Santander UK (SANS+) 20-F 7 Mar 23 2022 FY Annual report (foreign) Financial data

Cover Page

Cover Page	12 Months Ended
	Dec. 31, 2022 shares
Document And Entity Information [Line Items]
Document Type	20-F
Document Registration Statement	false
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
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	2022
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, 2022
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, 2022	Dec. 31, 2021	Dec. 31, 2020
Profit (loss) [abstract]
Interest and similar income	£ 6,708	£ 4,762	£ 5,031
Interest expense and similar charges	(2,283)	(813)	(1,643)
Net interest income	4,425	3,949	3,388
Fee and commission income	839	697	680
Fee and commission expense	(509)	(411)	(361)
Net fee and commission income	330	286	319
Other operating income	201	264	145
Total operating income	4,956	4,499	3,852
Operating expenses before credit impairment (charges)/write-backs, provisions and charges	(2,343)	(2,510)	(2,390)
Credit impairment (charges)/write-backs	(320)	233	(638)
Provisions for other liabilities and charges	(419)	(377)	(264)
Total operating credit impairment (charges)/write-backs, provisions and charges	(739)	(144)	(902)
Profit from continuing operations before tax	1,874	1,845	560
Tax on profit from continuing operations	(480)	(492)	(121)
Profit from continuing operations after tax	1,394	1,353	439
Profit from discontinued operations after tax	0	31	32
Profit after tax	1,394	1,384	471
Attributable to:
Equity holders of the parent	1,394	1,365	452
Non-controlling interests	0	19	19
Profit after tax	£ 1,394	£ 1,384	£ 471

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of comprehensive income [abstract]
Profit after tax	£ 1,394	£ 1,384	£ 471
Movement in fair value reserve (debt instruments):
- Change in fair value	(278)	(111)	114
- Income statement transfers	247	110	(107)
- Taxation	11	(2)	(2)
Other comprehensive income, fair value reserve (debt instruments)	(20)	(3)	5
Cash flow hedges:
- Effective portion of changes in fair value	425	(873)	971
- Income statement transfers	(2,129)	358	(809)
- Taxation	469	141	(52)
Other comprehensive income, cash flow hedges, total	(1,235)	(374)	110
Currency translation on foreign operations	0	0	0
Net other comprehensive (expense)/income that may be reclassified to profit or loss subsequently	(1,255)	(377)	115
Pension remeasurement:
- Change in fair value	(722)	1,264	(505)
- Taxation	267	(419)	133
Pension remeasurement, total	(455)	845	(372)
Own credit adjustment:
- Change in fair value	29	0	(3)
- Taxation	(9)	0	0
Own credit adjustment, total	20	0	(3)
Net other comprehensive (expense)/income that will not be reclassified to profit or loss subsequently	(435)	845	(375)
Total other comprehensive (expense)/income net of tax	(1,690)	468	(260)
Total comprehensive (expense)/income	(296)	1,852	211
Attributable to:
Equity holders of the parent	(296)	1,833	194
Non-controlling interests	0	19	17
Total comprehensive (expense)/income	£ (296)	£ 1,852	£ 211

Consolidated Balance Sheet

Consolidated Balance Sheet - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets
Cash and balances at central banks	£ 44,190	£ 48,139
Derivative financial instruments	2,407	1,681
Other financial assets at fair value through profit or loss	129	185
Loans and advances to customers	219,716	210,094
Loans and advances to banks	992	1,169
Reverse repurchase agreements - non trading	7,348	12,683
Other financial assets at amortised cost	156	506
Macro hedge of interest rate risk	(2,657)	77
Financial assets at fair value through other comprehensive income	6,024	5,851
Interests in other entities	252	201
Intangible assets	1,550	1,545
Property, plant and equipment	1,513	1,548
Current tax assets	478	347
Retirement benefit assets	1,050	1,572
Other assets	2,016	1,500
Assets held for sale	49	0
Total assets	285,213	287,098
Liabilities
Derivative financial instruments	951	777
Other financial liabilities at fair value through profit or loss	803	803
Deposits by customers	195,568	192,926
Deposits by banks	28,525	33,855
Repurchase agreements - non trading	7,982	11,718
Debt securities in issue	31,531	25,520
Subordinated liabilities	2,332	2,228
Macro hedge of interest rate risk	95	122
Other liabilities	2,581	2,067
Provisions	378	364
Deferred tax liabilities	35	579
Retirement benefit obligations	25	37
Total liabilities	270,806	270,996
Equity
Share capital	3,105	3,105
Share premium	5,620	5,620
Other equity instruments	1,956	2,191
Retained earnings	4,848	5,053
Other reserves	(1,122)	133
Total shareholders’ equity	14,407	16,102
Total equity	14,407	16,102
Total liabilities and equity	£ 285,213	£ 287,098

Consolidated Cash Flow Statemen

Consolidated Cash Flow Statement - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Profit after tax	£ 1,874	£ 1,888	£ 605
Non-cash items included in profit:
– Depreciation and amortisation	296	501	562
– Provisions for other liabilities and charges	419	381	273
– Impairment losses	284	(228)	672
– Other non-cash items	1,497	(147)	(267)
– Pension charge/(credit) for defined benefit pension schemes	28	38	38
Total adjustments to reconcile profit (loss)	2,524	545	1,278
Net change in operating assets and liabilities:
– Cash and balances at central banks	275	(659)	(52)
– Derivative assets	(726)	1,725	(90)
– Other financial assets at fair value through profit or loss	877	1,007	1,603
– Loans and advances to banks and customers	(9,966)	(971)	(2,654)
– Reverse repurchase agreements - non trading	6,818	7,024	3,924
– Other assets	(574)	324	(340)
– Deposits by banks and customers	(3,128)	10,735	19,977
– Repurchase agreements - non trading	(4,145)	(7,550)	(2,958)
– Derivative liabilities	174	(807)	136
– Other financial liabilities at fair value through profit or loss	(973)	(1,109)	(1,618)
– Debt securities in issue	3,120	(329)	(223)
– Other liabilities	(98)	(603)	(921)
Net change in operating assets and liabilities	(8,346)	8,787	16,784
Corporation taxes paid	(405)	(427)	(159)
Effects of exchange rate differences	1,383	(542)	410
Net cash flows from operating activities	(2,970)	10,251	18,918
Cash flows from investing activities
Purchase of property, plant and equipment and intangible assets	(496)	(613)	(373)
Proceeds from sale of property, plant and equipment and intangible assets	159	437	166
Purchase of financial assets at amortised cost and financial assets at FVOCI	(2,884)	(1,256)	(3,015)
Proceeds from sale and redemption of financial assets at amortised cost and financial assets at FVOCI	3,023	4,509	9,858
Net cash flows from investing activities	(198)	3,077	6,636
Cash flows from financing activities
Issue of other equity instruments	750	210	0
Issue of debt securities and subordinated notes	4,794	2,878	5,614
Issuance costs of debt securities and subordinated notes	(16)	(6)	(13)
Repayment of debt securities and subordinated notes	(3,076)	(11,914)	(12,037)
Disposal of non-controlling interests	0		0
Disposal of non-controlling interests		(181)
Repurchase of other equity instruments	(985)	(210)	0
Dividends paid on ordinary shares	(1,014)	(1,358)	(129)
Dividends paid on preference shares and other equity instruments	(150)	(147)	(148)
Dividends paid on non-controlling interests	0	0	(15)
Principal elements of lease payments	(26)	(25)	(45)
Net cash flows from financing activities	277	(10,753)	(6,773)
Change in cash and cash equivalents	(2,891)	2,575	18,781
Cash and cash equivalents at beginning of the year	49,254	46,697	27,871
Effects of exchange rate changes on cash and cash equivalents	121	(18)	45
Cash and cash equivalents at the end of the year	46,484	49,254	46,697
Cash and cash equivalents consist of:
Cash and balances at central banks	44,190	48,139	41,250
Less: restricted balances	(2,223)	(2,498)	(1,839)
Cash and bank balances at central banks less regulatory minimum cash balances	41,967	45,641	39,411
Other cash equivalents: Loans and advances to banks - Non trading	904	1,074	1,435
Other cash equivalents: Reverse repurchase agreements	3,613	2,539	5,851
Cash and cash equivalents at the end of the year	£ 46,484	£ 49,254	£ 46,697

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, 2019	£ 16,017	£ 15,857	£ 3,105	£ 5,620	£ 2,191	£ 23	£ 371	£ 1	£ 4,546	£ 160
Profit after tax	471	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 (expense)/income	211	194				5	110		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 after tax	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 (expense)/income	1,852	1,833				(3)	(374)		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)
Ending balance at Dec. 31, 2021	16,102	16,102	3,105	5,620	2,191	25	107	1	5,053	0
Profit after tax	1,394	1,394							1,394
Other comprehensive (expense)/income, net of tax:
- Fair value reserve (debt instruments)	(20)	(20)				(20)
- Cash flow hedges	(1,235)	(1,235)					(1,235)
- Pension remeasurement	(455)	(455)							(455)
- Own credit adjustment	20	20							20
Total comprehensive (expense)/income	(296)	(296)				(20)	(1,235)		959	0
Issue of other equity instruments	750	750			750
Repurchase of other equity instruments	(985)	(985)			(985)
Dividends on ordinary shares	(1,014)	(1,014)							(1,014)
Dividends on preference shares and other equity instruments	(150)	(150)							(150)
Ending balance at Dec. 31, 2022	£ 14,407	£ 14,407	£ 3,105	£ 5,620	£ 1,956	£ 5	£ (1,128)	£ 1	£ 4,848	£ 0

Risk Framework

Risk Framework	12 Months Ended
	Dec. 31, 2022
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 and risks including money laundering, bribery and corruption and sanctions compliance and monitors KPIs in line with approved Board risk appetite Board Responsible Banking Committee – Responsible for culture and operational risk from conduct, compliance, competition & legal matters – Reviews reports from the Director of Compliance (DoC) 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 Sustainability and Responsible Banking 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 the external 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 (ExCo) – 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 BRC 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 Economic Crime Committee – Ensures due reporting, consideration, oversight and informed decision making regarding compliance with financial crime laws and regulations, fraud, and best industry practice aligned to our 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 is made within our Risk Appetite. Accountable for control and oversight of credit, market, liquidity, capital, pension, strategic & business, operational, model, climate and enterprise risks. Chief Financial Officer Responsible for developing strategy, leadership and management of the CFO Division. The CFO is responsible for managing interest rate, liquidity, pension and capital risks. The CFO also aims to maximise the return on Regulatory and Economic Capital. 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 CRO 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. Director of Compliance (DoC) Responsible to the CRO for control and oversight of conduct and regulatory risk and Compliance 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, 2022
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 then analyse our key metrics, credit performance and forbearance. Key metrics Stage 3 ratio improved to 1.26% (2021: 1.45%). Loss allowances increased to £1,005m (2021: £865m). Balance weighted average LTV of 69% (2021: 66%) 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: – Residential mortgages for customers with good credit quality (prime lending). – We provide these mostly for owner-occupiers, with buy-to-let mortgages for non-professional landlords. In Everyday Banking: – Unsecured lending to individuals, such as loans, credit cards and overdrafts. – Banking services to businesses with turnover up to £6.5m per annum and simpler borrowing needs. We offer loans, credit cards and overdrafts. – Financing for cars, vans, motorbikes and leisure vehicles 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 turnover up to £500m per annum, Commercial Real Estate and Social Housing associations. – Asset and liability management of our balance sheet, as well as non-core and legacy portfolios in run-off. – Exposures include financial institutions (derivatives and other treasury products), structured products, and sovereign and supranational assets chosen for diversification and liquidity. The segmental basis of presentation in this Annual Report has changed following the transfer of Social Housing loans and non-core liabilities to our CCB segment from Corporate Centre. Comparatives have been restated accordingly. See Note 2 for more information. Our approach to credit risk We manage our portfolios across the credit risk lifecycle, from drawing up our risk strategy and planning, through assessment and origination, monitoring, arrears management and debt recovery. We make sure the actual risk profile of our exposures stays in line with our business plans and within our Risk Appetite. We tailor the way we manage risk 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 our process and application assessment based on the product. More complex transactions often need greater manual assessment using our credit underwriters’ skill and experience. In Everyday Banking, similar to Homes, many of our decisions are automated and we tailor the process based on the product. We assess affordability on a proportionate basis by reviewing the customer’s income, spending stressed for future inflation, their total credit commitments and accommodation stressed for expected interest rates. Credit risk mitigation The types of credit risk mitigation, including collateral, across each of our portfolios are: 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. We consider the UK Government guarantee supporting losses on amounts lent under its Coronavirus Loan Schemes as collateral with 100% for Bounce Back Loan Scheme (BBLS) and 80% for Coronavirus Business Interruption Loan Scheme (CBILS). Consumer Finance In Consumer Finance, similar to Retail Banking, many decisions are automated and we tailor the process to the product. Residual value risk is one of our top risks. 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 loans, with the customer being the registered keeper. Only a very small proportion of 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 the value of the vehicle is appropriate. Corporate & Commercial Banking We assign 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 As part of the Banco Santander group, we comply with the Equator Principles to factor social, ethical and environmental impacts into our risk analysis and decision making for qualifying financial transactions. We are committed to supporting clients and economies in their transition to a low carbon economy, providing financial products and/or services to business activities that are environmentally and socially responsible. Our ESCC policy sets out how we identify, assess, monitor and manage environmental and social risks and other climate change related activities in the Oil and Gas, Power Generation and Mining and Metals sectors and those arising from businesses engaged in soft commodities. Our ESCC policy prohibits project-related financing for new coal-fired power plants (CFPP) worldwide and we will only work with new clients with CFPPs to provide specific financing for renewable energy projects. In line with Banco Santander's commitment, by 2030 we will eliminate all exposure to thermal coal mining and stop providing financial services to power generation clients with more than 10% of revenue from thermal coal. More information on our approach to Responsible Lending can be found in the Sustainability and Responsible Banking section. 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 of 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 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. Commercial Real Estate We take a first charge on commercial property as collateral. The loan is subject to criteria such as the property condition, age and location, tenant quality, lease terms and length, and the sponsor’s experience and creditworthiness. Before advancing the loan and where appropriate, a bank representative visits the property, additionally we get an independent professional valuation which typically includes a site visit. Loan agreements typically allow us to obtain revaluations during the term of the loan. Social Housing We take a first 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 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) in our Eligible Liquidity Pool. They are mainly ABS and covered bonds, which hold senior positions in the creditor hierarchy. Their credit rating reflects over-collateralisation in the structure and the assets that underpin their cash flows. 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. 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 economy also impact our Homes portfolio. As part of our day-to-day risk monitoring, we use a Retail Risk Playbook tolerance framework that sets out the most relevant macroeconomic variables to retail portfolio performance. We monitor these variables against our forecasts. If the economy deviates materially from our forecasts, such as due to the effects of the cost of living crisis, high inflation, we formally review our retail risk management policy and strategy. 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 needed. 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 their probability of default has increased, such as they have breached a covenant or lost a major contract. We classify Watchlist cases as: – Enhanced monitoring: for less urgent cases. We monitor these cases 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 Watchlist cases for impairment as set out in the ‘Significant Increase in Credit Risk (SICR)’ section. When a customer is in enhanced monitoring, we do not consider it has suffered a SICR for ECL purposes, so it remains in Stage 1 for our loss allowance calculations. When a customer is in proactive management, we consider it has suffered a SICR, so we transfer it to Stage 2 and apply a lifetime ECL for our loss allowance calculations. We take into account any forbearance we offer. This includes any extra security, guarantees or equity available and the potential to enhance value by asset management. In Corporate & Commercial Banking, as part of our annual reviews, for loans nearing maturity, we look at the prospect of refinancing the loan on current market terms and applicable credit policy. If this is unlikely, we put the case on our Watchlist. We manage exposures not subject to annual reviews, mainly high volume and low value cases, using early warning indicators including credit reference agency data, supported by teams of expert analysts. In Corporate Centre, we typically monitor the credit quality of our exposures daily. We use 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 exposures subject to annual review. We aim to identify warning signs early by monitoring customers’ financial and trading data, checking to see they do not breach covenants, and having regular dialogue with them. We tailor our strategy to the type of customer, their circumstances and the level of risk. We try to help our customers find their own way out of financial difficulty and agree on a plan that works for both of us. We engage our Restructuring & Recoveries team as needed on Watchlist cases and we may hand over more serious cases to them. For exposures not subject to annual review, we have strategies to manage arrears that can be used as early as the day of the missed payment. 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. 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, we may use a debt collection agency, sell the debt, or take the customer to court. For retail mortgages, we may repossess the property as a last resort or to protect it from damage or third-party claims. We make sure our estimated losses from repossessed properties are realistic by getting two independent valuations and the estimated selling costs, and using them in our loss allowances calculations. Where we repossess a property, we do not take ownership. We use agents to realise the value and settle the debt. Any surplus funds are returned to the borrower or dealt with in line with insolvency rules. In Everyday Banking, we may use a debt collection agency, sell the debt, or take the customer to court, similar to our approach in Homes. Consumer Finance In Consumer Finance, similar to Retail Banking, we may use a debt collection agency, sell the debt, or take the customer to court. We may consider taking steps to re-possess 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 reach an agreement, 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 to recover what we are owed. If there is a shortfall, we write it off against our loss allowances. In very rare cases, 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. 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 (audited) We can change the terms of a customer's loan, temporarily or permanently, to help them through temporary periods of difficulty so they can get back on to sustainable terms. We assess what we offer to make sure the customer can afford it. Forbearance improves our customer relationships and we review our approach regularly to make sure it is still effective. We try to offer forbearance before a customer defaults and we only foreclose or repossess as a last resort. The main types of forbearance we offer are: Action Description Term extension We can extend the loan term, making each monthly payment smaller. We may offer this if the customer is up to date with payments but shows signs of financial difficulties. We may also offer this if the loan is about to mature and refinancing is not possible on market terms. Interest-only Prior to 2016, we offered retail customers temporary concessions to interest-only repayments due to financial difficulty. This concession is no longer available but any such loans that remain on interest-only repayment concession are classed as forborne. For corporate customers, we still consider interest-only concessions on a case by case basis. 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 may add the arrears to the mortgage balance (this is known as capitalisation) if they cannot afford to increase their monthly payment to pay off their arrears in a reasonable time but have been making their monthly payments, usually for at least six months. We can also capitalise property charges due to a landlord. We pay them for the customer to avoid the lease being forfeited. We may combine this help with term extensions and, in the past, interest-only concessions. In certain cases we may also offer interest rate concessions. For corporate customers, we may lower or stop their payments until they have time to recover. We may reschedule payments to better match the customer’s cash flow – for example if the business is seasonal - or provide a temporary increase in facilities to cover peak demand ahead of their trading improving. We might do this by arrears capitalisation or drawing from an overdraft. We may also offer to provide new facilities, interest rate concessions and interest roll-up. In rare cases, we agree to forgive or reduce part of the debt. When we agree forbearance, we consider the account has suffered a SICR, as we explain later on, and we classify it as Stage 2 or 3. If an account is already in Stage 2, we keep it in Stage 2 unless the account is deemed unlikely to pay, involves forgiving fees and interest or debt, or is being granted multiple forbearances. In these cases, we move it into Stage 3. If an account is already in Stage 3, we keep it in Stage 3. A loan moves out of forbearance once the exit criteria below are met. We monitor the performance of all forborne loans. 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 signs of financial difficulties, we can also change their loan terms. We do this to help them manage their financial liabilities. Retail Banking In Homes, apart from forbearance, we have sometimes changed the contract terms to keep a good relationship with a customer. In Homes and Everyday Banking, we do not classify insolvency solutions for any unsecured retail customers as forbearance. This is in line with industry guidelines. Consumer Finance We do not classify insolvency solutions for any unsecured retail customers as forbearance. This is in line with industry guidelines. Corporate & Commercial Banking and Corporate Centre 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 more collateral in return for revised financing terms. We may also take a guarantee from companies in the same group and/or major shareholders. We only do this where we believe the guarantor can 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. Risk measurement and control We measure and control credit risk at all stages across the credit risk lifecycle. We have a range of tools, processes and approaches. Retail Banking and Consumer Finance These businesses involve managing large numbers of accounts, so they produce a huge amount of data. This allows us to take a more analytical and data intense approach to measuring risk. This is reflected in the wide range of statistical models we use across the credit risk lifecycle. We use: – Risk strategy and planning: econometric models – Assessment and origination: application scorecards, and attrition, pricing, loss allowance and capital models – Monitoring: behavioural scorecards and profitability models – Arrears management: models to estimate the proportion of cases that will result in possession (known as roll rates) – Debt recovery: recovery models. We assess and review our loss allowances regularly and have them independently reviewed. We look at factors such as the cash flow available to service debt. We also use an agency to value any collateral – mainly mortgages. Corporate & Commercial Banking and Corporate Centre We measure the credit risk on treasury products by adding their potential future exposure to market movements over their lives to their fair value. Then we add it to any other exposure and measure the total against our credit limits for each client. We assess our loss allowances regularly by looking at factors such as the cash flow available to service debt and the value of collateral based on third-party professiona l valuations. Key metrics (audited) 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 or 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 CRD IV regulatory capital rules and gives us another view of credit risk. It is the product of the probability of default, exposure at default and loss given default, and we include direct and indirect costs. We base it on our risk models and our assessment of each customer’s credit quality. 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 impairment accounting policy, see Note 1 to the Consolidated Financial Statements. We also assess risks from other perspectives, such as geography, business area, product and process to identify areas to focus on. We also use stress testing to establish vulnerabilities to economic deterioration. Our business segments tailor their approach to credit risk to their customers, as we explain later on. Recognising ECL (audited) The ECL approach estimates the credit losses arising from defaults in the next 12 months on qualifying exposures, or defaults over the lifetime of the exposure where there is evidence of a Significant Increase in Credit Risk (SICR) since the origination date. The ECL approach takes into account forward-looking data, including a range of possible outcomes, which should be unbiased and probability-weighted to reflect the risk of a loss being incurred even when it is unlikely. Critical judgements and accounting estimates applied in calculating ECL (audited) The preparation of Santander UK's consolidated financial statements in accordance with IFRS requires management to make judgements, estimates and assumptions in applying the accounting policies that affect the reported amounts of assets, liabilities, income and expenses. Due to the inherent uncertainty in making estimates, actual results reported in future periods may be based on amounts which differ from those estimates. Estimates, judgements and assumptions are continually evaluated and are based on historical experience and other factors, including expectations of future events that are believed to be reasonable under the circumstances. There has been no change in the inherent sensitivity of the areas of judgement in the period. Management have considered the impact of developments in principal risks and uncertainties, as set out in the Risk review, on critical judgements and accounting estimates. The significant judgements, apart from those involving estimation, made by management in applying Santander UK's accounting policies in these financial statements (key judgements) and the key sources of estimation uncertainty that may have a significant risk of causing a material adjustment to the carrying amount of assets and liabilities within the next financial year (key estimates), which together are considered critical to Santander UK's results and financial position, are as follows: 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 assu

Market Risk

Market Risk	12 Months Ended
	Dec. 31, 2022
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. We have no significant traded market risk exposure. 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. Key metrics Net Interest Income (NII) sensitivity to +100bps was £241m and to ‑100bps was £(197)m (2021: £318m and £(440)m). Economic Value of Equity (EVE) sensitivity to +100bps was £(487)m and to ‑100bps was £635m (2021: £(431)m and £184m). BALANCE SHEET ALLOCATION BY MARKET RISK CLASSIFICATION (AUDITED) We classify all our assets and liabilities exposed to market risk as non-traded market risk, except for certain portfolios that we must classify as trading books for regulatory purposes (such as selling derivatives or derivative-based products to clients), of which we must fair value for accounting reasons (such as assets in the eligible liquidity pool). For accounting purposes, we classify all derivatives as held for trading unless they are designated as being in a hedging relationship. 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. 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. 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, and the Sterling Overnight Index Average (SONIA) rate. 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 credit 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 Structural and Market Risk framework sets out our high-level arrangements and standards to manage, control and oversee non-traded market risk, and is part of our overall Risk Framework. Our Risk Appetite sets the controls, risk limits and key risk metrics for non-traded market risk. We show 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 We mainly measure our exposures with NII and EVE sensitivity analysis. We support this with VaR risk measures and stress testing. We also monitor our interest rate repricing gap. We regularly review our risk models and metrics including underlying model assumptions to ensure they continue to reflect the risks inherent in the current rate environment and regulatory expectations. NII and EVE sensitivities (audited) The calculations for NII 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 NII 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. NII sensitivity NII 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 NII sensitivity by simulating the NII using 2 yield curves. The difference between the 2 NII totals is the NII sensitivity. 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. 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. 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. Value at Risk (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 to find how much we might lose, normally at a 99% confidence level. 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. 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 and a consistent starting point for setting limits. More complex, multi-factor and multi-time period stress tests give us information about specific potential events. They can also test outcomes that we might not capture through parallel stresses or VaR-type measures. We 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. We run individual business area stresses and Santander UK-wide scenarios. 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). 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. Risk mitigation (audited) We typically hedge the interest rate risk of the securities we hold for liquidity and investment purposes with interest rate swaps. We retain spread exposures, and these are the key drivers of the VaR and stress tests we use to assess the risk of the portfolio. 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 hedge our foreign currency funding positions back to sterling, so our foreign exchange positions tend to be residual exposures that remain after hedging. These exposures 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 our non-traded market risks 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 potential volatility. NON-TRADED MARKET RISK REVIEW Interest rate risk Yield curve risk The table below shows how our net interest income would be affected by a parallel shift (both up and down) applied instantaneously to the yield curve at 31 December 2022 and 31 December 2021 In 2022, we moved to focus on 100 basis points (bps) from previously disclosed sensitivities of 50bps and 25bps. The shift reflects a more realistic stress in the current rate environment. We have replaced the previously disclosed sensitivities of 50bps and 25bps for 2021 with 100 bps sensitivities for consistency with 2022. 2022 2021 +100bps -100bps +100bps -100bps £m £m £m £m NII sensitivity (audited) (1) 241 (197) 318 (440) EVE sensitivity (487) 635 (431) 184 Based on modelling assumptions of repricing behaviour. Basis risk We report basis risk using the EaR approach. 2022 2021 £m £m Basis risk EaR 2 2 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 2022 £m £m £m £m £m £m £m Assets 106,980 44,748 79,006 52,489 5,249 14,123 302,595 Liabilities 135,801 30,262 58,526 51,161 3,833 25,023 304,606 Off-balance sheet 31,378 (16,133) (16,972) 723 3,015 — 2,011 Net gap 2,557 (1,647) 3,508 2,051 4,431 (10,900) — 2021 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) — Spread risk The table below shows the risk metrics covering the portfolios of securities we hold for liquidity and investment purposes. 2022 2021 £m £m VaR 3 4 Worst three month stressed loss 46 56 2022 compared to 2021 We regularly review our risk models and metrics including underlying modelling assumptions to ensure they continue to reflect the risks inherent in the current rate environment and incorporate regulatory expectations. NII Sensitivity to a -100bps stress reduced to £(197)m (2021: £(440)m) as the risk of margin compression as a result of customer deposit rates becoming floored reduced in the higher rate environment. The NII sensitivity to a +100bps parallel stress reduced to £241m (2021: £318m), as the mix of customer liabilities changed in the higher rate environment. EVE Sensitivity to a +100bps stress increased to £(487)m (2021: £(431)m) in the higher rate environment. This was driven by changes in the mix of customer liabilities, offset by a reduction in the profile of the structural position and customer behaviour in response to higher rates. TRADED MARKET RISK We have no significant traded market risk exposure. Our only exposure to traded market risk comes from providing permitted financial services to permitted 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 hedge risks from client trades, and our books are as close to back-to-back as possible, with market risk 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. We calculate market risk capital using standard rules. The Internal VaR for exposure to traded market risk at 31 December 2022 was less than £1m (2021: less than £1m).

