchase agreements - non trading’. As a result, cash and cash equivalents for 2020 and 2019 have been restated by £2,096m and £1,128m respectively.

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 284 550 Loans and advances to customers – securitisations and covered bonds (See Note 14) 19,432 31,138 Loans and advances to customers – other 41,936 23,655 Other financial assets at amortised cost — 648 Financial assets at fair value through other comprehensive income 4,363 5,581 Total on-balance sheet 67,595 62,557 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 £45,936m at 31 December 2021 (2020: £30,040m) 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 £1,947m (2020: £1,598m) 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 931 2,063 Total on-balance sheet 931 2,063 Total off-balance sheet 17,781 30,510 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 £3,219m at 31 December 2021 (2020: £4,538m) 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, £931m (2020: £2,063m) 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 14 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 Range of exercise prices Weighted average remaining contractual life Weighted average exercise price Weighted average remaining contractual life Weighted average exercise price 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 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 5,495,852 5,353,980 5,025,665 Performance-related payments (1) 5,195,722 1,458,911 3,864,965 Other fixed remuneration (pension and other allowances & non-cash benefits) 929,935 1,107,348 1,367,069 Expenses 17,097 6,772 42,526 Total remuneration 11,638,606 7,927,011 10,300,225 2021 2020 2019 Directors' and Other Key Management Personnel compensation £ £ £ Short-term employee benefits (2) 25,114,949 18,432,698 21,925,975 Post-employment benefits (3) 1,344,883 2,084,645 3,590,466 Total compensation 26,459,832 20,517,343 25,516,441 (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) One Termination payment of £346,154 was paid in 2021 to a Director (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: £2,134,134) of which £2,913,000 (2020: £726,040) 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 12 3,640 18 4,920 Net movements (6) (3,280) (6) (1,280) At 31 December 6 360 12 3,640 Deposit, bank and instant access accounts and investments At 1 January 23 8,195 32 11,975 Net movements (2) (1,643) (9) (3,780) At 31 December 21 6,552 23 8,195 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 four Directors (2020: seven Directors), with a principal amount of £348,306 outstanding at 31 December 2021 (2020: £1,829,267). 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]
Disclosure Party Disclosures	39. RELATED PARTY DISCLOSURES a) Parent undertaking and controlling party The Company’s immediate parent is Santander UK Group Holdings plc, a company incorporated in England and Wales. Its 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 Santander UK Group Holdings plc and Banco Santander SA respectively, 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 (164) (119) (130) 33 105 266 816 1,557 (1,150) (2,151) Immediate parent (6) (7) (7) 263 316 317 7 8 (10,935) (10,121) Fellow subsidiaries (57) (58) (66) 163 157 173 159 223 (534) (559) Associates & joint ventures (34) (29) (29) 4 — — 3,075 2,234 (918) (1,034) (261) (213) (232) 463 578 756 4,057 4,022 (13,537) (13,865) 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 October 2020, Santander UK plc transferred a portfolio of mortgage assets with a book value of £3,163m to Santander Financial Services plc for a cash consideration of £3,174m , including a purchase price premium of £11m . 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 and mean reversion. 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 Fair value value Level 1 Level 2 Level 3 Fair value value £m £m £m £m £m £m £m £m £m £m Assets Loans and advances to customers — — 212,811 212,811 210,094 — — 211,279 211,279 208,750 Loans and advances to banks — 1,169 — 1,169 1,169 — 1,682 — 1,682 1,682 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 13,970 213,037 227,171 224,452 799 21,457 211,505 233,761 231,194 Liabilities Deposits by customers — 48 192,898 192,946 192,926 — 108 195,134 195,242 195,135 Deposits by banks — 33,770 85 33,855 33,855 — 20,951 16 20,967 20,958 Repurchase agreements - non trading — 11,718 — 11,718 11,718 — 15,847 — 15,847 15,848 Debt securities in issue 963 23,926 1,218 26,107 25,520 — 34,967 1,430 36,397 35,566 Subordinated liabilities 37 2,350 238 2,625 2,228 — 2,830 239 3,069 2,556 1,000 71,812 194,439 267,251 266,247 — 74,703 196,819 271,522 270,063 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 — 1,547 — 1,547 — 2,566 14 2,580 A & C Equity and credit contracts — 116 45 161 — 71 52 123 B & D Netting — (1,221) — (1,221) — (1,754) — (1,754) — 1,635 46 1,681 — 3,338 68 3,406 Other financial assets at FVTPL Loans and advances to customers — — 74 74 — — 99 99 A Debt securities — — 111 111 — — 109 109 A, B & D Equity securities — — — — — — — — B Reverse repurchase agreements – non trading — — — — — — — — A — — 185 185 — — 208 208 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 1,635 249 7,717 8,501 3,766 297 12,564 Liabilities Derivative financial instruments Exchange rate contracts — 506 — 506 — 833 — 833 A Interest rate contracts — 1,436 2 1,438 — 2,447 3 2,450 A & C Equity and credit contracts — 24 30 54 — 26 29 55 B & D Netting — (1,221) — (1,221) — (1,754) — (1,754) — 745 32 777 — 1,552 32 1,584 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 — 1,542 38 1,580 — 2,978 40 3,018 Transfers between levels of the fair value hierarchy In 2021 there were no significant (2020 : no significant) transfers of financial instruments between levels of the fair value hierarchy. 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 20 23 - Credit risk adjustment 6 11 - Funding fair value adjustment 3 3 20 29 Model-related — — Day One profit — — 20 29 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 Debt securities Credit linked notes 20 2 (5) (16) 7 6. FVOCI assets Loans and advances to customers Other loans 18 21 (3) (4) (2) 7. Derivative liabilities Equity contracts Property options and forwards (30) (29) (1) (3) — 8. FVTPL liabilities Financial guarantees Credit protection guarantee (1) (2) 6 16 (7) 217 249 (5) 11 (16) Other Level 3 assets 1 17 (1) 7 16 Other Level 3 liabilities (7) (9) 2 (1) (5) Total net assets 211 257 — — — Total income/(expense) (4) 17 (5) 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 – Debt securities (Credit linked notes) These consist of the retained senior tranches of credit linked notes in respect of credit protection vehicles sponsored by Santander UK and are mandatorily held at fair value through profit or loss. These vehicles provide credit protection on reference portfolios of Santander UK group loans with junior notes sold to external investors. The notes retained by Santander UK are classified as level 3 financial instruments as their valuation depends upon unobservable parameters relating to the underlying reference portfolios of loans, including credit spreads, correlations and prepayment speed, which have a significant effect on the overall valuation. For more information, see ‘Credit protection entities’ in Note 19. 6. FVOCI assets – Loans and advances to customers – other loans These relate to shipping loans. The fair value of these loans is estimated using the ‘present value’ model based on a credit curve derived from curren

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 Assets not subject to enforceable netting arrangements (2) Effects of offsetting on balance sheet Related amounts not offset 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 2,832 (1,221) 1,611 (754) (693) 164 72 1,683 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⁾ 4,251 (923) 3,328 — — 3,328 207,935 211,263 21,965 (4,343) 17,622 (1,189) (12,941) 3,492 208,007 225,629 Liabilities Derivative financial liabilities 1,955 (1,221) 734 (754) 59 39 43 777 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⁾ 8,609 (923) 7,686 — — 7,686 219,095 226,781 24,481 (4,343) 20,138 (1,189) (11,224) 7,725 219,138 239,276 2020 Assets Derivative financial assets 5,071 (1,754) 3,317 (782) (1,840) 695 89 3,406 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⁾ 7,454 (1,073) 6,381 — — 6,381 204,051 210,432 38,609 (9,312) 29,297 (911) (21,310) 7,076 204,140 233,437 Liabilities Derivative financial liabilities 3,261 (1,754) 1,507 (782) (551) 174 77 1,584 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⁾ 11,159 (1,073) 10,086 — (502) 9,584 206,007 216,093 36,753 (9,312) 27,441 (911) (16,772) 9,758 206,084 233,525 (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) — 1,480 — 1,480 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 1,561 1 2,943 Liabilities Derivatives (1)(2) 338 1,831 — 2,169 Other financial liabilities at fair value through profit and loss — 5 — 5 Financial liabilities at amortised cost (4) 34 185 — 219 372 2,021 — 2,393 Off-balance sheet commitments given 338 59 — 397 2020 Assets Derivatives (1)(2) 33,486 4,514 2,149 40,149 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 49,944 5,727 2,239 57,910 Liabilities Derivatives (1)(2) 35,217 5,205 88 40,510 Other financial liabilities at fair value through profit and loss 1,129 69 — 1,198 Financial liabilities at amortised cost 2,354 1,319 — 3,673 38,700 6,593 88 45,381 Off-balance sheet commitments given 11,400 2,126 573 14,099 (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. Group Group 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 32 55 68 Net fee and commission income 35 66 63 Other operating income 2 2 8 Total operating income 69 123 139 Operating expenses before credit impairment losses, provisions and charges (33) (62) (60) Credit impairment losses 11 (7) (22) Provisions for other liabilities and charges (4) (9) (16) Total operating credit impairment losses, provisions and charges 7 (16) (38) Profit from discontinued operations before tax 43 45 41 Tax on profit from discontinued operations (12) (13) (11) Profit from discontinued operations after tax 31 32 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 (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.
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 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.

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.
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. 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.
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 Upside 1 Base case Downside 1 Downside 2 Downside 3 Scenario weights % % % % % 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 for 2021 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 264 1 123 388 – Homes 119 1 70 190 – Everyday Banking 145 — 53 198 Consumer Finance 51 — 1 52 Corporate & Commercial Banking 106 100 217 423 Corporate Centre 2 — — 2 Total 423 101 341 865 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 313,347 313,347 313,347 313,347 313,347 313,347 Retail Banking 212,395 212,395 212,395 212,395 212,395 212,395 – Homes 190,663 190,663 190,663 190,663 190,663 190,663 – 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 70,963 70,963 70,963 70,963 70,963 70,963 ECL 865 740 738 849 1,123 1,288 Retail Banking 388 307 286 375 510 662 – Homes 190 134 125 177 283 437 – 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 4.9 5.1 6.2 7.0 Retail Banking 5.5 5.2 5.2 5.4 6.6 7.7 – Homes 5.8 5.5 5.5 5.7 6.9 8.2 – 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 322,745 322,745 322,745 322,745 322,745 322,745 Retail Banking 201,990 201,990 201,990 201,990 201,990 201,990 – Homes 180,006 180,006 180,006 180,006 180,006 180,006 – Everyday Banking 21,984 21,984 21,984 21,984 21,984 21,984 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 76,345 76,345 76,345 76,345 76,345 76,345 ECL 1,377 1,129 1,222 1,300 1,612 1,802 Retail Banking 588 495 470 544 730 740 – Homes 280 212 207 253 389 415 – 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 5.3 4.6 4.7 4.6 6.6 6.8 Retail Banking 5.4 4.5 4.6 4.7 7.2 7.2 – Homes 5.7 4.8 4.9 4.9 7.7 7.5 – Everyday Banking 2.8 2.4 2.1 2.6 3.3 4.9 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 48.1 — 48.1 — — — — — — 48.1 Financial assets at amortised cost: – Loans and advances to customers: (3) – Loans secured on residential properties (4) 174.7 (0.2) 174.5 16.0 — 16.0 — (177.8) — 12.7 – Corporate loans 19.3 (0.4) 18.9 7.6 — 7.6 (0.1) (16.8) — 9.6 – Finance leases 3.9 (0.1) 3.8 0.3 — 0.3 — (4.7) — (0.6) – Accrued interest and other adjustments 0.5 — 0.5 — — — — — — 0.5 – Other unsecured loans 9.4 (0.2) 9.2 13.4 — 13.4 — — — 22.6 – Amounts due from fellow Banco Santander group subsidiaries and joint ventures 3.2 — 3.2 — — — — — — 3.2 Total loans and advances to customers 211.0 (0.9) 210.1 37.3 — 37.3 (0.1) (199.3) — 48.0 – Loans and advances to banks 1.2 — 1.2 0.4 — 0.4 — — — 1.6 – 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 225.4 (0.9) 224.5 37.7 — 37.7 (0.1) (211.5) (0.4) 50.2 Financial assets at fair value at FVOCI: – Loans and advances to customers — — — — — — — — — — – Debt securities 5.9 — 5.9 — — — — — — 5.9 Total financial assets at FVOCI 5.9 — 5.9 — — — — — — 5.9 Total 279.4 (0.9) 278.5 37.7 — 37.7 (0.1) (211.5) (0.4) 104.2 2020 Cash and balances at central banks 41.3 — 41.3 — — — — — — 41.3 Financial assets at amortised cost: – Loans and advances to customers: (3) – Loans secured on residential properties (4) 166.7 (0.3) 166.4 13.3 — 13.3 — (170.0) — 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 9.9 (0.3) 9.6 13.3 — 13.3 — — — 22.9 – Amounts due from fellow Banco Santander group subsidiaries and joint ventures 2.4 — 2.4 — — — — — — 2.4 Total loans and advances to customers 210.1 (1.3) 208.8 42.2 (0.1) 42.1 (0.2) (196.2) — 54.5 – Loans and advances to banks 1.7 — 1.7 1.0 — 1.0 — — — 2.7 – 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 232.6 (1.3) 231.3 43.2 (0.1) 43.1 (0.2) (215.7) (0.1) 58.4 Financial assets at FVOCI: – Loans and advances to customers — — — — — — — — — — – Debt securities 9.0 — 9.0 — — — — — — 9.0 Total financial assets at FVOCI 9.0 — 9.0 — — — — — — 9.0 Total 282.9 (1.3) 281.6 43.2 (0.1) 43.1 (0.2) (215.7) (0.1) 108.7 (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) (0.8) 0.2 – Other financial assets at FVTPL 0.2 — — — 0.2 Total 1.9 — (0.7) (0.8) 0.4 2020 Financial assets at FVTPL: – Derivative financial instruments 3.4 — (1.8) (0.8) 0.8 – Other financial assets at FVTPL 0.2 — — — 0.2 Total 3.6 — (1.8) (0.8) 1.0 (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 48.1 — — — — — — — — 48.1 – Stage 1 48.1 — — — — — — — — 48.1 Financial assets at amortised cost: – Loans and advances to customers (2) 9.0 32.5 84.5 48.0 12.8 10.2 6.0 8.0 (0.9) 210.1 – Stage 1 9.0 31.7 83.1 44.9 10.0 5.0 0.6 7.4 (0.1) 191.6 – Stage 2 — 0.8 1.4 3.1 2.8 5.2 2.8 0.3 (0.4) 16.0 – Stage 3 — — — — — — 2.6 0.3 (0.4) 2.5 Of which mortgages: 9.0 29.7 79.3 42.5 6.4 4.7 3.1 — (0.2) 174.5 – Stage 1 9.0 29.5 78.0 39.6 4.1 1.6 — — — 161.8 – 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 0.8 — — — — — — 1.2 – Stage 1 0.2 0.2 0.8 — — — — — — 1.2 – 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 32.8 86.4 48.6 12.8 10.2 6.0 9.2 (0.9) 224.5 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 71.1 34.9 86.6 48.6 12.8 10.2 6.0 9.2 (0.9) 278.5 Total off–balance sheet 0.1 7.2 7.0 6.8 4.5 1.3 0.5 10.3 — 37.7 – Stage 1 0.1 6.9 6.7 6.6 4.3 1.0 0.2 10.3 — 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 71.2 42.1 93.6 55.4 17.3 11.5 6.5 19.5 (0.9) 316.2 ECL On balance sheet Cash and balances at central banks — — — — — — — — — – Stage 1 — — — — — — — — — Financial assets at amortised cost: – Loans and advances to customers (2) — — — — 0.2 0.1 0.6 — 0.9 – Stage 1 — — — — 0.1 — — — 0.1 – Stage 2 — — — — 0.1 0.1 0.2 — 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 — — — — 0.2 0.1 0.6 — 0.9 Financial assets at FVOCI: — — — — — — — — — – Stage 1 — — — — — — — — — Total on balance sheet — — — — 0.2 0.1 0.6 — 0.9 Total off–balance sheet — — — — — — — — — – Stage 1 — — — — — — — — — – Stage 2 — — — — — — — — — – Stage 3 — — — — — — — — — Total ECL — — — — 0.2 0.1 0.6 — 0.9 Santander UK risk grade Total 9 8 7 6 5 4 3 to 1 Other (1) 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) — — — — 1.6 1.0 10.0 — 0.4 – Stage 1 — — — — 1.0 — — — 0.1 – Stage 2 — — — — 3.6 1.9 7.1 — 2.5 – Stage 3 — — — — — — 15.4 — 16.0 Of which mortgages: — — — — — 2.1 3.2 — 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 — — — — 1.6 1.0 10.0 — 0.4 Financial assets at FVOCI: — — — — — — — — — – Stage 1 — — — — — — — — — Total on balance sheet — — — — 1.6 1.0 10.0 — 0.3 Total off–balance sheet — — — — — — — — — – Stage 1 — — — — — — — — — – Stage 2 — — — — — — — — — – Stage 3 — — — — — — — — — Total coverage ratio — — — — 1.2 0.9 9.2 — 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 41.3 — — — — — — — — 41.3 – Stage 1 41.3 — — — — — — — — 41.3 Financial assets at amortised cost: – Loans and advances to customers⁽²⁾ 8.0 27.7 74.4 44.1 13.5 27.0 8.2 7.2 (1.3) 208.8 – Stage 1 8.0 27.6 74.0 42.6 10.8 19.0 1.1 7.0 (0.2) 189.9 – 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 24.3 68.0 36.8 5.6 19.6 4.5 — (0.3) 166.4 – Stage 1 7.9 24.3 67.7 35.5 3.9 14.7 0.6 — — 154.6 – Stage 2 — — 0.3 1.3 1.7 4.9 2.1 — (0.2) 10.1 – Stage 3 — — — — — — 1.8 — (0.1) 1.7 – Loans and advances to banks 0.1 0.1 0.4 — — — — 1.1 — 1.7 – Stage 1 0.1 0.1 0.4 — — — — 1.1 — 1.7 – 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 31.1 76.3 46.5 13.5 27.0 8.2 8.5 (1.3) 231.3 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 68.1 34.5 76.5 46.6 13.5 27.0 8.2 8.5 (1.3) 281.6 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 68.5 43.3 86.0 55.4 18.6 28.6 8.7 17.0 (1.4) 324.7 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 1.0 — 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 183.0 169.2 11.7 2.1 108 388 – Homes 174.7 161.8 11.1 1.8 5 190 – 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 2.3 2.1 0.2 — — 2 207.3 187.9 16.5 2.9 191 865 Undrawn Balances 37.7 36.1 1.5 0.1 Stage 1, Stage 2 and Stage 3 (2) ratios % 90.65 7.93 1.45 2020 £bn £bn £bn £bn £m £m Retail Banking 175.4 162.6 10.9 1.9 155 588 – Homes 166.7 154.6 10.3 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 3.2 3.2 — — — 35 207.0 187.1 17.0 2.9 253 1,377 Undrawn Balances 43.2 41.8 1.3 0.1 Stage 1, Stage 2 and Stage 3 (2) ratios % 90.34 8.26 1.45 (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: 174,712 166,730 – Stage 1 161,845 154,586 – Stage 2 11,071 10,345 – Stage 3 1,796 1,799 Loss allowances (1) 190 280 % % Stage 1 ratio (2) 92.64 92.72 Stage 2 ratio (2) 6.34 6.20 Stage 3 ratio (3) 1.04 1.09 (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 174,712 40,654 13,638 8,549 528 14,893 116,767 – Stage 1 161,845 36,212 12,391 7,509 354 14,363 109,878 – Stage 2 11,071 3,626 1,020 796 109 489 6,188 – Stage 3 1,796 816 227 244 65 41 701 Stage 3 ratio (4) 1.04 % 2.03 % 1.66 % 3.06 % 12.34 % 0.27 % 0.60 % PIPs 2 1 1 — 1 — — Simple average LTV (indexed) 41 % 44 % 43 % 23 % 116 % 59 % 41 % 2020 Mortgage portfolio 166,730 38,441 13,234 9,953 734 11,608 110,854 – Stage 1 154,586 33,330 11,860 8,731 423 11,180 105,514 – Stage 2 10,345 4,228 1,126 989 221 393 4,728 – Stage 3 1,799 883 248 233 90 35 612 Stage 3 ratio (4) 1.09 % 2.31 % 1.88 % 2.48 % 12.30 % 0.30 % 0.55 % 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 £10,106m (2020: £9,847m) 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. Committed exposure Watchlist Fully performing Enhanced monitoring Proactive management Stage 3 Total (1) Loss allowances 2021 £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 5,344 — 165 — 5,509 2 20,464 724 2,521 826 24,535 423 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 5,009 — 73 — 5,082 — 20,044 573 3,043 1,020 24,680 603 (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. Committed exposure Watchlist Fully performing Enhanced monitoring Proactive management Stage 3 Total (1) Loss allowances 2021 £m £m £m £m £m £m Sovereign and Supranational 56,112 — — — 56,112 — Structured Products 1,875 — — — 1,875 — Social Housing 2,858 — — — 2,858 1 Financial Institutions 1,364 — — — 1,364 — Legacy Portfolios in run-off 48 — — 2 50 1 Derivatives — — — — — — 62,257 — — 2 62,259 2 2020 Sovereign and Supranational 50,962 — — — 50,962 — 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 — — — — — — 58,060 69 — — 58,129 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. Committed exposure Watchlist Fully performing Enhanced monitoring Proactive management Stage 3 Total (1) Loss allowances 2020 £m £m £m £m £m £m Large Corporate 9,374 252 1,260 — 10,886 33 Financial Institutions 1,461 — — — 1,461 — 10,835 252 1,260 — 12,347 33
Disclosure of IFRS 9 Credit Quality	Total on-balance sheet exposures at 31 December 2021 comprised £207.3bn of customer loans, loans and advances to banks of £1.2bn, £13.2bn of sovereign assets measured at amortised cost, £5.9bn of assets measured at FVOCI, and £48.1bn 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 169,255 11,646 2,122 183,023 – Homes 161,845 11,071 1,796 174,712 – 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 70,427 207 — 70,634 Total on-balance sheet 256,254 16,448 2,936 275,638 Off-balance sheet Retail Banking (1) 29,123 204 45 29,372 – Homes (1) 15,851 81 19 15,951 – Everyday Banking 13,272 123 26 13,421 Consumer Finance 314 — — 314 Corporate & Commercial Banking 6,392 1,266 36 7,694 Corporate Centre 283 46 — 329 Total off-balance sheet (2) 36,112 1,516 81 37,709 Total exposures 292,366 17,964 3,017 313,347 ECL On-balance sheet Retail Banking 52 178 137 367 – Homes 8 88 89 185 – Everyday Banking 44 90 48 182 Consumer Finance 18 17 17 52 Corporate & Commercial Banking 43 119 245 407 Corporate Centre 2 — — 2 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 17 16 4 37 Total ECL 132 330 403 865 Coverage ratio (3) % % % % On-balance sheet Retail Banking — 1.5 6.5 0.2 – Homes — 0.8 5.0 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 31.0 2.4 Corporate Centre — — — — Total on-balance sheet — 1.9 13.6 0.3 Off-balance sheet Retail Banking — 3.9 2.2 0.1 – Homes — — — — – Everyday Banking 0.1 6.5 3.8 0.1 Consumer Finance — — — — Corporate & Commercial Banking 0.1 0.6 8.3 0.2 Total off-balance sheet — 1.1 4.9 0.1 Total coverage — 1.8 13.4 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 £207.0bn of customer loans, loans and advances to banks of £1.7bn, £20.8bn of sovereign assets measured at amortised cost, £9.0bn of assets measured at FVOCI, and £41.3bn 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 162,541 10,962 1,877 175,380 – Homes 154,586 10,345 1,799 166,730 – Everyday Banking 7,955 617 78 8,650 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 75,743 27 — 75,770 Total on-balance sheet 259,625 17,064 2,896 279,585 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 558 17 — 575 Total off-balance sheet (2) 41,788 1,272 100 43,160 Total exposures 301,413 18,336 2,996 322,745 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 — 2.9 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 — 0.0 — — 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 556 5 0.9 130 4 3.1 445 19 4.3 — — — — — — 1,131 28 2.5 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 — — — — — — 3,109 78 2.5 — — — — — — 3,109 78 2.5 11,850 186 1.6 200 17 8.5 5,661 127 2.2 — — — 253 — — 17,964 330 1.8 2020 PD deterioration 7,752 247 3.2 88 13 14.8 2,128 39 1.8 — — — 32 — — 10,000 299 3.0 Forbearance 612 3 0.5 — — — 151 6 4.0 — — — 4 — — 767 9 1.2 Other 1,155 10 0.9 249 11 4.4 612 66 10.8 429 24 5.6 5 — — 2,450 111 4.5 30 DPD 870 46 5.3 27 12 44.4 250 5 2.0 — — — 3 — — 1,150 63 5.5 Payment holiday 829 26 3.1 15 1 6.7 — — — — — — — — — 844 27 3.2 Mortgage affordability — — — — — — — — — — — — — — — — — — High risk corporate — — — — — — 3,125 83 2.7 — — — — — — 3,125 83 2.7 11,218 332 3.0 379 37 9.8 6,266 199 3.2 429 24 5.6 44 — — 18,336 592 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 13,302 286 2.2 16,992 554 3.3 Stage 2 in cure period (for transfer to Stage 1) 4,662 44 0.9 1,344 38 2.8 17,964 330 1.8 18,336 592 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 2021 £m £m £m £m £m Retail Banking (1) 183,023 367 182,656 29,372 21 – Homes (1) 174,712 185 174,527 15,951 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 70,634 2 70,632 329 — Total exposures presented in Credit Quality tables 275,638 828 274,810 37,709 37 Other items (3) 3,632 Adjusted net carrying amount 278,442 Assets classified at FVTPL 1,866 Non-financial assets 6,790 Total assets per the Consolidated Balance Sheet 287,098 2020 Retail Banking (1) 175,380 550 174,830 26,610 38 – Homes (1) 166,730 277 166,453 13,276 3 – Everyday Banking (2) 8,650 273 8,377 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 75,770 35 75,735 575 — Total exposures presented in Credit Quality tables 279,585 1,302 278,283 43,160 75 Other items (3) 3,111 Adjusted net carrying amount 281,394 Assets classified at FVTPL 3,614 Non-financial assets 7,324 Total assets per the Consolidated Balance Sheet 292,332 (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 301,413 216 18,336 592 2,996 569 322,745 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) (571) (3) (532) (20) 1,103 23 — — Transfers from Stage 3 (3) 14 2 456 62 (470) (64) — — Transfers of financial instruments (1,479) 157 846 (116) 633 (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) 50,862 31 936 26 25 19 51,823 76 Redemptions, repayments and assets sold (7) (63,658) (70) (3,442) (67) (519) (68) (67,619) (205) Changes in risk parameters and other movements (6) 5,228 (62) 1,288 20 179 63 6,695 21 Assets written off (7) — — — — (297) (191) (297) (191) At 31 December 2021 292,366 132 17,964 330 3,017 403 313,347 865 Net movement in the period (9,047) (84) (372) (262) 21 (166) (9,398) (512) ECL charge/(release) to the Income Statement (84) (262) 25 (321) Less: Discount unwind — — (11) (11) Less: Recoveries net of collection costs — — 88 88 ECL charge/(release) to the Income Statement from continued operations (84) (262) 102 (244) Discontinued operations ECL adjustment 11 — — 11 Total ECL charge/(release) to the Income Statement (73) (262) 102 (233) At 1 January 2020 295,436 147 12,351 348 2,368 368 310,155 863 Transfers from Stage 1 to Stage 2 (3) (9,815) (47) 9,815 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 (7,010) 57 5,837 (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 1,371 64 104 52 57,021 156 Redemptions, repayments and assets sold (7) (50,698) (30) (2,295) (42) (441) (18) (53,434) (90) Changes in risk parameters and other movements (6) 8,141 88 1,072 (53) 185 98 9,398 133 Assets written off (7) (2) — — — (393) (253) (395) (253) At 31 December 2020 301,413 216 18,336 592 2,996 569 322,745 1,377 Net movement in the period 5,977 69 5,985 244 628 201 12,590 514 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 — — (7) (7) Total ECL charge/(release) to the Income Statement 69 244 325 638 (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 79 are also applicable to this table. 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 188,854 74 11,218 332 1,918 182 201,990 588 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) — (6) — (86) — (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) (14) (1,537) (22) (361) (21) (29,992) (57) Changes in risk parameters and other movements (6) 4,146 (10) 423 (7) 89 64 4,658 47 Assets written off (7) — — — (1) (129) (108) (129) (109) At 31 December 2021 198,378 64 11,850 186 2,167 138 212,395 388 Net movement in the period 9,524 (10) 632 (146) 249 (44) 10,405 (200) 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 59 8,872 232 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) — (78) — 144 — 42 — 108 Change in economic scenarios (2) — 7 — 81 — 10 — 98 Changes to model — — — — — 25 — 25 New lending and assets purchased (5) 31,499 15 345 30 6 4 31,850 49 Redemptions, repayments and assets sold (7) (26,727) (12) (1,031) (25) (314) (20) (28,072) (57) Changes in risk parameters and other movements (6) 1,177 11 310 (53) 109 101 1,596 59 Assets written off (7) — — — — (203) (155) (203) (155) At 31 December 2020 188,854 74 11,218 332 1,918 182 201,990 588 Net movement in the period 2,766 15 2,346 100 59 12 5,171 127 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 79 are also applicable to this table. 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 167,766 17 10,427 131 1,813 132 180,006 280 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) — (19) — 10 — 9 — — 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) (25,072) (3) (1,436) (6) (331) (16) (26,839) (25) Changes in risk parameters and other movements (6) 3,606 (4) 270 26 11 (10) 3,887 12 Assets written off (7) — — — — (16) (5) (16) (5) At 31 December 2021 177,696 13 11,152 88 1,815 89 190,663 190 Net movement in the period 9,930 (4) 725 (43) 2 (43) 10,657 (90) 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 15 (315) (15) — — Transfers of financial instruments (3,000) 12 2,595 (11) 405 (1) — — Net ECL remeasurement on stage transfer (4) — (15) — 49 — 17 — 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) (23,707) (4) (899) (7) (297) (15) (24,903) (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 167,766 17 10,427 131 1,813 132 180,006 280 Net movement in the period (1,064) 3 2,203 30 79 29 1,218 62 Charge/(release) to the Income Statement 3 29 43 75 Less: Discount unwind — — (2) (2) Less: Recoveries net of collection costs — — (1) (1) Total ECL charge/(release) to the Income Statement 3 29 40 72 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 79 are also applicable to this table. 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 79 are also applicable to this table. 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 79 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 79 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 76,301 35 44 — — — 76,345 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) (5,327) (17) (27) — — — (5,354) (17) Changes in risk parameters and other movements (6) (548) (17) 93 — — — (455) (17) Assets written off (7) — — — — — — — — At 31 December 2021 70,710 2 253 — — — 70,963 2 Net movement in the period (5,591) (33) 209 — — — (5,382) (33) ECL charge/(release) to the Income Statement (33) — — (33) Less: Discount unwind — — — — Less: Recoveries net of collection costs — — 22 22 Total ECL charge/(release) to the Income Statement (33) — 22 (11) £m £m £m £m £m £m £m £m At 1 January 2020 67,779 1 94 1 — — 67,873 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) — (3) — 3 — 1 — 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) (10,342) (1) (9) (1) (3) (1) (10,354) (3) Changes in risk parameters and other movements (6) 7,389 34 (65) (6) 1 — 7,325 28 Assets written off (7) — — — — (2) — (2) — At 31 December 2020 76,301 35 44 — — — 76,345 35 Net movement in the period 8,522 34 (50) (1) — — 8,472 33 ECL charge/(release) to the Income Statement 34 (1) — 33 Less: Discount unwind — — — — Less: Recoveries net of collection costs — — 4 4 Total ECL charge/(release) to the Income Statement 34 (1) 4 37 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 79 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 — 0.4 — — — 0.4 — 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 1.5 5.6 — 0.1 7.6 0.5 2.4 7.6 — 0.8 11.3 Other countries UK 47.9 2.0 9.3 215.1 28.7 303.0 42.0 2.8 14.8 206.1 40.4 306.1 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 — 0.1 0.7 0.3 0.5 0.1 — 0.7 1.6 49.7 3.2 9.4 215.1 28.8 306.2 45.5 5.2 15.0 206.1 41.4 313.2 Total 50.1 4.7 15.0 215.1 28.9 313.8 46.0 7.6 22.6 206.1 42.2 324.5 (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 0.8 — — 0.8 1.6 — — 1.6 UK — 3.3 — 3.3 — 2.4 — 2.4 0.8 3.3 — 4.1 1.6 2.4 — 4.0 Liabilities Spain 1.2 0.1 — 1.3 2.2 0.1 — 2.3 UK — 12.1 — 12.1 — 11.5 — 11.5 Uruguay 0.1 — — 0.1 0.1 — — 0.1 1.3 12.2 — 13.5 2.3 11.6 — 13.9
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 74,657 42 71,008 42 13,537 43 10,116 41 Remortgagers 50,645 29 50,934 31 8,031 25 6,861 27 First-time buyers 34,517 20 33,180 20 6,206 19 5,354 21 Buy-to-let 14,893 9 11,608 7 4,239 13 2,622 11 174,712 100 166,730 100 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 147,147 84 133,231 80 Variable rate 17,010 10 20,986 13 Standard Variable Rate (SVR) 7,836 4 10,627 6 Follow on Rate (FoR) 2,719 2 1,886 1 174,712 100 166,730 100
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 44.6 41.8 8.3 6.1 Midlands and East Anglia 23.8 22.5 4.7 3.7 North 23.1 22.6 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 55.5 52.5 10.5 8.3 South West, Wales and other 18.1 17.5 3.4 2.6 174.7 166.7 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 44,431 44,790 103,657 103,785 £0.25m to £0.50m 38,749 35,487 51,699 46,914 £0.50m to £1.0m 13,820 11,942 15,972 13,763 £1.0m to £2.0m 2,823 1,875 3,053 2,024 >£2.0m 318 236 331 244 100,141 94,330 174,712 166,730
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% 78,911 25 942 9 4,997 73,489 28 858 11 4,180 >50-75% 77,781 62 614 28 15,831 68,324 89 633 36 10,088 >75-85% 13,866 26 106 12 6,896 18,113 41 125 19 5,858 >85-100% 3,626 26 69 14 4,239 6,070 44 93 22 4,781 >100% 528 51 65 26 50 734 78 90 44 46 174,712 190 1,796 89 32,013 166,730 280 1,799 132 24,953 Collateral value of residential properties (1) 174,637 1,784 32,012 166,623 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 422 305 – 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 647 36,326 – 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 2 387 444 273 4 1,108 12 Stage 3 217 74 73 111 475 26 604 518 346 115 1,583 38 Proportion of portfolio 0.3 % 0.3 % 0.2 % 0.1 % 0.9 % 2020 Stage 2 409 393 310 — 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 392 1,892 3,795 19,633 14,942 40,654 – of which value weighted average LTV (indexed) is >75% 13 106 112 1,015 1,355 2,601 2020 Full interest-only portfolio 374 1,726 3,697 20,318 12,326 38,441 – of which value weighted average LTV (indexed) is >75% 13 131 154 1,397 1,017 2,712
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 — — 1 — — 5,509 52 3,577 3,480 3,081 5,338 5,624 2,646 737 24,535 Of which: Stage 1 52 2,890 3,168 2,750 4,796 3,388 309 577 17,930 Stage 2 — 687 312 331 542 2,236 1,511 160 5,779 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 — 3 5,082 112 3,099 3,687 2,854 3,516 7,204 3,274 934 24,680 Of which: Stage 1 112 3,060 3,626 2,589 2,776 4,027 454 749 17,393 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 55,061 1,051 — — — — — — 56,112 Structured Products 573 1,064 197 41 — — — — 1,875 Social Housing — 1,290 1,568 — — — — — 2,858 Financial Institutions 479 533 345 7 — — — — 1,364 Legacy Portfolios in run-off (2) — — — 6 — — — 44 50 Derivatives — — — — — — — — — 56,113 3,938 2,110 54 — — — 44 62,259 Of which: Stage 1 56,113 3,731 2,066 54 — — — 38 62,002 Stage 2 — 207 44 — — — — 4 255 Stage 3 — — — — — — — 2 2 2020 Sovereign and Supranational 48,579 2,383 — — — — — — 50,962 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 — — — — — — — — — 50,246 5,628 2,052 47 — — — 156 58,129 Of which: Stage 1 50,246 5,583 2,052 47 — — — 156 58,084 Stage 2 — 45 — — — — — — 45 Stage 3 — — — — — — — — — (1) Smaller exposures mainly in the commercial mortgage 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 1,802 3,267 3,882 1,523 157 81 — 10,886 Financial Institutions 367 443 622 23 6 — — — 1,461 541 2,245 3,889 3,905 1,529 157 81 — 12,347
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 5,509 — — — 5,509 5,082 — — — 5,082 24,492 43 — — 24,535 24,632 47 — 1 24,680 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 52,297 950 469 2,396 56,112 44,624 1,516 849 3,973 50,962 Structured Products 1,219 656 — — 1,875 1,683 799 — — 2,482 Social Housing 2,858 — — — 2,858 3,817 — — — 3,817 Financial Institutions 504 565 81 214 1,364 301 365 6 40 712 Legacy Portfolios in run-off 50 — — — 50 59 — — 97 156 Derivatives — — — — — — — — — — 56,928 2,171 550 2,610 62,259 50,484 2,680 855 4,110 58,129 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 9,814 1,052 — 20 10,886 Financial Institutions 642 435 130 254 1,461 10,456 1,487 130 274 12,347
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 2 — 2 2020 Legacy Portfolios in run–off — — — 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. 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. 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)