Liquidity Risk

Liquidity Risk	12 Months Ended
	Dec. 31, 2022
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 LCR of 157% (2021: 168% ) DoLSub LCR of 152% (2021: 166%) Wholesale funding with maturity <1 year £11.0bn (2021: £10.2bn) DoLSub LCR eligible liquidity pool of £46.3bn (2021: £51.4bn) 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, 26 and 27 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 them to collectively meet regulatory requirements to manage liquidity risk. Each member of the RFB DoLSub will support the other by transferring surplus liquidity in times of stress. Risk appetite Our LRA is based on the principles of liquidity management we use to manage our balance sheet. It also supports our need to meet or exceed regulatory rules. 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 on a timely basis. 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, 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 by 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 stress to create liquidity by repurchase or outright sale to the market. Stress testing Our liquidity stress testing framework is central to our LRA measurement and monitoring. 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 appropriate management actions. 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 banks, a slowdown in a major economy or a decline in access to 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 an idiosyncratic shock that would lead to retail and commercial outflows. We run a climate change stress, that assumes severe physical risks results in a reduction in retail deposits, increased use of corporate lending facilities and an increase in mortgage defaults. 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. 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 test, described above). We do this by maintaining a prudent balance sheet structure and approved liquid resources. Recovery and 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 we can take 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. We submitted our first self-assessment of our resolvability to the PRA in October 2021 and made targeted updates to it in February 2022. On 10 June 2022 we published our first resolvability public disclosure. This concludes that we have put in place capabilities that enable us to meet the Bank of England’s resolution outcomes and that these are sufficiently flexible, so that they can be adapted to the specifics of failure as it unfolds, in order to credibly support the resolution in practice. Our capabilities are underpinned by comprehensive governance, testing and assurance arrangements, which seek to ensure that our resolution readiness is maintained and, where appropriate, enhanced on an ongoing basis. On the same day, the Bank of England published its own assessment of UK major banks’ resolvability arrangements. The Santander UK specific section of the Bank of England’s disclosure confirms that the Bank of England has not identified any material issues in relation to our approach to achieving the three resolution outcomes set out in the Resolvability Assessment Framework. 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 BRC. LIQUIDITY RISK REVIEW Liquidity Coverage Ratio This table shows our LCR at 31 December 2022 and 31 December 2021 . RFB DoLSub LCR (1) 2022 2021 £bn £bn Eligible liquidity pool (liquidity value) (2) 46.2 51.3 Net stress outflows (30.4) (30.9) Surplus 15.8 20.4 Eligible liquidity pool as a percentage of anticipated net cash flows 152 % 166 % (1) The RFB LCR was 157% (2021:168%). (2) 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 2022 and 31 December 2021. It also shows the weighted average carrying value in the year. RFB DoLSub Carrying value Weighted average carrying 2022 2021 2022 2021 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 42.1 — 42.1 45.9 — 45.9 43.5 40.6 Government bonds 2.9 — 2.9 4.2 — 4.2 3.8 7.0 Supranational bonds and multilateral development banks 0.3 — 0.3 0.2 — 0.2 0.1 0.3 Covered bonds 0.1 0.9 1.0 0.8 — 0.8 0.9 1.1 Asset-backed securities — — — — 0.3 0.3 0.1 0.4 Equities — — — — — — — — 45.4 0.9 46.3 51.1 0.3 51.4 48.4 49.4 Currency analysis This table shows the carrying value of our eligible liquidity pool by major currencies at 31 December 2022 and 31 December 2021. 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 2022 0.8 1.3 44.2 — 46.3 2021 0.8 0.4 50.2 — 51.4 Net Stable Funding Ratio (NSFR) The NSFR was implemented on 1 January 2022. NSFR RFB DoLSub 2022 135 % 2022 compared to 2021 We remain in a strong liquidity position. We hold sufficient liquid resources and have adequate governance and controls in place to manage the liquidity risks arising from our business and strategy. At 31 December 2022, the LCR and NSFR significantly exceeded regulatory requirements. 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 that complies 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 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 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 have been fully implemented from 1 January 2022. 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. We also 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. Reconciliation of wholesale funding to the balance sheet (audited) This table reconciles our wholesale funding to our balance sheet at 31 December 2022 and 31 December 2021. Balance sheet line item Funding Deposits by banks (3) Deposits by customers (1) Repurchase agreements - non trading Financial Debt Subordinated Other equity instruments (2) 2022 £bn £bn £bn £bn £bn £bn £bn £bn Deposits by banks 0.5 0.5 — — — — — — Certificates of deposit and commercial paper 4.7 — — — — 4.7 — — Senior unsecured – public benchmark 14.3 — 4.6 — — 9.7 — — – privately placed 0.6 — 0.1 — 0.4 0.1 — — Covered bonds 14.9 — — — — 14.9 — — Securitisation and structured issuance 1.0 — — — — 1.0 — — TFSME 25.0 25.0 — — — — — — Subordinated liabilities and equity 3.9 — — — — — 1.9 2.0 Total wholesale funding 64.9 25.5 4.7 — 0.4 30.4 1.9 2.0 Repos 8.0 — — 8.0 — — — — Foreign exchange and hedge accounting 1.6 — 0.1 — — 1.1 0.4 — Other 3.4 3.0 — — 0.4 — — — Balance sheet total 77.9 28.5 4.8 8.0 0.8 31.5 2.3 2.0 2021 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 — — 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 (1) This is included in our balance sheet total of £195,568m (2021: £192,926m). (2) Consists of £nil (2021: £nil ) fixed/floating rate non-cumulative callable preference shares, £0m (2021: £235m) Step-up Callable Perpetual Reserve Capital Instruments and £1,956m (2021: £1,956m) Perpetual Capital Securities. See Notes 44 and 33 to the Consolidated Financial Statements. (3) Other consists of items in the course of transmission and other deposits. 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. For details of the maturities of financial liabilities and off-balance sheet commitments, see Note 39 to the Consolidated Financial Statements. ≤ 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 2022 £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 0.7 — 0.6 0.8 2.9 1.6 6.4 1.6 12.5 – privately placed — — — — — — — 0.1 — 0.1 Subordinated liabilities and equity (incl. AT1) — — — — — — 0.5 1.2 1.0 2.7 0.8 0.7 — 0.6 0.8 2.9 2.1 7.7 2.6 15.3 Other Santander UK plc Deposits by banks 0.2 0.3 — — — 0.5 — — — 0.5 Certificates of deposit and commercial paper 1.2 3.2 0.3 — — 4.7 — — — 4.7 Senior unsecured – public benchmark 0.3 — — — — 0.3 0.9 0.3 0.3 1.8 – privately placed — — — — — — 0.1 0.2 0.2 0.5 Covered bonds — 1.0 0.1 0.9 — 2.0 3.4 8.4 1.1 14.9 Securitisation & structured issuance (2) 0.1 — 0.1 — — 0.2 0.1 0.6 0.1 1.0 TFSME — — — — — — — 25.0 — 25.0 Subordinated liabilities — — — — 0.4 0.4 — — 0.8 1.2 1.8 4.5 0.5 0.9 0.4 8.1 4.5 34.5 2.5 49.6 Other group entities Securitisation & structured issuance (3) — — — — — — — — — — Total at 2022 2.6 5.2 0.5 1.5 1.2 11.0 6.6 42.2 5.1 64.9 Of which: – Secured 0.1 1.0 0.2 0.9 — 2.2 3.5 34.0 1.2 40.9 – Unsecured 2.5 4.2 0.3 0.6 1.2 8.8 3.1 8.2 3.9 24.0 2021 Total at 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 (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. 2022 compared to 2021 – Together with our immediate parent, Santander UK Group Holdings plc, o ur 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. – Our funding costs improved with maturities refinanced at lower cost. Total wholesale funding decreased in 2022. – We repaid £6.9bn of TFSME, with £25.0bn outstanding at year-end. In 2022, we utilised TFSME drawings to support mortgage lending in H122, but a successful retail funding campaign towards the end of the year and above-planned secured funding meant we were able to repay drawings. We expect similar annual repayments over the next 3 years. – We issued a total of £8.6bn. Maturities in 2022 were £5.3bn. – At 31 December 2022, 83% (2021:85%) of wholesale funding had a maturity of greater than one year, with an overall residual duration of 37 months (2021: 47 months). – Our structural hedge position increased, with an average of £110bn over the last 12 months, and an average duration of c2.5 years. – Our level of encumbrance from external and internal issuance of securitisations and covered bonds decreased again in 2022. Currency composition of wholesale funds (audited) This table shows our wholesale funding by major currency at 31 December 2022 and 31 December 2021. 2022 2021 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 18 58 24 — 9 59 32 — – privately placed — — — 100 — — — 100 Subordinated liabilities and equity (incl. AT1) 75 25 — — 73 27 — — 27 52 20 1 22 52 25 1 Other Santander UK plc Deposits by banks 29 71 — — 32 68 — — Certificates of deposit and commercial paper 56 42 2 — 45 53 2 — Senior unsecured – public benchmark 18 62 20 — 14 46 40 — – privately placed 95 — 5 — 92 — 6 2 Covered bonds 43 12 45 — 44 8 48 — Securitisation & structured issuance 100 — — — 74 26 — — TFSME 100 — — — 100 — — — Subordinated liabilities 48 52 — — 57 43 — — 74 12 14 — 77 10 13 — Total 63 21 16 — 66 18 15 1 Term issuance (audited) In 31 December 2022, our external term issuance (sterling equivalent) was: Sterling US Dollar Euro Other 2022 2021 £bn £bn £bn £bn £bn £bn Downstreamed from Santander UK Group Holdings plc to Santander UK plc Senior unsecured – public benchmark 1.2 2.1 0.6 — 3.9 2.8 Subordinated debt and equity (inc. AT1) 0.8 — — — 0.8 0.2 2.0 2.1 0.6 — 4.7 3.0 Other Santander UK plc Securitisations and other secured funding 0.6 — — — 0.6 — Covered bonds 1.8 0.8 1.4 — 4.0 — Senior unsecured – public benchmark — — — — — — – privately placed 0.1 — — — 0.1 0.1 TFSME — — — — — 20.2 2.5 0.8 1.4 — 4.7 20.3 Total gross issuances 4.5 2.9 2.0 — 9.4 23.3 Encumbrance We encumber an asset if we pledge or transfer it as collateral against a liability. This means it is no longer available to secure funding, meet our collateral needs or be sold to reduce funding needs. Being able to pledge or transfer assets as collateral is a key part of a bank’s operations. The main ways we encumber assets are that we: enter into securitisation, covered bonds, and repurchase agreements to access medium and long-term funding; enter into short-term funding transactions (including repurchase agreements and stock borrowing) as part of our liquidity management; pledge collateral as part of participating in payment and settlement systems; and post collateral as part of derivatives activity. We control levels of encumbrance by setting a minimum level of unencumbered assets after we factor in our funding plans, whether we can use our assets for our future collateral needs, the impact of a stress and our current encumbrance level. Assets classified as readily available for encumbrance include cash and securities 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 them in a stress. We can create liquidity by using them as collateral for secured funding or through outright sale. This includes excess collateral already in a secured funding structure and collateral pre-positioned at central banks that 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 securitised products to a diverse investor base through our prime 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 these programmes, 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 Assets positioned at central banks (3) Unencumbered assets not pre-positioned with central banks Covered Securitis- Other Total Readily Other Cannot be Total Total 2022 £m £m £m £m £m £m £m £m £m £m Cash and balances at central banks (1)(2) — 1,330 1,330 893 41,967 — — 42,860 44,190 Financial assets at FVTPL: – Derivative financial instruments — — — — — — — 2,407 2,407 2,407 – Other financial assets at FVTPL — — — — — — — 129 129 129 Financial assets at amortised cost: – Loans and advances to customers 21,304 2,851 56 24,211 68,535 91,761 18,284 16,925 195,505 219,716 – Loans and advances to banks — — 163 163 — — — 829 829 992 – Repurchase agreements – non trading — — — — — — — 7,348 7,348 7,348 – Other financial assets at amortised cost — — 48 48 — 108 — — 108 156 Financial assets at FVOCI — — 4,365 4,365 — 1,659 — — 1,659 6,024 Interests in other entities — — — — — — — 252 252 252 Intangible assets — — — — — — — 1,550 1,550 1,550 Property, plant and equipment — — — — — — 1,513 — 1,513 1,513 Current tax assets — — — — — — — 478 478 478 Retirement benefit assets — — — — — — — 1,050 1,050 1,050 Other assets — — — — — — — (592) (592) (592) Total assets 21,304 2,851 5,962 30,117 69,428 135,495 19,797 30,376 255,096 285,213 2021 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 (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, 2022
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 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 15.4% (2021: 16.1%) Total qualifying regulatory capital of £14.3bn (2021: £14.8bn) 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 Banco Santander SA and we operate as a standalone subsidiary. As we are part of the UK sub-group 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 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 environment we operate in, our strategy for each material risk and the potential impact of adverse scenarios or stresses on our capital. 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 expect 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 expect 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 using 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. In 2022, we developed a Climate Internal Scenario Analysis (CISA) to help understand better the potential impact of climate change on our business portfolios and balance sheet. The CISA outputs will form the basis of our 2022 ICAAP for climate risk by helping show if we need to hold more capital for climate risks and help us prioritise our actions for the next five years. We augment our regulatory minimum capital with internal buffers. We hold buffers to ensure we have enough time to take action against unexpected changes. Risk mitigation We 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, 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 'risk mitigation' in the ‘Liquidity risk’ section. At 31 December 2022, Santander UK plc (RFB), Cater Allen Limited, Santander ISA Managers Limited and certain other non-regulated subsidiaries within the RFB were party to the RFB Sub-Group Capital Support Deed dated 17 December 2021. These parties were permitted by the PRA to form a core UK group, as defined in the PRA Rulebook, a permission which will expire on 31 December 2024. 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. These intra-group exposures were risk-weighted at 0% and excluded from leverage exposure on a solo as well as consolidated basis. The purpose the 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. For more details, see Note 31. 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 current and expected future 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). Expected future regulatory CET1 requirements are impacted by the projected increase in the UK CCyB to 2% in July 2023. 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 so 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 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. Key capital ratios 2022 2021 % % CET1 capital ratio 15.4 16.1 AT1 2.8 2.9 Grandfathered Tier 1 — 0.2 Tier 2 2.2 2.7 Total capital ratio 20.4 21.9 The total subordination available to Santander UK plc senior unsecured bondholders was 20.4% (2021: 21.9%) of RWAs. Return on assets - profit after tax divided by average total assets was 0.49% (2021: 0.48%). 2022 compared to 2021 The CET1 capital ratio decreased 70bps to 15.4%. This was largely due to regulatory changes that took effect on 1 January 2022, and a special dividend paid in December 2022. The regulatory changes included the reintroduction of the full CET1 software asset deduction, and implementation of new definition of default regulatory guidance. The impact of increased RWAs £71.2bn (£68.1bn) and the special dividend were partially offset by post dividend retained earnings. We remain strongly capitalised with significant headroom to minimum requirements and MDA. Total capital ratio decreased by 150bps to 20.4%, due to the lower CET1 capital ratio as outlined above and the reduction in AT1 and Tier 2 capital securities recognised following the end of the CRR Grandfathering period on 1 January 2022. Regulatory capital resources (audited) This table shows our qualifying regulatory capital: 2022 2021 £m £m CET1 capital 10,799 10,820 AT1 capital 1,956 2,119 Tier 1 capital 12,755 12,939 Tier 2 capital 1,548 1,816 Total regulatory capital (1) 14,303 14,755 (1) Capital resources include a transitional IFRS 9 benefit at 31 December 2022 of £19m(2021: £21m). 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 was phased out by CRD IV rules in 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 was phased out under CRD IV in 2021. MREL recapitalisation As at the end of 2022, we have down streamed £11.7bn of senior unsecured bonds from Santander UK Group Holdings plc as Internal MREL compliant, secondary non-preferential debt to Santander UK plc.

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2022
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. 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. Compliance with International Financial Reporting Standards (IFRS) The consolidated financial statements of the Santander UK group and the separate financial statements of the Company comply with UK-adopted International Accounting Standards (IAS). The financial statements are also prepared in accordance with IFRS as issued by the International Accounting Standards Board (IASB), including interpretations issued by the IFRS Interpretations Committee, as there are no applicable differences from IFRS 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, have been included in the Risk review section of this Annual Report. This information forms an integral part of these financial statements by this cross reference, is marked as audited, and is covered by the Independent auditor's report. 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 2022 and 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 2022 and 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: 5 years ,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. Recent accounting developments Disclosure of Accounting Policies – Amendments to IAS 1 and IFRS Practice Statement 2 In February 2021, the IASB amended IAS 1 Presentation of Financial Statements to require entities to disclose their material rather than their significant accounting policies. To support this amendment, the IASB also amended IFRS Practice Statement 2 Making Materiality Judgements to provide guidance on how to apply the concept of materiality. The amendments are effective for annual periods beginning on or after 1 January 2023 with earlier application permitted. The amendments have been applied in preparing these financial statements and, consequently, only material accounting policy information is disclosed. Future accounting developments At 31 December 2022, for the Santander UK group, there were no other 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. Material accounting policy information The following material accounting policies have been applied in preparing these financial statements. For material accounting policies which involve the application of judgements or accounting estimates that are determined to be critical to the preparation of these financial statements see 'Critical judgements and accounting estimates'. Consolidation The consolidated financial statements incorporate the financial statements of the Company and entities (including structured entities) controlled by it and its subsidiaries. The acquisition method of accounting is used to account for the acquisition of subsidiaries which meet the definition of a business. 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. 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. 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. 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) 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. Defined benefit pension schemes (see 'Critical judgements and accounting estimates') 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. 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 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. Goodwill and other intangible assets (for goodwill see 'Critical judgements and accounting estimates') 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, or business at the date of acquisition. Goodwill on the acquisition of subsidiaries and businesses is included in intangible assets. 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 seven 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 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. 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 Shorter of the lease term or the useful life of the underlying asset Operating lease assets - vehicles 2 to 4 years Depreciation is not charged on freehold land and assets under construction. Depreciation of operating lease assets where the Santander UK group is the lessor is described in 'Leases' below. Financial instruments (for impairment of debt instrument financial assets see' Critical judgements and accounting estimates: Credit impairment losses') 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 advances, and issues of equity or financial liabilities measured at amortised cost are recognised on settlement date, being the date when the Santander UK group becomes a party to the contractual terms of the instrument; 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 u

Segments

Segments	12 Months Ended
	Dec. 31, 2022
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 four 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. Retail Banking delivers products through our omni-channel presence comprising branches, ATMs, telephony, digital and intermediary channels. Consumer Finance business is primarily introduced by car dealerships acting as our intermediary along with a small amount of new business introduced via digital channels. Corporate and Commercial 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. In addition, Corporate and Investment Banking (CIB) provided services to corporate clients with an annual turnover of £500m and above. 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. The residual parts of the business were wound down or transferred to other segments. In December 2022, we transferred £1.5bn (2021: £2.3bn; 2020: £3.2bn) of social housing loans, and £0.4bn of non-core Liabilities (2021: £0.9bn; 2020: £nil) to our CCB segment from Corporate Centre to reflect the way these assets are managed, and restated comparatives accordingly. This resulted in an increase in profit before tax in CCB of £2.9m (2021: decrease of £2.7m; 2020: decrease of £6.3m) and an equal but opposite impact in Corporate Centre. 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 For the years ended 31 December Retail Banking Consumer Finance Corporate & Commercial Banking Corporate Centre Total 2022 £m £m £m £m £m Net interest income / (expense) 3,671 180 580 (6) 4,425 Non-interest income / (expense) 209 195 146 (19) 531 Total operating income 3,880 375 726 (25) 4,956 Operating expenses before credit impairment (charges)/write-backs, provisions and charges (1,682) (144) (342) (175) (2,343) Credit impairment (charges)/write-backs (262) (27) (31) — (320) Provisions for other liabilities and charges (394) (6) (8) (11) (419) Total operating credit impairment (charges)/write-backs, provisions and charges (656) (33) (39) (11) (739) Profit/(loss) from continuing operations before tax 1,542 198 345 (211) 1,874 Revenue from external customers 4,109 513 732 (398) 4,956 Inter-segment revenue (229) (138) (6) 373 — Total operating income 3,880 375 726 (25) 4,956 Revenue from external customers includes the following fee and commission income: (1) – Current account and debit card fees 502 — 60 — 562 – Insurance, protection and investments 78 — — — 78 – Credit cards 95 — — — 95 – Non-banking and other fees (2) 2 20 77 5 104 Total fee and commission income 677 20 137 5 839 Fee and commission expense (478) (5) (18) (8) (509) Net fee and commission income/(expense) 199 15 119 (3) 330 Customer loans 191,836 5,384 18,518 — 215,738 Total assets (3) 200,872 10,371 18,518 55,452 285,213 Of which assets held for sale — — — 49 49 Customer deposits 161,748 — 24,798 3,365 189,911 Total liabilities 161,821 1,223 24,473 83,289 270,806 Average number of full-time equivalent staff 15,212 531 2,336 44 18,123 (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 charge allowances. Retail Banking Consumer Finance Corporate & Commercial Banking Corporate & Investment Banking Corporate Centre Total 2021 £m £m £m £m £m £m Net interest income/(expense) 3,356 233 397 — (37) 3,949 Non-interest income 205 178 112 — 55 550 Total operating income 3,561 411 509 — 18 4,499 Operating expenses before credit impairment (charges)/write-backs, provisions and charges (1,701) (163) (365) — (281) (2,510) Credit impairment (charges)/write-backs 98 33 90 — 12 233 Provisions for other liabilities and charges (185) 4 (34) — (162) (377) Total operating credit impairment (charges)/write-backs, provisions and charges (87) 37 56 — (150) (144) Profit/(loss) from continuing operations before tax 1,773 285 200 — (413) 1,845 Revenue from external customers 4,010 489 619 — (619) 4,499 Inter-segment revenue (449) (78) (110) — 637 — Total operating income/(expense) 3,561 411 509 — 18 4,499 Revenue from external customers includes the following fee and commission income: (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 190 10 90 — (4) 286 Customer loans 183,023 4,984 19,281 — — 207,288 Total assets (3) 190,629 8,873 19,281 — 68,315 287,098 Customer deposits 156,991 — 26,466 — 2,758 186,215 Total liabilities 157,622 1,173 26,513 — 85,688 270,996 Average number of full-time equivalent staff 16,149 670 2,281 528 76 19,704 2020 Net interest income 2,753 264 355 — 16 3,388 Non-interest income 245 127 96 — (4) 464 Total operating income 2,998 391 451 — 12 3,852 Operating expenses before credit impairment (charges)/write-backs, provisions and charges (1,792) (166) (324) — (108) (2,390) Credit impairment (charges)/write-backs (264) (44) (294) — (36) (638) Provisions for other liabilities and charges (157) (8) (6) — (93) (264) Total operating credit impairment (charges)/write-backs, provisions and charges (421) (52) (300) — (129) (902) Profit/(loss) from continuing operations before tax 785 173 (173) (225) 560 Revenue from external customers 3,669 501 608 — (926) 3,852 Inter-segment revenue (671) (110) (157) — 938 — Total operating income 2,998 391 451 — 12 3,852 Revenue from external customers includes the following fee and commission income: (1) – Current account and debit card fees 442 — 42 — — 484 – Insurance, protection and investments 65 — — — — 65 – Credit card fees 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 20,822 2,784 0 207,011 Total assets (3) 183,154 11,143 20,820 2,784 74,431 292,332 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 (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 charge allowances. (4) CIB results presented as discontinued operations. See Note42. The main differences between Customer loans and Loans and advances to customers (Note 13) are balances in Corporate Centre held for liquidity purposes. The main differences between Customer deposits and Deposits by customers (Note 23) are equity-linked deposits and intercompany deposits. 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, 2022
Analysis of income and expense [abstract]
Net Interest Income	3. NET INTEREST INCOME Group 2022 2021 2020 £m £m £m Interest and similar income: Loans and advances to customers 5,774 4,619 4,745 Loans and advances to banks 618 52 49 Reverse repurchase agreements – non trading 149 35 118 Other 167 56 119 Total interest and similar income (1) 6,708 4,762 5,031 Interest expense and similar charges: Deposits by customers (905) (430) (1,011) Deposits by banks (496) (25) (28) Repurchase agreements – non trading (120) (3) (43) Debt securities in issue (650) (252) (440) Subordinated liabilities (108) (92) (111) Other (4) (11) (10) Total interest expense and similar charges (2) (2,283) (813) (1,643) Net interest income 4,425 3,949 3,388 (1) Includes £87m (2021: £22m, 2020: £38m) of interest income on financial assets at FVOCI. (2) Includes £6m (2021: £317m, 2020: £451m) of interest expense on derivatives hedging debt issuances and £3m (2021: £3m , 2020, £3m) of interest expense on lease liabilities.

Net Fee and Commission Income

Net Fee and Commission Income	12 Months Ended
	Dec. 31, 2022
Fee and commission income (expense) [abstract]
Net Fee and Commission Income	4. NET FEE AND COMMISSION INCOME Group 2022 2021 2020 £m £m £m Fee and commission income: Current account and debit card fees 562 478 484 Insurance, protection and investments 78 67 65 Credit cards 95 73 66 Non-banking and other fees (1) 104 79 65 Total fee and commission income 839 697 680 Total fee and commission expense (509) (411) (361) Net fee and commission income 330 286 319 (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, 2022
Net Trading And Other Income [Abstract]
Other Operating Income	5. OTHER OPERATING INCOME Group 2022 2021 2020 £m £m £m Net gains/(losses) on financial instruments designated at fair value through profit or loss 62 (24) (77) Net (losses)/gains on financial instruments mandatorily at fair value through profit or loss (75) (2) 46 Hedge ineffectiveness 29 13 20 Net profit on sale of financial assets at fair value through other comprehensive income — 6 17 Income from operating lease assets 129 136 126 Other 56 135 13 201 264 145 Assets and liabilities held at FVTPL, including derivatives, are mainly 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 gains of £14m (2021: losses of £15m, 2020: gains of £89m) 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 losses of £14m (2021: gains of £15m, 2020: losses of £88m). 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 (2021: £nil, 2020: £1m). Exchange rate differences recognised in the Consolidated Income Statement on items not at FVTPL were £2,163m expense (2021: £242m income, 2020: £751m expense) and are presented in the line ‘Other'. These are principally offset by related releases from the cash flow hedge reserve of £2,129m income (2021: £358m expense, 2020: £809m income) 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 2022, the Santander UK group repurchased certain debt securities and subordinated liabilities as part of ongoing liability management exercises, resulting in a loss of £5m (2021 loss of £1m , 2020: loss of £24m).

Operating Expenses Before Credi

Operating Expenses Before Credit Impairment Charges, Provisions and Charges	12 Months Ended
	Dec. 31, 2022
Expenses by nature [abstract]
Operating Expenses Before Credit Impairment Charges, Provisions and Charges	6. OPERATING EXPENSES BEFORE CREDIT IMPAIRMENT CHARGES, PROVISIONS AND CHARGES For the years ended 31 December Group 2022 2021 2020 £m £m £m Staff costs: Wages and salaries 745 745 788 Performance-related payments 170 183 97 Social security costs 112 112 101 Pensions costs: – defined contribution plans 60 64 66 – defined benefit plans 28 38 38 Other share-based payments — — — Other personnel costs 44 41 33 1,159 1,183 1,123 Other administration expenses 888 826 706 Depreciation, amortisation and impairment 296 501 561 Total 2,343 2,510 2,390 Staff costs ’Performance-related payments’ include bonuses paid in cash and share awards granted under the arrangements described in Note 36. 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 ‘Shares awards’. Performance-related payments above include amounts related to deferred performance awards as follows: Costs recognised in 2022 Costs expected to be recognised in 2023 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 6 8 14 Shares 3 5 8 6 8 14 6 10 16 12 16 28 The following table shows the amount of bonus awarded to employees for the performance year 2022. In the case of deferred cash and shares awards, the final amount paid to an employee is influenced by forfeiture provisions and any performance conditions to which the awards are subject. The deferred shares award amount is based on the fair value of the awards at the date of grant. Expenses charged in the year Expenses deferred to future periods Total 2022 2021 2022 2021 2022 2021 £m £m £m £m £m £m Cash award – not deferred 145 156 — — 145 156 – deferred 8 8 14 15 22 23 Shares award – not deferred 9 11 — — 9 11 – deferred 8 8 14 14 22 22 Total discretionary bonus 170 183 28 29 198 212 '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 36. The average number of full-time equivalent staff was 18,123 (2021: 19,704, 2020: 21,998). Depreciation, amortisation and impairment In 2022, depreciation, amortisation and impairment included depreciation of £73m (2021: £81m, 2020 : £92m) on operating lease assets (where the Santander UK group is the lessor) with a carrying amount of £577m at 31 December 2022 (2021: £595m, 2020 : £542m). It also included depreciation of £19m (2021: £19m , 2020: £58m ) on right-of-use assets with a carrying amount of £112m at 31 December 2022 (2021: £117m , 2020: £100m ). 'Other administration expenses' includes £21m (2021: £23m, 2020 : £10m ) related to short-term leases. In 2022, 'Depreciation, amortisation and impairment' included an impairment charge of £10m ( 2021 : £88m , 2020: £nil) associated with branch and head office site closures as part of the transformation programme. For more, see Note 21.

Audit and Other Services

Audit and Other Services	12 Months Ended
	Dec. 31, 2022
Audit And Other Services [Abstract]
Audit and Other Services	7. AUDIT AND OTHER SERVICES Group 2022 2021 2020 £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 11.8 11.2 10.0 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 0.7 0.9 1.4 Total audit fees (1) 12.5 12.1 11.4 Non-audit fees: Audit-related assurance services 0.6 0.8 0.8 Other assurance services 0.3 0.1 0.3 Other non-audit services — 0.2 — Total non-audit fees 0.9 1.1 1.1 (1) 2022 audit fees included £0.6m (2021: £1.2m, 2020: £0.8m) which related to the prior year. Audit-related assurance services mainly comprised services performed in connection with review of the financial information of the Company and reporting to the Company's UK regulators. Other assurance services mainly comprised services performed in support of various debt issuance programmes. Of the total non-audit fees, £0.2m (2021: £0.4m, 2020: £0.4m) accords with the definition of 'Audit Fees' per US Securities and Exchange Commission (SEC) guidance, £0.7m (2021: £0.7m, 2020: £0.7m) accords with the definition of 'Audit related fees' per that guidance and £0.0m (2021: £0.0m, 2020: £0.0m) accords with the definition of 'All other fees' per that guidance. In 2022, the Company’s auditors earned no fees (2021: £27,000, 2020: £24,000 fees) payable by entities outside the Santander UK group for the review of the financial position of corporate and other borrowers. In 2022, the Company's auditors earned £1.6m (2021: £1.4m , 2020: £1.5m ), in relation to incremental work undertaken in support of the audit of Banco Santander SA.

Credit Impairment Charges and P

Credit Impairment Charges and Provisions	12 Months Ended
	Dec. 31, 2022
Disclosure Of Credit Impairment Loss And Provisions [Abstract]
Credit Impairment Charges and Provisions	8. CREDIT IMPAIRMENT CHARGES AND PROVISIONS For the years ended 31 December Group 2022 2021 2020 £m £m £m Credit impairment charges/(write-backs): Loans and advances to customers 248 (186) 665 Recoveries of loans and advances, net of collection costs 36 (17) (24) Off-balance sheet credit exposures (See Note 29) 36 (30) (3) 320 (233) 638 Provisions for other liabilities and charges (excluding off-balance sheet credit exposures) (See Note 29) 422 386 258 (Releases)/Provisions for residual value and voluntary termination (3) (9) 6 419 377 264 739 144 902 In 2022, 2021 and 2020 there were no material credit impairment charges 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, 2022
Major components of tax expense (income) [abstract]
Taxation	9. TAXATION Group 2022 2021 2020 £m £m £m Current tax: UK corporation tax on profit for the year 526 401 107 Adjustments in respect of prior years (81) (24) (24) Total current tax 445 377 83 Deferred tax: (Credit)/Charge for the year (29) 100 34 Adjustments in respect of prior years 64 15 4 Total deferred tax 35 115 38 Tax on profit from continuing operations 480 492 121 The standard rate of UK corporation tax was 27% for banking entities and 19% for non-banking entities (2021: 27% for banking entities and 19% for non-banking entities; 2020: 27% for banking entities and 19% for non-banking entities). Tax for other jurisdictions is calculated at the rates prevailing in those jurisdictions. The Santander UK group’s effective tax rate for 2022 was 25.6% (2021: 26.7%, 2020: 21.6%). The tax on profit from continuing operations before tax differs from the theoretical amount that would arise using the basic corporation tax rate as follows: For the years ended 31 December Group 2022 2021 2020 £m £m £m Profit from continuing operations before tax 1,874 1,845 560 Tax calculated at a tax rate of 19% (2021: 19%, 2020: 19%) 356 351 106 Bank surcharge on profits 121 104 27 Non-deductible preference dividends paid 9 9 8 Non-deductible UK Bank Levy 13 14 19 Non-deductible conduct remediation, fines and penalties 48 6 (4) Other non-deductible costs and non-taxable income 29 37 25 Effect of change in tax rate on deferred tax provision (29) 9 6 Tax relief on dividends in respect of other equity instruments (40) (40) (40) Adjustment to prior year provisions (27) 2 (26) Tax on profit from continuing operations 480 492 121 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 been reflected in the closing balance sheet position for deferred tax. Current tax assets and liabilities Movements in current tax assets and liabilities during the year were as follows: Group 2022 2021 £m £m Assets 347 264 Liabilities — — At 1 January 347 264 Income statement charge (including discontinued operations) (445) (389) Other comprehensive income credit 159 33 Corporate income tax paid 405 427 Other movements 12 12 478 347 Assets 478 347 Liabilities — — At 31 December 478 347 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 2022 (123) (508) (7) (12) 8 68 (5) (579) Income statement (charge)/credit 150 (49) — — (7) (33) (96) (35) Transfers/reclassifications — — 2 — (1) — (1) — Credited/(charged) to other comprehensive income — 267 310 11 — — (9) 579 At 31 December 2022 27 (290) 305 (1) — 35 (111) (35) 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)

Dividends on Ordinary Shares

Dividends on Ordinary Shares	12 Months Ended
	Dec. 31, 2022
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 2022 2021 2020 2022 2021 2020 Pence per share Pence per share Pence per share £m £m £m In respect of current year – first interim 1.25 0.90 0.42 389 281 129 – second interim 2.01 3.47 — 625 1,077 — 3.26 4.37 0.42 1,014 1,358 129 In 2022 an interim dividend of £1,014m (2021: £1,358m , 2020: £129m) was paid on the Company's ordinary shares in issue, £300m of which was a special dividend. These were paid following review and approval by the Board in line with our dividend policy.

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2022
Disclosure of nature and extent of risks arising from financial instruments [abstract]
Derivative Financial Instruments	11. DERIVATIVE FINANCIAL INSTRUMENTS a) Use of derivatives Santander UK undertakes derivative activities primarily to provide customers with risk management solutions and to manage and hedge its own risks. These 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, Santander UK employs the same credit risk management procedures to assess and approve potential credit exposures that are used for traditional lending. For information on how Santander UK is managing the transition to alternative benchmark interest rates, see Note 41. 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 2022 2021 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 14,006 315 281 11,036 159 168 Interest rate contracts 31,135 465 754 25,148 463 485 Equity and credit contracts 902 130 25 1,056 161 54 Total derivatives held for trading 46,043 910 1,060 37,240 783 707 Derivatives held for hedging Designated as fair value hedges: Exchange rate contracts 538 12 4 590 39 — Interest rate contracts 77,748 1,777 403 80,514 904 737 78,286 1,789 407 81,104 943 737 Designated as cash flow hedges: Exchange rate contracts 26,035 1,717 186 22,239 996 338 Interest rate contracts 26,108 164 1,471 21,466 180 216 52,143 1,881 1,657 43,705 1,176 554 Total derivatives held for hedging 130,429 3,670 2,064 124,809 2,119 1,291 Derivative netting (1) — (2,173) (2,173) — (1,221) (1,221) Total derivatives 176,472 2,407 951 162,049 1,681 777 (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 £1,368m (2021: £189m) and the amount of cash collateral paid that had been offset against the gross derivative liabilities was £70m (2021: £202m). For information about the impact of netting arrangements on derivative assets and liabilities in the table above, see Note 40. The table below analyses the notional and fair values of derivatives by trading and settlement method. Notional Traded over the counter Asset Liability Settled by central counterparties Not settled by central counterparties Total Traded over the counter Traded over the counter 2022 £m £m £m £m £m Exchange rate contracts — 40,579 40,579 2,044 471 Interest rate contracts 124,638 10,353 134,991 233 455 Equity and credit contracts — 902 902 130 25 124,638 51,834 176,472 2,407 951 2021 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 c) Analysis of derivatives designated as hedges Santander UK 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 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. Cash flow 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 BoE base rate. 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, Santander UK 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 foreign exchange contracts (spot, forward and swaps) or cross currency 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 41 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. 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 2022 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) 2,210 4,468 21,678 45,314 3,808 77,478 Average fixed interest rate - GBP 2.58 % 0.88 % 0.56 % 2.07 % 3.78 % Average fixed interest rate - EUR 1.77 % 1.60 % 0.77 % 0.28 % 3.09 % Average fixed interest rate - USD 1.35 % 3.47 % 3.51 % 2.00 % 4.92 % Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) — — 66 465 7 538 Interest rate contracts - Nominal amount (£m) — — — 263 7 270 Average GBP - EUR exchange rate — — 1.20 1.16 1.10 Average GBP - USD exchange rate — — — 1.19 — Average fixed interest rate - EUR — — 3.42 % 2.06 % — Average fixed interest rate - USD — — — 4.63 % — Cash flow hedges: Interest rate risk Interest rate contracts – Nominal amount (£m) 1,042 2,191 1,940 13,197 1,076 19,446 Average fixed interest rate - GBP 1.77 % 2.29 % 1.98 % 2.35 % 1.84 % FX risk Exchange rate contracts - Nominal amount (£m) 2,301 3,135 2,381 10,606 1,163 19,586 Interest rate contracts - Nominal amount (£m) 415 — — 2,325 997 3,737 Average GBP - JPY exchange rate — 157.45 160.04 — — Average GBP - CHF exchange rate — 1.13 — — — Average GBP - EUR exchange rate — — 1.12 1.18 1.17 Average GBP - USD exchange rate 1.22 1.25 1.17 1.31 1.39 Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) — — 1,173 4,626 650 6,449 Interest rate contracts - Nominal amount (£m) — — 585 2,132 208 2,925 Average GBP - EUR exchange rate 1.19 1.21 1.20 Average GBP - USD exchange rate 1.60 1.50 1.54 Average fixed interest rate – GBP — — 3.27 % 2.58 % 4.59 % 2021 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) — — 0 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 % Net gains or losses arising from fair value and cash flow hedges included in other operating income Group 2022 2021 2020 £m £m £m Fair value hedging: Gains/(losses) on hedging instruments 2,381 852 (299) (Losses)/gains on hedged items attributable to hedged risks (2,316) (800) 365 Fair value hedging ineffectiveness 65 52 66 Cash flow hedging ineffectiveness (36) (39) (46) 29 13 20 Hedge ineffectiveness can be analysed by risk category as follows: Group 2022 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 Change in FV of hedging instruments Change in FV of hedged items Recognised in income statement £m £m £m £m £m £m £m £m £m Fair value hedges: Interest rate risk 2,392 (2,333) 59 874 (834) 40 (358) 385 27 Interest rate/FX risk (11) 17 6 (22) 34 12 59 (20) 39 2,381 (2,316) 65 852 (800) 52 (299) 365 66 Group Hedging Instruments Income statement line item affected by reclassification Change in FV Recognised in OCI Recognised in Income Statement Reclassified from reserves to income £m £m £m £m Cash flow hedges: 2022 Interest rate risk Net interest income (1,161) 1,160 (1) (96) FX risk Net interest income/other operating income 1,604 (1,604) — 1,692 Interest rate/FX risk Net interest income/other operating income (54) 19 (35) 533 389 (425) (36) 2,129 2021 Interest rate risk Net interest income (317) 305 (12) 73 FX risk Net interest income/other operating income (54) 54 — (158) Interest rate/FX risk Net interest income/other operating income (541) 514 (27) (273) (912) 873 (39) (358) 2020 Interest rate risk Net interest income 185 (179) 6 33 FX risk Net interest income/other operating income (42) 38 (4) 2 Interest rate/FX risk Net interest income/other operating income 782 (830) (48) 773 925 (971) (46) 808 In 2022, cash flow hedge accounting of £0m (2021: £14m) 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 2022 2021 £m £m Balance at 1 January 129 644 Effective portion of changes in fair value: – Interest rate risk (1,160) (305) – Foreign currency risk 1,604 (54) – Equity risk — — – Interest rate/foreign currency risk (19) (514) 425 (873) Income statement transfers: – Interest rate risk 96 (73) – Foreign currency risk (1,692) 158 – Equity risk — – Interest rate/foreign currency risk (533) 273 (2,129) 358 Balance at 31 December (1,575) 129 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 2022 2021 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 60,783 — (2,640) (653) (2,707) 58,455 — 80 491 (1,092) Other financial assets at amortised cost 156 — (12) 2 (14) 160 — 2 3 (12) Reverse repurchase agreements – non trading 4,045 — (5) (1) — 9,570 — (5) — (6) Other financial assets at FVOCI 2,325 (200) — 35 (227) 3,728 23 — 47 (112) Deposits by customers (1,739) 24 5 — 33 (1,665) (46) — (44) 104 Deposits by banks — — — — — — — — — — Debt securities in issue (4,735) 321 (94) (172) 528 (2,567) (140) (114) (185) 235 Subordinated liabilities (250) (27) (6) (63) 54 (293) (75) (8) (70) 49 Interest rate/FX risk: Other financial assets at FVOCI 237 (21) — 1 (9) 227 — — 1 (20) Debt securities in issue (290) (18) — (37) 27 (423) (55) — (47) 55 Subordinated liabilities 1 1 — 1 (1) 2 2 — 2 (1) 60,533 80 (2,752) (887) (2,316) 67,194 (291) (45) 198 (800) Group 2022 2021 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 935 (1,010) (1) 235 (135) (2) Cash and balances at central banks 233 (274) (106) 71 (79) — Reverse repurchase agreements - non trading — — — — — — Deposits by banks (8) 7 — (1) 1 — Debt securities in issue — — — — — — Repurchase agreements - non trading — — — — — — FX risk: Other financial assets at FVOCI — (6) — (195) (1) — Not applicable – highly probable forecast transactions (349) 2 — 149 1 — Deposits by customers (167) (2) — 9 9 10 Deposits by banks — — — — — — Debt securities in issue (1,051) (17) (2) 85 57 (4) Repurchase agreements - non trading (37) — — 6 — — Equity risk: Other liabilities — — — — — — Interest rate/FX risk: Debt securities in issue/loans and advances to customers 56 (170) (3) 410 105 (4) Deposits by customers — (74) — 93 38 — Subordinated liabilities/loans and advances to customers (37) (31) 77 11 133 80 (425) (1,575) (35) 873 129 80

Other Financial Assets at Fair

Other Financial Assets at Fair Value Through Profit or Loss	12 Months Ended
	Dec. 31, 2022
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 2022 2021 £m £m Loans and advances to customers: Loans to housing associations 4 12 Other loans 41 62 45 74 Debt securities 84 111 129 185 For the Santander UK group, other financial assets at FVTPL comprised £16m (2021: £12m) of financial assets designated at FVTPL and £113m (2021: £173m) 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 in the year attributable to changes in credit risk for loans and advances at FVTPL was £1m (2021: £nil, 2020: £nil). The cumulative net loss attributable to changes in credit risk for loans and advances at FVTPL at 31 December 2022 was £3m (2021: £2m).

Loans and Advances to Customers

Loans and Advances to Customers	12 Months Ended
	Dec. 31, 2022
Net Loans And Advances To Customers [Abstract]
Loans and Advances to Customers	13. LOANS AND ADVANCES TO CUSTOMERS Group 2022 2021 £m £m Loans secured on residential properties 184,317 174,712 Corporate loans 19,057 19,282 Finance leases 4,645 3,916 Other unsecured loans 7,742 9,404 Accrued interest and other adjustments 688 452 Amounts due from fellow Banco Santander subsidiaries and joint ventures 4,220 3,175 Amounts due from Santander UK Group Holdings plc — 6 Loans and advances to customers 220,669 210,947 Credit impairment loss allowances on loans and advances to customers (931) (828) Residual value and voluntary termination provisions on finance leases (22) (25) Net loans and advances to customers 219,716 210,094 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 2022 2021 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 1,493 (182) 1,311 1,906 (5) 1,901 Later than one year and not later than two years 1,367 (168) 1,199 1,324 (200) 1,124 Later than two years and not later than three years 1,190 (147) 1,043 771 (141) 630 Later than three years and not later than four years 1,044 (129) 915 343 (82) 261 Later than four years and not later than five years 143 (18) 125 38 (38) — Later than five years 59 (7) 52 — — — 5,296 (651) 4,645 4,382 (466) 3,916 At 31 December 2022 and 2021 , the Company had no finance lease and hire purchase contract receivables. 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 £1,761m (2021: £1,510m) 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 (2021: £nil, 2020: £nil) was earned in the year, which was classified in ‘Interest and similar income’. Finance income on the net investment in finance leases was £230m (2021: £243m, 2020: £308m). 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 2022 and 2021 , the Santander UK group had contracted with lessees for the following future undiscounted minimum lease payments receivable under operating leases. Group 2022 2021 £m £m No later than one year 31 31 Later than one year and not later than two years 27 27 Later than two years and not later than three years 22 21 Later than three years and not later than four years 13 15 Later than four years and not later than five years 11 11 Later than five years 21 28 125 133

Securitisations and Covered Bon

Securitisations and Covered Bonds	12 Months Ended
	Dec. 31, 2022
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. 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 2022 and 2021 are listed below. Gross assets External notes in issue Notes issued to Santander UK plc/subsidiaries as collateral 2022 2021 2022 2021 2022 2021 £m £m £m £m £m £m Mortgage-backed master trust structures: - Holmes 1,646 2,294 790 430 176 183 - Fosse 2,028 2,154 100 288 1,365 1,402 3,674 4,448 890 718 1,541 1,585 Other asset-backed securitisation structures: - Motor 6 38 7 41 — — Total securitisation programmes 3,680 4,486 897 759 1,541 1,585 Covered bond programmes – Euro 35bn Global Covered Bond Programme 21,304 15,713 15,205 12,760 — — Total securitisation and covered bond programmes 24,984 20,199 16,102 13,519 1,541 1,585 The following table sets out the internal and external issuances and redemptions in 2022 and 2021 for each securitisation and covered bond programme. Internal issuances External issuances Internal redemptions External redemptions 2022 2021 2022 2021 2022 2021 2022 2021 £bn £bn £bn £bn £bn £bn £bn £bn Mortgage-backed master trust structures: – Holmes — — 0.6 — 0.1 0.2 0.2 0.4 – Fosse — — — — — — 0.2 — – Langton — — — — — 2.4 — — Other asset-backed securitisation structures: – Motor — — — — — 0.1 — 0.1 – Auto ABS UK Loans — — 0.1 0.1 Covered bond programme — — 4.2 — 0.1 — 1.7 6.5 — — 4.8 — 0.2 2.8 2.1 7.1 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. Redemptions for Auto ABS UK Loans, which were held in PSA Finance UK Limited (PSA), are included up to 30 July 2021, the date on which the Santander UK group sold its entire shareholding in PSA. Holmes Funding Ltd has a beneficial interest of £0.8bn (2021: £0.5bn) 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 £1.5bn (2021: £1.6bn) 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. The Holmes securitisation companies have cash deposits of £112m (2021: £60m), which have been accumulated to finance the redemption of a number of securities issued by the Holmes securitisation companies. The share of Holmes Funding Ltd in the trust assets is therefore reduced by this amount.