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 (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 12.3 — 5.8 — — 6.5 — — – privately placed 0.6 — 0.1 — 0.5 — — — 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 4.1 — — — — — 1.9 2.2 Total wholesale funding 67.4 32.1 5.9 — 0.5 24.8 1.9 2.2 Repos 11.7 — — 11.7 — — — — Foreign exchange and hedge accounting 1.1 — 0.1 — — 0.7 0.3 — Other 2.1 1.8 — — 0.3 — — — Balance sheet total 82.3 33.9 6.0 11.7 0.8 25.5 2.2 2.2 2020 Deposits by banks — — — — — — — — Certificates of deposit and commercial paper 5.7 — — — — 5.7 — — Senior unsecured – public benchmark 15.4 — 7.8 — — 7.6 — – privately placed 1.1 — 0.1 — 0.9 0.1 — — 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 4.4 — — — — — 2.2 2.2 Total wholesale funding 65.3 18.0 7.9 — 1.4 33.6 2.2 2.2 Repos 15.8 — — 15.8 — — — — Foreign exchange and hedge accounting 2.5 — 0.2 — — 2.0 0.3 — Other 3.0 3.0 — — — — — — Balance sheet total 86.6 21.0 8.1 15.8 1.4 35.6 2.5 2.2 (1) This is included in our balance sheet total of £192,926m (2020: £195,135m). (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 £1,956m (2020: £1,956m) Perpetual Capital Securities. 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 Downstreamed from Santander UK Group Holdings plc to Santander UK plc (1) Senior unsecured – public benchmark 0.8 — 0.4 — — 1.2 3.0 4.0 1.8 10.0 – privately placed — — — — — — — — 0.1 0.1 Subordinated liabilities and equity (incl. AT1) — — 0.8 — — 0.8 — 1.6 0.3 2.7 0.8 — 1.2 — — 2.0 3.0 5.6 2.2 12.8 Other 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 40.7 10.6 67.4 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 7.0 3.4 22.3 3.1 3.2 2.8 0.2 0.9 10.2 5.9 40.7 10.6 67.4 2020 Total at 31 December 2020 2.2 5.6 8.0 4.1 1.2 21.1 7.9 28.2 8.1 65.3 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 9.6 3.7 26.6 (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 % % % % % % % % Downstreamed from Santander UK Group Holdings plc to Santander UK plc Senior unsecured – public benchmark 9 59 32 — 10 62 28 — – privately placed — — — 100 — — — 100 Subordinated liabilities and equity (incl. AT1) 73 27 — — 73 27 — — 22 52 25 1 24 53 22 1 Other 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 66 18 15 1 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 Downstreamed from Santander UK Group Holdings plc to Santander UK plc Senior unsecured – public benchmark — 2.2 0.6 — 2.8 1.4 Subordinated debt and equity (inc. AT1) 0.2 — — — 0.2 — 0.2 2.2 0.6 — 3.0 1.4 Other 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 20.5 2.2 0.6 — 23.3 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 1,580 918 45,641 — — 46,559 48,139 Financial assets at FVTPL: – Derivative financial instruments — — — — — — — 1,681 1,681 1,681 – Other financial assets at FVTPL — — — — — — — 185 185 185 Financial assets at amortised cost: – Loans and advances to customers 15,713 3,720 100 19,533 80,624 74,890 18,893 16,154 190,561 210,094 – Loans and advances to banks — — 478 478 — — — 691 691 1,169 – Repurchase agreements – non trading — — — — — — — 12,683 12,683 12,683 – Other financial assets at amortised cost — — — — — 506 — — 506 506 Financial assets at FVOCI — — 4,363 4,363 — 1,488 — — 1,488 5,851 Interests in other entities — — — — — — — 201 201 201 Intangible assets — — — — — — — 1,545 1,545 1,545 Property, plant and equipment — — — — — — 1,548 — 1,548 1,548 Current tax assets — — — — — — — 347 347 347 Retirement benefit assets — — — — — — — 1,572 1,572 1,572 Other assets — — — — — — — 1,577 1,577 1,577 Total assets 15,713 3,720 6,521 25,954 81,542 122,525 20,441 36,636 261,144 287,098 2020 Cash and balances at central banks (1)(2) — — 985 985 854 39,411 — — 40,265 41,250 Financial assets at FVTPL: — – Derivative financial instruments — — — — — — — 3,406 3,406 3,406 – Other financial assets at FVTPL — — — — — — — 208 208 208 Financial assets at amortised cost: — – Loans and advances to customers 23,669 7,469 184 31,322 61,292 74,758 19,801 21,577 177,428 208,750 – Loans and advances to banks — — 804 804 — — — 878 878 1,682 – 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 — — 5,581 5,581 — 3,369 — — 3,369 8,950 Interests in other entities — — — — — — — 172 172 172 Intangible assets — — — — — — — 1,646 1,646 1,646 Property, plant and equipment — — — — — — 1,734 — 1,734 1,734 Current tax assets — — — — — — — 264 264 264 Retirement benefit assets — — — — — — — 495 495 495 Other assets — — — — — — — 3,013 3,013 3,013 Total assets 23,669 7,469 8,202 39,340 62,146 118,053 21,535 51,258 252,992 292,332 (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	2021 2020 £m £m CET1 capital 10,820 11,057 AT1 capital 2,119 2,281 Tier 1 capital 12,939 13,338 Tier 2 capital 1,816 1,909 Total regulatory capital (1) 14,755 15,247 (1) Capital resources include a transitional IFRS 9 benefit at 31 December 2021 of £21m(2020: £73m).

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) 3,356 233 401 — (41) 3,949 Non-interest income 205 178 109 — 58 550 Total operating income 3,561 411 510 — 17 4,499 Operating expenses before credit impairment write-backs, provisions and charges (1,701) (163) (365) — (281) (2,510) Credit impairment write-backs 98 33 91 — 11 233 Provisions for other liabilities and charges (185) 4 (34) — (162) (377) Total operating credit impairment write-backs, provisions and charges (87) 37 57 — (151) (144) Profit/(loss) from continuing operations before tax 1,773 285 202 — (415) 1,845 Revenue from external customers 4,010 489 553 — (553) 4,499 Inter-segment revenue (449) (78) (43) — 570 — Total operating income 3,561 411 510 — 17 4,499 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 — 5 79 Total fee and commission income 570 10 112 — 5 697 Fee and commission expense (380) — (22) — (9) (411) Net fee and commission income/(expense) 190 10 90 — (4) 286 Customer loans 183,023 4,984 16,997 — 2,284 207,288 Total assets (3) 190,629 8,873 16,997 — 70,599 287,098 Customer deposits 156,991 — 25,597 — 3,627 186,215 Total liabilities 157,622 1,173 25,613 — 86,588 270,996 Average number of full-time equivalent staff 16,149 670 2,281 528 76 19,704 (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) 2,753 264 363 — 8 3,388 Non-interest income 245 127 94 — (2) 464 Total operating income/(expense) 2,998 391 457 — 6 3,852 Operating expenses before credit impairment losses, provisions and charges (1,792) (166) (324) — (108) (2,390) Credit impairment losses (264) (44) (294) — (36) (638) Provisions for other liabilities and charges (157) (8) (6) — (93) (264) Total operating credit impairment losses, provisions and charges (421) (52) (300) — (129) (902) Profit/(loss) from continuing operations before tax 785 173 (167) — (231) 560 Revenue from external customers 3,669 501 549 — (867) 3,852 Inter-segment revenue (671) (110) (92) — 873 — Total operating income/(expense) 2,998 391 457 — 6 3,852 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 — 2 65 Total fee and commission income 576 10 92 — 2 680 Fee and commission expense (335) — (22) — (4) (361) Net fee and commission income 241 10 70 — (2) 319 Customer loans 175,380 8,025 17,626 2,784 3,196 207,011 Total assets (3) 183,154 11,143 17,626 2,784 77,625 292,332 Customer deposits 152,167 — 24,985 6,506 2,049 185,707 Total liabilities 152,687 2,397 25,011 6,517 89,784 276,396 Average number of full-time equivalent staff 18,198 640 2,405 716 39 21,998 2019 Net interest income 2,581 246 422 — (25) 3,224 Non-interest income 531 155 109 — 16 811 Total operating income 3,112 401 531 — (9) 4,035 Operating expenses before credit impairment losses, provisions and charges (1,860) (179) (334) — (66) (2,439) Credit impairment (losses)/write-backs (129) (27) (45) — 2 (199) Provisions for other liabilities and charges (273) (8) (24) — (121) (426) Total operating credit impairment losses, provisions and (charges)/releases (402) (35) (69) — (119) (625) Profit/(loss) from continuing operations before tax 850 187 128 — (194) 971 Revenue from external customers 3,748 525 633 — (871) 4,035 Inter-segment revenue (636) (124) (102) — 862 — Total operating income 3,112 401 531 — (9) 4,035 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 — 18 129 Total fee and commission income 899 13 108 — 18 1,038 Fee and commission expense (372) — (24) — (18) (414) Net fee and commission income 527 13 84 — 0 624 Customer loans 171,078 7,684 18,391 4,041 3,814 205,008 Total assets (3) 178,665 10,748 18,391 4,046 69,852 281,702 Customer deposits 142,735 — 20,546 6,102 2,332 171,715 Total liabilities 143,570 2,748 20,572 6,233 92,562 265,685 Average number of full-time equivalent staff 19,669 612 2,464 804 21 23,570 (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) 4,619 4,745 5,130 Loans and advances to banks 52 49 137 Reverse repurchase agreements – non trading 35 118 244 Other 56 119 306 Total interest and similar income (1) 4,762 5,031 5,817 Interest expense and similar charges: Deposits by customers (430) (1,011) (1,540) Deposits by banks (25) (28) (102) Repurchase agreements – non trading (3) (43) (126) Debt securities in issue (252) (440) (678) Subordinated liabilities (92) (111) (137) Other (11) (10) (10) Total interest expense and similar charges (2) (813) (1,643) (2,593) Net interest income 3,949 3,388 3,224 (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) 79 65 129 Total fee and commission income 697 680 1,038 Total fee and commission expense (411) (361) (414) Net fee and commission income 286 319 624 (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 (24) (77) (142) Net gains on financial instruments mandatorily at fair value through profit or loss (2) 46 70 Hedge ineffectiveness 13 20 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 13 112 264 145 187

Operating Expenses Before Cre_2

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 745 788 801 Performance-related payments 183 97 159 Social security costs 112 101 111 Pensions costs: – defined contribution plans 64 66 66 – defined benefit plans (2) 38 38 35 Other share-based payments — — — Other personnel costs 41 33 40 1,183 1,123 1,212 Other administration expenses 826 706 684 Depreciation, amortisation and impairment 501 561 543 Total 2,510 2,390 2,439 (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	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	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 77 — — 156 77 – deferred 8 9 15 11 23 20 Shares award – not deferred 11 3 — — 11 3 – deferred 8 8 14 11 22 19 Total discretionary bonus 183 97 29 22 212 119

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 11.2 10.0 8.0 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 0.9 1.4 1.3 Total audit fees (1) 12.1 11.4 9.3 Non-audit fees: Audit-related assurance services 0.8 0.8 0.8 Other assurance services 0.1 0.3 0.2 Other non-audit services 0.2 0.0 0.2 Total non-audit fees 1.1 1.1 1.2 (1) 2021 audit fees included £1.2m (2020: £0.8m, 2019: £0.1m) 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) 665 217 Recoveries of loans and advances, net of collection costs (17) (24) (40) Off-balance sheet exposures (See Note 29) (30) (3) 22 (233) 638 199 Provisions for other liabilities and charges (excluding off-balance sheet credit exposures) (See Note 29) 386 258 420 Provisions for residual value and voluntary termination (9) 6 6 377 264 426 144 902 625 (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 401 107 254 Adjustments in respect of prior years (24) (24) (25) Total current tax 377 83 229 Deferred tax: Charge for the year 100 34 46 Adjustments in respect of prior years 15 4 (7) Total deferred tax 115 38 39 Tax on profit from continuing operations 492 121 268 (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 26.7% (2020: 21.6%, 2019: 27.6%). 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 1,845 560 971 Tax calculated at a tax rate of 19% (2020: 19%, 2019: 19%) 351 106 184 Bank surcharge on profits 104 27 62 Non-deductible preference dividends paid 9 8 8 Non-deductible UK Bank Levy 14 19 24 Non-deductible conduct remediation, fines and penalties 6 (4) 44 Other non-deductible costs and non-taxable income 37 25 31 Effect of change in tax rate on deferred tax provision 9 6 (14) Tax relief on dividends in respect of other equity instruments (40) (40) (39) Adjustment to prior year provisions 2 (26) (32) Tax on profit from continuing operations 492 121 268 (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 264 200 Liabilities — — At 1 January 264 200 Income statement charge (including discontinued operations) (389) (96) Other comprehensive income credit 33 1 Corporate income tax paid 427 159 Other movements 12 — 347 264 Assets 347 264 Liabilities — — At 31 December 347 264
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 Tax losses carried forward Accelerated tax depreciation Other temporary differences Total £m £m £m £m £m £m £m £m At 1 January 2021 (65) (26) (99) (11) 15 38 37 (111) Income statement (charge)/credit (58) (67) — — (7) 40 (23) (115) Transfers/reclassifications — 4 (16) 1 — (10) (19) (40) Credited/(charged) to other comprehensive income — (419) 108 (2) — — — (313) At 31 December 2021 (123) (508) (7) (12) 8 68 (5) (579) At 1 January 2020 (52) (96) (58) (8) 13 17 35 (149) Income statement (charge)/credit (13) (63) — — 2 21 15 (38) Transfers/reclassifications — — 12 (1) — — (13) (2) Credited/(charged) to other comprehensive income — 133 (53) (2) — — — 78 At 31 December 2020 (65) (26) (99) (11) 15 38 37 (111)

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 0.90 0.42 0.53 281 129 164 – second interim 3.47 — 0.49 1,077 — 151 4.37 0.42 1.02 1,358 129 315