Transfers of Financial Assets N

Transfers of Financial Assets Not Qualifying for Derecognition	12 Months Ended
	Dec. 31, 2022
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 a result of these sale and repurchase and securities lending 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 2022 2021 Assets Liabilities Assets Liabilities Nature of transaction £m £m £m £m Sale and repurchase agreements 120 (128) 171 (172) Securities lending agreements 2,871 (2,509) 1,892 (1,742) Securitisations (See Notes 14 and 26) 3,680 (897) 4,486 (759) 6,671 (3,534) 6,549 (2,673)

Reverse Repurchase Agreements -

Reverse Repurchase Agreements - Non Trading	12 Months Ended
	Dec. 31, 2022
Disclosure Of Reserve Repurchase Agreements Non-Trading [Abstract]
Reverse Repurchase Agreements - Non Trading	16. REVERSE REPURCHASE AGREEMENTS – NON TRADING Group 2022 2021 £m £m Agreements with banks 885 447 Agreements with customers 6,463 12,236 7,348 12,683

Other Financial Assets at Amort

Other Financial Assets at Amortised Cost	12 Months Ended
	Dec. 31, 2022
Financial assets at fair value through profit or loss [abstract]
Other Financial Assets at Amortised Cost	17. OTHER FINANCIAL ASSETS AT AMORTISED COST Group 2022 2021 £m £m Asset backed securities 94 443 Debt securities 62 63 0 156 506

Financial Assets at Fair Value

Financial Assets at Fair Value Through Other Comprehensive Income	12 Months Ended
	Dec. 31, 2022
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 2022 2021 £m £m Debt securities 6,024 5,833 Loans and advances to customers — 18 6,024 5,851

Interests in Other Entities

Interests in Other Entities	12 Months Ended
	Dec. 31, 2022
Investments accounted for using equity method [abstract]
Interests in Other Entities	19. INTERESTS IN OTHER ENTITIES Group 2022 2021 £m £m Subsidiaries — — Joint Ventures 252 201 0 252 201 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. Interests in consolidated structured entities Structured entities are formed by Santander UK to accomplish specific and well-defined objectives. Santander UK consolidated these structured entities when the substance of the relationship indicates control, as described in Note 1. In addition to the structured entities disclosed in Note14 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 ion 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. In 2022, Santander UK’s share in the profit after tax of its joint ventures was £36m (2021: £22m) before elimination of transactions between Santander UK and the joint ventures. At 31 December 2022, the carrying amount of Santander UK’s interest was £252m (2021: £201m). At 31 December 2022 and 2021, 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 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 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 £8,646m (2021: £14,100m) 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 four (2021: 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 £180m (2021: £1,184m), are issued to, and held by, Santander UK. Junior credit linked notes, which amounted to £465m (2021: £619m), are all held by third party investors and suffer losses incurred in the referenced portfolios after any tranche of risk that has been assumed by Santander UK. 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, 2022
Disclosure of detailed information about intangible assets [abstract]
Intangible Assets	20. INTANGIBLE ASSETS a) Goodwill Group Cost Accumulated impairment Carrying amount £m £m £m At 31 December 2021 and 1 January 2022 1,269 (66) 1,203 Movement in the period — (4) (4) At 31 December 2022 1,269 (70) 1,199 Impairment of goodwill In 2022 and 2021, no significant impairment of goodwill was recognised. Goodwill is tested for impairment annually at 31 December, with a review for impairment indicators at 30 June. Goodwill is tested for impairment if reviews identify an impairment indicator or when events or changes in circumstances dictate. The annual review identified that the risks of Covid-19 have reduced significantly; however rising inflation, exacerbated by the conflict in Ukraine, places increasing uncertainty on the UK economic trajectory, 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 2022 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. Carrying amount of Goodwill by CGU and key assumptions in the VIU calculation Goodwill Discount rate Growth rate beyond initial cash flow projections 2022 2021 2022 2021 2022 2021 CGU £m £m % % % % Personal Financial Services 1,169 1,169 16.6 13.6 1.6 1.6 Private Banking 30 30 15.3 16.3 1.6 1.6 Other — 4 13.6 1.6 1,199 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 macroeconomic outlook. For the goodwill impairment tests conducted at 31 December 2022, the determination of the carrying amount of the Personal Financial Services CGU was based on an allocation of regulatory capital and management’s cash flow projections until the end of 2025. 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 recent events in the UK economic environment on 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 2022, see the Credit risk – Santander UK group level section of the Risk review. The cash flow projections take into account the likely impact of recent changes to the BoE Bank Rate, inflation and also consider the 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 2022. 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) and calculated on a post-tax basis. 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. The inputs to the CAPM are observable on a post-tax basis. 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. The Private Banking CGU has a different discount rate compared to the Personal Financial Services CGU because different market participants closely resemble each CGU. 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 higher living costs, driven by high inflation and rising interest rates. 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 2022 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 value in use At 31 December 2022 and 31 December 2021, 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, such as a decrease in mortgage new business. 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 – Higher interest rate environment impact on customer affordability – Customer remediation and regulatory action outcomes – Uncertain regulatory capital requirements. – Cash flow projections decrease by 5% (2021: 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 (2021: 100 basis points). At 31 December 2022 and 31 December 2021, 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 a reduction in headroom as follows. Reduction in headroom 2022 2021 CGU Reasonably possible change £m £m Personal Financial Services Cash flow projections decrease by 5% (2021: 5%) (538) (455) Discount rate increases by 100 basis points (2021: 100 basis points) (887) (943) Sensitivity of Value in use changes to current assumptions to achieve nil headroom Although there was no impairment of goodwill relating to the Personal Financial Services CGU or the Private Banking CGU at 31 December 2022, 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 2022, there was an increase in headroom arising from an increase in profitability and cash flows forecast as interest rates have risen, alongside a reduction in the required leverage capital requirement, which was partially offset by an increase in the discount rate. 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. 2022 Carrying value Value in use Headroom Increase in discount rate Decrease in cash flows CGU £m £m £m bps % Personal Financial Services 8,860 10,752 1,892 239 18 2021 Personal Financial Services 8,433 9,100 667 68 7 b) Other intangibles Group Cost Accumulated Carrying amount £m £m £m At 1 January 2022 1,334 (992) 342 Additions 112 — 112 Disposals (185) 185 — Charge — (100) (100) Impairment — (3) (3) At 31 December 2022 1,261 (910) 351 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 Other intangibles which consist of computer software, include computer software under development of £149m (2021: £83m ), of which £33m is internally generated (2021: £31m). The impairment charge of £3m (2021: £26m) 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, 2022
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 (1) £m £m £m £m £m £m Cost: At 1 January 2022 978 1,049 434 755 254 3,470 Additions 61 86 — 185 38 370 Reclassification to assets held for sale (98) (13) — — — (111) Disposals (52) (299) (362) (218) (25) (956) At 31 December 2022 889 823 72 722 267 2,773 Accumulated depreciation: At 1 January 2022 334 857 434 160 137 1,922 Charge for the year (2) 18 68 1 73 19 179 Impairment during the year 8 2 — — — 10 Reclassification to assets held for sale (49) (13) — — — (62) Disposals (41) (296) (363) (88) (1) (789) At 31 December 2022 270 618 72 145 155 1,260 Carrying amount 619 205 — 577 112 1,513 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 (2) 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 Carrying amount 644 192 — 595 117 1,548 In 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 April 2023. Expenditure at 31 December 2022 was approximately £204m.

Other Financial Liabilities at

Other Financial Liabilities at Fair Value Through Profit or Loss	12 Months Ended
	Dec. 31, 2022
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 2022 2021 £m £m US$30bn Euro Medium Term Note Programme 3 5 Structured Notes Programmes 375 413 Eurobonds 102 142 Structured deposits 321 223 Collateral and associated financial guarantees 2 20 803 803 For the Santander UK group all (2021: 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 19. 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 gain during the year attributable to changes in the Santander UK group’s own credit risk on the above securities was £25m (2021: £12m loss, 2020: £3m loss). The cumulative net gain attributable to changes in the Santander UK group’s own credit risk on the above securities at 31 December 2022 was £15m (2021: £10m loss, 2020: £3m loss). At 31 December 2022, the amount that would be required to be contractually paid at maturity of the securities above was £138m higher ( 2021: £nil) higher than the carrying value.

Deposits by Customers

Deposits by Customers	12 Months Ended
	Dec. 31, 2022
Deposits from customers [abstract]
Deposits by Customers	23. DEPOSITS BY CUSTOMERS Group 2022 2021 £m £m Demand and time deposits (1) 189,587 185,843 Amounts due to other Santander UK Group Holdings plc subsidiaries 67 59 Amounts due to Santander UK Group Holdings plc (2) 4,759 5,874 Amounts due to fellow Banco Santander subsidiaries and joint ventures 1,155 1,150 195,568 192,926 (1) Includes equity index-linked deposits of £408m (2021: £549m). The capital amount guaranteed/protected and the amount of return guaranteed in respect of the equity index-linked deposits were £408m and £2m (2021: £549m 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, 2022
Disclosure Of Deposits From Banks [Abstract]
Deposits by Banks	24. DEPOSITS BY BANKS Group 2022 2021 £m £m Items in the course of transmission 701 414 Deposits held as collateral 1,741 931 Other deposits (1) 26,082 32,507 Amounts due to Santander UK subsidiaries 1 3 28,525 33,855 (1) Includes drawdown from the TFSME of £25.0bn (2021: £31.9bn).

Repurchase Agreements - Non Tra

Repurchase Agreements - Non Trading	12 Months Ended
	Dec. 31, 2022
Disclosure Of Repurchase Agreements [Abstract]
Repurchase Agreements - Non Trading	25. REPURCHASE AGREEMENTS – NON TRADING Group 2022 2021 £m £m Agreements with banks (1) 50 43 Agreements with customers (1) 7,932 11,675 7,982 11,718 (1) In 2022, an administrative error was identified where some repurchase agreements had been incorrectly classified as 'agreements with banks, rather than 'agreements with customers'. As a result, the balance for 2021 has been restated to reclassify £4,102m from 'agreements with banks' to 'agreements with customers'.

Debt Securities in Issue

Debt Securities in Issue	12 Months Ended
	Dec. 31, 2022
Debt Securities In Issue [Abstract]
Debt Securities in Issue	26. DEBT SECURITIES IN ISSUE Group 2022 2021 £m £m Medium-term notes: – US$30bn Euro Medium Term Note Programme 739 1,405 – Euro 30bn Euro Medium Term Note Programme 3,211 1,261 - US SEC-registered Debt Programme - Santander UK plc 6,694 4,185 10,644 6,851 Euro 35bn Global Covered Bond Programme 15,205 12,760 US$20bn Commercial Paper Programmes 1,851 2,704 Certificates of deposit 2,874 2,387 Credit linked notes 60 59 Securitisation programmes 897 759 31,531 25,520

Subordinated Liabilities

Subordinated Liabilities	12 Months Ended
	Dec. 31, 2022
Disclosure Of Subordinated Liabilities [Abstract]
Subordinated Liabilities	27. SUBORDINATED LIABILITIES Group 2022 2021 £m £m £325m Sterling preference shares 344 344 Undated subordinated liabilities 219 240 Dated subordinated liabilities 1,769 1,644 2,332 2,228 In 2022, the Santander UK group repurchased certain debt securities and subordinated liabilities as part of ongoing liability management exercises, resulting in a loss of £5m (2021: a loss of £1m). 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 2022 and 2021, 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 2022 2021 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 14 35 219 240 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 2022 2021 Maturity £m £m 5% Subordinated notes (US$1,500m) 2023 591 548 4.75% Subordinated notes (US$1,000m) 2025 608 541 7.95% Subordinated notes (US$1,000m) 2029 207 221 6.50% Subordinated notes 2030 22 28 5.875%Subordinated notes 2031 7 9 5.625%Subordinated notes (US$500m) 2045 334 297 1,769 1,644 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, 2022
Subclassifications of assets, liabilities and equities [abstract]
Other Liabilities	28. OTHER LIABILITIES Group 2022 2021 £m £m Lease liabilities 125 132 Other (1) 2,456 1,935 2,581 2,067 (1) For more information on amounts restated see Note 44.

Provisions

Provisions	12 Months Ended
	Dec. 31, 2022
Disclosure of other provisions [abstract]
Provisions	29. PROVISIONS Group Customer remediation Litigation and other regulatory Bank Levy Property ECL on undrawn facilities and guarantees Restructuring Other Total £m £m £m £m £m £m £m £m At 1 January 2022 44 166 1 74 38 28 13 364 Additional provisions (See Note 8) 77 137 47 — 36 23 196 516 Provisions released (See Note 8) (18) (18) (4) (7) — — (11) (58) Utilisation and other (13) (149) (59) (20) — (30) (191) (462) Recharge (1) — — 18 — — — — 18 At 31 December 2022 90 136 3 47 74 21 7 378 (1) Recharge in respect of the UK Bank Levy paid on behalf of other UK entities in the Banco Santander group Provisions expected to be settled within no more than 12 months after 31 December 2022 were £130m (2021: £180m). a) Customer remediation Provisions of £77m were recognised in 2022 for two customer remediation exercises relating to our historical mortgage book. Most of the provision relates to the proposed refund of early repayment charges paid by a specific group of customers who historically switched mortgage products The provision remains subject to change as additional data becomes available and remediation boundaries are finalised. At 31 December 2022 there was no customer remediation provision (2021 : £6m ) for a systems-related historical issue identified by Santander UK, relating to compliance with certain requirements of the Consumer Credit Act (CCA). The remediation is now complete with all customers having been contacted. 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. The majority of the 2022 charge is the settlement of a financial penalty of £108m with the FCA for shortcomings in our anti-money laundering controls. Although the deadline for bringing PPI complaints has passed, customers can still commence Plevin related litigation. Amounts include a provision of £24m 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 the 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. c) Bank Levy A rate of 0.10% applied for 2022 (2021: 0.10%). e) ECL on undrawn facilities and guarantees Provisions include expected credit losses relating to guarantees given to third parties and undrawn loan commitments. f) Restructuring Restructuring provisions relate to severance costs associated with transformation and organisational changes. The provision includes a charge of £19m as part of our multi-year transformation programme to improve future returns, focused on simplifying, digitising and automating the bank. g) Other Other provisions do not fit into any of the other categories, such as some categories of operational losses, including fraud losses. In 2022, Other provisions included charges for operational risk provisions of £186m, including fraud losses of £153m .

Retirement Benefit Plans

Retirement Benefit Plans	12 Months Ended
	Dec. 31, 2022
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 2022 2021 £m £m Assets/(liabilities) Funded defined benefit pension scheme - surplus 1,050 1,572 Unfunded pension and post-retirement medical benefits (25) (37) Total net assets 1,025 1,535 Remeasurement losses/(gains) recognised in other comprehensive income in the year were as follows: Group 2022 2021 2020 £m £m £m Pension remeasurement 722 (1,264) 505 An expense of £60m (2021: £64m) 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 10% (2021: 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 six (2021:five) Directors selected by Santander UK Group Holdings plc, plus four (2021: 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 ten Trustee directors, who are the same as the directors of 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 2022 was finalised in November 2022, with an overall scheme deficit of £183m . The next scheduled triennial funding valuation will be at 31 March 2025. 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 are 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 2022 2021 2020 £m £m £m Net interest income (30) (5) (10) Current service cost 30 38 36 Past service and GMP costs — — 1 Past service curtailment costs 0 5 — Administration costs 9 8 8 9 46 35 The amounts recognised in other comprehensive income were as follows: Group 2022 2021 2020 £m £m £m Return on plan assets (excluding amounts included in net interest expense) 5,527 (454) (1,328) Actuarial (gains)/losses arising from changes in demographic assumptions (122) (17) 34 Actuarial (gains)/losses arising from experience adjustments 481 (19) (141) Actuarial (gains)/losses arising from changes in financial assumptions (5,164) (774) 1,940 Pension remeasurement 722 (1,264) 505 Movements in the present value of defined benefit scheme obligations were as follows: Group 2022 2021 £m £m At 1 January (12,878) (13,887) Current service cost paid by Santander UK plc (29) (29) Current service cost paid by subsidiaries (1) (9) Current service cost paid by fellow Banco Santander subsidiaries — — Interest cost (241) (188) Employer salary sacrifice contributions (2) (9) Past service cost — — Past service curtailment costs — (5) GMP equalisation cost — — Remeasurement due to actuarial movements arising from: – Changes in demographic assumptions 122 17 – Experience adjustments (481) 19 – Changes in financial assumptions 5,164 774 Benefits paid 413 398 Derecognition of pension scheme liabilities arising from the sale of PSA — 41 At 31 December (7,933) (12,878) Movements in the fair value of the schemes’ assets were as follows: Group 2022 2021 £m £m At 1 January 14,413 13,979 Interest income 271 193 Contributions paid by employer and scheme members 223 246 Contributions paid by fellow Banco Santander subsidiaries — — Administration costs paid (9) (8) Return on plan assets (excluding amounts included in net interest expense) (5,527) 454 Benefits paid (413) (398) Derecognition of pension scheme assets arising from the sale of PSA — (53) At 31 December 8,958 14,413 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 2022 £m % £m % £m % technique Overseas equities 0 0 1,172 13 1,172 13 A,C Corporate bonds 1,991 22 244 3 2,235 25 A,C Government fixed interest bonds 1,138 13 — — 1,138 13 A Government index-linked bonds 5,525 62 — — 5,525 62 A Property — — 1,202 13 1,202 13 B Derivatives — — (78) (1) (78) (1) A Cash — — 1,340 15 1,340 15 A Repurchase agreements (1) — — (4,312) (48) (4,312) (48) A Infrastructure — — 426 5 426 5 B,C Annuities — — 293 3 293 3 D Longevity swap — (12) 0 (12) 0 D Other — — 29 0 29 0 C 8,654 97 304 3 8,958 100 2021 UK equities 38 0 — — 38 0 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 (1) Sale and repurchase agreements net of purchase and resale agreements. Valuation techniques The main methods for measuring the fair value of the Scheme’s assets at 31 December 2022 and 2021 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. A number of insurance transactions have been entered into that have been included in the asset valuation under annuities and Longevity swap. The transactions were as follows:. – In March 2021, the Trustee entered into a longevity swap. Approximately 85% of pensioner liabilities were covered by the longevity swap at inception, excluding pensioners in the SMA and SPI sections. – In 2022, a pensioner buy-in was entered into by the Trustee covering pensioners in the SMA and SPI sections who were uninsured at 30 June 2021. – In July 2022, the Trustee entered into a second longevity swap, extending the insurance over uninsured pensioners in the same membership groups covered by the first swap transacted in March 2021, based on membership in the Scheme at 31 December 2021. At 31 December 2022, as highlighted above, the Scheme was invested in certain assets whose 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. The Scheme prior to 31 December 2022 invested in equities and had an equity collar in place to manage equity risk. The Scheme also hedges a proportion of its foreign exchange exposure to manage currency risk. At 31 December 2022 the equity collar had a notional value of £3m (2021: £1,259m) and the currency forwards had a notional value of £985m (2021: £2,296m). Significant asset de-risking took place in 2022, with the Scheme divesting entirely from listed equities, as well as its multi-asset funds. Significant investments were made in quoted corporate bonds over the year, largely funded from these sales. The sale proceeds also went to de-leveraging the asset portfolio. 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 2022 and 2021. 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 committed to a target of net zero by 2050, showing their full support for the Santander UK group's vision, commitment to sustainability and climate change. Funding In November 2022, 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 a schedule of contributions following the finalisation of the 31 March 2022 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 £218m in 2022 (2021: £241m) to the Scheme, of which £178m (2021: £194m) was in respect of agreed deficit repair contributions. The agreed schedule of the Santander UK group’s contributions to the Scheme covers the period up to 31 March 2026 and comprises of contingent contributions which become due if the funding position of any section falls behind the agreed plan . 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 Scheme were: Group 2022 2021 2020 % % % To determine benefit obligations (1) : – Discount rate for scheme liabilities 4.9 1.9 1.3 – General price inflation 3.1 3.4 3.0 – General salary increase 1.0 1.0 1.0 – Expected rate of pension increase 3.0 3.2 2.9 Years Years Years Longevity at 60 for current pensioners, on the valuation date: – Males 27.4 27.5 27.5 – Females 30.1 30.1 30.0 Longevity at 60 for future pensioners currently aged 40, on the valuation date: – Males 28.9 29.0 29.0 – Females 31.6 31.6 31.5 (1) The discount rate and inflation related assumptions set out in the table above 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. 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. In 2022, management updated the model used to construct the curve following a review of the Scheme's IAS 19 assumptions. The model which we use to construct the curve uses corporate bond data but excludes convertible bonds, asset-backed bonds and government related bonds. The curve is then constructed from this data by extrapolating the spot rates from 30 years to 50 years by holding the spread above nominal gilt spot rates constant. From 50 years onwards, it is assumed that spot rates remain constant. When considering an appropriate assumption, we project forward the expected cash flows of each section of the Scheme and adopt a single equivalent cash flow weighted discount rate for each section, subject to management judgement. General price inflation Consistent with our discount rate methodology, we set the inflation assumption using the expected cash flows for each section 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 2022, management refined the general price inflation assumption following a review of the Scheme’s IAS 19 assumptions, to reflect a different data set and different methodology used to construct the curve. 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 2022 the CMI 2021 projection model was adopted, with model parameters selected having had regard to the Scheme’s membership profile with an initial addition to improvements of 0.25% 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. A modest weight of 10% was placed on the 2021 data in the model, reflecting the likelihood of sustained indirect impacts of the pandemic. Both the mortality table and the projection model are published by the Continuous Mortality Investigation. In 2022, 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 2022 triennial valuation. These reviews resulted in changes in the assumptions for family statistics, early retirement and the withdrawal assumption. 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. Change in pension obligation at year end from (Decrease)/increase 2022 2021 2022 2021 Assumption £m £m Discount rate 50 bps increase 25 bps increase (501) (571) General price inflation 50 bps increase 25 bps increase 374 392 Mortality Each additional year of longevity assumed Each additional year of longevity assumed 203 478 The 50 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 2023 416 2024 360 2025 382 2026 404 2027 425 Five years ending 2032 2,325 The average duration of the defined benefit obligation at 31 December 2022 was 14.2 years (2021: 18.3 years). Emerging risks Actions taken in 2022 to reduce asset risk, in line with the agreements already in place with the Trustee, served to improve the Scheme’s resilience to market volatility. In 2022, the risks considered in relation to Covid-19 related mainly to the suitability of our long-term mortality assumption for our IAS 19 and funding valuations. The focus in 2022 shifted to the risks arising from the conflict in Ukraine, rising interest rates, the 2022 actuarial valuation, together with market volatility driven by the UK political landscape. The Santander UK group has collaborated with the Trustee 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, 2022
Disclosure of contingent liabilities [abstract]
Contingent Liabilities and Commitments	31. CONTINGENT LIABILITIES AND COMMITMENTS Group 2022 2021 £m £m Guarantees given to third parties 448 363 Formal standby facilities, credit lines and other commitments 31,388 37,346 31,836 37,709 Capital support arrangements At 31 December 2022 , Santander UK plc, Cater Allen Limited, Santander ISA Managers Limited and certain other non-regulated subsidiaries of Santander UK plc were party to a capital support deed entered into on 17 December 2021 and effective from 1 January 2022 (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 expires on 31 December 2024. Exposures of each of the regulated entities to other members of the core UK group are exempt from large exposure limits that would otherwise apply and these exposures are risk-weighted at 0% . Where applicable this permission also provides for intra-group exposures to be excluded from the leverage exposure measure. The purpose of the RFB Sub-Group Capital Support Deed is 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. 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 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. Corporate facilities can comprise standby and revolving facilities which are subject to ongoing compliance with covenants and may require the provision of agreed security. 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. FCA civil regulatory investigation into Santander UK plc financial crime systems, processes and controls, and compliance with the Money Laundering Regulations 2007 In December 2022, we paid a £108m financial penalty to settle the FCA's enforcement investigation into the anti-money laundering systems and controls in our Business Banking division in the period between 31 December 2012 and 18 October 2017. The settlement concluded the FCA's investigation. Payment Protection Insurance In relation to a specific PPI portfolio of complaints, a legal dispute regarding allocation of liability is 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 SA 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 the relevant 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 SA 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 SA. 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. Judgment in respect of the Santander Entities application for AXA France’s claim to be struck out/summarily dismissed, was handed down by the Commercial Court on 12 July 2022. In summary, the Commercial Court upheld a significant part of the Santander Entities’ strike-out application, striking out AXA France’s claim for contribution against Santander for alleged losses and requiring AXA France to re-plead a significant portion of its other pleadings. AXA France updated the amount of losses claimed from £636m to £670m in their Amended Particulars of Claim dated 21 October 2022. Overall, the 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 PPI provision includes an amount relating to legal claims 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. It is not currently practicable to provide an estimate of the risk and amount of any further financial impact. 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 2022 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. These uncertainties mean it is not currently possible to make a reliable assessment of the size of any related potential liability. 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. 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. This agreement was executed in April 2022, resulting in a final payment by the lessee to HMRC and the conclusion of HMRC’s review. There is no financial impact for the Santander UK group. Other On 2 November 2015, Visa Europe Ltd agreed to sell 100% of its share capital to Visa Inc. The deal closed on 21 June 2016. As a member and shareholder of Visa Europe Ltd, Santander UK received upfront consideration made up of cash and convertible preferred stock. Conversion of the preferred stock into Class A Common Stock of Visa Inc. depends on the outcome of litigation against Visa involving UK & Ireland (UK&I) multilateral interchange fees (MIFs). Following ring-fencing, all Visa stock is now held by Santander Equity Investments Limited (SEIL), outside the ring-fenced bank . In 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 35. 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, 2022
Disclosure of classes of share capital [abstract]
Share Capital	32. SHARE CAPITAL Group Ordinary shares of £0.10 each Total Issued and fully paid share capital No. £m £m At 31 December 2021, 1 January 2022 and 31 December 2022 31,051,768,866 3,105 3,105 Group 2022 2021 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, 2022
Disclosure of classes of share capital [abstract]
Other Equity Instruments	33. OTHER EQUITY INSTRUMENTS Group Interest rate 2022 2021 % Next call date £m £m £300m Step-up Callable Perpetual Reserve Capital Instruments 7.037 February 2026 — 235 AT1 securities: - £500m Perpetual Capital Securities 6.75 June 2024 496 496 - £750m Perpetual Capital Securities 7.375 June 2022 — 750 - £500m Perpetual Capital Securities 6.30 March 2025 500 500 - £210m Perpetual Capital Securities 4.25 March 2026 210 210 - £750m Perpetual Capital Securities 6.50 June 2027 750 — 1,956 2,191 Step-up Callable Perpetual Reserve Capital Instruments During 2022, the £300m Step-up Callable Perpetual Reserve Capital Instruments were called for value on 14 February 2022 and redeemed at their principal amount. AT1 securities The AT1 securities issued by the Company were subscribed for by its immediate parent company, Santander UK Group Holdings plc. The AT1 securities are perpetual and pay a quarterly distribution. 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, or the Company (calculated on a solo basis), fall below 7%. All AT1 securities are redeemable at the option of the Company, and only with the consent of the PRA.