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	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 11,036 159 168 14,951 395 418 Interest rate contracts 25,148 463 485 40,160 888 542 Equity and credit contracts 1,056 161 54 1,140 123 55 Total derivatives held for trading 37,240 783 707 56,251 1,406 1,015 Derivatives held for hedging Designated as fair value hedges: Exchange rate contracts 590 39 — 789 84 6 Interest rate contracts 80,514 904 737 93,748 1,225 1,885 81,104 943 737 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 21,466 180 216 19,407 467 23 43,705 1,176 554 46,427 2,445 432 Total derivatives held for hedging 124,809 2,119 1,291 140,964 3,754 2,323 Derivative netting (1) (1,221) (1,221) (1,754) (1,754) Total derivatives 162,049 1,681 777 197,215 3,406 1,584 (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 — — 33,865 33,865 — 1,194 — 507 Interest rate contracts — 117,559 9,569 127,128 — 326 — 216 Equity and credit contracts — — 1,056 1,056 — 161 — 54 — 117,559 44,490 162,049 — 1,681 — 777 2020 Exchange rate contracts — — 42,760 42,760 — 2,457 — 833 Interest rate contracts — 144,343 8,972 153,315 — 826 — 696 Equity and credit contracts — — 1,140 1,140 — 123 — 55 — 144,343 52,872 197,215 — 3,406 — 1,584
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 44,507 4,991 80,284 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 7,669 5,137 15,168 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 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) — — 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 — 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 852 (299) (360) (Losses)/gains on hedged items attributable to hedged risks (800) 365 414 Fair value hedging ineffectiveness 52 66 54 Cash flow hedging ineffectiveness (39) (46) (46) 13 20 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 874 (834) 40 (358) 385 27 Interest rate/FX risk (22) 34 12 59 (20) 39 852 (800) 52 (299) 365 66 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 (317) 305 (12) 73 185 (179) 6 33 FX risk Net interest income/other operating income (54) 54 — (158) (42) 38 (4) 2 Interest rate/FX risk Net interest income/other operating income (541) 514 (27) (273) 782 (830) (48) 773 (912) 873 (39) (358) 925 (971) (46) 808
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 644 481 Effective portion of changes in fair value: – Interest rate risk (305) 179 – Foreign currency risk (54) (38) – Equity risk — — – Interest rate/foreign currency risk (514) 830 (873) 971 Income statement transfers – Interest rate risk (73) (33) – Foreign currency risk 158 (2) – Equity risk — — – Interest rate/foreign currency risk 273 (773) 358 (808) Balances at 31 December 129 644 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 — 80 491 (1,092) 54,118 — 1,189 892 334 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 (1,665) (46) — (44) 104 (7,309) (158) (10) (77) (73) Deposits by banks — — — — — — — — — — Debt securities in issue (2,567) (140) (114) (185) 235 (5,885) (375) (137) (239) (61) 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) 67,194 (291) (45) 198 (800) 58,019 (649) 1,038 424 365 Group 2021 2020 Change in value to calculate hedge ineffectiveness Cash flow hedge reserve Balances on cash flow hedge reserve for discontinued hedges Change in value to calculate hedge ineffectiveness Cash flow hedge reserve 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 235 (135) (2) (183) 165 1 Cash and balances at central banks 71 (79) — (2) 1 — Reverse repurchase agreements – non trading — — — (2) 1 — Deposits by banks (1) 1 — 7 (2) — Debt securities in issue — — — — — — Repurchase agreements – non trading — — — 1 (1) — FX risk: Other financial assets at FVOCI (195) (1) — 40 6 — Not applicable – highly probable forecast transactions 149 1 — 33 3 — Deposits by customers 9 9 10 (5) 14 — Deposits by banks — — — — — — Debt securities in issue 85 57 (4) (15) (60) — Repurchase agreements – non trading 6 — — (15) — — Equity risk: Other liabilities — — — — — — Interest rate/FX risk: Debt securities in issue/loans and advances to customers 410 105 (4) (569) 236 (2) Deposits by customers 93 38 — (132) 87 — Subordinated liabilities/loans and advances to customers 11 133 80 (130) 194 — 873 129 80 (972) 644 (1)

Other Financial Assets at Fai_2

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 62 86 74 99 Debt securities 111 109 185 208

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 174,712 166,714 Corporate loans 19,282 23,613 Finance leases 3,916 6,554 Secured advances — — Other unsecured loans 9,404 9,933 Accrued interest and other adjustments 452 861 Amounts due from fellow Banco Santander subsidiaries and joint ventures 3,175 2,425 Amounts due from Santander UK Group Holdings plc 6 7 Amounts due from subsidiaries — — Loans and advances to customers 210,947 210,107 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 210,094 208,750
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 (200) 1,124 1,829 (173) 1,656 Later than two years and not later than three years 771 (141) 630 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 4,382 (466) 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 £m No later than one year 31 17 Later than one year and not later than two years 27 16 Later than two years and not later than three years 21 15 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 29 133 98

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_2

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 Subsidiaries — — Joint Ventures 201 172 0 201 172
Schedule of Subsidiaries With Significant Non-Controlling Interests	2021 2020 £m £m Profit attributable to non-controlling interests 19 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	a) Goodwill Group Cost Accumulated impairment Net book value £m £m £m At 31 December 2020, 1 January 2021 and 31 December 2021 1,269 (66) 1,203
Schedule of Goodwill for Cash Generating Units	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 — 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
Disclosure of Intangible Assets	b) Other intangibles Group Accumulated Net book value Cost £m £m £m At 1 January 2021 1,304 (861) 443 Additions 84 — 84 Disposals (54) 53 (1) Charge — (158) (158) Impairment — (26) (26) At 31 December 2021 1,334 (992) 342 At 1 January 2020 1,249 (686) 563 Additions 102 — 102 Disposals (47) 47 — Charge — (197) (197) Impairment — (25) (25) At 31 December 2020 1,304 (861) 443

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 1,272 1,375 436 720 218 4,021 Additions 126 26 — 284 65 501 Disposals (420) (352) (2) (249) (29) (1,052) At 31 December 2021 978 1,049 434 755 254 3,470 Accumulated depreciation: At 1 January 2021 489 1,068 434 178 118 2,287 Charge for the year (1) 32 86 1 81 19 219 Impairment during the year 46 28 — — 23 97 Disposals (233) (325) (1) (99) (23) (681) At 31 December 2021 334 857 434 160 137 1,922 Net book value 644 192 — 595 117 1,548 Cost: At 1 January 2020 1,270 1,436 439 738 212 4,095 Additions 61 43 2 185 8 299 Disposals (59) (104) (5) (203) (2) (373) At 31 December 2020 1,272 1,375 436 720 218 4,021 Accumulated depreciation: At 1 January 2020 454 1,016 434 164 60 2,128 Charge for the year (1) 55 111 — 92 58 316 Impairment during the year 24 — — — — 24 Disposals (44) (59) — (78) — (181) At 31 December 2020 489 1,068 434 178 118 2,287 Net book value 783 307 2 542 100 1,734 (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_2

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) 185,843 185,879 Amounts due to other Santander UK Group Holdings plc subsidiaries 59 59 Amounts due to Santander UK Group Holdings plc (2) 5,874 7,883 Amounts due to fellow Banco Santander subsidiaries and joint ventures 1,150 1,314 192,926 195,135 (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. (2) Includes downstreamed funding from our immediate parent company Santander UK Group Holdings plc.

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 931 2,063 Other deposits (1) 32,507 18,519 Amounts due to Santander UK subsidiaries 3 1 33,855 20,958 (1) Includes drawdown from the TFS of £0.0bn (2020: £6.3bn) and drawdown from the TFSME of

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) 1,261 1,061 – US SEC-registered Debt Programme – Santander UK plc (2) 4,185 5,457 6,851 8,212 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 25,520 35,566 (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. (2) Restated for 2020 to reclassify £734m previously disclosed as US$1bn Senior Unsecured Notes to US SEC-registered Debt Programme - Santander UK plc 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 132 97 Other 2,057 2,240 2,189 2,337

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 34 45 75 39 4 464 Additional provisions (See Note 8) 25 72 52 52 — 80 109 390 Provisions released (See Note 8) — — — (2) (30) — (2) (34) Utilisation and other (50) (104) (98) (21) (7) (91) (98) (469) Recharge (1) — — 13 — — — — 13 At 31 December 2021 44 166 1 74 38 28 13 364 (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 1,572 495 Funded defined benefit pension scheme - deficit — (361) Unfunded pension and post-retirement medical benefits (37) (42) Total net assets 1,535 92
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 (1,264) 505 522 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) (454) (1,328) (855) Actuarial (gains)/losses arising from changes in demographic assumptions (17) 34 42 Actuarial gains arising from experience adjustments (19) (141) (42) Actuarial (gains)/losses arising from changes in financial assumptions (774) 1,940 1,377 Pension remeasurement (1,264) 505 522
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) (23) 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 20
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 (13,887) (12,158) Current service cost paid by Santander UK plc (29) (24) Current service cost paid by subsidiaries (9) (12) Current service cost paid by fellow Banco Santander subsidiaries — — 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 774 (1,940) Benefits paid 398 396 Derecognition of pension scheme liabilities arising from the sale of PSA 41 — At 31 December (12,878) (13,887)
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 13,979 12,547 Interest income 193 263 Contributions paid by employer and scheme members 246 245 Contributions paid by fellow Banco Santander subsidiaries — — Administration costs paid (8) (8) Return on plan assets (excluding amounts included in net interest expense) 454 1,328 Benefits paid (398) (396) Derecognition of pension scheme assets arising from the sale of PSA (53) — At 31 December 14,413 13,979
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 — — 291 2 291 2 D Longevity swap — — (8) 0 (8) 0 D Other — — 336 2 336 2 C 14,993 104 (580) (4) 14,413 100 2020 UK equities 40 0 — — 40 0 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 — — 309 2 309 2 D Longevity swap — 0 0 0 0 D Other — — 329 3 329 3 C 10,745 77 3,234 23 13,979 100 (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 2021 2020 Assumption Change in pension obligation at period end from £m £m Discount rate 25 bps increase (571) (662) General price inflation (1) 25 bps increase 392 365 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_2

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 37,346 42,221 37,709 43,160

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 Total Issued and fully paid share capital No. £m £m At 31 December 2020, 1 January 2021 and 31 December 2021 31,051,768,866 3,105 3,105
Summary of Share Premium	Group 2021 2020 Share premium £m £m At 1 January and 31 December 5,620 5,620

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 750 750 - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 5.18 n/a — 210 - £500m Fixed Rate Reset Perpetual AT1 Capital Securities 6.30 March 2025 500 500 - £210m Fixed Rate Reset Perpetual AT1 Capital Securities 4.25 March 2026 210 — 2,191 2,191

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	2021 2020 £m £m PSA Finance UK Limited — 162 — 162

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 35,566 2,556 2,191 97 — 40,410 41,129 3,528 2,191 137 — 46,985 Proceeds from issue of debt securities 2,872 — — — — 2,872 5,602 — — — — 5,602 Repayment of debt securities (11,910) — — — — (11,910) (11,378) — — — — (11,378) Repayment of subordinated liabilities — (4) — — — (4) — (659) — — — (659) Issue of other equity instruments — — 450 — — 450 — — — — — — Repurchase of other equity instruments — — (500) — — (500) — — — — — — Payment of lease liability — — — (25) — (25) — — — (45) — (45) Dividends paid — — — — (1,494) (1,494) — — — — (292) (292) Liability-related other changes (447) (4) — 60 — (391) (250) (10) — 5 — (255) Non-cash changes: – Unrealised foreign exchange (806) 6 — — — (800) 376 22 — — — 398 – Other changes 245 (326) 50 — 1,494 1,463 87 (325) — — 292 54 At 31 December 25,520 2,228 2,191 132 — 30,071 35,566 2,556 2,191 97 — 40,410 (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 284 550 Loans and advances to customers – securitisations and covered bonds (See Note 14) 19,432 31,138 Loans and advances to customers – other 41,936 23,655 Other financial assets at amortised cost — 648 Financial assets at fair value through other comprehensive income 4,363 5,581 Total on-balance sheet 67,595 62,557 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 931 2,063 Total on-balance sheet 931 2,063 Total off-balance sheet 17,781 30,510

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 Range of exercise prices Weighted average remaining contractual life Weighted average exercise price Weighted average remaining contractual life Weighted average exercise price 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_2

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 5,495,852 5,353,980 5,025,665 Performance-related payments (1) 5,195,722 1,458,911 3,864,965 Other fixed remuneration (pension and other allowances & non-cash benefits) 929,935 1,107,348 1,367,069 Expenses 17,097 6,772 42,526 Total remuneration 11,638,606 7,927,011 10,300,225 2021 2020 2019 Directors' and Other Key Management Personnel compensation £ £ £ Short-term employee benefits (2) 25,114,949 18,432,698 21,925,975 Post-employment benefits (3) 1,344,883 2,084,645 3,590,466 Total compensation 26,459,832 20,517,343 25,516,441 (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) One Termination payment of £346,154 was paid in 2021 to a Director (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 12 3,640 18 4,920 Net movements (6) (3,280) (6) (1,280) At 31 December 6 360 12 3,640 Deposit, bank and instant access accounts and investments At 1 January 23 8,195 32 11,975 Net movements (2) (1,643) (9) (3,780) At 31 December 21 6,552 23 8,195

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 (164) (119) (130) 33 105 266 816 1,557 (1,150) (2,151) Immediate parent (6) (7) (7) 263 316 317 7 8 (10,935) (10,121) Fellow subsidiaries (57) (58) (66) 163 157 173 159 223 (534) (559) Associates & joint ventures (34) (29) (29) 4 — — 3,075 2,234 (918) (1,034) (261) (213) (232) 463 578 756 4,057 4,022 (13,537) (13,865)

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	The following tables analyse the fair value of the financial instruments carried at amortised cost at 31 December 2021 and 2020, including their levels in the fair value hierarchy - Level 1, Level 2 and Level 3. It does not include fair value information for financial assets and financial liabilities carried at amortised cost if the carrying amount is a reasonable approximation of fair value. Cash and balances at central banks, which consist of demand deposits with the Bank of England, together with cash in tills and ATMs, have been excluded from the table as the carrying amount is deemed an appropriate approximation of fair value. The fair value of the portfolio of UK Government debt securities, included in other financial assets at amortised cost, is the only material financial instrument categorised in Level 1 of the fair value hierarchy. Group 2021 2020 Fair value Carrying Fair value Carrying Level 1 Level 2 Level 3 Fair value value Level 1 Level 2 Level 3 Fair value value £m £m £m £m £m £m £m £m £m £m Assets Loans and advances to customers — — 212,811 212,811 210,094 — — 211,279 211,279 208,750 Loans and advances to banks — 1,169 — 1,169 1,169 — 1,682 — 1,682 1,682 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 13,970 213,037 227,171 224,452 799 21,457 211,505 233,761 231,194 Liabilities Deposits by customers — 48 192,898 192,946 192,926 — 108 195,134 195,242 195,135 Deposits by banks — 33,770 85 33,855 33,855 — 20,951 16 20,967 20,958 Repurchase agreements - non trading — 11,718 — 11,718 11,718 — 15,847 — 15,847 15,848 Debt securities in issue 963 23,926 1,218 26,107 25,520 — 34,967 1,430 36,397 35,566 Subordinated liabilities 37 2,350 238 2,625 2,228 — 2,830 239 3,069 2,556 1,000 71,812 194,439 267,251 266,247 — 74,703 196,819 271,522 270,063
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 — 1,547 — 1,547 — 2,566 14 2,580 A & C Equity and credit contracts — 116 45 161 — 71 52 123 B & D Netting — (1,221) — (1,221) — (1,754) — (1,754) — 1,635 46 1,681 — 3,338 68 3,406 Other financial assets at FVTPL Loans and advances to customers — — 74 74 — — 99 99 A Debt securities — — 111 111 — — 109 109 A, B & D Equity securities — — — — — — — — B Reverse repurchase agreements – non trading — — — — — — — — A — — 185 185 — — 208 208 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 1,635 249 7,717 8,501 3,766 297 12,564 Liabilities Derivative financial instruments Exchange rate contracts — 506 — 506 — 833 — 833 A Interest rate contracts — 1,436 2 1,438 — 2,447 3 2,450 A & C Equity and credit contracts — 24 30 54 — 26 29 55 B & D Netting — (1,221) — (1,221) — (1,754) — (1,754) — 745 32 777 — 1,552 32 1,584 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 — 1,542 38 1,580 — 2,978 40 3,018
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 20 23 - Credit risk adjustment 6 11 - Funding fair value adjustment 3 3 20 29 Model-related — — Day One profit — — 20 29
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 Debt securities Credit linked notes 20 2 (5) (16) 7 6. FVOCI assets Loans and advances to customers Other loans 18 21 (3) (4) (2) 7. Derivative liabilities Equity contracts Property options and forwards (30) (29) (1) (3) — 8. FVTPL liabilities Financial guarantees Credit protection guarantee (1) (2) 6 16 (7) 217 249 (5) 11 (16) Other Level 3 assets 1 17 (1) 7 16 Other Level 3 liabilities (7) (9) 2 (1) (5) Total net assets 211 257 — — — Total income/(expense) (4) 17 (5)
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 68 208 21 — 297 (32) (8) — (40) Total (losses)/gains recognised: - Fair value movements (1) (7) (3) — (11) — 7 — 7 - Foreign exchange and other movements — — — — — — — — — Transfers in — — — — — — — — — Transfers out — — — — — — — — — Netting (1) — 23 — — 23 — (5) — (5) Additions — — — — — — — — — Sales — (16) — — (16) — — — — Settlements (21) (23) — — (44) — — — — At 31 December 2021 46 185 18 — 249 (32) (6) — (38) Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period (1) (7) (3) — (11) — 7 — 7 At 1 January 2020 75 386 56 — 517 (32) (61) — (93) Total gains/(losses) recognised: - Fair value movements 10 (1) (4) — 5 (6) 18 — 12 - Foreign exchange and other movements — (5) — — (5) — 8 — 8 Transfers in 1 — — — 1 — — — — Transfers out — — — — — — 28 — 28 Netting (1) — (42) — — (42) — — — — Additions 2 — — — 2 — (2) — (2) Sales — (19) (19) — (38) — — — — Settlements (20) (111) (12) — (143) 6 1 — 7 At 31 December 2020 68 208 21 — 297 (32) (8) — (40) Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period 10 (6) (4) — — (6) 26 — 20 (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) 6. FVOCI - Loans and advances to customers: 18 Credit spreads 0.15% - 0.19% 0.04 % 20 % — — – Other loans 7. 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) 6. FVOCI - Loans and advances to customers: 21 Credit spreads 0.15% - 0.53% 0.32 % 20 % — — – Other loans 7. 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	The table below analyses the maturities of the undiscounted cash flows relating to financial liabilities and off-balance sheet commitments of Santander UK based on the remaining period to the contractual maturity date at the balance sheet date. Deposits by customers largely consist of retail deposits. This table is not intended to show the liquidity of Santander UK. 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 — 74 58 389 288 809 Other financial liabilities at fair value through profit or loss — 6 8 553 236 803 Deposits by customers 177,926 3,107 4,691 5,750 1,583 193,057 Deposits by banks 1,377 551 41 31,986 — 33,955 Repurchase agreements – non trading — 11,419 299 — — 11,718 Debt securities in issue — 4,993 2,725 11,921 6,552 26,191 Subordinated liabilities — 32 98 1,547 2,020 3,697 Lease liabilities — — 32 78 31 141 Total financial liabilities 179,303 20,182 7,952 52,224 10,710 270,371 Off-balance sheet commitments given 20,519 5,359 5,734 5,523 574 37,709 2020 Financial liabilities Derivative financial instruments — 279 133 582 638 1,632 Other financial liabilities at fair value through profit or loss — 1 107 570 759 1,437 Deposits by customers 176,911 3,443 5,453 7,483 2,273 195,563 Deposits by banks 2,410 1,912 2,596 14,230 212 21,360 Repurchase agreements – non trading — 15,350 500 — — 15,850 Debt securities in issue — 4,993 9,897 14,083 7,540 36,513 Subordinated liabilities — 30 92 1,515 2,424 4,061 Lease liabilities — — 17 56 36 109 Total financial liabilities 179,321 26,008 18,795 38,519 13,882 276,525 Off-balance sheet commitments given 21,054 4,493 4,974 11,493 1,146 43,160

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	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 Assets not subject to enforceable netting arrangements (2) Effects of offsetting on balance sheet Related amounts not offset 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 2,832 (1,221) 1,611 (754) (693) 164 72 1,683 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⁾ 4,251 (923) 3,328 — — 3,328 207,935 211,263 21,965 (4,343) 17,622 (1,189) (12,941) 3,492 208,007 225,629 Liabilities Derivative financial liabilities 1,955 (1,221) 734 (754) 59 39 43 777 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⁾ 8,609 (923) 7,686 — — 7,686 219,095 226,781 24,481 (4,343) 20,138 (1,189) (11,224) 7,725 219,138 239,276 2020 Assets Derivative financial assets 5,071 (1,754) 3,317 (782) (1,840) 695 89 3,406 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⁾ 7,454 (1,073) 6,381 — — 6,381 204,051 210,432 38,609 (9,312) 29,297 (911) (21,310) 7,076 204,140 233,437 Liabilities Derivative financial liabilities 3,261 (1,754) 1,507 (782) (551) 174 77 1,584 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⁾ 11,159 (1,073) 10,086 — (502) 9,584 206,007 216,093 36,753 (9,312) 27,441 (911) (16,772) 9,758 206,084 233,525 (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 (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	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) — 1,480 — 1,480 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 1,561 1 2,943 Liabilities Derivatives (1)(2) 338 1,831 — 2,169 Other financial liabilities at fair value through profit and loss — 5 — 5 Financial liabilities at amortised cost (4) 34 185 — 219 372 2,021 — 2,393 Off-balance sheet commitments given 338 59 — 397 2020 Assets Derivatives (1)(2) 33,486 4,514 2,149 40,149 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 49,944 5,727 2,239 57,910 Liabilities Derivatives (1)(2) 35,217 5,205 88 40,510 Other financial liabilities at fair value through profit and loss 1,129 69 — 1,198 Financial liabilities at amortised cost 2,354 1,319 — 3,673 38,700 6,593 88 45,381 Off-balance sheet commitments given 11,400 2,126 573 14,099 (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. Group Group 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 32 55 68 Net fee and commission income 35 66 63 Other operating income 2 2 8 Total operating income 69 123 139 Operating expenses before credit impairment losses, provisions and charges (33) (62) (60) Credit impairment losses 11 (7) (22) Provisions for other liabilities and charges (4) (9) (16) Total operating credit impairment losses, provisions and charges 7 (16) (38) Profit from discontinued operations before tax 43 45 41 Tax on profit from discontinued operations (12) (13) (11) Profit from discontinued operations after tax 31 32 30

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 - 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%	0.10%
Bank of England base rate, 2020	0.10%	0.25%
Bank of England base rate, 2021	0.25%	0.75%
Bank of England base rate, 2022	0.75%	1.25%
Bank of England base rate, 2023	0.75%	1.75%
Bank of England base rate, 2024	1.25%	3.70%
Bank of England base rate, 2025	1.75%	(4.60%)
House price growth, 2020	6.90%	(4.10%)
House price growth, 2021	5.40%	2.40%
House price growth, 2022	(0.80%)	5.50%
House price growth, 2023	(2.00%)	6.30%
House price growth, 2024	1.00%	6.10%
House price growth, 2025	3.80%	5.30%
Unemployment rate, 2020	5.20%	4.40%
Unemployment rate, 2021	4.40%	4.10%
Unemployment rate, 2022	4.40%
Unemployment rate, 2023	4.20%
Unemployment rate, 2024	3.90%
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%	0.10%
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%	0.25%
Bank of England base rate, 2024	0.75%	3.50%
Bank of England base rate, 2025	0.75%	(2.00%)
House price growth, 2020	6.90%	1.50%
House price growth, 2021	5.00%	2.00%
House price growth, 2022	2.00%	2.00%
House price growth, 2023	2.00%	6.80%
House price growth, 2024	2.00%	7.50%
House price growth, 2025	2.00%	6.20%
Unemployment rate, 2020	5.20%	5.60%
Unemployment rate, 2021	4.70%	5.50%
Unemployment rate, 2022	4.50%
Unemployment rate, 2023	4.40%
Unemployment rate, 2024	4.30%
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%	0.10%
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%	0.25%
Bank of England base rate, 2024	1.00%	3.70%
Bank of England base rate, 2025	1.00%	(5.40%)
House price growth, 2020	6.90%	(6.60%)
House price growth, 2021	5.40%	(1.80%)
House price growth, 2022	(1.80%)	0.50%
House price growth, 2023	(4.60%)	6.30%
House price growth, 2024	(3.10%)	6.50%
House price growth, 2025	(0.70%)	6.10%
Unemployment rate, 2020	5.20%	5.70%
Unemployment rate, 2021	4.40%	5.80%
Unemployment rate, 2022	4.80%
Unemployment rate, 2023	5.00%
Unemployment rate, 2024	5.10%
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%	0.10%
Bank of England base rate, 2020	0.10%	0.75%
Bank of England base rate, 2021	0.25%	1.75%
Bank of England base rate, 2022	1.00%	3.00%
Bank of England base rate, 2023	2.00%	2.75%
Bank of England base rate, 2024	3.00%	3.70%
Bank of England base rate, 2025	2.75%	(11.30%)
House price growth, 2020	6.90%	(14.50%)
House price growth, 2021	5.40%	(3.80%)
House price growth, 2022	(8.30%)	4.90%
House price growth, 2023	(13.10%)	6.30%
House price growth, 2024	(4.80%)	8.50%
House price growth, 2025	4.30%	7.90%
Unemployment rate, 2020	5.20%	6.90%
Unemployment rate, 2021	4.40%	6.50%
Unemployment rate, 2022	6.90%
Unemployment rate, 2023	6.90%
Unemployment rate, 2024	6.40%
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%	0.10%
Bank of England base rate, 2020	0.10%	(0.50%)
Bank of England base rate, 2021	0.25%	0.00%
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%	3.50%
Bank of England base rate, 2025	0.00%	(19.70%)
House price growth, 2020	6.90%	(8.20%)
House price growth, 2021	(2.50%)	1.30%
House price growth, 2022	(19.60%)	3.10%
House price growth, 2023	(9.30%)	6.80%
House price growth, 2024	2.40%	11.40%
House price growth, 2025	3.30%	8.70%
Unemployment rate, 2020	5.20%	8.00%
Unemployment rate, 2021	6.80%	7.40%
Unemployment rate, 2022	11.40%
Unemployment rate, 2023	8.70%
Unemployment rate, 2024	8.00%
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	£ 423	£ 803
Individually assessed	101	160
PMAs	341	414
Total ECL	865	1,377
Retail Banking
Disclosure of credit risk exposure [line items]
Modelled ECL	264	472
Individually assessed	1	3
PMAs	123	113
Total ECL	388	588
Homes
Disclosure of credit risk exposure [line items]
Modelled ECL	119	220
Individually assessed	1	3
PMAs	70	57
Total ECL	190	280
Everyday Banking
Disclosure of credit risk exposure [line items]
Modelled ECL	145	252
Individually assessed	0	0
PMAs	53	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
Disclosure of credit risk exposure [line items]
Individually assessed	100	157
Minimum | Stage 3
Disclosure of credit risk exposure [line items]
ECL under reasonably possible judgements	38
Maximum | Stage 3
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	£ 210,094	£ 208,750
Homes
Disclosure of credit risk exposure [line items]
Exposure	174,712	166,730
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	313,347	322,745
ECL	£ 865	£ 1,377
Proportion of assets in Stage 2	5.20%	5.30%
Weighted | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 212,395	£ 201,990
ECL	£ 388	£ 588
Proportion of assets in Stage 2	5.50%	5.40%
Weighted | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 190,663	£ 180,006
ECL - of which: mortgages	£ 190	£ 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	£ 21,984
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	£ 70,963	£ 76,345
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	£ 313,347	£ 322,745
ECL	£ 740	£ 1,129
Proportion of assets in Stage 2	4.90%	4.60%
Upside 1 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 212,395	£ 201,990
ECL	£ 307	£ 495
Proportion of assets in Stage 2	5.20%	4.50%
Upside 1 | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 190,663	£ 180,006
ECL - of which: mortgages	£ 134	£ 212
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	£ 21,984
ECL	£ 173	£ 283
Proportion of assets in Stage 2	2.30%	2.40%
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	£ 70,963	£ 76,345
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	£ 313,347	£ 322,745
ECL	£ 738	£ 1,222
Proportion of assets in Stage 2	4.90%	4.70%
Base case | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 212,395	£ 201,990
ECL	£ 286	£ 470
Proportion of assets in Stage 2	5.20%	4.60%
Base case | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 190,663	£ 180,006
ECL - of which: mortgages	£ 125	£ 207
Proportion of assets in Stage 2 - of which: mortgages	5.50%	4.90%
Base case | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 21,732	£ 21,984
ECL	£ 161	£ 263
Proportion of assets in Stage 2	2.10%	2.10%
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	£ 70,963	£ 76,345
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	£ 313,347	£ 322,745
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	£ 212,395	£ 201,990
ECL	£ 375	£ 544
Proportion of assets in Stage 2	5.40%	4.70%
Downside 1 | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 190,663	£ 180,006
ECL - of which: mortgages	£ 177	£ 253
Proportion of assets in Stage 2 - of which: mortgages	5.70%	4.90%
Downside 1 | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 21,732	£ 21,984
ECL	£ 198	£ 291
Proportion of assets in Stage 2	3.00%	2.60%
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	£ 70,963	£ 76,345
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	£ 313,347	£ 322,745
ECL	£ 1,123	£ 1,612
Proportion of assets in Stage 2	6.20%	6.60%
Downside 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 212,395	£ 201,990
ECL	£ 510	£ 730
Proportion of assets in Stage 2	6.60%	7.20%
Downside 2 | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 190,663	£ 180,006
ECL - of which: mortgages	£ 283	£ 389
Proportion of assets in Stage 2 - of which: mortgages	6.90%	7.70%
Downside 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 21,732	£ 21,984
ECL	£ 227	£ 341
Proportion of assets in Stage 2	3.50%	3.30%
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	£ 70,963	£ 76,345
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	£ 313,347	£ 322,745
ECL	£ 1,288	£ 1,802
Proportion of assets in Stage 2	7.00%	6.80%
Downside 3 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 212,395	£ 201,990
ECL	£ 662	£ 740
Proportion of assets in Stage 2	7.70%	7.20%
Downside 3 | Homes
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 190,663	£ 180,006
ECL - of which: mortgages	£ 437	£ 415
Proportion of assets in Stage 2 - of which: mortgages	8.20%	7.50%
Downside 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 21,732	£ 21,984
ECL	£ 225	£ 325
Proportion of assets in Stage 2	3.00%	4.90%
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	£ 70,963	£ 76,345
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	£ (11,224)	£ (16,772)
Netting	(1,189)	(911)
Net exposure	313,347	322,745
Credit risk
Disclosure of credit risk exposure [line items]
Collateral cash	(100)	(200)
Collateral non-cash	(211,500)	(215,700)
Netting	(400)	(100)
Net exposure	104,200	108,700
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	48,100	41,300
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
Balance sheet asset | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	278,500	281,600
Balance sheet asset | Credit risk | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	279,400	282,900
Balance sheet asset | Credit risk | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(900)	(1,300)
Balance sheet asset | Credit risk | Cash and balances at central banks
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	48,100	41,300
Balance sheet asset | Credit risk | Cash and balances at central banks | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	48,100	41,300
Balance sheet asset | Credit risk | Cash and balances at central banks | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Balance sheet asset | Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	5,900	9,000
Balance sheet asset | Credit risk | Financial assets at FVOCI | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	5,900	9,000
Balance sheet asset | Credit risk | Financial assets at FVOCI | Loss allowance
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 | Loss allowance
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 | Loss allowance
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 | Loss allowance
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	(211,500)	(215,700)
Netting	(400)	(100)
Net exposure	50,200	58,400
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	(199,300)	(196,200)
Netting	0	0
Net exposure	48,000	54,500
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	(177,800)	(170,000)
Netting	0	0
Net exposure	12,700	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	9,600	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	500	900
Financial assets at amortised cost | Credit risk | Loans and advances to customers | Other unsecured loans
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	22,600	22,900
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	3,200	2,400
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	1,600	2,700
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 | Balance sheet asset | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	224,500	231,300
Financial assets at amortised cost | Balance sheet asset | Credit risk | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	225,400	232,600
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(900)	(1,300)
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	210,100	208,800
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Loans secured on residential properties
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	174,500	166,400
Financial assets at amortised cost | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Credit risk | Loans and advances to customers | Accrued interest and other adjustments
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	500	900
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Other unsecured loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	9,200	9,600
Financial assets at amortised cost | Balance sheet asset | 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	3,200	2,400
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	211,000	210,100
Financial assets at amortised cost | Balance sheet asset | 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	174,700	166,700
Financial assets at amortised cost | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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	500	900
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Gross amounts | Other unsecured loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	9,400	9,900
Financial assets at amortised cost | Balance sheet asset | 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	3,200	2,400
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(900)	(1,300)
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Loss allowance | Loans secured on residential properties
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(200)	(300)
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Loss allowance | Corporate loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(400)	(600)
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Loss allowance | Finance leases
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(100)	(100)
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Loss allowance | Accrued interest and other adjustments
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Loss allowance | Other unsecured loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(200)	(300)
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to customers | Loss allowance | 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 | Balance sheet asset | Credit risk | Loans and advances to banks
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	1,200	1,700
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to banks | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	1,200	1,700
Financial assets at amortised cost | Balance sheet asset | Credit risk | Loans and advances to banks | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Credit risk | Reverse repurchase agreements – non trading | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Financial assets at amortised cost | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Credit risk | Other financial assets at amortised cost | Loss allowance
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 | Loss allowance
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	7,600	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 loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	13,400	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	7,600	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 loans
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	13,400	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 | Loss allowance
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 | Loss allowance | 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 | Loss allowance | 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 | Loss allowance | 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 | Loss allowance | 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 | Loss allowance | Other unsecured loans
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 | Loss allowance | 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 | Loss allowance
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 | Loss allowance
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 | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Loans and advances to customers | 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	0	0
Loans and advances to customers | Balance sheet asset | Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Loans and advances to customers | Balance sheet asset | Credit risk | Financial assets at FVOCI | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Loans and advances to customers | Balance sheet asset | Credit risk | Financial assets at FVOCI | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Loans and advances to customers | Off-balance sheet | Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	0	0
Loans and advances to customers | 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
Loans and advances to customers | Off-balance sheet | Credit risk | Financial assets at FVOCI | Loss allowance
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 | Balance sheet asset | Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	5,900	9,000
Debt securities | Balance sheet asset | 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 | Balance sheet asset | Credit risk | Financial assets at FVOCI | Loss allowance
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 | Loss allowance
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	£ (11,224)	£ (16,772)
Netting	(1,189)	(911)
Net exposure	313,347	322,745
Credit risk
Disclosure of credit risk exposure [line items]
Collateral cash	(100)	(200)
Collateral non-cash	(211,500)	(215,700)
Netting	(400)	(100)
Net exposure	104,200	108,700
Financial assets at fair value through profit loss | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	1,900	3,600
Collateral cash	0	0
Collateral non-cash	(700)	(1,800)
Netting	(800)	(800)
Net exposure	400	1,000
Derivative financial instruments | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	1,700	3,400
Collateral cash	0	0
Collateral non-cash	(700)	(1,800)
Netting	(800)	(800)
Net exposure	200	800
Other financial assets at FVTPL | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	200	200
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	£ 200	£ 200

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 | Santander UK risk grade 9
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.01%
Mid | Santander UK risk grade 8
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.032%
Mid | Santander UK risk grade 7
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.10%
Mid | Santander UK risk grade 6
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.316%
Mid | Santander UK risk grade 5
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	1.00%
Mid | Santander UK risk grade 4
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	3.162%
Mid | Santander UK risk grade 3
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	10.00%
Mid | Santander UK risk grade 2
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	31.623%
Mid | Santander UK risk grade 1
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	100.00%
Lower | Santander UK risk grade 9
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.00%
Lower | Santander UK risk grade 8
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.021%
Lower | Santander UK risk grade 7
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.066%
Lower | Santander UK risk grade 6
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.208%
Lower | Santander UK risk grade 5
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.658%
Lower | Santander UK risk grade 4
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	2.081%
Lower | Santander UK risk grade 3
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	6.581%
Lower | Santander UK risk grade 2
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	20.811%
Lower | Santander UK risk grade 1
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	100.00%
Upper | Santander UK risk grade 9
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.021%
Upper | Santander UK risk grade 8
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.066%
Upper | Santander UK risk grade 7
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.208%
Upper | Santander UK risk grade 6
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0.658%
Upper | Santander UK risk grade 5
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	2.081%
Upper | Santander UK risk grade 4
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	6.581%
Upper | Santander UK risk grade 3
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	20.811%
Upper | Santander UK risk grade 2
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	99.999%
Upper | 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	£ 316,200	£ 324,700
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	£ 71,200	£ 68,500
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	£ 42,100	£ 43,300
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	£ 93,600	£ 86,000
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	£ 55,400	£ 55,400
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	£ 17,300	£ 18,600
Coverage	1.20%	0.50%
Internal grade 5 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
Internal grade 4 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 11,500	£ 28,600
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	9.20%	11.50%
Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 600	£ 1,000
Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 19,500	£ 17,000
Coverage	0.00%	0.00%
Other | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	278,500	281,600
Loss allowance	£ (900)	£ (1,300)
Coverage	0.30%	0.50%
Balance sheet asset | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 900	£ 1,300
Balance sheet asset | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	224,500	231,300
Loss allowance	£ (900)	£ (1,300)
Coverage	0.40%	0.60%
Balance sheet asset | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 174,500	£ 166,400
Loss allowance	£ (200)	£ (300)
Coverage	0.10%	0.20%
Balance sheet asset | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 900	£ 1,300
Balance sheet asset | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	200	300
Balance sheet asset | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	48,100	41,300
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Balance sheet asset | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	210,100	208,800
Loss allowance	£ (900)	£ (1,300)
Coverage	0.40%	0.40%
Balance sheet asset | 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
Balance sheet asset | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	1,200	1,700
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Balance sheet asset | Loans and advances to banks | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | 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%
Balance sheet asset | Reverse repurchase agreements – non trading | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 9 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 71,100	£ 68,100
Coverage	0.00%	0.00%
Balance sheet asset | Internal grade 9 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | 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%
Balance sheet asset | 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%
Balance sheet asset | Internal grade 9 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 9 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
Balance sheet asset | Internal grade 9 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 48,100	£ 41,300
Coverage	0.00%	0.00%
Balance sheet asset | Internal grade 9 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | Internal grade 9 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 8 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 34,900	£ 34,500
Coverage	0.00%	0.00%
Balance sheet asset | Internal grade 8 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 8 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 32,800	£ 31,100
Coverage	0.00%	0.00%
Balance sheet asset | Internal grade 8 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 29,700	£ 24,300
Coverage	0.00%	0.00%
Balance sheet asset | Internal grade 8 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 8 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
Balance sheet asset | 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%
Balance sheet asset | Internal grade 8 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | 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	£ 32,500	£ 27,700
Coverage	0.00%	0.00%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | Internal grade 8 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 7 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 86,600	£ 76,500
Coverage	0.00%	0.00%
Balance sheet asset | Internal grade 7 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 7 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 86,400	£ 76,300
Coverage	0.00%	0.00%
Balance sheet asset | Internal grade 7 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 79,300	£ 68,000
Coverage	0.00%	0.00%
Balance sheet asset | Internal grade 7 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 7 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
Balance sheet asset | 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%
Balance sheet asset | Internal grade 7 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | 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	£ 84,500	£ 74,400
Coverage	0.00%	0.00%
Balance sheet asset | 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
Balance sheet asset | 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	£ 800	£ 400
Coverage	0.00%	0.00%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | Internal grade 7 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 6 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 48,600	£ 46,600
Coverage	0.00%	0.20%
Balance sheet asset | Internal grade 6 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
Balance sheet asset | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 48,600	£ 46,500
Coverage	0.00%	0.20%
Balance sheet asset | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 42,500	£ 36,800
Coverage	0.00%	0.00%
Balance sheet asset | Internal grade 6 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 100
Balance sheet asset | Internal grade 6 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
Balance sheet asset | 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%
Balance sheet asset | Internal grade 6 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | 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	£ 48,000	£ 44,100
Coverage	0.00%	0.20%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | Internal grade 6 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 5 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 12,800	£ 13,500
Coverage	1.60%	0.70%
Balance sheet asset | Internal grade 5 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
Balance sheet asset | Internal grade 5 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 12,800	£ 13,500
Coverage	1.60%	0.70%
Balance sheet asset | Internal grade 5 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 6,400	£ 5,600
Coverage	0.00%	0.00%
Balance sheet asset | Internal grade 5 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
Balance sheet asset | Internal grade 5 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
Balance sheet asset | 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%
Balance sheet asset | Internal grade 5 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | 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	£ 12,800	£ 13,500
Coverage	1.60%	0.70%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | Internal grade 5 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 4 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,200	£ 27,000
Coverage	1.00%	0.70%
Balance sheet asset | Internal grade 4 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
Balance sheet asset | Internal grade 4 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,200	£ 27,000
Coverage	1.00%	0.70%
Balance sheet asset | Internal grade 4 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 4,700	£ 19,600
Coverage	2.10%	0.50%
Balance sheet asset | Internal grade 4 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
Balance sheet asset | Internal grade 4 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	100	100
Balance sheet asset | 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%
Balance sheet asset | Internal grade 4 | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | 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	£ 27,000
Coverage	1.00%	0.70%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | Internal grade 4 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 3 to 1 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 6,000	£ 8,200
Coverage	10.00%	11.00%
Balance sheet asset | Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 600	£ 900
Balance sheet asset | 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	10.00%	11.00%
Balance sheet asset | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 3,100	£ 4,500
Coverage	3.20%	4.40%
Balance sheet asset | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 600	£ 900
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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	10.00%	11.00%
Balance sheet asset | 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	£ 600	£ 900
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | Internal grade 3 to 1 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 9,200	£ 8,500
Coverage	0.00%	0.00%
Balance sheet asset | Other | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Other | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 9,200	£ 8,500
Coverage	0.00%	0.00%
Balance sheet asset | 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%
Balance sheet asset | Other | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Other | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	0	0
Balance sheet asset | 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%
Balance sheet asset | Other | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Other | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 8,000	£ 7,200
Coverage	0.00%	0.00%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | 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%
Balance sheet asset | 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
Balance sheet asset | Other | Financial assets at FVOCI | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage	0.00%	0.00%
Balance sheet asset | 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	£ 7,200	£ 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	£ 0	£ 100
Off-balance sheet | Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 10,300	£ 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 | Balance sheet asset | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	161,800	154,600
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	48,100	41,300
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	191,600	189,900
Loss allowance	£ (100)	£ (200)
Coverage	0.10%	0.10%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | Loans and advances to banks | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	1,200	1,700
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Internal grade 9 | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 48,100	£ 41,300
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Internal grade 9 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | Internal grade 8 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 29,500	£ 24,300
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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	£ 31,700	£ 27,600
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Internal grade 8 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | Internal grade 7 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 78,000	£ 67,700
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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	£ 83,100	£ 74,000
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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	£ 800	£ 400
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Internal grade 7 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 39,600	£ 35,500
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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	£ 44,900	£ 42,600
Coverage	0.00%	0.20%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Internal grade 6 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | Internal grade 5 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 4,100	£ 3,900
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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	£ 10,000	£ 10,800
Coverage	1.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Internal grade 5 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | Internal grade 4 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 1,600	£ 14,700
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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	£ 19,000
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Internal grade 4 | Financial assets at FVOCI | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | Internal grade 3 to 1 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 600
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 1 | Balance sheet asset | Other | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | Other | Cash and balances at central banks | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Balance sheet asset | Other | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 7,400	£ 7,000
Coverage	0.00%	0.00%
Stage 1 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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	£ 6,900	£ 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	£ 10,300	£ 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 | Balance sheet asset | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	11,000	10,100
Loss allowance	£ (100)	£ (200)
Coverage	0.90%	2.00%
Stage 2 | Balance sheet asset | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 200
Stage 2 | Balance sheet asset | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	16,000	16,600
Loss allowance	£ (400)	£ (500)
Coverage	2.50%	3.00%
Stage 2 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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	£ 1,400	£ 400
Coverage	0.00%	0.00%
Stage 2 | Balance sheet asset | 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 | Balance sheet asset | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 2,900	£ 1,300
Coverage	0.00%	0.00%
Stage 2 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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	3.60%	3.70%
Stage 2 | Balance sheet asset | 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	£ 100
Stage 2 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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	7.10%	4.80%
Stage 2 | Balance sheet asset | 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	£ 200	£ 200
Stage 2 | Balance sheet asset | 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 | Balance sheet asset | Other | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 2 | Balance sheet asset | 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 | Balance sheet asset | 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	£ 0	£ 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 | Balance sheet asset | 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 | Balance sheet asset | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 100
Stage 3 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | 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 | Balance sheet asset | Other | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 3 | Balance sheet asset | 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 | Balance sheet asset | 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	£ 210,094	£ 208,750
Exposures	313,347	322,745
Loss allowances	828	1,303
Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	207,300	207,000
Gross write- offs	191	253
Loss allowances	865	1,377
Loans to customers | Undrawn Balances
Disclosure of credit risk exposure [line items]
Loans and advances to customers	37,700	43,200
Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposures	187,900	187,100
Loans to customers | Stage 1 | Undrawn Balances
Disclosure of credit risk exposure [line items]
Exposures	36,100	41,800
Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	16,500	17,000
Loans to customers | Stage 2 | Undrawn Balances
Disclosure of credit risk exposure [line items]
Exposures	1,500	1,300
Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposures	2,900	2,900
Loans to customers | Stage 3 | Undrawn Balances
Disclosure of credit risk exposure [line items]
Exposures	100	100
Retail Banking | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	183,000	175,400
Gross write- offs	108	155
Loss allowances	388	588
Retail Banking | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposures	169,200	162,600
Retail Banking | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	11,700	10,900
Retail Banking | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposures	2,100	1,900
Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	174,712	166,730
Homes | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	174,700	166,700
Gross write- offs	5	14
Loss allowances	190	280
Homes | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposures	161,800	154,600
Homes | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	11,100	10,300
Homes | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposures	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 allowances	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 allowances	198	308
Everyday Banking | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposures	7,400	8,000
Everyday Banking | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	600	600
Everyday Banking | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposures	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 allowances	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 allowances	52	118
Consumer Finance | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposures	4,800	7,600
Consumer Finance | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	200	400
Consumer Finance | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposures	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 allowances	423	603
Corporate & Commercial Banking | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposures	11,800	11,100
Corporate & Commercial Banking | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	4,400	5,500
Corporate & Commercial Banking | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposures	800	1,000
Corporate Centre | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,300	3,200
Gross write- offs	0	0
Loss allowances	2	35
Corporate Centre | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposures	2,100	3,200
Corporate Centre | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	200	0
Corporate Centre | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposures	£ 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 allowances		33
Corporate & Investment Banking | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposures		2,600
Corporate & Investment Banking | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposures		200
Corporate & Investment Banking | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposures		£ 0
Corporate loans | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure ratio	90.65%	90.34%
Corporate loans | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure ratio	7.93%	8.26%
Corporate loans | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure ratio	1.45%	1.45%