Notes to Cash Flows

Notes to Cash Flows	12 Months Ended
	Dec. 31, 2022
Cash Flows Explanatory Notes [Abstract]
Notes to Cash Flows	34. 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 Balance sheet line item Debt securities in issue Subordinated liabilities Other equity instruments Lease liabilities Dividends paid Total 2022 £m £m £m £m £m £m At 1 January 25,520 2,228 2,191 132 — 30,071 Proceeds from issue of debt securities 4,778 — — — — 4,778 Repayment of debt securities (3,036) — — — — (3,036) Repayment of subordinated liabilities — (40) — — — (40) Issue of other equity instruments — — 750 — — 750 Repurchase of other equity instruments — — (985) — — (985) Principal elements of lease payments — — — (26) — (26) Dividends paid — — — — (1,164) (1,164) Liability-related other changes 3,155 2 — 19 — 3,176 Non-cash changes: – Unrealised foreign exchange 1,554 87 — — — 1,641 – Other changes (440) 55 — — 1,164 779 At 31 December 31,531 2,332 1,956 125 — 35,944 2021 At 1 January 35,566 2,556 2,191 97 — 40,410 Proceeds from issue of debt securities 2,872 — — — — 2,872 Repayment of debt securities (11,910) — — — — (11,910) Repayment of subordinated liabilities — (4) — — — (4) Issue of other equity instruments (2) — — 210 — — 210 Repurchase of other equity instruments (2) — — (210) — — (210) Principal elements of lease payments — — — (25) — (25) Dividends paid (1) — — — — (1,505) (1,505) Liability-related other changes (447) (4) — 60 — (391) Non-cash changes: – Unrealised foreign exchange (806) 6 — — — (800) – Other changes 245 (326) — — 1,505 1,424 At 31 December 25,520 2,228 2,191 132 — 30,071 2020 At 1 January 41,129 3,528 2,191 137 — 46,985 Proceeds from issue of debt securities 5,602 — — — — 5,602 Repayment of debt securities (11,378) — — — — (11,378) Repayment of subordinated liabilities — (659) — — — (659) Principal elements of lease payments — — — (45) — (45) Dividends paid — — — — (292) (292) Liability-related other changes (250) (10) — 5 — (255) Non-cash changes: – Unrealised foreign exchange 376 22 — — — 398 – Other changes 87 (325) — — 292 54 At 31 December 35,566 2,556 2,191 97 — 40,410 (1) Dividends paid have been restated for 2021 from the £1,494m previously disclosed to £1,505m due to an administrative error. (2) Issue and Repurchase of other equity instruments and Other Equity Instrument Other changes have been restated for 2021 from £450m, £500m and £50m previously disclosed to £210m for both Issue and Repurchase of Other equity instrument and £nil for Other changes due to an administrative error. Footnotes to the consolidated cash flow statement Net cash flows from operating activities includes interest received of £6,508m (2021: £4,806m, 2020: £5,139m), interest paid of £2,089m (2021: £1,064m, 2020: £1,857m) and dividends received of £nil (2021: £nil, 2020: £nil). Total cash outflow for leases was £28m (2021: £28m, 2020: £48m). Restatements in the consolidated cash flow statement The presentation of the consolidated cash flow statement has changed to present 'profit before tax' within cash flows from operating activities instead of 'profit after tax'. Prior periods have been restated. As a result, for the year ended 31 December 2021 and 31 December 2020, the adjustment for 'corporation tax charge' in 'non-cash items included in profit' within cash flows from operating activities has been decreased by £504m and £134m respectively. Following a decision by the IFRS Interpretations Committee in April 2022, Santander UK updated its accounting policy to exclude from cash and cash equivalents Reserves Collateralisation Accounts (RCAs) balances held at the BoE relating to Santander UK’s participation in certain payments schemes. Instead, RCAs balances are classified as restricted balances and included within 'change in operating assets' in the cash flow statement. Prior periods have been restated. As a result, opening cash and cash equivalents at 1 January 2022 and 1 January 2021 have been restated by £1,580m and £985m respectively. At 31 December 2021, cash and cash equivalents were reduced by £1,580m and restricted balances were increased by £1,580m. At 31 December 2020, cash and cash equivalents were reduced by £985m and restricted balances were increased by £985m. The net change in cash and balances at central banks was restated as a result of a decrease in cash inflows from operating activities of £595m in 2021(2020: increase of £95m). Other matters In addition, in 2021, there was a disposal of non-controlling interests of £181m.

Assets Charged as Security for

Assets Charged as Security for Liabilities and Collateral Accepted as Security for Assets	12 Months Ended
	Dec. 31, 2022
Disclosure Of Assets Pledged As Security [Abstract]
Assets Charged as Security for Liabilities and Collateral Accepted as Security for Assets	35. 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 2022 2021 £m £m On-balance sheet: Cash and balances at central banks 1,330 1,580 Loans and advances to banks 130 284 Loans and advances to customers - securitisations and covered bonds (See Note 14) 24,155 19,432 Loans and advances to customers - other 32,001 41,936 Other financial assets at amortised cost 48 — Financial assets at fair value through other comprehensive income 4,365 4,363 Total on-balance sheet 62,029 67,595 Total off-balance sheet 9,146 14,449 The Santander UK group provides assets as collateral in the following areas of the business. Sale and repurchase agreements The Santander UK group also enters into sale and repurchase agreements and similar transactions of debt securities. 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 2022 was £11,553m (2021: £15,368m), of which £900m (2021: £639m) 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, Santander UK plc and certain of its subsidiaries issue securitisations and covered bonds. At 31 December 2022, there were £24,984m (2021: £20,199m) of gross assets in these secured programmes and £829m (2021: £767m) of these related to internally retained issuances that were available for use as collateral for liquidity purposes in the future. At 31 December 2022, a total of £1,725m (2021: £1,855m) 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 2022 (2021: £500m), 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 £34,861m at 31 December 2022 (2021: £45,936m) and are offset by contractual commitments to return stock borrowed or cash received. Derivatives business In addition to the arrangements described above, collateral is also provided in the normal course of derivative business to counterparties. At 31 December 2022 £1,506m (2021: £1,947m) 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 2022 2021 £m £m On-balance sheet: Deposits by banks 1,741 931 Total on-balance sheet 1,741 931 Total off-balance sheet 10,141 17,781 Purchase and resale agreements The Santander UK group also enters into purchase and resale agreements and similar transactions of debt securities. 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 2022, the fair value of such collateral received was £8,628m (2021: £14,562m). 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 £1,513m at 31 December 2022 (2021: £3,219m) 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 2022, £1,741m (2021: £931m) 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, 2022
Disclosure of terms and conditions of share-based payment arrangement [abstract]
Share-Based Compensation	36. 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 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 2022, the carrying amount of liabilities arising from share-based payment transactions, excluding any cash element was £6.6m (2021: £3.7m), of which £0.1m had vested at 31 December 2022 (2021: £0.4m). a) Sharesave Schemes The Santander UK group launched its fifteenth HM Revenue & Customs approved Sharesave invitation under Banco Santander SA sponsorship in September 2022. 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 group. Participants in the scheme have six months from the date of vesting 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. 2022 2021 Number of options Weighted average exercise price Number of options Weighted average exercise price ‘000 £ ‘000 £ Outstanding at 1 January 25,993 2.25 21,162 2.32 Granted 13,068 1.89 9,414 2.43 Exercised (242) 1.69 (48) 1.86 Forfeited/expired (8,831) 2.59 (4,535) 2.95 Outstanding at 31 December 29,988 2.00 25,993 2.25 Exercisable at 31 December 3,439 3.22 1,321 2.75 The weighted average share price at the date the options were exercised was £2.34 (2021: £2.65). The following table summarises the range of exercise prices and weighted average remaining contractual life of the options at 31 December 2022 and 2021. 2022 2021 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 1.79 3 1.65 £2 to £3 2 2.56 3 2.81 £3 to £4 1 3.46 1 3.38 £4 to £5 0 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 £0.23 (2021: £0.20). 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 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 seven one 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. 3,974,698 shares were outstanding at 31 December 2022 (2021: 3,618,796 shares). 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. £1m and the liability arising from share-based payment transactions, excluding any cash element was £1.8m

Transactions with Directors and

Transactions with Directors and Other Key Management Personnel	12 Months Ended
	Dec. 31, 2022
Disclosure Of Remuneration Of Directors And Other Key Management Personnel [Abstract]
Transactions with Directors and Other Key Management Personnel	37. 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 (KMP) of the Santander UK group is set out in aggregate below. 2022 2021 2020 Directors’ remuneration £ £ £ Salaries and fees (1) 4,696,699 5,488,388 5,361,444 Performance-related payments (2) 3,701,569 3,431,294 933,703 Other fixed remuneration (allowances and non-cash benefits) 906,201 929,935 1,107,348 Expenses 27,715 17,097 6,772 Total remuneration 9,332,184 9,866,714 7,409,267 Compensation for loss of office (3) 172,856 356,054 — 2022 2021 2020 Directors' and Other Key Management Personnel compensation £ £ £ Short-term employee benefits (2) 22,627,595 20,553,672 16,663,726 Post-employment benefits 1,026,848 988,829 1,821,548 Compensation for loss of office (3) 1,713,256 356,054 263,097 Total compensation 25,367,699 21,898,555 18,748,371 (1) 2021 and 2020 salaries and fees have been restated to reflect fees earned in respect of services rendered during the year. Fees of £7,463 have been reallocated from 2021 to 2020. (2) 2021 and 2020 Performance related payments have been restated to account for 36% of Directors and selected KMP awards being subject to long-term metrics. Performance against these metrics can decrease the award to 0% and may not increase the award value. Previously, the value of the Variable Pay Plan awards have been disclosed in full which has resulted in an overstatement post the application of performance conditions. The value of the 2021 and 2020 Variable Pay Plan awards subject to long-term performance conditions will be disclosed after the close of the performance period upon vesting. In addition to the remuneration in the table above, no grants of shares in Banco Santander SA were made to Directors and KMPs as part of buy-outs of deferred performance-related payments in connection with previous employment in 2022 (2021: one to a KMP with a value of £107,225, of which £25,413 vested in the year, 2020: one to a Director of £1,293,678 of which £242,605 vested in the year and one to a KMP of £924,133 of which £60,500 vested in the year). A payment of guaranteed variable remuneration of £660,648 was made to a Director in 2022 ( 2021 : £nil, 2020: £nil) part of which was awarded in Banco Santander SA shares. The element of the guaranteed remuneration which vested in respect of 2022 has been disclosed above, 40%, and the remaining 60% will be disclosed upon vesting. (3) Compensation for loss of office of £172,856 was paid in 2022 to two Directors (2021: £356,054 for two Directors, 2020: £nil). Compensation for loss of office was paid to three KMPs in 2022 totalling £1,540,400 (2021: £nil , 2020: one KMP: £263,097). In 2022, the remuneration, excluding pension contributions, of the highest paid Director, was £3,510,441 (2021: £3,740,810, 2020: £2,093,149) of which £1,900,506 (2021: £1,864,320, 2020: £nil) was performance related. In 2022, the accrued defined benefit pension relating to the highest paid director was £nil (2021: £22,119, 2020: £21,309 per annum for a different 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 2022, which have been provided for previously, amounted to £379,945 (2021: £370,668; 2020: £366,248). Since the Company became part of the Banco Santander group, the Board has not awarded any new 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. 2022 2021 No. £000 No. £000 Secured loans, unsecured loans and overdrafts At 1 January 6 360 12 3,640 Net movements 4 511 (6) (3,280) At 31 December 10 871 6 360 Deposit, bank and instant access accounts and investments At 1 January 21 6,552 23 8,195 Net movements 2 (2,419) (2) (1,643) At 31 December 23 4,133 21 6,552 In 2022 and 2021, 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 2022 and 2021, 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 2022, loans were made to six Directors (2021: four Directors), with a principal amount of £540,450 outstanding at 31 December 2022 (2021: £348,306). In 2022, loans were made to four Other Key Management Personnel (2021: two), with a principal amount of £330,972 outstanding at 31 December 2022 (2021: £11,678). In 2022 and 2021, 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 2022 and 2021, no Director had a material interest in any contract of significance with Santander UK other than a service contract or appointment letter, as appropriate.

Related Party Disclosures

Related Party Disclosures	12 Months Ended
	Dec. 31, 2022
Disclosure of transactions between related parties [abstract]
Related Party Disclosures	38. 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 2022 2021 2020 2022 2021 2020 2022 2021 2022 2021 £m £m £m £m £m £m £m £m £m £m Ultimate parent (710) (164) (119) 47 33 105 1,363 816 (1,673) (1,150) Immediate parent (6) (6) (7) 308 263 316 1 7 (14,390) (10,935) Fellow subsidiaries (69) (57) (58) 177 163 157 108 159 (348) (534) Associates & joint ventures (76) (34) (29) 17 4 — 4,151 3,075 (973) (918) (861) (261) (213) 549 463 578 5,623 4,057 (17,384) (13,537) For more on this, see ‘Balances with other Banco Santander group members’ in the Risk review, Note 13. Loans and advances to customers, Note 23. Deposits by customers and Note 33. Other Equity Instruments. In addition, transactions with pension schemes operated by the Santander UK group are described in Note 30. In November 2022, Santander (UK) Group Pension Scheme Trustees Limited entered into an unsecured committed liquidity facility with Santander UK plc for £600m with a maturity date of 31 December 2024. This facility provides an alternate source of short-term liquidity for day-to-day operational needs. At the balance sheet date, no drawings had been made from this facility and the entire facility remained undrawn. 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 carrying amount 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. In 2021, a significant part of the CIB 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 42. In 2021, we sold our current head office site in Triton Square, London to Santander UK Investments, a wholly owned subsidiary of our ultimate parent. Santander UK occupies space within the building and paid fees of £6m (2021: £4m) under an occupational licence arrangement. In May 2022, Santander UK plc transferred a portfolio of mortgage assets with a carrying amount of £624m to Santander Financial Services plc for a cash consideration of £631m, including a purchase price premium of £7m .

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2022
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Abstract]
Financial Instruments	39. FINANCIAL INSTRUMENTS a) 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. b) Valuation techniques The main valuation techniques employed in internal models to measure the fair value of the financial instruments at 31 December 2022 and 2021 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 2022, 2021 and 2020. 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. c) 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 2022 2021 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 — — 212,479 212,479 219,716 — — 212,811 212,811 210,094 Loans and advances to banks — 992 — 992 992 — 1,169 — 1,169 1,169 Reverse repurchase agreements - non trading — 7,341 — 7,341 7,348 — 12,453 226 12,679 12,683 Other financial assets at amortised cost 144 — — 144 156 164 348 — 512 506 144 8,333 212,479 220,956 228,212 164 13,970 213,037 227,171 224,452 Liabilities Deposits by customers — 51 195,483 195,534 195,568 — 48 192,898 192,946 192,926 Deposits by banks — 27,979 55 28,034 28,525 — 33,770 85 33,855 33,855 Repurchase agreements - non trading — 7,982 — 7,982 7,982 — 11,718 — 11,718 11,718 Debt securities in issue 2,574 26,349 1,582 30,505 31,531 963 23,926 1,218 26,107 25,520 Subordinated liabilities 19 2,358 224 2,601 2,332 37 2,350 238 2,625 2,228 2,593 64,719 197,344 264,656 265,938 1,000 71,812 194,439 267,251 266,247 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 as a separate line item 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 typically short and relate to relatively new business. For unsecured personal loans and consumer (auto) finance loans, 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. Where reliable prices are not available, internal models have been used to determine fair values, which take into account, among other things, contract terms and observable market data, which include such factors as interest rates, credit risk and exchange rates. 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. e) 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 2022 and 31 December 2021, analysed by their levels in the fair value hierarchy - Level 1, Level 2 and Level 3. Group 2022 2021 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 — 2,044 — 2,044 — 1,193 1 1,194 A Interest rate contracts — 2,399 7 2,406 — 1,547 — 1,547 A & C Equity and credit contracts — 100 30 130 — 116 45 161 B & D Netting — (2,173) — (2,173) — (1,221) — (1,221) — 2,370 37 2,407 — 1,635 46 1,681 Other financial assets at FVTPL Loans and advances to customers — — 45 45 — — 74 74 A Debt securities — 12 72 84 — — 111 111 A, B & D — 12 117 129 — — 185 185 Financial assets at FVOCI Debt securities 5,996 28 — 6,024 5,833 — — 5,833 D Loans and advances to customers — — — — — — 18 18 D 5,996 28 — 6,024 5,833 — 18 5,851 Total assets at fair value 5,996 2,410 154 8,560 5,833 1,635 249 7,717 Liabilities Derivative financial instruments Exchange rate contracts — 471 — 471 — 506 — 506 A Interest rate contracts — 2,624 4 2,628 — 1,436 2 1,438 A & C Equity and credit contracts — 17 8 25 — 24 30 54 B & D Netting — (2,173) — (2,173) — (1,221) — (1,221) — 939 12 951 — 745 32 777 Other financial liabilities at FVTPL Debt securities in issue — 477 3 480 — 555 5 560 A Structured deposits — 321 — 321 — 223 — 223 A Collateral and associated financial guarantees — 2 — 2 — 19 1 20 D — 800 3 803 — 797 6 803 Total liabilities at fair value — 1,739 15 1,754 — 1,542 38 1,580 Transfers between levels of the fair value hierarchy In 2022 there were no significant (2021: no significant) transfers of financial instruments between levels of the fair value hierarchy. f) 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 fair value adjustments are set out in the following table: 2022 2021 £m £m Risk-related: - Bid-offer and trade specific adjustments (12) (9) - Uncertainty 12 20 - Credit risk adjustment 2 6 - Funding fair value adjustment 1 3 3 20 Day One profit 1 — 4 20 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, 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 (2021: £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. Day One profit adjustments Day One profit adjustments are adopted where the fair value estimated by a valuation model is based on one or more significant unobservable inputs. Day One profit adjustments are calculated and reported on a portfolio basis. The timing of recognition of deferred Day One profit and loss is determined individually. It is deferred until either the instrument’s fair value can be determined using market observable inputs or is realised through settlement. The financial instrument is subsequently measured at fair value, adjusted for the deferred Day One profit and loss. Subsequent changes in fair value are recognised immediately in the Income Statement without immediate reversal of deferred Day One profits and losses. 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) 2022 2021 2022 2021 2020 Balance sheet line item Category Financial instrument product type £m £m £m £m £m 1. Derivative assets Equity and credit contracts Reversionary property interests 30 45 (8) — 3 2. FVTPL assets Loans and advances to customers Roll-up mortgage portfolio 28 48 (18) (5) 6 3. FVTPL assets Loans and advances to customers Other loans 17 26 (4) (2) 3 4. FVTPL assets Debt securities Reversionary property securities 70 91 — 5 6 5. FVTPL assets Debt securities Credit linked notes 2 20 4 (5) (16) 6. FVOCI assets Loans and advances to customers Other loans — 18 — (3) (4) 7. Derivative liabilities Equity contracts Property options and forwards (8) (30) 4 (1) (3) 8. FVTPL liabilities Financial guarantees Credit protection guarantee — (1) 1 6 16 139 217 (21) (5) 11 Other Level 3 assets 7 1 6 (1) 7 Other Level 3 liabilities (7) (7) (2) 2 (1) Total net assets 139 211 Total income/(expense) (17) (4) 17 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 does not have to 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

Offsetting Financial Assets and

Offsetting Financial Assets and Liabilities	12 Months Ended
	Dec. 31, 2022
Disclosure of offsetting of financial liabilities [abstract]
Offsetting Financial Assets and Liabilities	40. OFFSETTING FINANCIAL ASSETS AND LIABILITIES 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) 2022 £m £m £m £m £m £m £m £m Assets Derivative financial assets 4,525 (2,173) 2,352 (515) (1,720) 117 55 2,407 Reverse repurchase, securities borrowing & similar agreements: – Amortised cost 8,826 (1,478) 7,348 (9) (7,339) — — 7,348 – Fair value — — — — — — — — Loans and advances to customers and banks⁽⁴⁾ 5,169 (908) 4,261 — — 4,261 216,447 220,708 18,520 (4,559) 13,961 (524) (9,059) 4,378 216,502 230,463 Liabilities Derivative financial liabilities 3,085 (2,173) 912 (515) (115) 282 39 951 Repurchase, securities lending & similar agreements: – Amortised cost 9,460 (1,478) 7,982 (9) (7,973) — — 7,982 – Fair value — — — — — — — — Deposits by customers and banks⁽⁴⁾ 8,077 (908) 7,169 — — 7,169 216,924 224,093 20,622 (4,559) 16,063 (524) (8,088) 7,451 216,963 233,026 2021 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 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 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 (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, 2022
Interest Rate Benchmark Reform [Abstract]
Interest Rate Benchmark Reform	41. INTEREST RATE BENCHMARK REFORM Regulatory announcements In March 2021, the FCA and ICE Benchmark Administration (IBA, the administrator of LIBOR) announced that GBP, Euro, Swiss franc and Japanese yen LIBOR settings, as well as settings for 1-week and 2-month US dollar LIBOR, would cease at the end of 2021, with the remaining US dollar LIBOR settings ceasing at the end of June 2023. To help mitigate the risk of widespread disruption to legacy LIBOR contracts which had not transitioned by the end of 2021, in September 2021 the FCA confirmed its decision to use powers granted under the UK Benchmarks Regulation, to require continued publication using a synthetic methodology for the 1-month, 3-month and 6-month GBP and Japanese yen LIBOR settings until at least the end of 2022. In September 2022, the FCA announced that for synthetic yen LIBOR setting, market participants should be prepared for publication to cease permanently at the end of 2022. The FCA also announced the continued publication of the 1-month and 6-month synthetic GBP LIBOR settings for a further 3 months after the end of 2022 until 31 March 2023 to support any remaining transition efforts. The FCA has no intention to use its powers to compel IBA to continue to publish the 1- and 6-month synthetic GBP LIBOR settings beyond this date and these settings will permanently cease immediately after their final publication on 31 March 2023. In November 2022, the FCA proposed to require the IBA to continue to publish the 1-month, 3-month and 6-month US dollar LIBOR settings under an unrepresentative synthetic methodology until the end of September 2024, after which it is expected to cease permanently. For GBP LIBOR, the FCA announced that they intend to continue to require IBA to publish the 3-month synthetic GBP LIBOR setting until the end of March 2024, after which it will cease permanently. The effect of these announcements and proposals is that the final LIBOR publication would be the end of September 2024: – the 3 synthetic Japanese yen LIBOR settings ceased at end of December 2022 – the 1-month and 6-month synthetic GBP LIBOR settings will cease at the end of March 2023 – the overnight and 12-month USD LIBOR settings will cease at the end of June 2023 – the 3-month synthetic GBP LIBOR setting will cease at the end of March 2024, and – the 1-month, 3-month and 6-month synthetic USD LIBOR settings would cease at the end of September 2024 (proposed). Amendments to accounting standards The IASB amended IFRS 9 ‘Financial Instruments’, IAS 39 ‘Financial Instruments: Recognition and Measurement’ and IFRS 7 ‘Financial Instruments: Disclosures’ in 2019 (the Phase 1 amendments) to provide temporary exceptions to specific hedge accounting requirements because of the uncertainty arising from the reform. 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 Phase 1 amendments continue to apply to Santander UK's GBP LIBOR cash flow hedges, for remaining legacy contracts, and USD LIBOR cash flow hedges (but not any using 1-week or 2-month USD LIBOR settings). The IASB made further amendments to various IFRSs (the Phase 2 amendments) in 2020 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 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, as long as the change is directly required by IBOR reform and takes place on an economically equivalent basis. The practical expedient was applied to all instruments or contracts that transitioned to alternative benchmark interest rates during 2022 and had no material impact for the Santander UK group. The Phase 2 amendments also 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 remaining legacy contracts using 1-month and 6-month synthetic settings, the transition to alternative benchmark interest rates will take place no later than March 2023 and, for those using the 3-month synthetic setting, no later than March 2024. For USD LIBOR cash flow hedges, transition will take place no later than June 2023 for those using overnight and 12-month USD LIBOR settings and no later than September 2024 for those using 1-month, 3-month and 6-month synthetic USD LIBOR settings. Managing LIBOR transition During 2021, Santander UK along with its customers and counterparties, agreed the transition to alternative reference rates for the majority of agreements referencing the LIBOR settings that ceased at the end of 2021. During 2022, the LIBOR transition project was closed, and local business areas have continued to work with customers and counterparties to further reduce the number of untransitioned agreements, including those referencing synthetic LIBOR and the continuing USD LIBOR settings. The following tables show the notional amounts of assets, liabilities and off-balance sheet commitments at 31 December 2022 and 31 December 2021 affected by IBOR reform that have yet to transition to an alternative benchmark interest rate. Group 2022 GBP (2) LIBOR USD (2) LIBOR Other (2) Total £m £m £m £m Assets Derivatives (1) — 1,665 — 1,665 Financial assets at amortised cost 76 57 — 133 76 1,722 — 1,798 Liabilities Derivatives (1) 66 1,846 — 1,912 66 1,846 — 1,912 Off-balance sheet commitments given 2 — — 2 2021 Assets Derivatives (1) — 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) 338 1,831 — 2,169 Other financial liabilities at fair value through profit and loss — 5 — 5 Financial liabilities at amortised cost 34 185 — 219 372 2,021 — 2,393 Off-balance sheet commitments given 338 59 — 397 1. Many of the Santander UK group's derivatives subject to IBOR reform are standard ISDA contracts and are subject to supplementary ISDA fallback provisions which became effective on 25 January 2021. 2. Settings for GBP, JPY & NOK LIBOR & 1-week and 2-month USD LIBOR ceased on 31 December 2021 and for EONIA on 3 January 2022. For certain legacy contracts, while 1-month, 3-month and 6-month settings for JPY LIBOR ceased on 31 December 2022, 1-month and 6-month synthetic GBP LIBOR settings have been extended until the end of March 2023 and until the end of March 2024 for the 3-month synthetic GBP LIBOR setting. Overnight, and 12-month USD LIBOR settings will cease on 30 June 2023. For certain legacy contract, 1-month, 3-month and 6-month synthetic USD LIBOR settings would cease at the end of September 2024. The following tables show the notional amount of derivatives in hedging relationships directly affected by uncertainties related to IBOR reform. Group 2022 2021 USD Total USD Total £m £m £m £m Total notional value of hedging instruments – Cash flow hedges 2,906 2,906 2,586 2,586 – Fair value hedges 178 178 160 160 3,084 3,084 2,746 2,746 Maturing after cessation date (1) – Cash flow hedges 2,906 2,906 2,586 2,586 – Fair value hedges 178 178 160 160 3,084 3,084 2,746 2,746 (1) The 2-month USD LIBOR setting ceased on 31 December 2021. Overnight and 12-month USD LIBOR settings will cease on 30 June 2023. For certain legacy contracts, 1-month, 3-month and 6-month synthetic USD LIBOR settings would cease at the end of September 2024. 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 and Ass