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]
Exposures	£ 313,347	£ 322,745
Loss allowances	828	1,303
Loss allowance	364	464
Total ECL	£ 865	£ 1,377
Coverage	0.30%	0.40%
Retail mortgage offers in pipeline	£ 10,600	£ 7,700
Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	275,638	279,585
Loss allowances	£ 828	£ 1,302
Coverage	0.30%	0.50%
Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 37,709	£ 43,160
Loss allowance	£ 37	£ 75
Coverage	0.10%	0.20%
Customer loans | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 207,300	£ 207,000
Loans and advances to banks | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	1,200	1,700
Sovereign assets measured at amortized cost | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	13,200	20,800
Financial assets measured at fair value through other comprehensive income | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	5,900	9,000
Cash and balances at central banks | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	48,100	41,300
Retail Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	183,023	175,380
Loss allowances	£ 367	£ 550
Coverage	0.20%	0.30%
Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 29,372	£ 26,610
Loss allowance	£ 21	£ 38
Coverage	0.10%	0.10%
Homes | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 174,712	£ 166,730
Loss allowances	£ 185	£ 277
Coverage	0.10%	0.20%
Homes | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 15,951	£ 13,276
Loss allowance	£ 5	£ 3
Coverage	0.00%	0.00%
Everyday Banking
Disclosure of credit risk exposure [line items]
Loss allowances	£ 198	£ 308
Everyday Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	8,311	8,650
Loss allowances	£ 182	£ 273
Coverage	2.20%	3.20%
Everyday Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 13,421	£ 13,334
Loss allowance	£ 16	£ 35
Coverage	0.10%	0.30%
Consumer Finance
Disclosure of credit risk exposure [line items]
Loss allowances	£ 52	£ 118
Consumer Finance | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	4,984	8,024
Loss allowances	£ 52	£ 118
Coverage	1.00%	1.50%
Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 314	£ 237
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Corporate & Commercial Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 16,997	£ 17,626
Loss allowances	£ 407	£ 577
Coverage	2.40%	3.30%
Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 7,694	£ 6,877
Loss allowance	£ 16	£ 26
Coverage	0.20%	0.40%
Corporate Centre | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 70,634	£ 75,770
Loss allowances	£ 2	£ 35
Coverage	0.00%	0.00%
Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 329	£ 575
Corporate & Investment Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures		2,785
Loss allowances		£ 22
Coverage		0.80%
Corporate & Investment Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures		£ 8,861
Loss allowance		£ 11
Coverage		0.10%
Stage 1
Disclosure of credit risk exposure [line items]
Exposures	292,366	£ 301,413
Total ECL	£ 132	£ 216
Coverage	0.00%	0.10%
Stage 1 | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 256,254	£ 259,625
Loss allowances	£ 115	£ 186
Coverage	0.00%	0.10%
Stage 1 | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 36,112	£ 41,788
Loss allowance	£ 17	£ 30
Coverage	0.00%	0.10%
Stage 1 | Retail Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 169,255	£ 162,541
Loss allowances	£ 52	£ 56
Coverage	0.00%	0.00%
Stage 1 | Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 29,123	£ 26,313
Loss allowance	£ 12	£ 18
Coverage	0.00%	0.10%
Stage 1 | Homes | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 161,845	£ 154,586
Loss allowances	£ 8	£ 15
Coverage	0.00%	0.00%
Stage 1 | Homes | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 15,851	£ 13,180
Loss allowance	£ 5	£ 2
Coverage	0.00%	0.00%
Stage 1 | Everyday Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 7,410	£ 7,955
Loss allowances	£ 44	£ 41
Coverage	0.60%	0.50%
Stage 1 | Everyday Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 13,272	£ 13,133
Loss allowance	£ 7	£ 16
Coverage	0.10%	0.10%
Stage 1 | Consumer Finance | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 4,760	£ 7,587
Loss allowances	£ 18	£ 44
Coverage	0.40%	0.60%
Stage 1 | Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 314	£ 237
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 1 | Corporate & Commercial Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 11,812	£ 11,167
Loss allowances	£ 43	£ 46
Coverage	0.40%	0.40%
Stage 1 | Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 6,392	£ 6,050
Loss allowance	£ 5	£ 8
Coverage	0.10%	0.10%
Stage 1 | Corporate Centre | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 70,427	£ 75,743
Loss allowances	£ 2	£ 35
Coverage	0.00%	0.00%
Stage 1 | Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 283	£ 558
Stage 1 | Corporate & Investment Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures		2,587
Loss allowances		£ 5
Coverage		0.20%
Stage 1 | Corporate & Investment Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures		£ 8,630
Loss allowance		£ 4
Coverage		0.00%
Stage 2
Disclosure of credit risk exposure [line items]
Exposures	17,964	£ 18,336
Total ECL	£ 330	£ 592
Coverage	1.80%	3.20%
Stage 2 | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 16,448	£ 17,064
Loss allowances	£ 314	£ 556
Coverage	1.90%	3.30%
Stage 2 | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 1,516	£ 1,272
Loss allowance	£ 16	£ 36
Coverage	1.10%	2.80%
Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 11,850	£ 11,218
Coverage	1.60%	3.00%
Stage 2 | Retail Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 11,646	£ 10,962
Loss allowances	£ 178	£ 313
Coverage	1.50%	2.90%
Stage 2 | Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 204	£ 256
Loss allowance	£ 8	£ 19
Coverage	3.90%	7.40%
Stage 2 | Homes | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 11,071	£ 10,345
Loss allowances	£ 88	£ 130
Coverage	0.80%	1.30%
Stage 2 | Homes | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 81	£ 82
Loss allowance	£ 0	£ 1
Coverage	0.00%	1.20%
Stage 2 | Everyday Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 575	£ 617
Loss allowances	£ 90	£ 183
Coverage	15.70%	29.70%
Stage 2 | Everyday Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 123	£ 174
Loss allowance	£ 8	£ 18
Coverage	6.50%	10.30%
Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 200	£ 379
Coverage	8.50%	9.80%
Stage 2 | Consumer Finance | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 200	£ 379
Loss allowances	£ 17	£ 37
Coverage	8.50%	9.80%
Stage 2 | Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 5,661	£ 6,266
Coverage	2.20%	3.20%
Stage 2 | Corporate & Commercial Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 4,395	£ 5,498
Loss allowances	£ 119	£ 189
Coverage	2.70%	3.40%
Stage 2 | Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 1,266	£ 768
Loss allowance	£ 8	£ 10
Coverage	0.60%	1.30%
Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 253	£ 44
Coverage	0.00%	0.00%
Stage 2 | Corporate Centre | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 207	£ 27
Loss allowances	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 2 | Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 46	£ 17
Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 429
Coverage	0.00%	5.60%
Stage 2 | Corporate & Investment Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures		£ 198
Loss allowances		£ 17
Coverage		8.60%
Stage 2 | Corporate & Investment Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures		£ 231
Loss allowance		£ 7
Coverage		3.00%
Stage 3
Disclosure of credit risk exposure [line items]
Exposures	£ 3,017	£ 2,996
Total ECL	£ 403	£ 569
Coverage	13.40%	19.00%
Stage 3 | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 2,936	£ 2,896
Loss allowances	£ 399	£ 560
Coverage	13.60%	19.30%
Stage 3 | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 81	£ 100
Loss allowance	£ 4	£ 9
Coverage	4.90%	9.00%
Stage 3 | Retail Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 2,122	£ 1,877
Loss allowances	£ 137	£ 181
Coverage	6.50%	9.60%
Stage 3 | Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 45	£ 41
Loss allowance	£ 1	£ 1
Coverage	2.20%	2.40%
Stage 3 | Homes | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 1,796	£ 1,799
Loss allowances	£ 89	£ 132
Coverage	5.00%	7.30%
Stage 3 | Homes | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 19	£ 14
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Everyday Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 326	£ 78
Loss allowances	£ 48	£ 49
Coverage	14.70%	62.80%
Stage 3 | Everyday Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 26	£ 27
Loss allowance	£ 1	£ 1
Coverage	3.80%	3.70%
Stage 3 | Consumer Finance | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 24	£ 58
Loss allowances	£ 17	£ 37
Coverage	70.80%	63.80%
Stage 3 | Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 826	£ 1,020
Stage 3 | Corporate & Commercial Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	790	961
Loss allowances	£ 245	£ 342
Coverage	31.00%	35.60%
Stage 3 | Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 36	£ 59
Loss allowance	£ 3	£ 8
Coverage	8.30%	13.60%
Stage 3 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 2	£ 0
Stage 3 | Corporate Centre | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	0	0
Loss allowances	£ 0	£ 0
Coverage	0.00%	0.00%
Stage 3 | Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Stage 3 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures		0
Stage 3 | Corporate & Investment Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures		0
Loss allowances		£ 0
Coverage		0.00%
Stage 3 | Corporate & Investment Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures		£ 0
Loss allowance		£ 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]
Exposures	£ 313,347	£ 322,745
Coverage	0.30%	0.40%
Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 17,964	£ 18,336
ECL	£ 330	£ 592
Coverage	1.80%	3.20%
Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 11,850	£ 11,218
ECL	£ 186	£ 332
Coverage	1.60%	3.00%
Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 200	£ 379
ECL	£ 17	£ 37
Coverage	8.50%	9.80%
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 5,661	£ 6,266
ECL	£ 127	£ 199
Coverage	2.20%	3.20%
Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 429
ECL	£ 0	£ 24
Coverage	0.00%	5.60%
Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 253	£ 44
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
PD deterioration | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 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]
Exposures	£ 5,644	£ 7,752
ECL	£ 125	£ 247
Coverage	2.20%	3.20%
PD deterioration | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 42	£ 88
ECL	£ 6	£ 13
Coverage	14.30%	14.80%
PD deterioration | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 1,522	£ 2,128
ECL	£ 20	£ 39
Coverage	1.30%	1.80%
PD deterioration | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
PD deterioration | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 214	£ 32
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Forbearance | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 947	£ 767
ECL	£ 14	£ 9
Coverage	1.50%	1.20%
Forbearance | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 664	£ 612
ECL	£ 4	£ 3
Coverage	0.60%	0.50%
Forbearance | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 11	£ 0
ECL	£ 2	£ 0
Coverage	18.20%	0.00%
Forbearance | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 272	£ 151
ECL	£ 8	£ 6
Coverage	2.90%	4.00%
Forbearance | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Forbearance | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 4
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Other | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 1,131	£ 2,450
ECL	£ 28	£ 111
Coverage	2.50%	4.50%
Other | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 556	£ 1,155
ECL	£ 5	£ 10
Coverage	0.90%	0.90%
Other | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 130	£ 249
ECL	£ 4	£ 11
Coverage	3.10%	4.40%
Other | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 445	£ 612
ECL	£ 19	£ 66
Coverage	4.30%	10.80%
Other | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 429
ECL	£ 0	£ 24
Coverage	0.00%	5.60%
Other | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 5
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
30 DPD | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 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]
Exposures	£ 745	£ 870
ECL	£ 33	£ 46
Coverage	4.40%	5.30%
30 DPD | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 17	£ 27
ECL	£ 5	£ 12
Coverage	29.40%	44.40%
30 DPD | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 313	£ 250
ECL	£ 2	£ 5
Coverage	0.60%	2.00%
30 DPD | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
30 DPD | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 39	£ 3
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Payment holiday | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 844
ECL	£ 0	£ 27
Coverage	0.00%	3.20%
Payment holiday | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 829
ECL	£ 0	£ 26
Coverage	0.00%	3.10%
Payment holiday | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 15
ECL	£ 0	£ 1
Coverage	0.00%	6.70%
Payment holiday | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Payment holiday | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Payment holiday | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Mortgages affordability | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 4,241	£ 0
ECL	£ 19	£ 0
Coverage	0.40%	0.00%
Mortgages affordability | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 4,241	£ 0
ECL	£ 19	£ 0
Coverage	0.40%	0.00%
Mortgages affordability | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Mortgages affordability | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Mortgages affordability | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
Mortgages affordability | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
High risk corporate | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 3,109	£ 3,125
ECL	£ 78	£ 83
Coverage	2.50%	2.70%
High risk corporate | Stage 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
High risk corporate | Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
High risk corporate | Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 3,109	£ 3,125
ECL	£ 78	£ 83
Coverage	2.50%	2.70%
High risk corporate | Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
ECL	£ 0	£ 0
Coverage	0.00%	0.00%
High risk corporate | Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 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]
Exposures	£ 313,347	£ 322,745
Coverage	0.30%	0.40%
Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 17,964	£ 18,336
ECL	£ 330	£ 592
Coverage	1.80%	3.20%
Stage 2 not in cure period | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 13,302	£ 16,992
ECL	£ 286	£ 554
Coverage	2.20%	3.30%
Stage 2 in cure period (for transfer to Stage 1) | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 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]
Exposures	£ 313,347	£ 322,745
Loss allowances	828	1,303
Assets classified at FVTPL	173	195
Total assets	287,098	292,332	£ 281,702
Loss allowance	364	464
Retail Banking
Disclosure of credit risk exposure [line items]
Total assets	190,629	183,154	178,665
Everyday Banking
Disclosure of credit risk exposure [line items]
Loss allowances	198	308
Consumer Finance
Disclosure of credit risk exposure [line items]
Loss allowances	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	70,599	77,625	69,852
Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Total assets	0	2,784	£ 4,046
Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	275,638	279,585
Loss allowances	828	1,302
Net carrying amount	274,810	278,283
Other items	3,632	3,111
Adjusted net carrying amount	278,442	281,394
Assets classified at FVTPL	1,866	3,614
Non-financial assets	6,790	7,324
Total assets	287,098	292,332
Balance sheet asset | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	183,023	175,380
Loss allowances	367	550
Net carrying amount	182,656	174,830
Balance sheet asset | Homes
Disclosure of credit risk exposure [line items]
Exposures	174,712	166,730
Loss allowances	185	277
Net carrying amount	174,527	166,453
Balance sheet asset | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposures	8,311	8,650
Loss allowances	182	273
Net carrying amount	8,129	8,377
Balance sheet asset | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	4,984	8,024
Loss allowances	52	118
Net carrying amount	4,932	7,906
Balance sheet asset | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	16,997	17,626
Loss allowances	407	577
Net carrying amount	16,590	17,049
Balance sheet asset | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	70,634	75,770
Loss allowances	2	35
Net carrying amount	70,632	75,735
Balance sheet asset | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures		2,785
Loss allowances		22
Net carrying amount		2,763
Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	37,709	43,160
Loss allowance	37	75
Off-balance sheet | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	29,372	26,610
Loss allowance	21	38
Off-balance sheet | Homes
Disclosure of credit risk exposure [line items]
Exposures	15,951	13,276
Loss allowance	5	3
Off-balance sheet | Everyday Banking
Disclosure of credit risk exposure [line items]
Exposures	13,421	13,334
Loss allowance	16	35
Off-balance sheet | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	314	237
Loss allowance	0	0
Off-balance sheet | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	7,694	6,877
Loss allowance	16	26
Off-balance sheet | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	329	575
Loss allowance	£ 0	0
Off-balance sheet | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures		8,861
Loss allowance		£ 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	865	£ 1,377
Less: Recoveries net of collection costs	17	24		£ 40
Total ECL charge/(release) to the Income Statement	(233)	638	[1]	199	[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	156
Redemptions, repayments and assets sold	(205)	(90)
Changes in risk parameters and other movements	21	133
Assets written off	(191)	(253)
Ending balance	865	1,377		863
Net movement in the period	(512)	514
ECL charge/(release) to the Income Statement	(321)	767
Less: Discount unwind	(11)	(14)
Less: Recoveries net of collection costs	88	(108)
ECL charge/(release) to the Income Statement from continued operations	(244)	645
Discontinued operations ECL adjustment	11	(7)
Total ECL charge/(release) to the Income Statement	(233)	638
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	132	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	322,745	310,155
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	57,021
Redemptions, repayments and assets sold	(67,619)	(53,434)
Changes in risk parameters and other movements	6,695	9,398
Assets written off	(297)	(395)
Ending balance	313,347	322,745		310,155
Net movement in the period	(9,398)	12,590
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	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	(62)	88
Assets written off	0	0
Ending balance	132	216		147
Net movement in the period	(84)	69
ECL charge/(release) to the Income Statement	(84)	69
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	(84)	69
Discontinued operations ECL adjustment	11	0
Total ECL charge/(release) to the Income Statement	(73)	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	301,413	295,436
Transfers from Stage 1 to Stage 2	(6,805)	(9,815)
Transfers from Stage 2 to Stage 1	5,883	3,178
Transfers to Stage 3	(571)	(385)
Transfers from Stage 3	14	12
Transfers of financial instruments	(1,479)	(7,010)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	50,862	55,546
Redemptions, repayments and assets sold	(63,658)	(50,698)
Changes in risk parameters and other movements	5,228	8,141
Assets written off	0	(2)
Ending balance	292,366	301,413		295,436
Net movement in the period	(9,047)	5,977
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	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	18,336	12,351
Transfers from Stage 1 to Stage 2	6,805	9,815
Transfers from Stage 2 to Stage 1	(5,883)	(3,178)
Transfers to Stage 3	(532)	(1,126)
Transfers from Stage 3	456	326
Transfers of financial instruments	846	5,837
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	1,371
Redemptions, repayments and assets sold	(3,442)	(2,295)
Changes in risk parameters and other movements	1,288	1,072
Assets written off	0	0
Ending balance	17,964	18,336		12,351
Net movement in the period	(372)	5,985
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	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	52
Redemptions, repayments and assets sold	(68)	(18)
Changes in risk parameters and other movements	63	98
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	88	(108)
ECL charge/(release) to the Income Statement from continued operations	102	332
Discontinued operations ECL adjustment	0	(7)
Total ECL charge/(release) to the Income Statement	102	325
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	2,368
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	1,103	1,511
Transfers from Stage 3	(470)	(338)
Transfers of financial instruments	633	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	25	104
Redemptions, repayments and assets sold	(519)	(441)
Changes in risk parameters and other movements	179	185
Assets written off	(297)	(393)
Ending balance	3,017	2,996		£ 2,368
Net movement in the period	£ 21	£ 628
[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]
Exposures	£ 313,347	£ 322,745
Governments
Disclosure of credit risk exposure [line items]
Exposures	50,100	46,000
Banks
Disclosure of credit risk exposure [line items]
Exposures	4,700	7,600
Other
Disclosure of credit risk exposure [line items]
Exposures	15,000	22,600
Retail
Disclosure of credit risk exposure [line items]
Exposures	215,100	206,100
Corporate
Disclosure of credit risk exposure [line items]
Exposures	28,900	42,200
Total
Disclosure of credit risk exposure [line items]
Exposures	313,800	324,500
Eurozone | Netherlands
Disclosure of credit risk exposure [line items]
Exposures	200	600
Eurozone | Belgium
Disclosure of credit risk exposure [line items]
Exposures	700	900
Eurozone | Governments
Disclosure of credit risk exposure [line items]
Exposures	400	500
Eurozone | Governments | Ireland
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Governments | Italy
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Governments | Spain
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Governments | France
Disclosure of credit risk exposure [line items]
Exposures	100	100
Eurozone | Governments | Germany
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Governments | Luxembourg
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Governments | Other
Disclosure of credit risk exposure [line items]
Exposures	300	400
Eurozone | Banks
Disclosure of credit risk exposure [line items]
Exposures	1,500	2,400
Eurozone | Banks | Ireland
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Banks | Italy
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Banks | Spain
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Banks | France
Disclosure of credit risk exposure [line items]
Exposures	300	500
Eurozone | Banks | Germany
Disclosure of credit risk exposure [line items]
Exposures	400	700
Eurozone | Banks | Luxembourg
Disclosure of credit risk exposure [line items]
Exposures	0	100
Eurozone | Banks | Other
Disclosure of credit risk exposure [line items]
Exposures	800	1,100
Eurozone | Other
Disclosure of credit risk exposure [line items]
Exposures	5,600	7,600
Eurozone | Other | Ireland
Disclosure of credit risk exposure [line items]
Exposures	5,300	6,000
Eurozone | Other | Italy
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Other | Spain
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Other | France
Disclosure of credit risk exposure [line items]
Exposures	200	200
Eurozone | Other | Germany
Disclosure of credit risk exposure [line items]
Exposures	0	100
Eurozone | Other | Luxembourg
Disclosure of credit risk exposure [line items]
Exposures	100	1,300
Eurozone | Other | Other
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Retail
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Retail | Ireland
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Retail | Italy
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Retail | Spain
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Retail | France
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Retail | Germany
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Retail | Luxembourg
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Retail | Other
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Corporate
Disclosure of credit risk exposure [line items]
Exposures	100	800
Eurozone | Corporate | Ireland
Disclosure of credit risk exposure [line items]
Exposures	0	100
Eurozone | Corporate | Italy
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Corporate | Spain
Disclosure of credit risk exposure [line items]
Exposures	100	100
Eurozone | Corporate | France
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Corporate | Germany
Disclosure of credit risk exposure [line items]
Exposures	0	100
Eurozone | Corporate | Luxembourg
Disclosure of credit risk exposure [line items]
Exposures	0	100
Eurozone | Corporate | Other
Disclosure of credit risk exposure [line items]
Exposures	0	400
Eurozone | Total
Disclosure of credit risk exposure [line items]
Exposures	7,600	11,300
Eurozone | Total | Ireland
Disclosure of credit risk exposure [line items]
Exposures	5,300	6,100
Eurozone | Total | Italy
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Total | Spain
Disclosure of credit risk exposure [line items]
Exposures	100	100
Eurozone | Total | France
Disclosure of credit risk exposure [line items]
Exposures	600	800
Eurozone | Total | Germany
Disclosure of credit risk exposure [line items]
Exposures	400	900
Eurozone | Total | Luxembourg
Disclosure of credit risk exposure [line items]
Exposures	100	1,500
Eurozone | Total | Other
Disclosure of credit risk exposure [line items]
Exposures	1,100	1,900
Other countries | Switzerland
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Governments | Other
Disclosure of credit risk exposure [line items]
Exposures	300	300
Other countries | Governments | UK
Disclosure of credit risk exposure [line items]
Exposures	47,900	42,000
Other countries | Governments | US
Disclosure of credit risk exposure [line items]
Exposures	500	800
Other countries | Governments | Japan
Disclosure of credit risk exposure [line items]
Exposures	1,000	2,400
Other countries | Governments | Switzerland
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Governments | Denmark
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Banks | Other
Disclosure of credit risk exposure [line items]
Exposures	200	500
Other countries | Banks | UK
Disclosure of credit risk exposure [line items]
Exposures	2,000	2,800
Other countries | Banks | US
Disclosure of credit risk exposure [line items]
Exposures	800	900
Other countries | Banks | Japan
Disclosure of credit risk exposure [line items]
Exposures	200	1,000
Other countries | Banks | Switzerland
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Banks | Denmark
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Other | Other
Disclosure of credit risk exposure [line items]
Exposures	100	100
Other countries | Other | UK
Disclosure of credit risk exposure [line items]
Exposures	9,300	14,800
Other countries | Other | US
Disclosure of credit risk exposure [line items]
Exposures	0	100
Other countries | Other | Japan
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Other | Switzerland
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Other | Denmark
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Retail | Other
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Retail | UK
Disclosure of credit risk exposure [line items]
Exposures	215,100	206,100
Other countries | Retail | US
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Retail | Japan
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Retail | Switzerland
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Retail | Denmark
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Corporate | Other
Disclosure of credit risk exposure [line items]
Exposures	100	700
Other countries | Corporate | UK
Disclosure of credit risk exposure [line items]
Exposures	28,700	40,400
Other countries | Corporate | US
Disclosure of credit risk exposure [line items]
Exposures	0	300
Other countries | Corporate | Japan
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Corporate | Switzerland
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Corporate | Denmark
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Total | Other
Disclosure of credit risk exposure [line items]
Exposures	700	1,600
Other countries | Total | UK
Disclosure of credit risk exposure [line items]
Exposures	303,000	306,100
Other countries | Total | US
Disclosure of credit risk exposure [line items]
Exposures	1,300	2,100
Other countries | Total | Japan
Disclosure of credit risk exposure [line items]
Exposures	1,200	3,400
Other countries | Total | Denmark
Disclosure of credit risk exposure [line items]
Exposures	0	0
All countries excluding Eurozone countries | Governments
Disclosure of credit risk exposure [line items]
Exposures	49,700	45,500
All countries excluding Eurozone countries | Banks
Disclosure of credit risk exposure [line items]
Exposures	3,200	5,200
All countries excluding Eurozone countries | Other
Disclosure of credit risk exposure [line items]
Exposures	9,400	15,000
All countries excluding Eurozone countries | Retail
Disclosure of credit risk exposure [line items]
Exposures	215,100	206,100
All countries excluding Eurozone countries | Corporate
Disclosure of credit risk exposure [line items]
Exposures	28,800	41,400
All countries excluding Eurozone countries | Total
Disclosure of credit risk exposure [line items]
Exposures	£ 306,200	£ 313,200