Discontinued Operations and Assets and Liabilities Held for Sale	12 Months Ended
	Dec. 31, 2022
Discontinued Operations and Assets and Liabilities Held for Sale [Abstract]
Discontinued Operations and Assets Held for Sale	42. DISCONTINUED OPERATIONS AND ASSETS HELD FOR SALE Discontinued operations Transfer of the CIB Business Santander UK plc transferred a significant part of its CIB 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 CIB business were wound down or transferred to other segments. For the periods prior to its sale, the CIB business met the requirements for presentation as discontinued operations. The financial performance and cash flow information relating to the discontinued operations were as follows: For the years ended 31 December 2022 2021 2020 £m £m £m Net interest income — 32 55 Net fee and commission income — 35 66 Other operating income — 2 2 Total operating income — 69 123 Operating expenses before credit impairment (charges)/write-backs, provisions and charges — (33) (62) Credit impairment (charges)/write-backs — 11 (7) Provisions for other liabilities and charges — (4) (9) Total operating credit impairment (charges)/write-backs, provisions and charges — 7 (16) Profit from discontinued operations before tax — 43 45 Tax on profit from discontinued operations — (12) (13) Profit from discontinued operations after tax — 31 32 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 2022, the net cash flows attributable to the operating activities in respect of discontinued operations were £nil outflow (2021: £3,612m ou tflow, 2020: £1,815m outflow). There were no investing or financing activities in respect of discontinued operations. Assets held for sale Sale of property Management considered the sale of Santander House and Shenley Wood freehold land and buildings, part of an agreement with the developer for the construction of Unity Place, to be highly probable at the balance sheet date. As such, the Santander UK group reclassified these properties, which are included in the Corporate Centre segment and carried at their sales prices, as held for sale. The sale is expected to complete in H2 2023 with no gain or loss. At 31 December 2022, assets held for sale comprised: 2022 2021 £m £m Assets Property, plant and equipment 49 — Total assets held for sale 49 —

Events After the Balance Sheet

Events After the Balance Sheet Date	12 Months Ended
	Dec. 31, 2022
Disclosure of non-adjusting events after reporting period [abstract]
Events After the Balance Sheet Date	43. EVENTS AFTER THE BALANCE SHEET DATE There have been no significant events between 31 December 2022 and the date of approval of these financial statements which would require a change to or additional disclosure in the financial statements.

Notes to the Balance Sheet

Notes to the Balance Sheet	12 Months Ended
	Dec. 31, 2022
Balance Sheet Explanatory Notes [Abstract]
Notes to the Balance Sheet	44. NOTES TO THE BALANCE SHEET Restatement in the consolidated Balance sheet In 2022, the macro hedge of interest rate risk balances increased significantly and are now disclosed separately on the face of the balance sheet rather than being included in Other assets and Other liabilities. Prior periods have been restated accordingly. As a result, at 31 December 2021, £77m (2020: £1,226m) has been reclassified from Other assets into the Macro hedge of interest rate risk asset, and £122m (2020: £188m) has been reclassified from Other liabilities into the Macro hedge of interest rate risk liability.

Accounting Policies (Policies)

Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Disclosure Of Significant Accounting Policies [Abstract]
Basis of preparation , accounting developments and material accounting policy information	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. Compliance with International Financial Reporting Standards (IFRS) The consolidated financial statements of the Santander UK group and the separate financial statements of the Company comply with UK-adopted International Accounting Standards (IAS). The financial statements are also prepared in accordance with IFRS as issued by the International Accounting Standards Board (IASB), including interpretations issued by the IFRS Interpretations Committee, as there are no applicable differences from IFRS 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, have been included in the Risk review section of this Annual Report. This information forms an integral part of these financial statements by this cross reference, is marked as audited, and is covered by the Independent auditor's report. 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 2022 and 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 2022 and 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: 5 years ,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. Recent accounting developments Disclosure of Accounting Policies – Amendments to IAS 1 and IFRS Practice Statement 2 In February 2021, the IASB amended IAS 1 Presentation of Financial Statements to require entities to disclose their material rather than their significant accounting policies. To support this amendment, the IASB also amended IFRS Practice Statement 2 Making Materiality Judgements to provide guidance on how to apply the concept of materiality. The amendments are effective for annual periods beginning on or after 1 January 2023 with earlier application permitted. The amendments have been applied in preparing these financial statements and, consequently, only material accounting policy information is disclosed. Future accounting developments At 31 December 2022, for the Santander UK group, there were no other 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. Material accounting policy information The following material accounting policies have been applied in preparing these financial statements. For material accounting policies which involve the application of judgements or accounting estimates that are determined to be critical to the preparation of these financial statements see 'Critical judgements and accounting estimates'.
Consolidation	Consolidation The consolidated financial statements incorporate the financial statements of the Company and entities (including structured entities) controlled by it and its subsidiaries. The acquisition method of accounting is used to account for the acquisition of subsidiaries which meet the definition of a business. 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. 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.
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. 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) 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.
Defined benefit pension schemes	Defined benefit pension schemes (see 'Critical judgements and accounting estimates') 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.
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 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.
Goodwill and other intangible assets	Goodwill and other intangible assets (for goodwill see 'Critical judgements and accounting estimates') 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, or business at the date of acquisition. Goodwill on the acquisition of subsidiaries and businesses is included in intangible assets. 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 seven 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. 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 Shorter of the lease term or the useful life of the underlying asset Operating lease assets - vehicles 2 to 4 years Depreciation is not charged on freehold land and assets under construction. Depreciation of operating lease assets where the Santander UK group is the lessor is described in 'Leases' below.
Financial instruments	Financial instruments (for impairment of debt instrument financial assets see' Critical judgements and accounting estimates: Credit impairment losses') 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 advances, and issues of equity or financial liabilities measured at amortised cost are recognised on settlement date, being the date when the Santander UK group becomes a party to the contractual terms of the instrument; 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, 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 charges are not included in the impairment loss allowance but are taken to income and offset against credit impairment charges. Recoveries of credit impairment charges are classified in the income statement as ‘Credit impairment charges’. 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 41. 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. 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 and exchange rates. 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 (for goodwill see 'Critical judgements and accounting estimates') 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 value 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. For conducting goodwill impairment reviews, cash generating units are the lowest level at which management monitors the return on investment on assets.
Leases (as lessor)	Leases (as lessor) Operating lease assets are recorded at cost and the difference between cost and residual value (RV) is depreciated over the life of the asset. 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.
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. 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 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 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 equivalents Following a decision by the IFRS Interpretations Committee in April 2022, Santander UK updated its accounting policy to exclude from cash and cash equivalents Reserves Collateralisation Accounts (RCAs) balances held at the Bank of England relating to Santander UK’s participation in certain payments schemes. Instead, RCAs balances are classified as restricted balances and included within 'change in operating assets' in the cash flow statement. Prior periods have been restated see Note34.
Provisions and contingent liabilities	Provisions and contingent liabilities (see 'Critical judgements and accounting estimates') 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.
Critical judgements and accounting estimates	Critical judgements and accounting estimates The preparation of Santander UK's consolidated financial statements in accordance with IFRS requires management to make judgements, estimates and assumptions in applying the accounting policies that affect the reported amounts of assets, liabilities, income and expenses. Due to the inherent uncertainty in making estimates, actual results reported in future periods may be based on amounts which differ from those estimates. Estimates, judgements and assumptions are continually evaluated and are based on historical experience and other factors, including expectations of future events that are believed to be reasonable under the circumstances. There has been no change in the inherent sensitivity of the areas of judgement in the period. Management have considered the impact of developments in principal risks and uncertainties, as set out in the Risk review, on critical judgements and accounting estimates. a) Credit impairment charges 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 the cost of living crisis has increased 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 the cost of living crisis mainly reflect the increased uncertainty around forward-looking economic data and the need for additional judgemental 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 the need for any judgemental adjustments – Determining the need to assess corporate Stage 3 exposures individually 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, 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 – credit risk management’ section of the Risk review. b) Provisions and contingent liabilities Key judgements – Determining whether a present obligation exists – Determining 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 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. 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 these key judgements and estimates, see Notes 29 and 31. c) Defined benefit pension schemes 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, see Note 30. Sensitivity of defined benefit pension scheme estimates For detailed disclosures, see ‘Actuarial assumption sensitivities’ in Note 30. The Scheme is 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 amount 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 testing methodology, including the need for planning assumptions and internal capital allocations 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
Segmentation of business	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, 2022
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: – Residential mortgages for customers with good credit quality (prime lending). – We provide these mostly for owner-occupiers, with buy-to-let mortgages for non-professional landlords. In Everyday Banking: – Unsecured lending to individuals, such as loans, credit cards and overdrafts. – Banking services to businesses with turnover up to £6.5m per annum and simpler borrowing needs. We offer loans, credit cards and overdrafts. – Financing for cars, vans, motorbikes and leisure vehicles 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 turnover up to £500m per annum, Commercial Real Estate and Social Housing associations. – Asset and liability management of our balance sheet, as well as non-core and legacy portfolios in run-off. – Exposures include financial institutions (derivatives and other treasury products), structured products, and sovereign and supranational assets 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 are: 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. We consider the UK Government guarantee supporting losses on amounts lent under its Coronavirus Loan Schemes as collateral with 100% for Bounce Back Loan Scheme (BBLS) and 80% for Coronavirus Business Interruption Loan Scheme (CBILS). 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 loans, with the customer being the registered keeper. Only a very small proportion of 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 the value of the vehicle 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 of 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 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. Commercial Real Estate We take a first charge on commercial property as collateral. The loan is subject to criteria such as the property condition, age and location, tenant quality, lease terms and length, and the sponsor’s experience and creditworthiness. Before advancing the loan and where appropriate, a bank representative visits the property, additionally we get an independent professional valuation which typically includes a site visit. Loan agreements typically allow us to obtain revaluations during the term of the loan. Social Housing We take a first 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) in our Eligible Liquidity Pool. They are mainly ABS and covered bonds, which hold senior positions in the creditor hierarchy. Their credit rating reflects over-collateralisation in the structure and the assets that underpin their cash flows. 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.
Disclosure of Types of Forbearance	The main types of forbearance we offer are: Action Description Term extension We can extend the loan term, making each monthly payment smaller. We may offer this if the customer is up to date with payments but shows signs of financial difficulties. We may also offer this if the loan is about to mature and refinancing is not possible on market terms. Interest-only Prior to 2016, we offered retail customers temporary concessions to interest-only repayments due to financial difficulty. This concession is no longer available but any such loans that remain on interest-only repayment concession are classed as forborne. For corporate customers, we still consider interest-only concessions on a case by case basis. 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 may add the arrears to the mortgage balance (this is known as capitalisation) if they cannot afford to increase their monthly payment to pay off their arrears in a reasonable time but have been making their monthly payments, usually for at least six months. We can also capitalise property charges due to a landlord. We pay them for the customer to avoid the lease being forfeited. We may combine this help with term extensions and, in the past, interest-only concessions. In certain cases we may also offer interest rate concessions. For corporate customers, we may lower or stop their payments until they have time to recover. We may reschedule payments to better match the customer’s cash flow – for example if the business is seasonal - or provide a temporary increase in facilities to cover peak demand ahead of their trading improving. We might do this by arrears capitalisation or drawing from an overdraft. We may also offer to provide new facilities, interest rate concessions 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 more collateral in return for revised financing terms. We may also take a guarantee from companies in the same group and/or major shareholders. We only do this where we believe the guarantor can 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 or 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 CRD IV regulatory capital rules and gives us another view of credit risk. It is the product of the probability of default, exposure at default and loss given default, and we include direct and indirect costs. We base it on our risk models and our assessment of each customer’s credit quality. 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 impairment accounting policy, 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 2022: Upside 1 Base case Downside 1 Downside 2 Stubborn Inflation Weighted % % % % % % GDP (1) 2021 (actual) 7.5 7.5 7.5 7.5 7.5 7.5 2022 4.4 4.4 4.3 3.7 4.2 4.3 2023 (1.0) (1.3) (1.9) (6.4) (2.7) (2.2) 2024 0.8 0.5 (0.3) (0.7) (0.9) 0.0 2025 2.0 1.6 0.5 1.7 0.2 1.2 2026 2.0 1.5 0.4 1.5 0.6 1.2 Bank Rate (1) 2021 (actual) 0.25 0.25 0.25 0.25 0.25 0.25 2022 3.50 3.50 3.50 3.50 3.50 3.50 2023 3.75 4.00 3.50 3.75 6.00 4.29 2024 3.00 3.25 2.75 3.00 5.50 3.59 2025 2.50 2.75 2.50 2.75 3.50 2.85 2026 2.25 2.50 2.25 2.50 3.00 2.55 HPI (1) 2021 (actual) 8.7 8.7 8.7 8.7 8.7 8.7 2022 7.6 7.0 7.6 7.6 7.6 7.3 2023 (8.8) (10.0) (10.0) (15.8) (10.9) (10.7) 2024 (4.3) 0.0 (6.7) (14.3) (8.8) (4.4) 2025 0.6 2.0 (3.1) (4.1) (4.9) (0.8) 2026 4.1 3.0 (0.2) 4.7 (0.6) 2.0 Unemployment (1) 2021 (actual) 4.0 4.0 4.0 4.0 4.0 4.0 2022 3.7 3.8 3.7 4.4 3.7 3.8 2023 4.7 4.7 5.1 8.5 5.5 5.3 2024 4.5 5.1 5.4 8.0 5.9 5.6 2025 4.5 4.5 5.8 7.4 6.4 5.4 2026 4.4 4.3 6.1 6.8 6.6 5.3 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 Weighted % % % % % % GDP (1) 2020 (9.7) (9.7) (9.7) (9.7) (9.7) (9.7) 2021 7.0 6.9 6.8 6.2 5.6 6.7 2022 4.8 4.6 4.1 (0.7) (7.5) 2.8 2023 2.2 1.7 0.9 0.5 3.1 1.4 2024 1.9 1.5 0.5 1.6 1.5 1.3 2025 2.1 1.6 0.5 1.7 1.5 1.4 Bank Rate (1) 2020 0.10 0.10 0.10 0.10 0.10 0.10 2021 0.25 0.25 0.25 0.25 0.25 0.10 2022 0.75 0.75 0.75 1.00 (0.50) 0.55 2023 0.75 0.75 0.75 2.00 0.00 0.96 2024 1.25 0.75 1.00 3.00 0.00 1.24 2025 1.75 0.75 1.00 2.75 0.00 1.21 HPI (1) 2020 6.9 6.9 6.9 6.9 6.9 6.9 2021 5.4 5.0 5.4 5.4 (2.5) 4.8 2022 (0.8) 2.0 (1.8) (8.3) (19.6) (2.0) 2023 (2.0) 2.0 (4.6) (13.1) (9.3) (3.1) 2024 1.0 2.0 (3.1) (4.8) 2.4 (0.4) 2025 3.8 2.0 (0.7) 4.3 3.3 2.1 Unemployment (1) 2020 5.2 5.2 5.2 5.2 5.2 5.2 2021 4.4 4.7 4.4 4.4 6.8 4.7 2022 4.4 4.5 4.8 6.9 11.4 5.4 2023 4.2 4.4 5.0 6.9 8.7 5.2 2024 3.9 4.3 5.1 6.4 8.0 5.0 2025 3.7 4.3 5.4 6.1 7.4 5.0 (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 31 December 2022 and 31 December 2021 were: Upside 1 Base case Downside 1 Downside 2 Stubborn Inflation 2022 % % % % % House price growth 5-year average increase/decrease (0.73) (0.62) (3.79) (4.82) (4.69) Peak/(trough) at (1) (12.79) (11.19) (19.00) (30.69) (23.12) GDP 5-year average increase/decrease 1.17 0.75 (0.17) (0.63) (0.45) Cumulative growth/(fall) to peak/(trough) (2) 5.98 3.80 (0.84) (3.12) (2.23) Unemployment rate 5-year end period 4.17 4.28 6.09 6.23 6.40 Peak/(trough) at (1) 4.72 5.10 6.12 8.50 6.64 Bank of England bank rate 5-year end period 2.25 2.50 2.25 2.50 3.00 Peak/(trough) at (1) 3.75 4.00 3.50 4.00 6.00 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) (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 2022 and 2021 were: Upside 1 Base case Downside 1 Downside 2 Stubborn Inflation Weighted Scenario weights % % % % % % 2022 5 50 15 10 20 100 Upside 1 Base case Downside 1 Downside 2 Downside 3 Weighted Scenario weights % % % % % % 2021 5 45 25 20 5 100
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 that suggests the customer is 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 and are in arrears – Their loan term has ended, but they still owe us money more than three months later – They have had forbearance while in default and have failed to perform under the new arrangement terms, or have had multiple forbearance. Performing forborne accounts while not in default are reported in Stage 2 – 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 – Loans restructured under financial difficulties, classified as forborne transactions, in last 12 months.
Disclosure of Quantitative Criteria to Identify When Exposure Has Increased Credit Risk	The criteria for 2022 were: For 2022 and 2021 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 changes in PD. The criteria for 2022 and 2021 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	Homes Everyday Banking Consumer Finance CCB Corporate Centre Total Mortgages Credit Cards Other 2022 £m £m £m £m £m £m £m Modelled ECL 133 112 93 65 194 — 597 Individually assessed — — — — 112 — 112 ECL before JAs 133 112 93 65 306 — 709 JAs Long-term indeterminate arrears 13 — — — — — 13 12+ months in arrears 22 — — — — — 22 UPL loss floor — — 15 — — — 15 Model underestimation 36 2 19 — — — 57 Corporate single large exposure — — — — 23 — 23 Other 20 1 10 2 3 — 36 Total JAs 91 3 44 2 26 — 166 Affordability and Cost of Living JAs Corporate lending to segments affected by supply chain — — — — 61 — 61 Mortgages affordability 27 — — — — — 27 Retail Unsecured Affordability — 15 20 — — — 35 SME debt burden — — 7 — — — 7 Total Affordability and Cost of Living JAs 27 15 27 — 61 — 130 Total ECL 251 130 164 67 393 — 1,005 Homes Everyday Banking Consumer Finance CCB Corporate Centre Total Mortgages Credit Cards Other 2021 £m £m £m £m £m £m £m Modelled ECL 120 88 57 52 108 425 Individually assessed — — — — 100 — 100 ECL before JAs 120 88 57 52 208 — 525 JAs Long-term indeterminate arrears 14 — — — — — 14 12+ months in arrears 29 — — — — — 29 Cladding Risk 15 — — — — — 15 UPL loss floor — — 21 — — — 21 Other (20) 1 8 — 18 — 7 Total JAs 38 1 29 — 18 — 86 Covid-19 JAs Corporate lending to segments affected by Covid-19 — — — — 176 — 176 Corporate single large exposure — — — — 23 — 23 Model underestimation 14 — 14 — — — 28 SME debt burden — — 9 — — — 9 Total Covid-19 JAs 14 — 23 — 199 — 236 Affordability and Cost of Living JAs Mortgages affordability 18 — — — — — 18 Total Affordability and Cost of Living JAs 18 — — — — — 18 Total ECL 190 89 109 52 425 — 865 2022 compared to 2021
Disclosure of Base Expected Credit Losses to Probability Weighted Estimated Credit Losses	Upside 1 Base case Downside 1 Downside 2 Stubborn Inflation Weighted 2022 £m £m £m £m £m £m Exposure 306,284 306,284 306,284 306,284 306,284 306,284 Retail Banking 213,557 213,557 213,557 213,557 213,557 213,557 – Homes - Mortgages 192,346 192,346 192,346 192,346 192,346 192,346 – EDB - Credit Cards 12,845 12,845 12,845 12,845 12,845 12,845 – EDB - Other 8,366 8,366 8,366 8,366 8,366 8,366 Consumer Finance 5,740 5,740 5,740 5,740 5,740 5,740 CCB 28,277 28,277 28,277 28,277 28,277 28,277 Corporate Centre 58,710 58,710 58,710 58,710 58,710 58,710 ECL 930 932 993 1,383 1,149 1,005 Retail Banking 489 497 529 830 647 544 – Homes - Mortgages 214 218 244 501 324 251 – EDB - Credit Cards 122 123 127 142 140 130 – EDB - Other 153 156 158 187 183 163 Consumer Finance 65 66 65 69 68 67 CCB 376 369 399 484 434 394 Corporate Centre — — — — — — % % % % % % Proportion of assets in Stage 2 4.0 4.0 5.0 11.0 7.0 7.0 Retail Banking 4.0 4.0 4.0 10.0 6.0 7.0 – Homes - Mortgages 4.0 4.0 4.0 11.0 6.0 7.0 – EDB - Credit Cards 3.0 3.0 3.0 3.0 3.0 3.0 – EDB - Other 7.0 7.0 7.0 9.0 8.0 8.0 Consumer Finance 6.0 6.0 6.0 6.0 6.0 6.0 CCB 8.0 9.0 9.0 18.0 14.0 12.0 Corporate Centre — — — — — — % % % % % % Proportion of assets in Stage 3 1.0 1.0 1.0 1.0 1.0 1.0 Retail Banking 1.0 1.0 1.0 1.0 1.0 1.0 – Homes - Mortgages 1.0 1.0 1.0 1.0 1.0 1.0 – EDB - Credit Cards — — — — — — – EDB - Other 2.0 2.0 2.0 2.0 2.0 2.0 Consumer Finance 1.0 1.0 1.0 1.0 1.0 1.0 CCB 2.0 2.0 2.0 2.0 2.0 2.0 Corporate Centre — — — — — — Upside 1 Base case Downside 1 Downside 2 Downside 3 Weighted 2021 £m £m £m £m £m £m Exposure 313,348 313,348 313,348 313,348 313,348 313,348 Retail Banking 212,396 212,396 212,396 212,396 212,396 212,396 – Homes - Mortgages 190,663 190,663 190,663 190,663 190,663 190,663 – EDB - Credit Cards 12,301 12,301 12,301 12,301 12,301 12,301 – EDB - Other 9,432 9,432 9,432 9,432 9,432 9,432 Consumer Finance 5,298 5,298 5,298 5,298 5,298 5,298 CCB 27,305 27,305 27,305 27,305 27,305 27,305 Corporate Centre 68,349 68,349 68,349 68,349 68,349 68,349 ECL 782 762 851 988 1,141 865 Retail Banking 307 286 375 510 662 388 – Homes - Mortgages 134 125 177 283 437 190 – EDB - Credit Cards 78 72 89 102 101 89 – EDB - Other 95 89 109 125 124 109 Consumer Finance 50 51 51 53 54 52 CCB 425 425 425 425 425 425 Corporate Centre 0 0 0 0 0 0 % % % % % % Proportion of assets in Stage 2 5.0 5.0 5.0 6.0 7.0 5.0 Retail Banking 5.0 5.0 5.0 7.0 8.0 6.0 – Homes - Mortgages 6.0 6.0 6.0 7.0 8.0 6.0 – EDB - Credit Cards 2.0 1.0 2.0 2.0 2.0 2.0 – EDB - Other 3.0 3.0 4.0 5.0 4.0 4.0 Consumer Finance 4.0 4.0 4.0 4.0 4.0 4.0 CCB 16.0 16.0 17.0 21.0 21.0 18.0 Corporate Centre — — — — — — % % % % % % Proportion of assets in Stage 3 1.0 1.0 1.0 1.0 1.0 1.0 Retail Banking 1.0 1.0 1.0 1.0 1.0 1.0 – Homes - Mortgages 1.0 1.0 1.0 1.0 1.0 1.0 – EDB - Credit Cards 0.0 0.0 0.0 0.0 0.0 0.0 – EDB - Other 2.0 2.0 2.0 2.0 2.0 2.0 Consumer Finance 1.0 1.0 1.0 1.0 1.0 1.0 CCB 2.0 2.0 2.0 2.0 2.0 2.0 Corporate Centre 0.0 0.0 0.0 0.0 0.0 0.0
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	Increase/decrease in house prices +20% +10% -10% -20% Increase/(decrease) in profit before tax £m £m £m £m 2022 48 32 (61) (176) 2021 64 40 (69) (197)
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 occurs. We determine EAD for each month of the forecast period by the expected payment profile, which varies by product. 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 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 2022 £bn £bn £bn £bn £bn £bn £bn £bn £bn £bn Cash and balances at central banks 44.2 — 44.2 — — — — — — 44.2 Financial assets at amortised cost: – Loans and advances to customers: (3) – Retail Mortgages (4) 184.3 (0.2) 184.1 8.0 — 8.0 — (187.4) — 4.7 – Corporate loans 19.1 (0.4) 18.7 9.3 — 9.3 (0.1) (16.5) — 11.4 – Finance leases 4.6 (0.1) 4.5 0.4 0.4 — (4.8) — 0.1 – Accrued interest and other adjustments 0.7 — 0.7 — — — — — — 0.7 – Other unsecured loans 7.7 (0.2) 7.5 13.7 (0.1) 13.6 21.1 – Amounts due from fellow Banco Santander group subsidiaries and joint ventures 4.2 — 4.2 — — — — — — 4.2 Total loans and advances to customers 220.6 (0.9) 219.7 31.4 (0.1) 31.3 (0.1) (208.7) — 42.2 – Loans and advances to banks 1.0 1.0 0.4 0.4 1.4 – Reverse repurchase agreements – non trading 7.3 — 7.3 — — — — (7.3) — — – Other financial assets at amortised cost 0.2 — 0.2 — — — — — — 0.2 Total financial assets at amortised cost 229.1 (0.9) 228.2 31.8 (0.1) 31.7 (0.1) (216.0) — 43.8 Financial assets at fair value at FVOCI: – Loans and advances to customers — — — — — — — — — — – Debt securities 6.0 — 6.0 — — — — — — 6.0 Total financial assets at FVOCI 6.0 — 6.0 — — — — — — 6.0 Total 279.3 (0.9) 278.4 31.8 (0.1) 31.7 (0.1) (216.0) — 94.0 2021 Cash and balances at central banks 48.1 — 48.1 — — — — — — 48.1 Financial assets at amortised cost: – Loans and advances to customers: (3) – Retail Mortgages (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 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 (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. 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 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 2022 £bn £bn £bn £bn £bn Financial assets at FVTPL: – Derivative financial instruments 2.4 (1.7) (0.5) 0.2 – Other financial assets at FVTPL 0.1 — — 0.1 Total 2.5 — (1.7) (0.5) 0.3 2021 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 (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. JAs 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) 2022 £bn £bn £bn £bn £bn £bn £bn £bn £bn £bn Exposures On balance sheet Cash and balances at central banks 44.2 — — — — — — — — 44.2 – Stage 1 44.2 — — — — — — — — 44.2 Financial assets at amortised cost: – Loans and advances to customers (2) 9.5 35.9 85.6 52.1 15.2 9.2 5.4 7.7 (0.9) 219.7 – Stage 1 9.5 35.6 83.9 47.9 11.1 3.9 0.5 7.3 (0.1) 199.6 – Stage 2 — 0.3 1.7 4.2 4.1 5.2 2.6 0.2 (0.5) 17.8 – Stage 3 — — — — — 0.1 2.3 0.2 (0.3) 2.3 Of which mortgages: 9.5 33.4 82.3 45.0 7.2 3.8 3.1 — (0.2) 184.1 – Stage 1 9.5 33.1 80.7 41.1 4.1 0.5 0.1 — — 169.1 – Stage 2 — 0.3 1.6 3.9 3.1 3.2 1.3 — (0.1) 13.3 – Stage 3 — — — — — 0.1 1.7 — (0.1) 1.7 – Loans and advances to banks 0.1 (0.1) — — — — — 1.0 — 1.0 – Stage 1 0.1 (0.1) — — — — — 1.0 — 1.0 – Reverse repo agreements – non trading 5.4 0.6 0.1 1.1 — — — 0.1 — 7.3 – Stage 1 5.4 0.6 0.1 1.1 — — — 0.1 — 7.3 – Other financial assets at amortised cost 0.2 — — — — — — — 0.2 – Stage 1 0.2 — — — — — — — 0.2 Total financial assets at amortised cost 15.2 36.4 85.7 53.2 15.2 9.2 5.4 8.8 (0.9) 228.2 Financial assets at FVOCI: 3.5 2.2 0.3 — — — — — — 6.0 – Stage 1 3.5 2.2 0.3 — — — — — — 6.0 Total on balance sheet 62.9 38.6 86.0 53.2 15.2 9.2 5.4 8.8 (0.9) 278.4 Total off–balance sheet 0.1 7.2 6.9 6.5 4.9 2.1 0.4 3.7 (0.1) 31.7 – Stage 1 0.1 7.2 6.8 6.4 4.7 1.7 0.2 3.7 — 30.8 – Stage 2 — — 0.1 0.1 0.2 0.4 0.1 — (0.1) 0.8 – Stage 3 — — — — — — 0.1 — — 0.1 Total exposures 63.0 45.8 92.9 59.7 20.1 11.3 5.8 12.5 (1.0) 310.1 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 0.2 0.5 — 0.9 – Stage 1 — — — — 0.1 — — — 0.1 – Stage 2 — — — — 0.1 0.2 0.2 — 0.5 – Stage 3 — — — — — — 0.3 — 0.3 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 0.2 0.5 — 0.9 Financial assets at FVOCI: — — — — — — — — — – Stage 1 — — — — — — — — — Total on balance sheet — — — — 0.2 0.2 0.5 — 0.9 Total off–balance sheet — — — — — — 0.1 — 0.1 – Stage 1 — — — — — — — — — – Stage 2 — — — — — — 0.1 — 0.1 – Stage 3 — — — — — — — — — Total ECL — — — — 0.2 0.2 0.6 — 1.0 Santander UK risk grade Total 9 8 7 6 5 4 3 to 1 Other (1) 2022 % % % % % % % % % Coverage ratio On balance sheet Cash and balances at central banks — — — — — — — — — – Stage 1 — — — — — — — — — Financial assets at amortised cost: – Loans and advances to customers (2) — — — — 1.3 2.2 9.3 — 0.4 – Stage 1 — — — — 0.9 — — — 0.1 – Stage 2 — — — — 2.4 3.8 7.7 — 2.8 – Stage 3 — — — — — — 13.0 — 13.0 Of which mortgages: — — — — 1.4 2.6 — — 0.1 – Stage 1 — — — — — — — — — – Stage 2 — — — — 3.2 — — — 0.8 – Stage 3 — — — — — 100.0 — — 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 — — — — 1.3 2.2 9.3 — 0.4 Financial assets at FVOCI: — — — — — — — — — – Stage 1 — — — — — — — — — Total on balance sheet — — — — 1.3 2.2 9.3 — 0.3 Total off–balance sheet — — — — — — 25.0 — 0.3 – Stage 1 — — — — — — — — — – Stage 2 — — — — — — 100.0 — 12.5 – Stage 3 — — — — — — — — — Total coverage ratio — — — — 1.0 1.8 10.3 — 0.3 Santander UK risk grade Loss allowance 9 8 7 6 5 4 3 to 1 Other (1) Total 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 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 (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 Covid-19 support schemes. 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 2022 £bn £bn % £bn % £bn % £m £m Retail Banking 191.8 175.4 91.4 14.4 7.5 2.0 1.10 113 502 – Homes - Mortgages 184.3 169.1 91.7 13.4 7.3 1.8 1.00 3 248 – EDB - Credit Cards 2.5 2.1 85.7 0.3 12.9 0.1 2.53 40 120 – EDB - Other (1) 5.0 4.2 82.8 0.7 13.0 0.1 4.30 70 134 Consumer Finance (2) 5.4 5.0 93.0 0.4 6.5 — 0.54 19 67 CCB 18.5 14.5 78.3 3.5 18.8 0.5 3.08 24 362 Corporate Centre — — — — — — — — — Total Drawn 215.7 194.9 90.4 18.3 8.5 2.5 1.26 156 931 Retail Banking 21.7 21.1 0.5 0.1 — 42 – Homes - Mortgages 8.0 7.9 0.1 — — 3 – EDB - Credit Cards 10.2 10.1 0.1 — — 10 – EDB - Other (1) 3.5 3.1 0.3 0.1 — 29 Consumer Finance (2) 0.4 0.4 — — — — CCB 9.7 9.3 0.4 — — 32 Corporate Centre — — — — — — Total Undrawn 31.8 30.8 0.9 0.1 — 74 Total 247.5 225.7 19.2 2.6 156 1,005 2021 £bn £bn % £bn % £bn % £m £m Retail Banking 183.0 169.2 92.5 11.7 6.4 2.1 1.10 107 367 – Homes - Mortgages 174.7 161.8 92.6 11.1 6.4 1.8 1.00 5 185 – EDB - Credit Cards 2.4 2.2 91.7 0.2 7.7 — 2.54 39 82 – EDB - Other 5.9 5.2 88.1 0.4 6.6 0.3 4.90 63 100 Consumer Finance 5.0 4.8 96.0 0.2 4.0 — 0.48 25 52 CCB 19.3 13.9 72.0 4.6 23.9 0.8 4.28 58 408 Corporate Centre — — — — — — — — — Total Drawn 207.3 187.9 90.6 16.5 7.9 2.9 1.45 190 827 Retail Banking 29.4 29.2 0.2 — — 21 – Homes - Mortgages 16.0 15.9 0.1 — — 5 – EDB - Credit Cards 9.9 9.9 — — — 7 – EDB - Other 3.5 3.4 0.1 — — 9 Consumer Finance 0.3 0.3 — — — — CCB 8.0 6.7 1.3 — — 17 Corporate Centre — — — — — — Total Undrawn 37.7 36.2 1.5 — — 38 Total 245.0 224.1 18.0 2.9 190 865 (1) EDB - Other includes £2.5bnof BBLS lending (£2.4bn is BBLS with 100% Government Guarantee), £2.0bn unsecured personal loans and£0.5bn overdrafts. (2) Consumer Finance - 84% of lending is collateralised on the vehicle. 2022 2021 £m £m Mortgage loans and advances to customers of which: 184,317 174,712 – Stage 1 169,066 161,845 – Stage 2 13,424 11,071 – Stage 3 1,827 1,796 Loss allowances (1) 251 190 % % Stage 1 ratio (2) 91.73 92.64 Stage 2 ratio (2) 7.28 6.34 Stage 3 ratio (3) 1.00 1.04 (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. Portfolio of particular interest (1) Total Interest-only Part interest-only, part repayment (2) Flexible LTV >100% Buy-to-let Other 2022 £m £m £m £m £m £m £m Mortgage portfolio 184,317 40,825 13,510 6,765 370 16,799 126,996 – Stage 1 169,066 35,702 12,143 5,713 217 15,884 118,507 – Stage 2 13,424 4,250 1,149 839 101 876 7,791 – Stage 3 1,827 873 218 213 52 39 698 Stage 3 ratio 1.00 % 2.16 % 1.62 % 3.45 % 13.94 % 0.23 % 0.55 % Properties in possession 47 18 8 3 7 1 16 Balance weighted LTV (indexed) 50 % 47 % 49 % 36 % 117 % 58 % 52 % 2021 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 1.04 % 2.03 % 1.66 % 3.06 % 12.34 % 0.27 % 0.60 % Properties in possession 2 1 1 — 1 — — Balance weighted LTV (indexed) 52 % 49 % 52 % 39 % 118 % 61 % 53 % (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 £10,010m (2021: £10,106m) and the non-interest-only part of the loan. Business banking Other unsecured Personal Credit Overdrafts Total other unsecured Total 2022 £m £m £m £m £m £m Loans and advances to customers of which: 2,519 1,982 2,558 461 5,001 7,520 – Stage 1 2,223 1,730 2,192 155 4,077 6,300 – Stage 2 133 231 329 282 842 975 – Stage 3 163 21 37 24 82 245 Loss allowances (1) 19 62 130 82 274 293 Stage 3 undrawn exposures 3 32 35 Stage 3 ratio 6.58 % 2.27 % 3.71 % Gross write-offs 11 99 110 2021 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 7.20 % 2.03 % 4.23 % Gross write-offs 6 97 103 (1) The ECL allowance is for both on and off–balance sheet exposures 2022 2021 £m £m Loans and advances to customers of which: 5,384 4,984 – Stage 1 5,005 4,760 – Stage 2 350 200 – Stage 3 29 24 Loss allowances (1) 67 52 Stage 3 undrawn exposures — — Stage 3 ratio 0.54 % 0.49 % Gross write offs 19 25 (1) The ECL allowance is for both on and off–balance sheet exposures. 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 2022 and 31 December 2021. Committed exposure Watchlist Fully performing Enhanced monitoring Proactive management Stage 3 Total (1) Loss allowances 2022 £m £m £m £m £m £m SME and mid corporate 11,796 431 1,383 513 14,123 355 Commercial Real Estate 4,765 103 480 59 5,407 38 Social Housing 7,978 46 10 — 8,034 1 24,539 580 1,873 572 27,564 394 2021 (2) SME and mid corporate 11,227 520 2,161 747 14,655 376 Commercial Real Estate 4,344 204 220 81 4,849 46 Social Housing 7,799 140 7,939 3 23,370 724 2,521 828 27,443 425 (1) Includes committed facilities and derivatives. (2) New customer management systems have introduced improved portfolio segmentation information. This has led to a realignment of portfolio segmentation and improved the identification of portfolios of particular interest. Due to this a restatement of the 2021 figures has taken place.
Disclosure of IFRS 9 Credit Quality	Total on-balance sheet exposures at 31 December 2022 comprised £215.7bn of customer loans, loans and advances to banks of £1.0bn, £7.5bn of sovereign assets measured at amortised cost £6.0bn of assets measured at FVOCI, and £44.2bn of cash and balances at central banks. Stage 1 Stage 2 Stage 3 Total 2022 £m £m £m £m Exposures On-balance sheet Retail Banking 175,365 14,399 2,072 191,836 – Homes - Mortgages 169,066 13,424 1,827 184,317 – EDB - Credit Cards 2,192 328 37 2,557 – EDB - Other 4,107 647 208 4,962 Consumer Finance 5,005 350 29 5,384 CCB 14,507 3,476 535 18,518 Corporate Centre 58,710 — — 58,710 Total on-balance sheet 253,587 18,225 2,636 274,448 Off-balance sheet Retail Banking (1) 21,175 490 56 21,721 – Homes - Mortgages 7,899 109 21 8,029 – EDB - Credit Cards 10,137 122 29 10,288 – EDB - Other 3,139 259 6 3,404 Consumer Finance 356 — — 356 CCB 9,310 412 37 9,759 Corporate Centre — — — — Total off-balance sheet (2) 30,841 902 93 31,836 Total exposures 284,428 19,127 2,729 306,284 ECL On-balance sheet Retail Banking 56 295 151 502 – Homes - Mortgages 23 130 95 248 – EDB - Credit Cards 14 85 21 120 – EDB - Other 19 80 35 134 Consumer Finance 19 27 21 67 CCB 69 155 138 362 Corporate Centre — — — — Total on-balance sheet 144 477 310 931 Off-balance sheet Retail Banking 12 28 2 42 – Homes - Mortgages 2 1 — 3 – EDB - Credit Cards 3 6 1 10 – EDB - Other 7 21 1 29 Consumer Finance — — — — CCB 14 11 7 32 Corporate Centre — — — — Total off-balance sheet 26 39 9 74 Total ECL 170 516 319 1,005 Coverage ratio(3) % % % % On-balance sheet Retail Banking — 2.0 7.3 0.3 – Homes - Mortgages — 1.0 5.2 0.1 – EDB - Credit Cards 0.6 25.9 56.8 4.7 – EDB - Other 0.5 12.4 16.8 2.7 Consumer Finance 0.4 7.7 72.4 1.2 CCB 0.5 4.5 25.8 2.0 Corporate Centre — — — — Total on-balance sheet 0.1 2.6 11.8 0.3 Off-balance sheet Retail Banking 0.1 5.7 3.6 0.2 – Homes - Mortgages — 0.9 — — – EDB - Credit Cards — 4.9 3.4 0.1 – EDB - Other 0.2 8.1 16.7 0.9 Consumer Finance — — — — CCB 0.2 2.7 18.9 0.3 Corporate Centre — — — — Total off-balance sheet 0.1 4.3 9.7 0.2 Total coverage 0.1 2.7 11.7 0.3 (1) Off-balance sheet exposures include£2.8bn of residential mortgage offers in the pipeline. (2) Off-balance sheet amounts consist of contingent liabilities and commitments. For more, see Note 31. (3) ECL as a percentage of the related exposure. 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 - Mortgages 161,845 11,071 1,796 174,712 – EDB - Credit Cards 2,125 181 35 2,341 – EDB - Other 5,285 394 291 5,970 Consumer Finance 4,760 200 24 4,984 CCB 13,890 4,602 790 19,282 Corporate Centre 68,349 — — 68,349 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 - Mortgages 15,851 81 19 15,951 – EDB - Credit Cards 9,887 49 24 9,960 – EDB - Other 3,385 74 2 3,461 Consumer Finance 314 — — 314 CCB 6,675 1,312 36 8,023 Corporate Centre — — — — 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 - Mortgages 8 88 89 185 – EDB - Credit Cards 15 47 20 82 – EDB - Other 29 43 28 100 Consumer Finance 18 17 17 52 CCB 45 119 244 408 Corporate Centre — — — — Total on-balance sheet 115 314 398 827 Off-balance sheet Retail Banking 12 8 1 21 – Homes - Mortgages 5 — — 5 – EDB - Credit Cards 3 3 1 7 – EDB - Other 4 5 — 9 Consumer Finance — — — — CCB 5 8 4 17 Total off-balance sheet 17 16 5 38 Total ECL 132 330 403 865 Coverage ratio (3) % % % % On-balance sheet Retail Banking — 1.5 6.5 0.2 – Homes - Mortgages — 0.8 5.0 0.1 – EDB - Credit Cards 0.7 26.0 57.1 3.5 – EDB - Other 0.5 10.9 9.6 1.7 Consumer Finance 0.4 8.5 70.8 1.0 CCB 0.3 2.6 30.9 2.1 Corporate Centre — — — — Total on-balance sheet — 1.9 13.6 0.3 Off-balance sheet Retail Banking — 3.9 2.2 0.1 – Homes - Mortgages — 0.0 — — – EDB - Credit Cards — 6.1 4.2 0.1 – EDB - Other 0.1 6.8 — 0.3 Consumer Finance — — — — CCB 0.1 0.6 11.1 0.2 Total off-balance sheet — 1.1 6.2 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. (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. 2022 PD deterioration Forbearance Other 30 DPD Mortgage affordability Retail Unsecured affordability High risk corporate Total Retail Banking Homes - Mortgages Exposure £m 7,310 449 241 463 4,961 — — 13,424 ECL £m 86 2 5 10 27 — — 130 Coverage % 1.2 0.4 2.1 2.2 0.5 — — 1.0 Retail Banking EDB - Credit Cards Exposure £m 239 — 22 8 — 59 — 328 ECL £m 63 — 4 4 — 14 — 85 Coverage % 26.4 — 18.2 50.0 — 23.7 — 25.9 Retail Banking EDB - Other Exposure £m 304 — 26 178 — 139 — 647 ECL £m 43 — 6 14 — 17 — 80 Coverage % 14.1 — 23.1 7.9 — 12.2 — 12.4 Consumer Finance Exposure £m 159 — 164 27 — — — 350 ECL £m 11 — 6 10 — — — 27 Coverage % 6.9 — 3.7 37.0 — — — 7.7 CCB Exposure £m 1,548 64 684 214 — — 966 3,476 ECL £m 81 4 1 10 — — 59 155 Coverage % 5.2 6.3 0.1 4.7 — — 6.1 4.5 Corporate Centre Exposure £m — — — — — — — — ECL £m — — — — — — — — Coverage % — — — — — — — — Total Drawn Exposure £m 9,560 513 1,137 890 4,961 198 966 18,225 ECL £m 284 6 22 48 27 31 59 477 Coverage % 3.0 1.2 1.9 5.4 0.5 15.7 6.1 2.6 Undrawn ECL £m 19 — 8 6 — 4 2 39 Total Reported Exposure £m 10,323 625 1,116 937 4,961 199 966 19,127 ECL £m 303 6 30 54 27 35 61 516 2021 Retail Banking Homes - Mortgages Exposure £m 5,091 650 600 489 4,241 — — 11,071 ECL £m 57 4 2 7 18 — — 88 Coverage % 1.1 0.6 0.3 1.4 0.4 — — 0.8 Retail Banking EDB - Credit Cards Exposure £m 160 — 13 7 — — — 180 ECL £m 41 — 2 4 — — — 47 Coverage % 25.6 — 15.4 57.1 — — — 26.1 Retail Banking EDB - Other Exposure £m 150 — 6 239 — — — 395 ECL £m 22 — 1 20 — — — 43 Coverage % 14.7 — 16.7 8.4 — — — 10.9 Consumer Finance Exposure £m 42 11 130 17 — — — 200 ECL £m 6 2 4 5 — — — 17 Coverage % 14.3 18.2 3.1 29.4 — — — 8.5 CCB Exposure £m 463 272 445 313 — — 3,109 4,602 ECL £m 19 8 17 1 — — 74 119 Coverage % 4.1 2.9 3.8 0.3 — — 2.4 2.6 Corporate Centre Exposure £m — — — — — — — — ECL £m — — — — — — — — Coverage % — Total Drawn Exposure £m 5,906 933 1,194 1,065 4,241 — 3,109 16,448 ECL £m 145 14 26 37 18 — 74 314 Coverage % 2.5 1.5 2.2 3.5 0.4 — 2.4 1.9 Undrawn ECL £m 8 1 1 2 — — 4 16 Total Reported Exposure £m 6,373 1,004 1,302 1,183 4,272 — 3,830 17,964 ECL £m 153 15 27 39 18 — 78 330
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: 2022 2021 Exposure ECL Coverage Exposure ECL Coverage £m £m % £m £m % Stage 2 not in cure period 13,001 439 3.4 13,302 286 2.2 Stage 2 in cure period (for transfer to Stage 1) 6,126 77 1.3 4,662 44 0.9 19,127 516 2.7 17,964 330 1.8 2022 compared to 2021
Disclosure of Stage 3 Exposures by Cure Period	The following table analyses our Stage 3 exposures and the related ECL by whether or not they are in a cure period at the balance sheet date. 2022 2021 Exposure ECL Coverage Exposure ECL Coverage £m £m % £m £m % Stage 3 not in cure period 2,415 285 11.8 N/A N/A N/A Stage 3 in cure period (for transfer to Stage 2) 314 34 10.8 N/A N/A N/A 2,729 319 11.7 3,017 403 13.4
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. The Credit risk review disclosures exclude Joint ventures, as they carry low credit risk and therefore have an immaterial ECL, and Other items, mainly accrued interest that we have not yet charged to the customer's account, and cash collateral. On-balance sheet Off-balance sheet Exposures Loss Net carrying Exposures Loss 2022 £m £m £m £m £m Retail Banking 191,836 502 191,334 21,721 42 – Homes - Mortgages (1) 184,317 248 184,069 8,029 3 – EDB - Credit Cards (2) 2,557 120 2,437 10,288 10 – EDB - Other (3) 4,962 134 4,828 3,404 29 Consumer Finance 5,384 67 5,317 356 — Corporate & Commercial Banking 18,518 362 18,156 9,759 32 Corporate Centre 58,710 — 58,710 — — Total exposures presented in Credit Quality tables 274,448 931 273,517 31,836 74 Joint ventures 4,164 Other items 745 Adjusted net carrying amount 278,426 Assets classified at FVTPL 2,536 Non-financial assets (3) 4,251 Total assets per the Consolidated Balance Sheet 285,213 2021 Retail Banking 183,023 367 182,656 29,372 21 – Homes (1) 174,712 185 174,527 15,951 5 – EDB - Credit Cards (2) 2,341 82 2,259 9,960 7 – EDB - Other (3) 5,970 100 5,870 3,461 9 Consumer Finance 4,984 52 4,932 314 — Corporate & Commercial Banking 19,282 408 18,874 8,023 17 Corporate Centre 68,349 — 68,349 — — Total exposures presented in Credit Quality tables 275,638 827 274,810 37,709 38 Joint ventures 3,079 Other items 553 Adjusted net carrying amount 278,442 Assets classified at FVTPL 1,866 Non-financial assets (3) 6,790 Total assets per the Consolidated Balance Sheet 287,098 (1) Off-balance sheet exposures include offers in the pipeline and undrawn flexible mortgages products. (2) Off-balance sheet exposures include credit cards. (3) Non-financial assets include £ (2,657)m (2021: £77m) of Macro hedge of interest rate risk. 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 2022 292,366 132 17,964 330 3,017 403 313,347 865 Transfers from Stage 1 to Stage 2 (3) (9,100) (25) 9,100 25 — — — — Transfers from Stage 2 to Stage 1 (3) 7,207 133 (7,207) (133) — — — — Transfers to Stage 3 (3) (621) (4) (624) (32) 1,245 36 — — Transfers from Stage 3 (3) 10 1 758 150 (768) (151) — — Transfers of financial instruments (2,504) 105 2,027 10 477 (115) — — Net ECL remeasurement on stage transfer (4) — (110) — 98 — 110 — 98 Change in economic scenarios (2) — 37 — 123 — 3 — 163 Changes to model — — — — — — — — New lending and assets purchased (5) 48,194 42 1,119 76 64 24 49,377 142 Redemptions, repayments and assets sold (7) (54,546) (35) (2,065) (60) (950) (35) (57,561) (130) Changes in risk parameters and other movements (6) 918 (1) 82 (61) 375 86 1,375 24 Assets written off (7) — — — — (254) (157) (254) (157) At 31 December 2022 284,428 170 19,127 516 2,729 319 306,284 1,005 Net movement in the period (7,938) 38 1,163 186 (288) (84) (7,063) 140 ECL charge/(release) to the Income Statement 38 186 73 297 Less: Discount unwind — — (13) (13) Less: Recoveries net of collection costs — — 36 36 Total ECL charge/(release) to the Income Statement 38 186 96 320 Discontinued operations ECL adjustment — — — — ECL charge/(release) to the Income Statement from continued operations 38 186 96 320 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 remeasurement of ECL on stage transfer (4) — (133) — 26 — 64 — (43) Change in economic scenarios (2) — (7) — (151) — (12) — (170) 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 Total ECL charge/(release) to the Income Statement (84) (262) 102 (244) Discontinued operations ECL adjustment 11 — — 11 ECL charge/(release) to the Income Statement from continued operations (73) (262) 102 (233) (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 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 74 also apply to these tables. 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 2022 177,696 13 11,152 88 1,815 89 190,663 190 Transfers from Stage 1 to Stage 2 (3) (5,834) (1) 5,834 1 — — — — Transfers from Stage 2 to Stage 1 (3) 2,961 16 (2,961) (16) — — — — Transfers to Stage 3 (3) (278) (2) (448) (11) 726 13 — — Transfers from Stage 3 (3) 4 — 279 9 (283) (9) — — Transfers of financial instruments (3,147) 13 2,704 (17) 443 4 — — Net ECL remeasurement on stage transfer (4) — (15) — 40 — 8 — 33 Change in economic scenarios (2) — 1 — 21 — 2 — 24 Changes to model — — — — — — — — New lending and assets purchased (5) 35,028 7 529 11 1 — 35,558 18 Redemptions, repayments and assets sold (7) (32,565) (3) (1,229) (11) (415) (12) (34,209) (26) Changes in risk parameters and other movements (6) (47) 9 377 (1) 14 7 344 15 Assets written off (7) — — — — (10) (3) (10) (3) At 31 December 2022 176,965 25 13,533 131 1,848 95 192,346 251 Net movement in the period (731) 12 2,381 43 33 6 1,683 61 ECL charge/(release) to the Income Statement 12 43 9 64 Less: Discount unwind — — (2) (2) Less: Recoveries net of collection costs — — (1) (1) Total ECL charge/(release) to the Income Statement 12 43 6 61 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) ECL charge/(release) to the Income Statement (4) (43) (38) (85) Less: Discount unwind — — (2) (2) Less: Recoveries net of collection costs — — (1) (1) Total ECL charge/(release) to the Income Statement (4) (43) (41) (88) 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 74 also apply to these tables. 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 2022 20,682 51 698 98 352 49 21,732 198 Transfers from Stage 1 to Stage 2 (3) (841) (7) 840 8 — — (1) 1 Transfers from Stage 2 to Stage 1 (3) 155 22 (155) (22) — — — — Transfers to Stage 3 (3) (158) (1) (56) (7) 214 7 — (1) Transfers from Stage 3 (3) 7 — 14 4 (21) (5) — (1) Transfers of financial instruments (837) 14 643 (17) 193 2 (1) (1) Net ECL remeasurement on stage transfer (4) — (22) — 91 — 30 — 99 Change in economic scenarios (2) — (2) — 26 — — — 24 Changes to model — — — — — — — — New lending and assets purchased (5) 2,312 12 253 38 16 10 2,581 60 Redemptions, repayments and assets sold (7) (2,829) (11) (176) (10) (483) (5) (3,488) (26) Changes in risk parameters and other movements (6) 249 1 (62) (35) 324 83 511 49 Assets written off (7) — — — — (122) (110) (122) (110) At 31 December 2022 19,577 43 1,356 191 280 59 21,213 293 Net movement in the period (1,105) (8) 658 93 (72) 10 (519) 95 Charge/(release) to the Income Statement (8) 93 120 205 Less: Discount unwind — — (4) (4) Less: Recoveries net of collection costs — — 1 1 Total ECL charge/(release) to the Income Statement (8) 93 117 202 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) The following table shows changes in total on and off-balance sheet exposures and ECL in the period. The footnotes to the Santander UK group level analysis on page 74 also apply 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 2022 5,074 18 200 17 24 17 5,298 52 Transfers from Stage 1 to Stage 2 (3) (232) (2) 232 2 — — — — Transfers from Stage 2 to Stage 1 (3) 68 2 (68) (2) — — — — Transfers to Stage 3 (3) (13) — (10) (2) 22 2 (1) — Transfers from Stage 3 (3) — — 1 1 (1) (1) — — Transfers of financial instruments (177) — 155 (1) 21 1 (1) — Net ECL remeasurement on stage transfer (4) — (2) — 9 — 10 — 17 Change in economic scenarios (2) — — — — — — — — Changes to model — — — — — — — — New lending and assets purchased (5) 2,225 7 110 8 3 2 2,338 17 Redemptions, repayments and assets sold (7) (1,232) (5) (77) (7) — — (1,309) (12) Changes in risk parameters and other movements (6) (529) 1 (38) 1 18 10 (549) 12 Assets written off (7) — — — — (37) (19) (37) (19) At 31 December 2022 5,361 19 350 27 29 21 5,740 67 Net movement in the period 287 1 150 10 5 4 442 15 Charge/(release) to the Income Statement 1 10 23 34 Less: Discount unwind — — (2) (2) Less: Recoveries net of collection costs — — (5) (5) Total ECL charge/(release) to the Income Statement 1 10 16 27 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) 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 74 also apply to these tables. 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 2022 20,604 50 5,914 127 827 248 27,345 425 Transfers from Stage 1 to Stage 2 (3) (2,195) (14) 2,195 14 — — — — Transfers from Stage 2 to Stage 1 (3) 4,023 92 (4,023) (92) — — — — Transfers to Stage 3 (3) (172) (1) (111) (13) 283 14 — — Transfers from Stage 3 (3) — — 463 135 (463) (135) — — Transfers of financial instruments 1,656 77 (1,476) 44 (180) (121) — — Net ECL remeasurement on stage transfer (4) — (72) — (41) — 61 — (52) Change in economic scenarios (2) — 38 — 76 — — — 114 Changes to model — — — — — — — — New lending and assets purchased (5) 8,629 16 228 19 43 12 8,900 47 Redemptions, repayments and assets sold (7) (9,019) (15) (584) (32) (53) (17) (9,656) (64) Changes in risk parameters and other movements (6) 1,968 (11) (194) (27) 21 (14) 1,795 (52) Assets written off (7) — — — — (86) (24) (86) (24) At 31 December 2022 23,838 83 3,888 166 572 145 28,298 394 Net movement in the period 3,234 33 (2,026) 39 (255) (103) 953 (31) ECL charge/(release) to the Income Statement 33 39 (79) (7) Less: Discount unwind — — (3) (3) Less: Recoveries net of collection costs — — 42 42 Total ECL charge/(release) to the Income Statement 33 39 (40) 32 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 20,952 77 6,311 199 1,020 350 28,283 626 Transfers from Stage 1 to Stage 2 (3) (1,055) (4) 1,055 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 487 56 (473) (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) 13,208 6 450 8 12 13 13,670 27 Redemptions, repayments and assets sold (7) (16,644) (15) (1,357) (17) (139) (42) (18,140) (74) Changes in risk parameters and other movements (6) 2,601 (33) 983 40 54 (7) 3,638 — Assets written off (7) — — — — (106) (59) (106) (59) At 31 December 2021 20,604 50 5,914 127 827 248 27,345 425 Net movement in the period (348) (27) (397) (72) (193) (102) (938) (201) ECL charge/(release) to the Income Statement (27) (72) (43) (142) Less: Discount unwind — — (4) (4) Less: Recoveries net of collection costs — — 56 56 Total ECL charge/(release) to the Income Statement (27) (72) 9 (90) 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 74 also apply to these tables. 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 2022 68,349 — — — — — 68,349 — Transfers from Stage 1 to Stage 2 (3) — — — — — — — — Transfers from Stage 2 to Stage 1 (3) — — — — — — — — Transfers to Stage 3 (3) — — — — — — — — Transfers from Stage 3 (3) — — — — — — — — Transfers of financial instruments — — — — — — — — Net ECL remeasurement on stage transfer (4) — — — — — — — — Change in economic scenarios (2) — — — — — — — — Changes to model — — — — — — — — New lending and assets purchased (5) — — — — — — — — Redemptions, repayments and assets sold (7) (8,901) — — — — — (8,901) — Changes in risk parameters and other movements (6) (738) — — — — — (738) — Assets written off (7) — — — — — — — — At 31 December 2022 58,710 — — — — — 58,710 — Net movement in the period (9,639) — — — — — (9,639) — ECL charge/(release) to the Income Statement — — Less: Discount unwind — — Less: Recoveries net of collection costs — — Total ECL charge/(release) to the Income Statement — — — — £m £m £m £m £m £m £m £m At 1 January 2021 72,575 35 — — — — 72,575 35 Transfers from Stage 1 to Stage 2 (3) — — — — — — — — Transfers from Stage 2 to Stage 1 (3) — — — — — — — — Transfers to Stage 3 (3) — — — — — — — — Transfers from Stage 3 (3) — — — — — — — — Transfers of financial instruments 0 — — — — — — — Net ECL remeasurement on stage transfer (4) — — — — — — — — Change in economic scenarios (2) — — — — — — — — Changes to model — — — — — — — — New lending and assets purchased (5) — — — — — — — — Redemptions, repayments and assets sold (7) (3,749) (18) — — — — (3,749) (18) Changes in risk parameters and other movements (6) (477) (17) — — — — (477) (17) Assets written off (7) — — — — — — — — At 31 December 2021 68,349 — — — — — 68,349 — Net movement in the period (4,226) (35) — — — — (4,226) (35) ECL charge/(release) to the Income Statement (35) — — (35) Less: Discount unwind — — — — Less: Recoveries net of collection costs — — — — Total ECL charge/(release) to the Income Statement (35) — — (35)
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 line 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. If so, we use the guarantor’s country of domicile. If a client has operations in many countries, we use their country of incorporation. The table below excludes balances with other Banco Santander group members. We show them separately in the section that immediately follows. 2022 2021 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 — — 2.3 — 0.1 2.4 — — 5.3 — — 5.3 Spain — — — — — — — — — — 0.1 0.1 France 0.1 0.8 0.5 — — 1.4 0.1 0.3 0.2 — — 0.6 Germany — 0.3 — — 0.1 0.4 — 0.4 — — — 0.4 Luxembourg — — — — — — — — 0.1 — — 0.1 Other (3) 0.3 0.5 — — — 0.8 0.3 0.8 — — — 1.1 0.4 1.6 2.8 — 0.2 5.0 0.4 1.5 5.6 — 0.1 7.6 Other countries UK 44.1 1.8 5.8 217.3 26.9 295.9 47.9 2.0 9.3 215.1 28.7 303.0 US 0.1 0.9 0.1 — — 1.1 0.5 0.8 — — — 1.3 Japan 1.1 0.3 — — — 1.4 1.0 0.2 — — — 1.2 Switzerland 1.2 — — — — 1.2 — — — — — — Other 0.1 0.7 0.2 0.5 1.5 0.3 0.2 0.1 — 0.1 0.7 46.6 3.7 6.1 217.3 27.4 301.1 49.7 3.2 9.4 215.1 28.8 306.2 Total 47.0 5.3 8.9 217.3 27.6 306.1 50.1 4.7 15.0 215.1 28.9 313.8 (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. 1. Includes The Netherlands £0.1bn (2021: £0.2bn), Belgium £0.6bn (2021: £0.7bn), and Finland £0.1bn (2021: £nil).
Disclosure of Balances with Other Banco Santander Group Companies	At 31 December 2022 and 31 December 2021, we had gross balances with other Banco Santander group members as follows: 2022 2021 Financial institutions Financial institutions Banks Other Corporate Total Banks Other Corporate Total £bn £bn £bn £bn £bn £bn £bn £bn Assets Spain 1.4 — — 1.4 0.8 — — 0.8 UK — 4.2 — 4.2 — 3.3 — 3.3 1.4 4.2 — 5.6 0.8 3.3 — 4.1 Liabilities Spain 1.7 0.1 — 1.8 1.2 0.1 — 1.3 UK — 15.6 — 15.6 — 12.1 — 12.1 Uruguay — — — — 0.1 — — 0.1 1.7 15.7 — 17.4 1.3 12.2 — 13.5
Disclosure of Borrower Profile	Stock New business 2022 2021 2022 2021 £m % £m % £m % £m % Home movers (1) 76,357 41 74,657 42 12,221 36 13,537 43 Remortgagers (2) 53,190 29 50,645 29 10,644 31 8,031 25 First-time buyers 37,971 21 34,517 20 8,129 24 6,206 19 Buy-to-let 16,799 9 14,893 9 3,133 9 4,239 13 184,317 100 174,712 100 34,127 100 32,013 100 (1) '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. (2) 'Remortgagers’ are new customers who are taking a new mortgage with us
Disclosure of Interest Rate Profile of Mortgage Assets Stock	The interest rate profile of our maturing mortgage asset stock was: 2022 2021 £m % £m % Fixed rate 163,622 89 147,147 84 Of which maturing: – < 12 months 38,233 21 29,644 17 – Later than 1 year but no later than 3 years 38,213 21 40,967 23 – Later than 3 years but no later than 4 years 24,310 13 24,074 14 – Later than 4 years but no later than 5 years 24,888 14 21,140 12 – Later than 5 years 37,978 21 31,322 18 Variable rate 12,430 7 17,010 10 Standard Variable Rate (SVR) 5,645 3 7,836 4 Follow on Rate (FoR) 2,620 1 2,719 2 184,317 100 174,712 100
Disclosure of Geographic Distribution of Mortgage Assets Stock	The geographical distribution of our mortgage asset stock and new business was: Stock New business 2022 2021 2022 2021 Region £bn £bn £bn £bn London 47.0 44.6 8.3 8.3 Midlands and East Anglia 25.6 23.8 5.3 4.7 North 24.4 23.1 4.7 3.8 Northern Ireland 2.9 3.0 0.3 0.3 Scotland 6.8 6.6 1.2 1.0 South East excluding London 58.4 55.5 10.6 10.5 South West, Wales and other 19.2 18.1 3.7 3.4 184.3 174.7 34.1 32.0
Disclosure of Mortgage Loan Size	Mortgage loan size 2022 2021 >£1.0m 2 % 2 % £0.5m to £1.0m 10 % 9 % £0.25m to £0.5m 31 % 30 % <£0.25m 57 % 59 % Average loan size (stock) £183k £174k Average loan size (new business) £237k £234k
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, and new business. We also show the collateral value and average LTV. We use our estimate of the property value at the balance sheet date and include fees that have been added to the loan. For flexible products, we only include the drawn amount, not undrawn limits. 2022 2021 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% 87,379 37 1,111 14 4,890 78,911 25 942 9 4,997 >50-60% 35,664 29 283 11 4,014 30,328 22 301 10 4,379 >60-70% 33,868 50 197 16 6,104 32,803 25 227 11 6,517 >70-80% 17,824 45 110 15 10,094 24,217 30 154 14 10,242 >80-90% 7,339 29 42 9 6,002 6,565 21 68 10 4,558 >90-100% 1,873 17 32 9 2,999 1,360 16 39 9 1,270 >100% 370 45 52 21 24 528 51 65 26 50 184,317 252 1,827 95 34,127 174,712 190 1,796 89 32,013 Collateral value (1) 184,269 1,818 34,126 174,637 1,784 32,012 % % % % % % Average LTV - Balance weighted (2)(3) 50 47 69 52 51 66 (1) Collateral value is limited to the balance of each loan and excludes the impact of any over-collateralisation. Includes collateral against loans in negative equity of £323m (2021: £455m). (2) Balance weighted LTV = (Loan 1 balance x (Loan 1 Balance/Loan 1 latest property valuation) + (Loan 2 balance x (loan 2 balance/Loan 2 latest property valuation)+ ...) /(Loan 1 balance + Loan 2 balance+...). (3) Simple average stock LTV 39% (2021: 41%).
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. 2022 2021 £m £m Financial assets modified in the period: – Amortised cost before modification 315 422 – Net modification loss 7 9 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 91 152 From March 2020 to March 2021, we provided mortgage customers with payment holiday terms in line with UK Government and FCA guidance. The scheme has now ceased. The following table provides information on such loan modifications. 2022 2021 £m £m Financial assets modified in the period: – Amortised cost before modification — 647 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 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 2022 £m £m £m £m Financial assets modified in the period: – Amortised cost before modification — 7 7 14 – Net modification gain — 7 6 13 Financial assets modified since initial recognition: – Gross carrying amount of financial assets for which the loss allowance changed to 12m ECL in the period — 3 1 4 2021 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 From March 2020 to March 2021, we provided business banking and other unsecured lending customers with payment holiday terms. The following table provides information on such loan modifications. Business banking Other unsecured Total 2022 £m £m £m Financial assets modified in the period: – Amortised cost before modification — — — – 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 — — — 2021 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 From March 2020 to March 2021, we provided Consumer Finance customers with payment holiday terms. The following table provides information on such loan modifications. 2022 2021 £m £m Financial assets modified in the period: – Amortised cost before modification — 54 – Net modification loss — — 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 95 226 The following table (audited) sets out the financial assets that were forborne while they had a loss allowance measured at lifetime ECL. 2022 2021 £m £m Financial assets modified in the period: – Amortised cost before modification 240 243 – Net modification gain/ (loss) 8 (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 15 29
Disclosure of Forbearance Balances	The balances at 31 December 2022 and 31 December 2021, analysed by their staging at the period-end and the forbearance we applied, were: Capitalisation Term extension Interest-only Concessionary interest rate Total (audited) Loss allowances 2022 £m £m £m £m £m £m Stage 2 309 319 240 6 874 11 Stage 3 298 140 65 190 693 31 607 459 305 196 1,567 42 Proportion of portfolio 0.3 % 0.3 % 0.2 % 0.1 % 0.9 % 2021 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 % (1) We base forbearance type on the first forbearance on the accounts. The balances at 31 December 2022 and 31 December 2021 were: Interest-only (2) Flexible LTV >100% Buy-to-Let 2022 £m £m £m £m Total 290 36 9 15 – Stage 2 111 19 — 11 – Stage 3 179 17 9 4 2021 Total 419 35 13 11 – Stage 2 280 24 3 8 – Stage 3 139 11 10 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 2022 and 31 December 2021 were: Other unsecured Business banking Personal loans Credit cards Overdrafts Total other Total 2022 £m £m £m £m £m £m Total 3 1 34 16 51 54 – Stage 2 — 1 6 2 9 9 – Stage 3 3 — 28 14 42 45 2021 Total 2 1 38 15 54 56 – Stage 2 — — 7 3 10 10 – Stage 3 2 1 31 12 44 46 We only make forbearance arrangements for lending to customers. The balances (audited) at 31 December 2022 and 31 December 2021, analysed by their staging at the period–end and the forbearance we applied, were: 2022 2021 £m £m Stock (1) – Term extension 98 150 – Interest-only 238 239 – Other payment rescheduling 219 204 555 593 Of which: – Stage 1 17 20 – Stage 2 173 303 – Stage 3 365 270 555 593 Proportion of portfolio 2.0 % 2.4 % (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 Segments Exposure 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 2022 £m £m £m £m £m £m £m £m £m SME and mid corporate — 336 923 2,341 3,299 5,327 1,791 106 14,123 Commercial Real Estate — 2 111 2,044 2,128 936 185 1 5,407 Social Housing 44 4,028 3,956 6 — — — — 8,034 44 4,366 4,990 4,391 5,427 6,263 1,976 107 27,564 Of which: Stage 1 39 4,364 4,944 4,202 4,773 4,289 386 107 23,104 Stage 2 5 2 46 189 654 1,974 1,018 — 3,888 Stage 3 — — — — — — 572 — 572 2021 SME and mid corporate — 659 714 2,397 3,067 5,545 2,207 66 14,655 Commercial Real Estate — 126 137 1,471 2,228 638 249 — 4,849 Social Housing 52 3,961 3,759 9 — 53 105 7,939 52 4,746 4,610 3,877 5,295 6,236 2,456 171 27,443 Of which: Stage 1 52 3,809 4,359 3,604 4,192 4,138 380 168 20,702 Stage 2 — 937 251 239 1,086 2,005 1,509 (114) 5,913 Stage 3 — — — 34 17 93 567 117 828 (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 2022 £m £m £m £m £m £m £m £m £m Corporate Centre Sovereign and Supranational 47,040 1,077 — — — — — — 48,117 Structured Products 136 1,162 875 — — — — — 2,173 Financial Institutions 1,191 672 521 26 — — — — 2,410 48,367 2,911 1,396 26 — — — — 52,700 Of which: Stage 1 48,367 2,911 1,396 26 — — — — 52,700 Stage 2 — — — — — — — — — Stage 3 — — — — — — — — — 2021 Corporate Centre Sovereign and Supranational 55,061 1,051 — — — — — — 56,112 Structured Products 573 1,064 197 41 — — — — 1,875 Financial Institutions 479 533 345 7 — — — — 1,364 56,113 2,648 542 48 — — — — 59,351 Of which: Stage 1 56,113 2,648 542 46 — — — — 59,349 Stage 2 — — — 2 — — — — 2 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).
Disclosure of Segments Exposure 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. 2022 2021 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 14,091 32 — — 14,123 14,612 43 — — 14,655 Commercial Real Estate 5,407 — — — 5,407 4,849 — — — 4,849 Social Housing 8,034 — — — 8,034 7,939 — — — 7,939 27,532 32 — — 27,564 27,400 43 — — 27,443 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. 2022 2021 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 43,936 1,886 83 2,212 48,117 52,297 950 469 2,396 56,112 Structured Products 1,379 422 4 368 2,173 1,219 656 — — 1,875 Financial Institutions 988 1,005 230 187 2,410 504 565 81 214 1,364 46,303 3,313 317 2,767 52,700 54,020 2,171 550 2,610 59,351
Disclosure of Segments Exposure by Gross and Net Credit Exposure	Gross exposure Collateral Net exposure Stage 3 Stage 3 Stage 3 2022 £m £m £m SME and mid corporate 513 169 344 Commercial Real Estate 59 30 29 572 199 373 2021 SME and mid corporate 747 307 440 Commercial Real Estate 81 37 44 828 344 484