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
Financial liabilities	13.5	13.9
Spain
Disclosure of detailed information about financial instruments [line items]
Financial assets	0.8	1.6
Financial liabilities	1.3	2.3
UK
Disclosure of detailed information about financial instruments [line items]
Financial assets	3.3	2.4
Financial liabilities	12.1	11.5
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	0.8	1.6
Financial liabilities	1.3	2.3
Banks | Spain
Disclosure of detailed information about financial instruments [line items]
Financial assets	0.8	1.6
Financial liabilities	1.2	2.2
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	3.3	2.4
Financial liabilities	12.2	11.6
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	3.3	2.4
Financial liabilities	12.1	11.5
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	865	£ 1,377
Less: Recoveries net of collection costs	17	24		£ 40
Total ECL charge/(release) to the Income Statement	(233)	638	[1]	199	[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)	36		(2)
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	132	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	301,413	295,436
Transfers from Stage 1 to Stage 2	(6,805)	(9,815)
Transfers from Stage 2 to Stage 1	5,883	3,178
Transfers to Stage 3	(571)	(385)
Transfers from Stage 3	14	12
Transfers of financial instruments	(1,479)	(7,010)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	50,862	55,546
Redemptions, repayments and assets sold	(63,658)	(50,698)
Changes in risk parameters and other movements	5,228	8,141
Assets written off	0	(2)
Ending balance	292,366	301,413		295,436
Net movement in the period	(9,047)	5,977
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	188,854	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)	(26,727)
Changes in risk parameters and other movements	4,146	1,177
Assets written off	0	0
Ending balance	198,378	188,854		186,088
Net movement in the period	9,524	2,766
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	167,766	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	(25,072)	(23,707)
Changes in risk parameters and other movements	3,606	(459)
Assets written off	0	0
Ending balance	177,696	167,766		168,830
Net movement in the period	9,930	(1,064)
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	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	76,301	67,779
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	(5,327)	(10,342)
Changes in risk parameters and other movements	(548)	7,389
Assets written off	0	0
Ending balance	70,710	76,301		67,779
Net movement in the period	(5,591)	8,522
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	18,336	12,351
Transfers from Stage 1 to Stage 2	6,805	9,815
Transfers from Stage 2 to Stage 1	(5,883)	(3,178)
Transfers to Stage 3	(532)	(1,126)
Transfers from Stage 3	456	326
Transfers of financial instruments	846	5,837
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	1,371
Redemptions, repayments and assets sold	(3,442)	(2,295)
Changes in risk parameters and other movements	1,288	1,072
Assets written off	0	0
Ending balance	17,964	18,336		12,351
Net movement in the period	(372)	5,985
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	11,218	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)	(1,031)
Changes in risk parameters and other movements	423	310
Assets written off	0	0
Ending balance	11,850	11,218		8,872
Net movement in the period	632	2,346
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	10,427	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	(1,436)	(899)
Changes in risk parameters and other movements	270	270
Assets written off	0	0
Ending balance	11,152	10,427		8,224
Net movement in the period	725	2,203
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	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	44	94
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)	(9)
Changes in risk parameters and other movements	93	(65)
Assets written off	0	0
Ending balance	253	44		94
Net movement in the period	209	(50)
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	2,368
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	1,103	1,511
Transfers from Stage 3	(470)	(338)
Transfers of financial instruments	633	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	25	104
Redemptions, repayments and assets sold	(519)	(441)
Changes in risk parameters and other movements	179	185
Assets written off	(297)	(393)
Ending balance	3,017	2,996		2,368
Net movement in the period	21	628
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	6
Redemptions, repayments and assets sold	(361)	(314)
Changes in risk parameters and other movements	89	109
Assets written off	(129)	(203)
Ending balance	2,167	1,918		1,859
Net movement in the period	249	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	(331)	(297)
Changes in risk parameters and other movements	11	24
Assets written off	(16)	(54)
Ending balance	1,815	1,813		1,734
Net movement in the period	2	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	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	0	(3)
Changes in risk parameters and other movements	0	1
Assets written off	0	(2)
Ending balance	0	0		0
Net movement in the period	0	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	322,745	310,155
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	57,021
Redemptions, repayments and assets sold	(67,619)	(53,434)
Changes in risk parameters and other movements	6,695	9,398
Assets written off	(297)	(395)
Ending balance	313,347	322,745		310,155
Net movement in the period	(9,398)	12,590
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	201,990	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	31,850
Redemptions, repayments and assets sold	(29,992)	(28,072)
Changes in risk parameters and other movements	4,658	1,596
Assets written off	(129)	(203)
Ending balance	212,395	201,990		196,819
Net movement in the period	10,405	5,171
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	180,006	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	(26,839)	(24,903)
Changes in risk parameters and other movements	3,887	(165)
Assets written off	(16)	(54)
Ending balance	190,663	180,006		178,788
Net movement in the period	10,657	1,218
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	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	76,345	67,873
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	(5,354)	(10,354)
Changes in risk parameters and other movements	(455)	7,325
Assets written off	0	(2)
Ending balance	70,963	76,345		67,873
Net movement in the period	(5,382)	8,472
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 | 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	(62)	88
Assets written off	0	0
Ending balance	132	216		147
Net movement in the period	(84)	69
ECL charge/(release) to the Income Statement	(84)	69
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(73)	69
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	74	59
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)	(78)
Change in economic scenarios	(6)	7
Changes to model	0	0
New lending and assets purchased	19	15
Redemptions, repayments and assets sold	(14)	(12)
Changes in risk parameters and other movements	(10)	11
Assets written off	0	0
Ending balance	64	74		59
Net movement in the period	(10)	15
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 | 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	(19)	(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	13	17		14
Net movement in the period	(4)	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 | 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 | 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 | 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	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 | 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	(3)
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	1	1
Redemptions, repayments and assets sold	(17)	(1)
Changes in risk parameters and other movements	(17)	34
Assets written off	0	0
Ending balance	2	35		1
Net movement in the period	(33)	34
ECL charge/(release) to the Income Statement	(33)	34
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(33)	34
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	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 | 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 | 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	232
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	144
Change in economic scenarios	(86)	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	(7)	(53)
Assets written off	(1)	0
Ending balance	186	332		232
Net movement in the period	(146)	100
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 | 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	15
Transfers of financial instruments	(8)	(11)
Net ECL remeasurement on stage transfer	10	49
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)	29
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	(43)	29
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	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 | 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 | 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	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 | 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 | 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 | 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	52
Redemptions, repayments and assets sold	(68)	(18)
Changes in risk parameters and other movements	63	98
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	88	(108)
Total ECL charge/(release) to the Income Statement	102	325
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	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)	10
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	101
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 | 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)	(15)
Transfers of financial instruments	(9)	(1)
Net ECL remeasurement on stage transfer	9	17
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 | 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 | 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 | 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	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 | 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	0	(1)
Changes in risk parameters and other movements	0	0
Assets written off	0	0
Ending balance	0	0		0
Net movement in the period	0	0
ECL charge/(release) to the Income Statement	0	0
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	22	4
Total ECL charge/(release) to the Income Statement	22	4
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	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	156
Redemptions, repayments and assets sold	(205)	(90)
Changes in risk parameters and other movements	21	133
Assets written off	(191)	(253)
Ending balance	865	1,377		863
Net movement in the period	(512)	514
ECL charge/(release) to the Income Statement	(321)	767
Less: Discount unwind	(11)	(14)
Less: Recoveries net of collection costs	88	(108)
Total ECL charge/(release) to the Income Statement	(233)	638
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)	108
Change in economic scenarios	(104)	98
Changes to model	0	25
New lending and assets purchased	37	49
Redemptions, repayments and assets sold	(57)	(57)
Changes in risk parameters and other movements	47	59
Assets written off	(109)	(155)
Ending balance	388	588		461
Net movement in the period	(200)	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	0	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	190	280		218
Net movement in the period	(90)	62
ECL charge/(release) to the Income Statement	(84)	75
Less: Discount unwind	(2)	(2)
Less: Recoveries net of collection costs	(1)	(1)
Total ECL charge/(release) to the Income Statement	(87)	72
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	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	1
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)	28
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	4
Total ECL charge/(release) to the Income Statement	(11)	37
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	£ 174,712	£ 166,730
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	£ 74,657	£ 71,008
Percentage of residential mortgage loans	42.00%	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	£ 50,645	£ 50,934
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	£ 34,517	£ 33,180
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	9.00%	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	£ 29,800	£ 31,600
>£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	£ 174,712	£ 166,730
Percentage of residential mortgage loans	100.00%	100.00%
Fixed rate
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 147,147	£ 133,231
Percentage of residential mortgage loans	84.00%	80.00%
Variable rate
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 17,010	£ 20,986
Percentage of residential mortgage loans	10.00%	13.00%
Standard Variable Rate (SVR)
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 7,836	£ 10,627
Percentage of residential mortgage loans	4.00%	6.00%
Follow on Rate (FoR)
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 2,719	£ 1,886
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	£ 174,712	£ 166,730
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	44,600	41,800
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	23,800	22,500
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	23,100	22,600
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	55,500	52,500
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	18,100	17,500
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	£ 100,141	£ 94,330
UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	174,712	166,730
£0.25m | South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	44,431	44,790
£0.25m | UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	103,657	103,785
£0.25m to £0.50m | South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	38,749	35,487
£0.25m to £0.50m | UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	51,699	46,914
£0.50m to £1.0m | South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	13,820	11,942
£0.50m to £1.0m | UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	15,972	13,763
£1.0m to £2.0m | South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	2,823	1,875
£1.0m to £2.0m | UK
Disclosure of credit risk exposure [line items]
Residential mortgage loans	3,053	2,024
>£2.0m | South East including London
Disclosure of credit risk exposure [line items]
Residential mortgage loans	318	236
>£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	£ 174,712	£ 166,730
Collateral value of residential properties, stock	174,637	166,623
Loan-to-value, stage 3	1,796	1,799
Collateral value of residential properties, stage 3	1,784	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	190	280
Loan-to-value, stage 3	89	132
Up to 50%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	78,911	73,489
Loan-to-value, stage 3	942	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	77,781	68,324
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	62	89
Loan-to-value, stage 3	28	36
>75-85%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	13,866	18,113
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	3,626	6,070
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	528	734
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	78
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	£ 210,094	£ 208,750
Loss allowances	828	1,303
Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	174,712	166,730
Everyday Banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	8,311	8,650
Loss allowances	£ 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 allowances	£ 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 allowances	47	80
Everyday Banking | Credit cards
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,341	2,349
Loss allowances	89	158
Everyday Banking | Overdrafts
Disclosure of credit risk exposure [line items]
Loans and advances to customers	438	408
Loss allowances	40	61
Everyday Banking | Other unsecured loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	4,779	4,795
Loss allowances	£ 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 loans
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 allowances	£ 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	24,535	24,680
Loss allowances	423	603
Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	62,259	58,129
Loss allowances	2	35
Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		12,347
Loss allowances		33
Credit risk | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	174,712	166,730
Loss allowances	£ 190	£ 280
Stage 1 ratio	92.64%	92.72%
Stage 2 ratio	6.34%	6.20%
Stage 3 ratio	1.04%	1.09%
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	5,509	5,082
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	56,112	50,962
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	1,364	712
Loss allowances	0	0
Financial Institutions | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,461
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
Large Corporate | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		10,886
Loss allowances		33
Stage 1 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	161,845	154,586
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 loans
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	17,930	17,393
Stage 1 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	62,002	58,084
Stage 1 | Credit risk | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	161,845	154,586
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	11,071	10,345
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 loans
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	5,779	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	11,071	10,345
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 1,796	£ 1,799
Stage 3 ratio	1.04%	1.09%
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 loans
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	1,796	1,799
Fully performing | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	20,464	20,044
Fully performing | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	62,257	58,060
Fully performing | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		10,835
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	5,344	5,009
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	56,112	50,962
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	1,364	712
Fully performing | Financial Institutions | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,461
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 | Large Corporate | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		9,374
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 | 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 | 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 | 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	£ 422	£ 305
Net modification loss	9	7
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period		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 loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period	£ 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	£ 604	£ 628
Term extension	518	476
Interest-only	346	396
Concessionary interest rate	115	28
Total(2)	1,583	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]
Total(2)	£ 56	£ 63
Consumer Finance
Disclosure of credit risk exposure [line items]
Total(2)	0	9
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Capitalisation	204	180
Term extension	150	141
Interest-only	239	175
Total(2)	£ 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
Total(2)		£ 23
Proportion of portfolio		0.20%
Stage 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Total(2)	£ 20	£ 13
Stage 1 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Total(2)		0
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Capitalisation	387	409
Term extension	444	393
Interest-only	273	310
Concessionary interest rate	4	0
Total(2)	1,108	1,112
Loss allowances	12	13
Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	10	15
Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Total(2)	0	4
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Total(2)	303	179
Stage 2 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Total(2)		23
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Capitalisation	217	219
Term extension	74	83
Interest-only	73	86
Concessionary interest rate	111	28
Total(2)	475	416
Loss allowances	26	29
Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	46	48
Stage 3 | Consumer Finance
Disclosure of credit risk exposure [line items]
Total(2)	0	5
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Total(2)	270	304
Stage 3 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Total(2)		0
Business banking | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	2	4
Business banking | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	0	0
Business banking | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	2	4
Personal loans | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	1	0
Personal loans | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	0	0
Personal loans | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	1	0
Credit cards | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	38	43
Credit cards | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	7	10
Credit cards | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	31	33
Overdrafts | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	15	16
Overdrafts | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	3	5
Overdrafts | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	12	11
Total other unsecured | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	54	59
Total other unsecured | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	10	15
Total other unsecured | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Total(2)	£ 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	£ 422	£ 305
Net modification loss	9	7
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period		0
Other loans | Homes
Disclosure of credit risk exposure [line items]
Amortised cost before modification	647	36,326
Net modification loss	0	0
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period	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 loss allowance changed to 12 months ECL in the period	0	0
Other unsecured 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 loss allowance changed to 12 months ECL in the period	£ 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	£ 210,094	£ 208,750
PIPs	£ 2	£ 10
Simple average LTV (indexed)	41.00%	42.00%
Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 174,712	£ 166,730
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	£ 40,654	£ 38,441
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	£ 10,106	£ 9,847
Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	13,638	13,234
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	£ 528	£ 734
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	£ 116,767	£ 110,854
Stage 1 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	161,845	154,586
Stage 1 | Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	36,212	33,330
Stage 1 | Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	12,391	11,860
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	354	423
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	109,878	105,514
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	11,071	10,345
Stage 2 | Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	3,626	4,228
Stage 2 | Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	1,020	1,126
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	6,188	4,728
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 1,796	£ 1,799
Stage 3 ratio	1.04%	1.09%
Stage 3 | Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 816	£ 883
Stage 3 ratio	2.03%	2.31%
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	1.66%	1.88%
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	12.34%	12.30%
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	£ 701	£ 612
Stage 3 ratio	0.60%	0.55%

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	£ 40,654	£ 38,441
Term expired
Disclosure of credit risk exposure [line items]
carrying amount of interest-only loans	392	374
Within 2 years
Disclosure of credit risk exposure [line items]
carrying amount of interest-only loans	1,892	1,726
Between 2-5 years
Disclosure of credit risk exposure [line items]
carrying amount of interest-only loans	3,795	3,697
Between 5-15 years
Disclosure of credit risk exposure [line items]
carrying amount of interest-only loans	19,633	20,318
Greater than 15 years
Disclosure of credit risk exposure [line items]
carrying amount of interest-only loans	14,942	12,326
Weighted average LTV
Disclosure of credit risk exposure [line items]
carrying amount of interest-only loans	2,601	2,712
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	112	154
Weighted average LTV | Between 5-15 years
Disclosure of credit risk exposure [line items]
carrying amount of interest-only loans	1,015	1,397
Weighted average LTV | Greater than 15 years
Disclosure of credit risk exposure [line items]
carrying amount of interest-only loans	£ 1,355	£ 1,017

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	£ 1,583	£ 1,528
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	1,108	1,112
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Forbearance	475	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	£ 24,535	£ 24,680
Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	17,930	17,393
Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,779	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	5,509	5,082
Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	62,259	58,129
Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	62,002	58,084
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	56,112	50,962
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	1,364	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 & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		12,347
Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,461
Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		10,886
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	56,113	50,246
Internal grade 9 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	56,113	50,246
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	55,061	48,579
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	479	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 & 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	2,890	3,060
Internal grade 8 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	687	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	3,938	5,628
Internal grade 8 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,731	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	533	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 & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		2,245
Internal grade 8 | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		443
Internal grade 8 | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,802
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	2,110	2,052
Internal grade 7 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,066	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	345	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 & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		3,889
Internal grade 7 | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		622
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 & 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 & 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	5,624	7,204
Internal grade 4 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,388	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	1	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 & 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	309	454
Internal grade 3 to 1 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,511	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 & 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	934
Other | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	577	749
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	3
Other | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	44	156
Other | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	38	156
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 & 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	£ 24,535	£ 24,680
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	5,509	5,082
Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	62,259	58,129
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	56,112	50,962
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	1,364	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 & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		12,347
Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,461
Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		10,886
UK | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	24,492	24,632
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	5,509	5,082
UK | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	56,928	50,484
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	52,297	44,624
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	504	301
UK | Corporate Centre | Legacy Portfolios in run-off
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	50	59
UK | Corporate Centre | Derivatives
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		10,456
UK | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		642
UK | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		9,814
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	2,171	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	565	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 & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		1,487
Europe | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		435
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 & Investment Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		130
US | Corporate & Investment Banking | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk		130
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	2,610	4,110
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	97
Rest of World | Corporate Centre | Derivatives
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	£ 0	0
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]
Exposures	£ 313,347	£ 322,745
Stage 3
Disclosure of credit risk exposure [line items]
Exposures	3,017	2,996
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	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]
Exposures	723	853
Collateral	354	286
Net exposure	369	567
Stage 3 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Exposures	103	167
Collateral	85	105
Net exposure	18	62
Stage 3 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	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]
Exposures	2
Collateral	0
Net exposure	£ 2
Stage 3 | Corporate & Investment Banking
Disclosure of credit risk exposure [line items]
Exposures		0
Collateral		0
Net exposure		0
Stage 3 | Corporate & Investment Banking | Large Corporate
Disclosure of credit risk exposure [line items]
Exposures		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	£ 33,855	£ 20,958
Deposits by customers	192,926	195,135
Repurchase agreements - non trading	11,718	15,848
Debt securities in issue	25,520	35,566
Subordinated liabilities	2,228	2,556
Other equity interest	2,191	2,191
Liquidity risk
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	82,300	86,600
Deposits by banks	33,900	21,000
Deposits by customers	6,000	8,100
Repurchase agreements - non trading	11,700	15,800
Financial liabilities designated at fair value	800	1,400
Debt securities in issue	25,500	35,600
Subordinated liabilities	2,200	2,500
Other equity instruments	2,200	2,200
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	0	0
Liquidity risk | Foreign exchange and hedge accounting
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	1,100	2,500
Deposits by banks	0	0
Deposits by customers	100	200
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	700	2,000
Subordinated liabilities	300	300
Other equity instruments	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	0	0
Liquidity risk | Wholesale funding
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	67,400	65,300
Deposits by banks	32,100	18,000
Deposits by customers	5,900	7,900
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	500	1,400
Debt securities in issue	24,800	33,600
Subordinated liabilities	1,900	2,200
Other equity instruments	2,200	2,200
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	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	0	0
Liquidity risk | Wholesale funding | Senior unsecured – public benchmark
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	12,300	15,400
Deposits by banks	0	0
Deposits by customers	5,800	7,800
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	6,500	7,600
Subordinated liabilities	0
Other equity instruments	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	100	100
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	500	900
Debt securities in issue	0	100
Subordinated liabilities	0	0
Other equity instruments	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	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	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	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	0	0
Liquidity risk | Wholesale funding | Subordinated liabilities and equity
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	4,100	4,400
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	1,900	2,200
Other equity instruments	2,200	2,200
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	£ 1,956	£ 1,956

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	£ 67,400	£ 65,300
Deposits by banks	33,855	20,958
Subordinated liabilities	2,228	2,556
Of which secured	45,100	38,700
Of which unsecured	£ 22,300	26,600
Unsecured debt issued	95.00%
Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	£ 10,000
Senior unsecured – privately placed	100
Subordinated liabilities and equity (incl. AT1)	2,700
Wholesale fund amount	12,800
Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	2,300
Senior unsecured – privately placed	500
Subordinated liabilities and equity (incl. AT1)	700
Wholesale fund amount	54,600
Deposits by banks	200
Certificates of deposit and commercial paper	5,100
Covered bonds	12,500
Term Funding Scheme (TFS)	0
TFSME	31,900
Subordinated liabilities	1,400
Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	67,400
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 | Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	600
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	200
Wholesale fund amount	2,300
Deposits by banks	200
Certificates of deposit and commercial paper	1,300
Covered bonds	0
Term Funding Scheme (TFS)	0
TFSME	0
Subordinated liabilities	0
≤ 1 month | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	3,100
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 | Other Santander UK 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	3,200
Deposits by banks	0
Certificates of deposit and commercial paper	3,000
Covered bonds	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]
Wholesale fund amount	3,200
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 | Other Santander UK 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)	100
Wholesale fund amount	1,600
Deposits by banks	0
Certificates of deposit and commercial paper	700
Covered bonds	800
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]
Wholesale fund amount	2,800
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 | Other Santander UK 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)	100
Wholesale fund amount	200
Deposits by banks	0
Certificates of deposit and commercial paper	100
Covered bonds	0
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]
Wholesale fund amount	200
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 | Other Santander UK 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	900
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	900
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]
Wholesale fund amount	900
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 | Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	600
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	400
Wholesale fund amount	8,200
Deposits by banks	200
Certificates of deposit and commercial paper	5,100
Covered bonds	1,700
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]
Wholesale fund amount	10,200
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 | Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	300
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	200
Wholesale fund amount	2,900
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	1,900
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]
Wholesale fund amount	5,900
Securitisation and structured issuance	0
>2 and ≤ 5 years
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	40,700	28,200
Of which secured	33,700	18,600
Of which unsecured	7,000	9,600
>2 and ≤ 5 years | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	4,000
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	1,600
Wholesale fund amount	5,600
>2 and ≤ 5 years | Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	1,100
Senior unsecured – privately placed	300
Subordinated liabilities and equity (incl. AT1)	100
Wholesale fund amount	35,100
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	5,600
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]
Wholesale fund amount	40,700
Securitisation and structured issuance	0
>5 years
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	10,600	8,100
Of which secured	7,200	4,400
Of which unsecured	3,400	£ 3,700
>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 | Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	300
Senior unsecured – privately placed	200
Subordinated liabilities and equity (incl. AT1)	0
Wholesale fund amount	8,400
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	3,300
Term Funding Scheme (TFS)	0
TFSME	3,900
Subordinated liabilities	700
>5 years | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	10,600
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	66.00%	57.00%
Sterling | Santander UK Group Holdings plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	22.00%	24.00%
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	9.00%	10.00%
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	73.00%	73.00%
Sterling | Other Santander UK plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	77.00%	63.00%
Sterling | Other 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 | Other 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 | Other 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 | 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	45.00%	51.00%
Sterling | Other 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 | Other 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 | 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%	100.00%
Sterling | Other 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 | Other 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	52.00%	53.00%
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%	62.00%
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	27.00%	27.00%
US Dollar | Other 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 | Other 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 | Other 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 | Other 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 | 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	53.00%	44.00%
US Dollar | Other 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 | Other 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 | 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%
US Dollar | 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%
US Dollar | Other 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	25.00%	22.00%
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	32.00%	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 | Other Santander UK plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	13.00%	19.00%
Euro | Other 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 | Other 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 | 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%
Euro | 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	2.00%	4.00%
Euro | Other 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 | 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%
Euro | 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%
Euro | 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%
Euro | 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%
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	1.00%	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 | 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 | 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 | 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 | 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 | 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 | 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 | 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 | 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 | 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 | 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
Santander UK Group Holdings plc
Disclosure of detailed information about borrowings [line items]
Borrowings	£ 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	0.2	0
Other Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	20.3	15.7
Other Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0	1
Other Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0	0
Other Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	0	3
Other Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0.1	0
Other Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	20.2	11.7
Other group entities
Disclosure of detailed information about borrowings [line items]
Borrowings	23.3	17.1
Other group entities | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0	£ 0
Sterling | Santander UK Group Holdings plc
Disclosure of detailed information about borrowings [line items]
Borrowings	0.2
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	0.2
Sterling | Other Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	20.3
Sterling | Other Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Sterling | Other Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Sterling | Other Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Sterling | Other Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0.1
Sterling | Other Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	20.2
Sterling | Other group entities
Disclosure of detailed information about borrowings [line items]
Borrowings	20.5
Sterling | Other group entities | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
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 | Other Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Other Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Other Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Other Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Other Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Other Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	0
US Dollar | Other group entities
Disclosure of detailed information about borrowings [line items]
Borrowings	2.2
US Dollar | Other group entities | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
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 | Other Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Other Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Other Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Other Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Other Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Other Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Euro | Other group entities
Disclosure of detailed information about borrowings [line items]
Borrowings	0.6
Euro | Other group entities | Securitisations and other secured funding
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 | Other Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Other Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Other Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Other Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Other Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Other Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	0
Other | Other group entities
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	£ 48,139	£ 41,250	£ 21,180
Financial assets at fair value through profit or loss:
Derivative financial instruments	1,681	3,406
Other financial assets at FVTPL	185	208
Financial assets at amortised cost:
Loans and advances to customers	210,094	208,750
Loans and advances to banks	1,169	1,682
Repurchase agreements – non trading	12,683	19,599
Other financial assets at amortised cost	506	1,163
Financial assets at FVOCI	5,851	8,950
Interests in other entities	201	172
Intangible assets	1,545	1,646
Property, plant and equipment	1,548	1,734
Current tax assets	347	264	200
Retirement benefit assets	1,572	495
Other assets	1,577	3,013
Total assets	287,098	292,332	£ 281,702
Liquidity risk
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	48,139	41,250
Financial assets at fair value through profit or loss:
Derivative financial instruments	1,681	3,406
Other financial assets at FVTPL	185	208
Financial assets at amortised cost:
Loans and advances to customers	210,094	208,750
Loans and advances to banks	1,169	1,682
Repurchase agreements – non trading	12,683	19,599
Other financial assets at amortised cost	506	1,163
Financial assets at FVOCI	5,851	8,950
Interests in other entities	201	172
Intangible assets	1,545	1,646
Property, plant and equipment	1,548	1,734
Current tax assets	347	264
Retirement benefit assets	1,572	495
Other assets	1,577	3,013
Total assets	287,098	292,332
Liquidity risk | Total
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	46,559	40,265
Financial assets at fair value through profit or loss:
Derivative financial instruments	1,681	3,406
Other financial assets at FVTPL	185	208
Financial assets at amortised cost:
Loans and advances to customers	190,561	177,428
Loans and advances to banks	691	878
Repurchase agreements – non trading	12,683	19,599
Other financial assets at amortised cost	506	515
Financial assets at FVOCI	1,488	3,369
Interests in other entities	201	172
Intangible assets	1,545	1,646
Property, plant and equipment	1,548	1,734
Current tax assets	347	264
Retirement benefit assets	1,572	495
Other assets	1,577	3,013
Total assets	261,144	252,992
Liquidity risk | Assets positioned at central banks
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	918	854
Financial assets at fair value through profit or loss:
Derivative financial instruments	0	0
Other financial assets at FVTPL	0	0
Financial assets at amortised cost:
Loans and advances to customers	80,624	61,292
Loans and advances to banks	0	0
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at FVOCI	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Retirement benefit assets	0	0
Other assets	0	0
Total assets	81,542	62,146
Liquidity risk | Readily available
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	45,641	39,411
Financial assets at fair value through profit or loss:
Derivative financial instruments	0	0
Other financial assets at FVTPL	0	0
Financial assets at amortised cost:
Loans and advances to customers	74,890	74,758
Loans and advances to banks	0	0
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	506	515
Financial assets at FVOCI	1,488	3,369
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Retirement benefit assets	0	0
Other assets	0	0
Total assets	122,525	118,053
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 FVTPL	0	0
Financial assets at amortised cost:
Loans and advances to customers	18,893	19,801
Loans and advances to banks	0	0
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at FVOCI	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	1,548	1,734
Current tax assets	0	0
Retirement benefit assets	0	0
Other assets	0	0
Total assets	20,441	21,535
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	1,681	3,406
Other financial assets at FVTPL	185	208
Financial assets at amortised cost:
Loans and advances to customers	16,154	21,577
Loans and advances to banks	691	878
Repurchase agreements – non trading	12,683	19,599
Other financial assets at amortised cost	0	0
Financial assets at FVOCI	0	0
Interests in other entities	201	172
Intangible assets	1,545	1,646
Property, plant and equipment	0	0
Current tax assets	347	264
Retirement benefit assets	1,572	495
Other assets	1,577	3,013
Total assets	36,636	51,258
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 FVTPL	0	0
Financial assets at amortised cost:
Loans and advances to customers	19,533	31,322
Loans and advances to banks	478	804
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	648
Financial assets at FVOCI	4,363	5,581
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Retirement benefit assets	0	0
Other assets	0	0
Total assets	25,954	39,340
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 FVTPL	0	0
Financial assets at amortised cost:
Loans and advances to customers	15,713	23,669
Loans and advances to banks	0	0
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at FVOCI	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Retirement benefit assets	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 FVTPL	0	0
Financial assets at amortised cost:
Loans and advances to customers	3,720	7,469
Loans and advances to banks	0	0
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at FVOCI	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Retirement benefit assets	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 FVTPL	0	0
Financial assets at amortised cost:
Loans and advances to customers	100	184
Loans and advances to banks	478	804
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	648
Financial assets at FVOCI	4,363	5,581
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Retirement benefit assets	0	0
Other assets	0	0
Total assets	£ 6,521	£ 8,202

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 Capital Risk Exposure [Abstract]
CET1 capital	£ 10,820	£ 11,057
AT1 capital	2,119	2,281
Tier 1 capital	12,939	13,338
Tier 2 capital	1,816	1,909
Total regulatory capital	14,755	15,247
Transitional IFRS 9 Benefit	£ 21	£ 73

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, 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)	£ 3,949	£ 3,388	[1]	£ 3,224	[1]
Non-interest income	550	464		811
Total operating income	4,499	3,852		4,035
Operating expenses before credit impairment write-backs/losses, provisions and charges	(2,510)	(2,390)	[1]	(2,439)	[1]
Credit impairment write-backs	233	(638)	[1]	(199)	[1]
Provisions for other liabilities and charges	(377)	(264)	[1]	(426)	[1]
Total operating credit impairment write-backs/losses, provisions and charges	(144)	(902)	[1]	(625)	[1]
Profit from continuing operations before tax	1,845	560	[1]	971	[1]
Revenue from external customers	4,499	3,852		4,035
Inter-segment revenue	4,499	3,852	[1]	4,035	[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	79	65		129
Total fee and commission income	697	680	[1]	1,038	[1]
Fee and commission expense	(411)	(361)	[1]	(414)	[1]
Net fee and commission income/(expense)	286	319		624
Customer loans	207,288	207,011		205,008
Total assets	287,098	292,332		281,702
Customer deposits	186,215	185,707		171,715
Total liabilities	£ 270,996	£ 276,396		£ 265,685
Average number of full-time equivalent staff | employee	19,704	21,998		23,570
Inter-segment revenue
Disclosure of operating segments [line items]
Inter-segment revenue	£ 0	£ 0		£ 0
Retail Banking
Disclosure of operating segments [line items]
Net interest income/(expense)	3,356	2,753		2,581
Non-interest income	205	245		531
Total operating income	3,561	2,998		3,112
Operating expenses before credit impairment write-backs/losses, provisions and charges	(1,701)	(1,792)		(1,860)
Credit impairment write-backs	98	(264)		(129)
Provisions for other liabilities and charges	(185)	(157)		(273)
Total operating credit impairment write-backs/losses, provisions and charges	(87)	(421)		(402)
Profit from continuing operations before tax	1,773	785		850
Revenue from external customers	4,010	3,669		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	(380)	(335)		(372)
Net fee and commission income/(expense)	190	241		527
Customer loans	183,023	175,380		171,078
Total assets	190,629	183,154		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 | Inter-segment revenue
Disclosure of operating segments [line items]
Inter-segment revenue	£ (449)	£ (671)		£ (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	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 | Inter-segment revenue
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	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 | Inter-segment revenue
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	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 | Inter-segment revenue
Disclosure of operating segments [line items]
Inter-segment revenue	£ 0	£ 0		£ 0
Corporate Centre
Disclosure of operating segments [line items]
Net interest income/(expense)	(41)	8		(25)
Non-interest income	58	(2)		16
Total operating income	17	6		(9)
Operating expenses before credit impairment write-backs/losses, provisions and charges	(281)	(108)		(66)
Credit impairment write-backs	11	(36)		2
Provisions for other liabilities and charges	(162)	(93)		(121)
Total operating credit impairment write-backs/losses, provisions and charges	(151)	(129)		(119)
Profit from continuing operations before tax	(415)	(231)		(194)
Revenue from external customers	(553)	(867)		(871)
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	5	2		18
Total fee and commission income	5	2		18
Fee and commission expense	(9)	(4)		(18)
Net fee and commission income/(expense)	(4)	(2)		0
Customer loans	2,284	3,196		3,814
Total assets	70,599	77,625		69,852
Customer deposits	3,627	2,049		2,332
Total liabilities	£ 86,588	£ 89,784		£ 92,562
Average number of full-time equivalent staff | employee	76	39		21
Corporate Centre | Inter-segment revenue
Disclosure of operating segments [line items]
Inter-segment revenue	£ 570	£ 873		£ 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	£ 4,619	£ 4,745		£ 5,130
Loans and advances to banks	52	49		137
Reverse repurchase agreements – non trading	35	118		244
Other	56	119		306
Total interest and similar income	4,762	5,031	[1]	5,817	[1]
Interest expense and similar charges:
Deposits by customers	(430)	(1,011)		(1,540)
Deposits by banks	(25)	(28)		(102)
Repurchase agreements – non trading	(3)	(43)		(126)
Debt securities in issue	(252)	(440)		(678)
Subordinated liabilities	(92)	(111)		(137)
Other	(11)	(10)		(10)
Total interest expense and similar charges	(813)	(1,643)	[1]	(2,593)	[1]
Net interest income	3,949	3,388	[1]	£ 3,224	[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]
Total fee and commission income	£ 697	£ 680	[1]	£ 1,038	[1]
Total fee and commission expense	(411)	(361)	[1]	(414)	[1]
Net fee and commission income	286	319	[1]	624	[1]
Current account and debit card fees
Net Fee And Commission Income [Line Items]
Total fee and commission income	478	484		754
Insurance, protection and investments
Net Fee And Commission Income [Line Items]
Total fee and commission income	67	65		69
Credit cards
Net Fee And Commission Income [Line Items]
Total fee and commission income	73	66		86
Non-banking and other fees
Net Fee And Commission Income [Line Items]
Total fee and commission income	£ 79	£ 65		£ 129
[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	£ (24)	£ (77)		£ (142)
Net gains on financial instruments mandatorily at fair value through profit or loss	(2)	46		70
Hedge ineffectiveness	13	20		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	13		112
Other operating income (expense)	£ 264	£ 145	[1]	£ 187	[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	242	(751)	1,102
Principally offset from cash flow hedge reserve	(358)	809	(1,013)
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_3

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	£ 745	£ 788		£ 801
Performance-related payments	183	97		159
Social security costs	112	101		111
Pensions costs: – defined contribution plans	64	66		66
Pension costs, defined benefit plans	38	38		35
Other share-based payments	0	0		0
Other personnel costs	41	33		40
Total employee benefits expense	1,183	1,123		1,212
Other administration expenses	826	706		684
Depreciation, amortisation and impairment	501	561		543
Total operating expenses before impairment losses, provisions and charges	2,510	2,390	[1]	2,439	[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_4

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_5

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	£ 77
Cash award - deferred	23	20
Shares award – not deferred	11	3
Share award - deferred	22	19
Total discretionary bonus	212	119
Expenses charged in the year
Disclosure Of Amount Of Bonus Awarded To Employees [Line Items]
Cash award – not deferred	156	77
Cash award - deferred	8	9
Shares award – not deferred	11	3
Share award - deferred	8	8
Total discretionary bonus	183	97
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_6

Operating Expenses Before Credit Impairment Losses, Provisions and Charges - Additional Information (Details) £ in Millions	Oct. 26, 2018GBP (£)	Dec. 31, 2021GBP (£)employee	Dec. 31, 2020GBP (£)employee	Dec. 31, 2019GBP (£)employee
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Decrease in GMP allowance		£ 5	£ 5	£ 5
GMP allowance included in scheme liabilities		£ 45	£ 50	£ 45
Average number of full-time equivalent staff | employee		19,704	21,998	23,570
Property, plant and equipment		£ 1,548	£ 1,734
Expense relating to short-term leases		23	10	£ 13
Present value of defined benefit obligations
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Estimated increase in liabilities in relation to judgment on GMP equalisation	£ 40
Accumulated depreciation:
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Property, plant and equipment		(1,922)	(2,287)	(2,128)
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		19	58	60
Operating lease assets		£ 118	£ 100	£ 152

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	£ 11.2	£ 10	£ 8
Audit of the Santander UK group's subsidiaries	0.9	1.4	1.3
Total audit fees	12.1	11.4	9.3
Non-audit fees:
Audit-related assurance services	0.8	0.8	0.8
Other assurance services	0.1	0.3	0.2
Other non-audit services	0.2	0	0.2
Total non-audit fees	1.1	1.1	1.2
Prior year audit services
Non-audit fees:
Auditors fee	£ 1.2	£ 0.8	£ 0.1

Audit and Other Services - Addi

Audit and Other Services - Additional Information (Details) - GBP (£)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Audit Fees And Non Audit Fees [Line Items]
Non-audit fees - Audit fees per US Securities and Exchange Commission guidance	£ 400,000	£ 400,000	£ 600,000
Non-audit fees - Audit related fees per US Securities and Exchange Commission guidance	700,000	700,000	400,000
Non-audit fees - All other fees per US Securities and Exchange Commission guidance	0	0	200,000
Audit fees payable for statutory audit	12,100,000	11,400,000	9,300,000
Incremental Work In Support Of Audit Of Banco Santander
Disclosure Of Audit Fees And Non Audit Fees [Line Items]
Audit fees payable for statutory audit	1,400,000	1,500,000	1,500,000
Corporate and Other Borrowers
Disclosure Of Audit Fees And Non Audit Fees [Line Items]
Audit fees payable for statutory audit	£ 27,000	£ 24,000	£ 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)	£ 665		£ 217
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)	638	[1]	199	[1]
Provisions for other liabilities and charges (excluding off-balance sheet credit exposures) (See Note 29)	386	258		420
Provisions for residual value and voluntary termination	(9)	6		6
Provisions for other liabilities and charges	377	264	[1]	426	[1]
Total operating credit impairment loss/(release), provisions and charges	£ 144	£ 902	[1]	£ 625	[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	£ 401	£ 107		£ 254
Adjustments in respect of prior years	(24)	(24)		(25)
Total current tax	377	83		229
Deferred tax:
Charge for the year	100	34		46
Adjustments in respect of prior years	15	4		(7)
Total deferred tax	115	38		39
Tax on profit from continuing operations	£ 492	£ 121	[1]	£ 268	[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	£ 23
Expected decrease in deferred tax liaiblity	£ 90
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)	26.70%	21.60%		27.60%
Profit from continuing operations before tax	£ 1,845	£ 560	[1]	£ 971	[1]
Tax calculated at a tax rate of 19% (2020: 19%, 2019: 19%)	351	106		184
Bank surcharge on profits	104	27		62
Non-deductible preference dividends paid	9	8		8
Non-deductible UK Bank Levy	14	19		24
Non-deductible conduct remediation, fines and penalties	6	(4)		44
Other non-deductible costs and non-taxable income	37	25		31
Effect of change in tax rate on deferred tax provision	9	6		(14)
Tax relief on dividends in respect of other equity instruments	(40)	(40)		(39)
Adjustment to prior year provisions	2	(26)		(32)
Tax on profit from continuing operations	£ 492	£ 121	[1]	£ 268	[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	£ 264	£ 200
Liabilities	0	0
Beginning balance	264	200
Income statement charge (including discontinued operations)	(389)	(96)
Other comprehensive income credit	33	1
Corporate income tax paid	427	159	£ 292
Other movements	12	0
Ending balance	347	264	200
Assets	347	264	200
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	£ (111)	£ (149)
Income statement (charge)/credit	(115)	(38)
Transfers/reclassifications	(40)	(2)
Credited/(charged) to other comprehensive income	(313)	78
Ending balance	(579)	(111)
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	(26)	(96)
Income statement (charge)/credit	(67)	(63)
Transfers/reclassifications	4	0
Credited/(charged) to other comprehensive income	(419)	133
Ending balance	(508)	(26)
Cash flow hedges
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(99)	(58)
Income statement (charge)/credit	0	0
Transfers/reclassifications	(16)	12
Credited/(charged) to other comprehensive income	108	(53)
Ending balance	(7)	(99)
Fair value reserve
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(11)	(8)
Income statement (charge)/credit	0	0
Transfers/reclassifications	1	(1)
Credited/(charged) to other comprehensive income	(2)	(2)
Ending balance	(12)	(11)
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	38	17
Income statement (charge)/credit	40	21
Transfers/reclassifications	(10)	0
Credited/(charged) to other comprehensive income	0	0
Ending balance	68	38
Other temporary differences
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	37	35
Income statement (charge)/credit	(23)	15
Transfers/reclassifications	(19)	(13)
Credited/(charged) to other comprehensive income	0	0
Ending balance	£ (5)	£ 37

Dividends on Ordinary Shares -

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	£ 4.37	£ 0.42	£ 1.02
Dividends	£ 1,358	£ 129	£ 315
First interim
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividend per share	£ 0.90	£ 0.42	£ 0.53
Dividends	£ 281	£ 129	£ 164
Second interim
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividend per share	£ 3.47	£ 0	£ 0.49
Dividends	£ 1,077	£ 0	£ 151

Dividends on Ordinary Shares _2

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	£ 1,358	£ 129

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	£ 162,049	£ 197,215
Assets	1,681	3,406
Liabilities	777	1,584
Cash collateral received subject to enforceable master netting arrangement or similar agreement not set off against financial assets	12,941	21,310
Collateral cash	11,224	16,772
Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	37,240	56,251
Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	124,809	140,964
Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	81,104	94,537
Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	43,705	46,427
Exchange rate contracts
Disclosure of detailed information about hedges
Notional amount	33,865	42,760
Exchange rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	11,036	14,951
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	127,128	153,315
Interest rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	25,148	40,160
Interest rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	80,514	93,748
Interest rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	21,466	19,407
Equity and credit contracts
Disclosure of detailed information about hedges
Notional amount	1,056	1,140
Equity and credit contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	1,056	1,140
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
Assets	1,681	3,406
Liabilities	777	1,584
Fair value | Derivatives held for trading:
Disclosure of detailed information about hedges
Assets	783	1,406
Liabilities	707	1,015
Fair value | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	2,119	3,754
Liabilities	1,291	2,323
Fair value | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	943	1,309
Liabilities	737	1,891
Fair value | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	1,176	2,445
Liabilities	554	432
Fair value | Exchange rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Assets	159	395
Liabilities	168	418
Fair value | Exchange rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	39	84
Liabilities	0	6
Fair value | Exchange rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	996	1,978
Liabilities	338	409
Fair value | Interest rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Assets	463	888
Liabilities	485	542
Fair value | Interest rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	904	1,225
Liabilities	737	1,885
Fair value | Interest rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	180	467
Liabilities	216	23
Fair value | Equity and credit contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Assets	161	123
Liabilities	54	55
Fair value | Derivative netting
Disclosure of detailed information about hedges
Assets	(1,221)	(1,754)
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	£ 162,049	£ 197,215
Exchange rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	33,865	42,760
Interest rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	127,128	153,315
Equity and credit contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	1,056	1,140
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	117,559	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	117,559	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	44,490	52,872
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	33,865	42,760
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	9,569	8,972
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	1,056	1,140
Traded over the counter
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Asset	1,681	3,406
Liability	777	1,584
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	1,194	2,457
Liability	507	833
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	326	826
Liability	216	696
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	161	123
Liability	£ 54	£ 55

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	£ 162,049	£ 197,215
Interest rate contracts
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	127,128	153,315
Interest rate contracts | Interest rate risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	80,284	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	15,168	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	33,865	42,760
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
≤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 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
>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
>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	£ 44,507	£ 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	£ 7,669	£ 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
>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

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	£ 13	£ 20	£ 8
Fair Value and Cash Flow Hedges
Disclosure of detailed information about hedges
Gains/(losses) on hedging instruments	852	(299)	(360)
(Losses)/gains on hedged items attributable to hedged risks	(800)	365	414
Fair value hedging ineffectiveness	52	66	54
Cash flow hedging ineffectiveness	(39)	(46)	(46)
Hedge ineffectiveness	£ 13	£ 20	£ 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	£ 852	£ (299)
Change in FV of hedged items	(800)	365
Recognised in income statement	52	66
Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	874	(358)
Change in FV of hedged items	(834)	385
Recognised in income statement	40	27
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	(912)	925
Change in FV of hedged items	873	(972)
Recognised in OCI	873	(971)
Recognised in income statement	(39)	(46)
Reclassified from reserves to income	(358)	808
Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(317)	185
Recognised in OCI	305	(179)
Recognised in income statement	(12)	6
Reclassified from reserves to income	73	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 | Interest rate/FX risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(541)	782
Recognised in OCI	514	(830)
Recognised in income statement	(27)	(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	£ 4

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	£ 644	£ 481
Effective portion of changes in fair value:	(873)	971
Income statement transfers	358	(808)
Ending Balance	129	644
Interest rate risk
Disclosure of detailed information about hedges
Effective portion of changes in fair value:	(305)	179
Income statement transfers	(73)	(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:	0	0
Income statement transfers	0	0
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	£ 129	£ 644	£ 481
Fair value hedges
Disclosure of detailed information about hedges
Carrying value of assets	67,194	58,019
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	(291)	(649)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks assets	(45)	1,038
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	198	424
Change in value to calculate hedge ineffectiveness	(800)	365
Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	(834)	385
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	873	(972)
Cash flow hedge reserve	129	644
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	(1,665)	(7,309)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	(46)	(158)
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	(44)	(77)
Change in value to calculate hedge ineffectiveness	104	(73)
Deposits by customers | Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	9	(5)
Cash flow hedge reserve	9	14
Balances on cash flow hedge reserve for discontinued hedges	10	0
Deposits by banks | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of liabilities	0	0
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	0	0
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	0	0
Change in value to calculate hedge ineffectiveness	0	0
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
Deposits by banks | Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	0	0
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	(2,567)	(5,885)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	(140)	(375)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks liabilities	(114)	(137)
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	(185)	(239)
Change in value to calculate hedge ineffectiveness	235	(61)
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	85	(15)
Cash flow hedge reserve	57	(60)
Balances on cash flow hedge reserve for discontinued hedges	(4)	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)
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	0	0
Cash flow hedge reserve	0	0
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	80	1,189
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	491	892
Change in value to calculate hedge ineffectiveness	(1,092)	334
Loans and advances to customers | Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	235	(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	(79)	1
Balances on cash flow hedge reserve for discontinued hedges	0	0
Debt securities in issue | Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	0	0
Cash flow hedge reserve	0	0
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	(195)	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	149	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	410	(569)
Cash flow hedge reserve	105	236
Balances on cash flow hedge reserve for discontinued hedges	(4)	(2)
Deposits by customers | Deposits by customers | Cash flow hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	93	(132)
Cash flow hedge reserve	38	87
Balances on cash flow hedge reserve for discontinued hedges	0	0
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_3

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	£ 185	£ 208
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	74	99
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	62	86
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	£ 111	£ 109

Other Financial Assets at Fai_4

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	£ 12	£ 13
Financial assets mandatorily at FVTPL	173	195
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	£ 174,712	£ 166,714
Corporate loans	19,282	23,613
Finance leases	3,916	6,554
Secured advances	0	0
Other unsecured loans	9,404	9,933
Accrued interest and other adjustments	452	861
Amounts due from fellow Banco Santander subsidiaries and joint ventures	3,175	2,425
Amounts due from Santander UK Group Holdings plc	6	7
Amounts due from subsidiaries	0	0
Loans and advances to customers	210,947	210,107
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	£ 210,094	£ 208,750

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	£ 4,382	£ 7,210
Unearned finance income	(466)	(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	(200)	(173)
Net investment	1,124	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	771	1,099
Unearned finance income	(141)	(106)
Net investment	630	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	£ 133	£ 98
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	16
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	21	15
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	£ 29

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	162,049	197,215
Securitisation programmes (See Note 14)
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 (See Note 14) | 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 (See Note 14) | 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 (See Note 14) | 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 (See Note 14) | 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 (See Note 14) | 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 (See Note 14) | 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 (See Note 14) | 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 (See Note 14) | 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%
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
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

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]
Repurchase agreements – non trading	£ 12,683	£ 19,599
Agreements with banks
Disclosure Of Reserve Repurchase Agreements Non-Trading [Line Items]
Repurchase agreements – non trading	447	1,258
Agreements with customers
Disclosure Of Reserve Repurchase Agreements Non-Trading [Line Items]
Repurchase agreements – non trading	£ 12,236	£ 18,341

Other Financial Assets at Amo_3

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 FVOCI	£ 5,851	£ 8,950
Debt securities
Disclosure Of Financial Assets At Fair Value Through Other Comprehensive Income [Line Items]
Financial assets at FVOCI	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 FVOCI	£ 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]
Subsidiaries	£ 0	£ 0
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 -_2

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	£ 19	£ 19	[1]	£ 19	[1]
Accumulated non-controlling interests of the subsidiary	0	162
Total assets	287,098	292,332		281,702
Total liabilities	270,996	276,396		265,685
Profit for the year	1,384	471	[1]	733	[1]
Total comprehensive income for the year	1,852	211		£ 395
Subsidiaries with material non-controlling interests
Disclosure of subsidiaries [line items]
Profit attributable to non-controlling interests	19	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 for the year	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 -_3

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 -_4

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	1,269	1,269
Accumulated impairment
Disclosure Of Goodwill [Line Items]
Carrying value	£ (66)	£ (66)

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	£ 26,000,000	£ 25,000,000

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) - 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%
Personal Financial Services
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]
Other intangibles at beginning of period	£ 443	£ 563
Additions	84	102
Disposals	(1)	0
Charge	(158)	(197)
Impairment	(26)	(25)
Other intangibles at end of period	342	443
Cost
Disclosure of detailed information about intangible assets [line items]
Other intangibles at beginning of period	1,304	1,249
Additions	84	102
Disposals	(54)	(47)
Charge	0	0
Impairment	0	0
Other intangibles at end of period	1,334	1,304
Accumulated amortisation/ impairment
Disclosure of detailed information about intangible assets [line items]
Other intangibles at beginning of period	(861)	(686)
Additions	0	0
Disposals	53	47
Charge	(158)	(197)
Impairment	(26)	(25)
Other intangibles at end of period	£ (992)	£ (861)

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	£ 1,734
Property, plant and equipment at end of period	1,548	£ 1,734
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	4,021	4,095
Additions	501	299
Disposals	(1,052)	(373)
Property, plant and equipment at end of period	3,470	4,021
Accumulated depreciation:
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(2,287)	(2,128)
Additions	(219)	(316)
Disposals	681	181
Impairment during the year	97	24
Property, plant and equipment at end of period	(1,922)	(2,287)
Property
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	783
Property, plant and equipment at end of period	644	783
Property | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	1,272	1,270
Additions	126	61
Disposals	(420)	(59)
Property, plant and equipment at end of period	978	1,272
Property | Accumulated depreciation:
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(489)	(454)
Additions	(32)	(55)
Disposals	233	44
Impairment during the year	46	24
Property, plant and equipment at end of period	(334)	(489)
Office fixtures and equipment
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	307
Property, plant and equipment at end of period	192	307
Office fixtures and equipment | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	1,375	1,436
Additions	26	43
Disposals	(352)	(104)
Property, plant and equipment at end of period	1,049	1,375
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	(1,068)	(1,016)
Additions	(86)	(111)
Disposals	325	59
Impairment during the year	28	0
Property, plant and equipment at end of period	(857)	(1,068)
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	0	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	0	2
Disposals	(2)	(5)
Property, plant and equipment at end of period	434	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	1	0
Impairment during the year	0	0
Property, plant and equipment at end of period	(434)	(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	100
Property, plant and equipment at end of period	117	100
Right-of-use assets | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	218	212
Additions	65	8
Disposals	(29)	(2)
Property, plant and equipment at end of period	254	218
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	(118)	(60)
Additions	(19)	(58)
Disposals	23	0
Impairment during the year	23	0
Property, plant and equipment at end of period	£ (137)	£ (118)

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_3

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		162,049		197,215
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_4

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	£ 192,926	£ 195,135
Demand and time deposits
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	185,843	185,879
Amounts due to other Santander UK Group Holdings plc subsidiaries
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	59	59
Amounts due to Santander UK Group Holdings plc
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	5,874	7,883
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	£ 33,855	£ 20,958
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	931	2,063
Other deposits
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	32,507	18,519
Amounts due to Santander UK subsidiaries
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	£ 3	£ 1

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	£ 162,049			£ 197,215
Debt securities	25,520			35,566
Medium-term notes:
Debt Securities In Issue [Line Items]
Debt securities	6,851			8,212
Euro 35bn Global Covered Bond Programme (See Note 14)
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 (See Note 14)
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
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	1,261			1,061
US$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 plc | Medium-term notes:
Debt Securities In Issue [Line Items]
Debt securities	£ 4,185			5,457
US SEC-registered Debt Programme – Santander UK plc | Medium-term notes: | US Dollar One Billion Senior Unsecured Notes
Debt Securities In Issue [Line Items]
Debt securities				£ 734
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

Debt Securities in Issue - Addi

Debt Securities in Issue - 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 | £		£ 162,049		£ 197,215
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

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)	£ 0.1	£ 0.1		£ 0.1
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%
10.0625% Exchangeable capital securities
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	10.0625%	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]
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]
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]
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]
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]
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]
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	£ 132	£ 97
Other	2,057	2,240
Other liabilities	£ 2,189	£ 2,337

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	£ 464
Additional provisions (See Note 8)	390
Provisions released (See Note 8)	(34)
Utilisation and other	(469)
Recharge	13
Ending balance	364
Customer remediation
Disclosure of other provisions [line items]
Beginning balance	69
Additional provisions (See Note 8)	25
Provisions released (See Note 8)	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 (See Note 8)	72
Provisions released (See Note 8)	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	34
Additional provisions (See Note 8)	52
Provisions released (See Note 8)	0
Utilisation and other	(98)
Recharge	13
Ending balance	1
Property
Disclosure of other provisions [line items]
Beginning balance	45
Additional provisions (See Note 8)	52
Provisions released (See Note 8)	(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 (See Note 8)	0
Provisions released (See Note 8)	(30)
Utilisation and other	(7)
Recharge	0
Ending balance	38
Restructuring
Disclosure of other provisions [line items]
Beginning balance	39
Additional provisions (See Note 8)	80
Provisions released (See Note 8)	0
Utilisation and other	(91)
Recharge	0
Ending balance	28
Restructuring | Other
Disclosure of other provisions [line items]
Beginning balance	39
Other
Disclosure of other provisions [line items]
Beginning balance	4
Additional provisions (See Note 8)	109
Provisions released (See Note 8)	(2)
Utilisation and other	(98)
Recharge	0
Ending balance	£ 13

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
Loss allowance	£ 364	£ 364	£ 464
Additional provisions (See Note 8)		390
No later than one year
Future expected provision number
Loss allowance	180	180	323
PPI
Future expected provision number
Loss allowance	0	0	59
Discount plans
Future expected provision number
Additional provisions (See Note 8)	16
Consumer Credit Act Compliance
Future expected provision number
Loss allowance	6	6	£ 47
PPI, current stock and estimated future claim
Future expected provision number
Additional provisions (See Note 8)		21
Legal provision
Future expected provision number
Additional provisions (See Note 8)		29
Regulatory And Other
Future expected provision number
Additional provisions (See Note 8)		£ 22
Regulatory related UK Bank Levy
Future expected provision number
Bank Levy rate		0.10%	0.14%
Property
Future expected provision number
Loss allowance	74	£ 74	£ 45
Additional provisions (See Note 8)		52
Off-balance sheet ECL, transfer of CIB
Future expected provision number
Loss allowance	7	7
Restructuring
Future expected provision number
Loss allowance	£ 28	28	£ 39
Additional provisions (See Note 8)		80
Provisions for costs related to transformation programs		76
Operational risk provisions
Future expected provision number
Additional provisions (See Note 8)		£ 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)
Net defined benefit assets	£ 1,535	£ 92
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	1,572	495
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	£ (1,264)	£ 505	£ 522

Retirement Benefit Plans - Addi

Retirement Benefit Plans - Additional Information (Details) £ in Millions	Oct. 26, 2018GBP (£)	Dec. 31, 2021GBP (£)	Dec. 31, 2021GBP (£)directordirectorssection	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			£ 64	£ 66	£ 66
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	£ 20
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%
Assets at fair value		£ 7,717	£ 7,717	£ 12,564
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 | directors			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
Longevity swap
Disclosure of defined benefit plans [line items]
Percentage of pensioner liabilities covered by longevity swap						85.00%
Assets at fair value		£ 8	8
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 | directors			5
Santander (UK) Group Pension Scheme Trustees Limited
Disclosure of defined benefit plans [line items]
Number of trustee directors | directors			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)	£ (23)
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	£ 20

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)	£ (454)	£ (1,328)	£ (855)
Actuarial (gains)/losses arising from changes in demographic assumptions	(17)	34	42
Actuarial gains arising from experience adjustments	(19)	(141)	(42)
Actuarial (gains)/losses arising from changes in financial assumptions	(774)	1,940	1,377
Pension remeasurement	£ (1,264)	£ 505	£ 522

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	£ (92)
Current service cost paid by Santander UK plc	38	£ 36	£ 34
Interest cost	(5)	(10)	(23)
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)	(42)
Changes in financial assumptions	(774)	1,940	1,377
Ending balance	(1,535)	(92)
Present value of defined benefit obligations
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	(13,887)	(12,158)
Current service cost paid by Santander UK plc	(29)	(24)
Current service cost paid by subsidiaries	(9)	(12)
Current service cost paid by fellow Banco Santander subsidiaries	0	0
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	774	(1,940)
Benefits paid	398	396
Derecognition of pension scheme liabilities arising from the sale of PSA	41	0
Ending balance	£ (12,878)	£ (13,887)	£ (12,158)

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	£ (92)
Interest cost	(5)	£ (10)	£ (23)
Return on plan assets (excluding amounts included in net interest expense)	(454)	(1,328)	(855)
Ending balance	(1,535)	(92)
Fair value of scheme assets
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	13,979	12,547
Interest cost	193	263
Contributions paid by employer and scheme members	246	245
Contributions paid by fellow Banco Santander subsidiaries	0	0
Administration costs paid	(8)	(8)
Return on plan assets (excluding amounts included in net interest expense)	454	1,328
Benefits paid	(398)	(396)
Derecognition of pension scheme liabilities arising from the sale of PSA	(53)	0
Ending balance	£ 14,413	£ 13,979	£ 12,547

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	291	309
Longevity swap	(8)	0
Other	336	329
Total	£ 14,413	£ 13,979
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%
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	291	309
Longevity swap	(8)	0
Other	336	329
Total	£ (580)	£ 3,234
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
Discount rate
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%
General price 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	365
Percentage of reasonably possible increase in actuarial assumption	0.25%
General price inflation | Previously stated
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Increase (decrease) in defined benefit obligation		365
Mortality
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_3

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	£ 37,709	£ 43,160
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	£ 37,346	£ 42,221

Contingent Liabilities and Co_4

Contingent Liabilities and Commitments - Additional Information (Details) £ in Millions	Nov. 02, 2015	Dec. 31, 2021EUR (€)	Dec. 31, 2021GBP (£)	Dec. 31, 2021EUR (€)	Dec. 31, 2020GBP (£)	Jul. 31, 2020GBP (£)
Disclosure of contingent liabilities [line items]
Capital support arrangements, risk-weighted exposures of regulated entities			0.00%	0.00%
Provisions			£ 364		£ 464
Lease arrangements, potential final payment to HMRC			50
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%
Compliance with Consumer Credit Act
Disclosure of contingent liabilities [line items]
Provisions			£ 6		£ 47

Share Capital - Schedule of Sha

Share Capital - Schedule of Share Capital Issued and Fully Paid (Details) - GBP (£) £ / shares in Units, £ in Millions	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Disclosure of classes of share capital [line items]
Ordinary shares, price per share (in GBP per share)	£ 0.1	£ 0.1	£ 0.1
Issued capital	£ 3,105	£ 3,105	£ 3,105
Ordinary shares
Disclosure of classes of share capital [line items]
Number of shares issued and fully paid (in shares)	31,051,768,866	31,051,768,866	31,051,768,866
Issued capital	£ 3,105	£ 3,105	£ 3,105

Share Capital - Summary of Shar

Share Capital - Summary of Share Premium (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Jan. 01, 2021	Dec. 31, 2020	Jan. 01, 2020
Disclosure of classes of share capital [abstract]
Share premium	£ 5,620	£ 5,620	£ 5,620	£ 5,620

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	£ 2,191,000,000
- £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		£ 750,000,000	£ 750,000,000
- £500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities		£ 500,000,000
Interest rate	0.0518	0.0518	0.0518
Other equity instruments		£ 0	£ 210,000,000
- £500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities		£ 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
- £210m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities	£ 210,000,000	£ 210,000,000
Interest rate	0.0425	0.0425	0.0425
Other equity interest maturity period		2026-03	2026-03
Other equity instruments		£ 210,000,000	£ 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
- £210m 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	£ 210,000,000	£ 210,000,000
- £500m Fixed Rate Reset Perpetual AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Interest rate	0.0518	0.0518	0.0518
Capital securities purchased and redeemed, remaining amount	£ 210,000,000
Capital securities purchased and redeemed	£ 500,000,000
Capital securities issued		£ 500,000,000

Non-Controlling Interests - Sch

Non-Controlling Interests - Schedule of Amounts Attributable to Non-Controlling Interests (Details) - GBP (£) £ in Millions	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Noncontrolling Interests [Line Items]
Non-controlling interests	£ 0	£ 162
PSA Finance UK Limited
Disclosure Of Noncontrolling Interests [Line Items]
Non-controlling interests	£ 0	£ 162

Non-Controlling Interests - Add

Non-Controlling Interests - Additional Information (Details) - PSA Finance UK Limited - Santander Consumer (UK) £ in Millions	Jul. 30, 2021GBP (£)
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
Non-controlling interests
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	£ 40,410	£ 46,985
Proceeds from issue of debt securities	2,872	5,602
Repayment of debt securities	(11,910)	(11,378)
Repayment of subordinated liabilities	(4)	(659)
Issue of other equity instruments	450	0
Repurchase of other equity instruments	(500)	0
Payment of lease liability	(25)	(45)
Dividends paid	(1,494)	(292)
Liability-related other changes	(391)	(255)
Non-cash changes:
Unrealised foreign exchange	(800)	398
Other changes	1,463	54
Ending Balance	30,071	40,410
Debt securities in issue
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	35,566	41,129
Proceeds from issue of debt securities	2,872	5,602
Repayment of debt securities	(11,910)	(11,378)
Liability-related other changes	(447)	(250)
Non-cash changes:
Unrealised foreign exchange	(806)	376
Other changes	245	87
Ending Balance	25,520	35,566
Subordinated liabilities
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	2,556	3,528
Repayment of subordinated liabilities	(4)	(659)
Liability-related other changes	(4)	(10)
Non-cash changes:
Unrealised foreign exchange	6	22
Other changes	(326)	(325)
Ending Balance	2,228	2,556
Other equity instruments
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	2,191	2,191
Issue of other equity instruments	450
Repurchase of other equity instruments	(500)
Non-cash changes:
Other changes	50
Ending Balance	2,191	2,191
Lease liabilities
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	97	137
Payment of lease liability	(25)	(45)
Liability-related other changes	60	5
Non-cash changes:
Other changes	0	0
Ending Balance	132	97
Dividends paid
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	0	0
Dividends paid	(1,494)	(292)
Non-cash changes:
Other changes	1,494	292
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	£ 45	£ 54
Cash outflow for leases	28	48
Interest received	4,806	5,139	5,801
Interest paid	1,064	1,857	2,538
Dividends received	0	0	0
Cash and cash equivalents restated	£ 50,834	47,682	28,951	£ 26,264
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		£ 45	£ 54

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	67,595	62,557
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	284	550
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	41,936	23,655
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	4,363	5,581
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
Off-balance sheet
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	14,449	24,701
Collateral accepted as security for assets	17,781	30,510
Securities lending
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	45,936	30,040
Collateral accepted as security for assets	3,219	4,538
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	1,947	1,598
Collateral accepted as security for assets	£ 931	£ 2,063

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	£ 931	£ 2,063
On-balance sheet: | Deposits by banks
Disclosure Of Assets Pledged As Security [Line Items]
Total on-balance sheet/ off-balance sheet	931	2,063
Off-balance sheet
Disclosure Of Assets Pledged As Security [Line Items]
Total on-balance sheet/ off-balance sheet	£ 17,781	£ 30,510

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details)	12 Months Ended		48 Months Ended
	Dec. 31, 2021GBP (£)£ / sharesshares	Dec. 31, 2020GBP (£)£ / sharesshares	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 share price for share options in share-based payment arrangement exercised during period at date of exercise | £ / shares	£ 2.65	£ 2.92
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
Actual discount applied	10.00%
Maximum discount applicable	20.00%
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_3

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 (£)directorindividual	Dec. 31, 2020GBP (£)individual	Dec. 31, 2019GBP (£)individual
Disclosure Of Directors And Key Management Remuneration [Line Items]
Salaries and fees	£ 5,495,852	£ 5,353,980	£ 5,025,665
Performance-related payments	5,195,722	1,458,911	3,864,965
Other fixed remuneration (pension and other allowances & non-cash benefits)	929,935	1,107,348	1,367,069
Expenses	17,097	6,772	42,526
Total remuneration	11,638,606	7,927,011	10,300,225
Short-term employee benefits	25,114,949	18,432,698	21,925,975
Post-employment benefits	1,344,883	2,084,645	3,590,466
Total compensation	£ 26,459,832	£ 20,517,343	25,516,441
Number of previously employed individuals for buy-out of deferred performance related payment | individual		2
Number of directors who receive termination payment | director	1
Termination payment	£ 346,154	£ 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_4

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	£ 2,134,134
Remuneration excluding pension contribution performance related | £	2,913,000	726,040
Accrued defined benefit pension related 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	4	7
Loans made to directors | £	£ 348,306	£ 1,829,267
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_5

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 (£)depositsloans	Dec. 31, 2020GBP (£)loansdeposits
Disclosure Of Directors And Key Management Remuneration [Line Items]
Number of secured loans, unsecured loans and overdrafts, beginning balance | loans	12	18
Number of secured loans, unsecured loans and overdrafts, net movements | loans	(6)	(6)
Number of secured loans, unsecured loans and overdrafts, ending balance | loans	6	12
Beginning balance	£ 3,640	£ 4,920
Net movements	(3,280)	(1,280)
Ending balance	£ 360	£ 3,640
Number of deposit, bank and instant access accounts and investments, beginning balance | deposits	23	32
Number of deposit, bank and instant access accounts and investments, net movements | deposits	(2)	(9)
Number of deposit, bank and instant access accounts and investments, ending balance | deposits	21	23
Beginning balance	£ 8,195	£ 11,975
Net movements	(1,643)	(3,780)
Ending balance	£ 6,552	£ 8,195

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	£ (261)	£ (213)	£ (232)
Interest, fees and other expenses paid	463	578	756
Amounts owed by related parties	4,057	4,022
Amounts owed to related parties	(13,537)	(13,865)
Ultimate parent
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	(164)	(119)	(130)
Interest, fees and other expenses paid	33	105	266
Amounts owed by related parties	816	1,557
Amounts owed to related parties	(1,150)	(2,151)
Immediate parent
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	(6)	(7)	(7)
Interest, fees and other expenses paid	263	316	317
Amounts owed by related parties	7	8
Amounts owed to related parties	(10,935)	(10,121)
Fellow subsidiaries
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	(57)	(58)	(66)
Interest, fees and other expenses paid	163	157	173
Amounts owed by related parties	159	223
Amounts owed to related parties	(534)	(559)
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	1 Months Ended	12 Months Ended
	Oct. 31, 2020	Dec. 31, 2020
Santander Financial Services PLC | Mortgages
Disclosure of transactions between related parties [line items]
Book value of financial assets transferred	£ 3,163
Proceeds from transfer of financial assets	3,174
Price premium on transfer of financial assets	£ 11
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	£ 210,094	£ 208,750
Loans and advances to banks	1,169	1,682
Reverse repurchase agreements - non trading	12,683	19,599
Deposits by customers	192,926	195,135
Deposits by banks	33,855	20,958
Repurchase agreements - non trading	11,718	15,848
Debt securities in issue	25,520	35,566
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	266,247	270,063
Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	224,452	231,194
Deposits by customers | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by customers	192,926	195,135
Deposits by banks | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by banks	33,855	20,958
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	25,520	35,566
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	210,094	208,750
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	1,169	1,682
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	1,000	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	963	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	37	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	71,812	74,703
Level 2 | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	13,970	21,457
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	48	108
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	33,770	20,951
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	23,926	34,967
Level 2 | Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	2,350	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	1,169	1,682
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	194,439	196,819
Level 3 | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	213,037	211,505
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	192,898	195,134
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	85	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	212,811	211,279
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	267,251	271,522
Fair value | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	227,171	233,761
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	192,946	195,242
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	33,855	20,967
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	26,107	36,397
Fair value | Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	2,625	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	212,811	211,279
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	1,169	1,682
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	£ 7,717	£ 12,564
Total liabilities at fair value	1,580	3,018
Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total liabilities at fair value	777	1,584
Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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	1,681	3,406
Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	185	208
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	8,501
Total liabilities at fair value	0	0
Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total liabilities at fair value	0	0
Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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	0
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	1,635	3,766
Total liabilities at fair value	1,542	2,978
Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total liabilities at fair value	745	1,552
Level 2 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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	1,635	3,338
Level 2 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
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	249	297
Total liabilities at fair value	38	40
Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total liabilities at fair value	32	32
Level 3 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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	46	68
Level 3 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	185	208
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]
Valuation technique	A
Total liabilities at fair value	£ 506	833
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]
Total 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]
Total liabilities at fair value	506	833
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]
Total 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]
Valuation technique	A & C
Total liabilities at fair value	£ 1,438	2,450
Interest rate contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 1,547	2,580
Valuation technique	A & C
Interest rate contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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]
Total liabilities at fair value	1,436	2,447
Interest rate contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	1,547	2,566
Interest rate contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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]
Valuation technique	B & D
Total liabilities at fair value	£ 54	55
Equity and credit contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 161	123
Valuation technique	B & D
Equity and credit contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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]
Total liabilities at fair value	24	26
Equity and credit contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	116	71
Equity and credit contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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	45	52
Netting | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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]
Total 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]
Total 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]
Total 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	£ 74	99
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	0	0
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	£ 111	109
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	0	0
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	£ 0	0
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	0
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	0	0
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]
Valuation technique	A
Total liabilities at fair value	£ 560	1,057
Debt securities in issue | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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]
Total 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]
Total liabilities at fair value	£ 5	6
Structured deposits | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Valuation technique	A
Total liabilities at fair value	£ 223	375
Structured deposits | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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]
Total 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]
Total 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]
Valuation technique	A
Total liabilities at fair value	£ 0	0
Repurchase agreements - non trading | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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]
Total 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]
Total 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]
Valuation technique	D
Total liabilities at fair value	£ 20	2
Collateral and associated financial guarantees | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Total 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]
Total 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]
Total 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	£ 0
Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period	0	0
Transfers into Level 3 of fair value hierarchy, assets	0	0
Transfers out of Level 3 of fair value hierarchy, assets	0	0
Liabilities
Transfers out of Level 1 into Level 2 of fair value hierarchy, liabilities held at end of reporting period	0	0
Transfers out of Level 2 into Level 1 of fair value hierarchy, liabilities held at end of reporting period	0	0
Transfers into Level 3 of fair value hierarchy, liabilities	0	0
Transfers out of Level 3 of fair value hierarchy, liabilities	0	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	£ 20	£ 29
- 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	20	23
- 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	20	29
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	£ 185	£ 208
Financial assets at FVOCI	5,851	8,950
Total net assets	211	257
Financial asset liabilities	0	0	£ 0
Total income/(expense)	(4)	17	(5)
Loans and advances to customers
Disclosure Of Financial Assets And Liabilities [Line Items]
Financial assets at FVOCI	18	21
Level 3
Disclosure Of Financial Assets And Liabilities [Line Items]
Financial assets and liabilities	217	249
Financial asset liabilities	(5)	11	(16)
Other Level 3 assets | Level 3
Disclosure Of Financial Assets And Liabilities [Line Items]
Other Level 3 assets	1	17
Other Level 3 liabilities	(7)	(9)
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	(1)	7	16
Derivative liabilities and other Level 3 liabilities, fair value movements recognised in profit/(loss)	2	(1)	(5)
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
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 FVOCI	18	21
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	(3)	(4)	(2)
Credit linked notes | Debt securities
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)	£ 6	£ 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	£ 292,332	£ 281,702
Beginning balance	(276,396)	(265,685)
Transfers in	0	0
Transfers in	0	0
Transfers out	0	0
Transfers out	0	0
Ending Balance	287,098	292,332
Ending Balance	(270,996)	(276,396)
Level 3 | Other financial assets at FVTPL
Disclosure of fair value measurement of assets [line items]
Beginning balance	208	386
Fair value movements	(7)	(1)
Foreign exchange and other movements	0	(5)
Transfers in	0	0
Transfers out	0	0
Netting	23	(42)
Additions	0	0
Sales	(16)	(19)
Settlements	(23)	(111)
Ending Balance	185	208
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period	(7)	(6)
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 period	(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 period	0	0
Level 3 | Financial assets at fair value
Disclosure of fair value measurement of assets [line items]
Beginning balance	297	517
Fair value movements	(11)	5
Foreign exchange and other movements	0	(5)
Transfers in	0	1
Transfers out	0	0
Netting	23	(42)
Additions	0	2
Sales	(16)	(38)
Settlements	(44)	(143)
Ending Balance	249	297
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period	(11)	0
Level 3 | Derivatives
Disclosure of fair value measurement of assets [line items]
Beginning balance	68	75
Fair value movements	(1)	10
Foreign exchange and other movements	0	0
Transfers in	0	1
Transfers out	0	0
Netting	0	0
Additions	0	2
Sales	0	0
Settlements	(21)	(20)
Ending Balance	46	68
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period	(1)	10
Derivatives | Level 3
Disclosure of fair value measurement of assets [line items]
Beginning balance	(32)	(32)
Fair value movements	0	(6)
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	6
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 period	0	(6)
Other financial liabilities at FVTPL | Level 3
Disclosure of fair value measurement of assets [line items]
Beginning balance	(8)	(61)
Fair value movements	7	18
Foreign exchange and other movements	0	8
Transfers in	0	0
Transfers out	0	28
Netting	(5)	0
Additions	0	(2)
Sales	0	0
Settlements	0	1
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 period	7	26
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 period	0	0
Financial liabilities at fair value | Level 3
Disclosure of fair value measurement of assets [line items]
Beginning balance	(40)	(93)
Fair value movements	7	12
Foreign exchange and other movements	0	8
Transfers in	0	0
Transfers out	0	28
Netting	(5)	0
Additions	0	(2)
Sales	0	0
Settlements	0	7
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 period	£ 7	£ 20

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	£ 7,717	£ 12,564
Liabilities at fair value	(1,580)	(3,018)
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 | 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 | 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 | 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%
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	192,926	195,135
Deposits by banks	33,855	20,958
Repurchase agreements - non trading	11,718	15,848
Debt securities in issue	25,520	35,566
Subordinated liabilities	2,228	2,556
Lease liabilities	132	97
Undiscounted Cash Flow
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	809	1,632
Other financial liabilities at fair value through profit or loss	803	1,437
Deposits by customers	193,057	195,563
Deposits by banks	33,955	21,360
Repurchase agreements - non trading	11,718	15,850
Debt securities in issue	26,191	36,513
Subordinated liabilities	3,697	4,061
Lease liabilities	141	109
Total financial liabilities	270,371	276,525
Off-balance sheet commitments given	37,709	43,160
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	177,926	176,911
Deposits by banks	1,377	2,410
Repurchase agreements - non trading	0	0
Debt securities in issue	0	0
Subordinated liabilities	0	0
Lease liabilities	0	0
Total financial liabilities	179,303	179,321
Off-balance sheet commitments given	20,519	21,054
Undiscounted Cash Flow | Not later than 3 months
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	74	279
Other financial liabilities at fair value through profit or loss	6	1
Deposits by customers	3,107	3,443
Deposits by banks	551	1,912
Repurchase agreements - non trading	11,419	15,350
Debt securities in issue	4,993	4,993
Subordinated liabilities	32	30
Lease liabilities	0	0
Total financial liabilities	20,182	26,008
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	58	133
Other financial liabilities at fair value through profit or loss	8	107
Deposits by customers	4,691	5,453
Deposits by banks	41	2,596
Repurchase agreements - non trading	299	500
Debt securities in issue	2,725	9,897
Subordinated liabilities	98	92
Lease liabilities	32	17
Total financial liabilities	7,952	18,795
Off-balance sheet commitments given	5,734	4,974
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	389	582
Other financial liabilities at fair value through profit or loss	553	570
Deposits by customers	5,750	7,483
Deposits by banks	31,986	14,230
Repurchase agreements - non trading	0	0
Debt securities in issue	11,921	14,083
Subordinated liabilities	1,547	1,515
Lease liabilities	78	56
Total financial liabilities	52,224	38,519
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	288	638
Other financial liabilities at fair value through profit or loss	236	759
Deposits by customers	1,583	2,273
Deposits by banks	0	212
Repurchase agreements - non trading	0	0
Debt securities in issue	6,552	7,540
Subordinated liabilities	2,020	2,424
Lease liabilities	31	36
Total financial liabilities	10,710	13,882
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	£ 21,965	£ 38,609
Amounts offset, Assets	(4,343)	(9,312)
Net amounts reported on the balance sheet, Assets	17,622	29,297
Financial instruments, Assets	(1,189)	(911)
Financial collateral, Assets	(12,941)	(21,310)
Net amount, Assets	3,492	7,076
Assets not subject to enforceable netting arrangements, Assets	208,007	204,140
Balance sheet total, Assets	225,629	233,437
Gross amounts, Liabilities	24,481	36,753
Amounts offset, Liabilities	(4,343)	(9,312)
Net amounts reported on the balance sheet, Liabilities	20,138	27,441
Financial instruments, Liabilities	(1,189)	(911)
Financial collateral, Liabilities	(11,224)	(16,772)
Net amount, Liabilities	7,725	9,758
Assets not subject to enforceable netting arrangements, Liabilities	219,138	206,084
Balance sheet total, Liabilities	239,276	233,525
Derivative financial instruments
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	2,832	5,071
Amounts offset, Assets	(1,221)	(1,754)
Net amounts reported on the balance sheet, Assets	1,611	3,317
Financial instruments, Assets	(754)	(782)
Financial collateral, Assets	(693)	(1,840)
Net amount, Assets	164	695
Assets not subject to enforceable netting arrangements, Assets	72	89
Balance sheet total, Assets	1,683	3,406
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	4,251	7,454
Amounts offset, Assets	(923)	(1,073)
Net amounts reported on the balance sheet, Assets	3,328	6,381
Financial instruments, Assets	0	0
Financial collateral, Assets	0	0
Net amount, Assets	3,328	6,381
Assets not subject to enforceable netting arrangements, Assets	207,935	204,051
Balance sheet total, Assets	211,263	210,432
Derivative financial liabilities
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Liabilities	1,955	3,261
Amounts offset, Liabilities	(1,221)	(1,754)
Net amounts reported on the balance sheet, Liabilities	734	1,507
Financial instruments, Liabilities	(754)	(782)
Financial collateral, Liabilities	59	(551)
Net amount, Liabilities	39	174
Assets not subject to enforceable netting arrangements, Liabilities	43	77
Balance sheet total, Liabilities	777	1,584
Deposits by customers and banks
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Liabilities	8,609	11,159
Amounts offset, Liabilities	(923)	(1,073)
Net amounts reported on the balance sheet, Liabilities	7,686	10,086
Financial instruments, Liabilities	0	0
Financial collateral, Liabilities	0	(502)
Net amount, Liabilities	7,686	9,584
Assets not subject to enforceable netting arrangements, Liabilities	219,095	206,007
Balance sheet total, Liabilities	£ 226,781	£ 216,093

Interest Rate Benchmark Refor_2

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	£ 1,681	£ 3,406
Other financial assets at FVTPL	185	208
Financial assets at amortised cost	506	1,163
Financial assets at fair value through other comprehensive income	5,851	8,950
Total assets	287,098	292,332	£ 281,702
Liabilities
Derivative financial instruments	777	1,584
Other financial liabilities at fair value through profit or loss	803	1,434
Total liabilities	270,996	276,396	£ 265,685
GBP LIBOR
Assets
Derivative financial instruments	0	33,486
Other financial assets at FVTPL	8	968
Financial assets at amortised cost	1,373	15,062
Financial assets at fair value through other comprehensive income		428
Total assets	1,381	49,944
Liabilities
Derivative financial instruments	338	35,217
Other financial liabilities at fair value through profit or loss	0	1,129
Financial liabilities at amortised cost	34	2,354
Total liabilities	372	38,700
Off-balance sheet commitments given	338	11,400
USD LIBOR
Assets
Derivative financial instruments	1,480	4,514
Other financial assets at FVTPL	0	22
Financial assets at amortised cost	81	1,191
Financial assets at fair value through other comprehensive income		0
Total assets	1,561	5,727
Liabilities
Derivative financial instruments	1,831	5,205
Other financial liabilities at fair value through profit or loss	5	69
Financial liabilities at amortised cost	185	1,319
Total liabilities	2,021	6,593
Off-balance sheet commitments given	59	2,126
Other
Assets
Derivative financial instruments	0	2,149
Other financial assets at FVTPL	0	0
Financial assets at amortised cost	1	90
Financial assets at fair value through other 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	1,480	40,149
Other financial assets at FVTPL	8	990
Financial assets at amortised cost	1,455	16,343
Financial assets at fair value through other comprehensive income		428
Total assets	2,943	57,910
Liabilities
Derivative financial instruments	2,169	40,510
Other financial liabilities at fair value through profit or loss	5	1,198
Financial liabilities at amortised cost	219	3,673
Total liabilities	2,393	45,381
Off-balance sheet commitments given	£ 397	£ 14,099

Interest Rate Benchmark Refor_3

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	£ 3,949	£ 3,388	[1]	£ 3,224	[1]
Net fee and commission income	286	319	[1]	624	[1]
Other operating income	264	145	[1]	187	[1]
Total operating income	4,499	3,852	[1]	4,035	[1]
Operating expenses before credit impairment write-backs/losses, provisions and charges	(2,510)	(2,390)	[1]	(2,439)	[1]
Credit impairment write-backs/ (losses)	233	(638)	[1]	(199)	[1]
Provisions for other liabilities and charges	(377)	(264)	[1]	(426)	[1]
Total operating credit impairment write-backs/losses, provisions and charges	(144)	(902)	[1]	(625)	[1]
Profit from discontinued operations before tax	43	45		41
Tax on profit from discontinued operations	(12)	(13)		(11)
Profit from discontinued operations after tax	31	32	[1]	30	[1]
Discontinued operations
Disclosure of analysis of single amount of discontinued operations [line items]
Net interest income	32	55		68
Net fee and commission income	35	66		63
Other operating income	2	2		8
Total operating income	69	123		139
Operating expenses before credit impairment write-backs/losses, provisions and charges	(33)	(62)		(60)
Credit impairment write-backs/ (losses)	11	(7)		(22)
Provisions for other liabilities and charges	(4)	(9)		(16)
Total operating credit impairment write-backs/losses, provisions and charges	£ 7	£ (16)		£ (38)
[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		£ 287,098	£ 292,332	£ 281,702
Liabilities		270,996	276,396	265,685
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]
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
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
Liabilities		£ 0	£ 6,517	£ 6,233

Events After the Balance Shee_2

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.