Market Risk (Tables)

Market Risk (Tables)	12 Months Ended
	Dec. 31, 2022
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. 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, and the Sterling Overnight Index Average (SONIA) rate. 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 credit 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 NII and EVE Sensitivities Measurement	NII sensitivity NII 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 NII sensitivity by simulating the NII using 2 yield curves. The difference between the 2 NII totals is the NII sensitivity. 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.
Summary of Detailed Information about VaR	Value at Risk (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 to find how much we might lose, normally at a 99% confidence level.
Summary of NII and EVE Sensitivity of Interest Rate Risk	The table below shows how our net interest income would be affected by a parallel shift (both up and down) applied instantaneously to the yield curve at 31 December 2022 and 31 December 2021 In 2022, we moved to focus on 100 basis points (bps) from previously disclosed sensitivities of 50bps and 25bps. The shift reflects a more realistic stress in the current rate environment. We have replaced the previously disclosed sensitivities of 50bps and 25bps for 2021 with 100 bps sensitivities for consistency with 2022. 2022 2021 +100bps -100bps +100bps -100bps £m £m £m £m NII sensitivity (audited) (1) 241 (197) 318 (440) EVE sensitivity (487) 635 (431) 184 Based on modelling assumptions of repricing behaviour.

Liquidity Risk (Tables)

Liquidity Risk (Tables)	12 Months Ended
	Dec. 31, 2022
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 2022 and 31 December 2021. Balance sheet line item Funding Deposits by banks (3) Deposits by customers (1) Repurchase agreements - non trading Financial Debt Subordinated Other equity instruments (2) 2022 £bn £bn £bn £bn £bn £bn £bn £bn Deposits by banks 0.5 0.5 — — — — — — Certificates of deposit and commercial paper 4.7 — — — — 4.7 — — Senior unsecured – public benchmark 14.3 — 4.6 — — 9.7 — — – privately placed 0.6 — 0.1 — 0.4 0.1 — — Covered bonds 14.9 — — — — 14.9 — — Securitisation and structured issuance 1.0 — — — — 1.0 — — TFSME 25.0 25.0 — — — — — — Subordinated liabilities and equity 3.9 — — — — — 1.9 2.0 Total wholesale funding 64.9 25.5 4.7 — 0.4 30.4 1.9 2.0 Repos 8.0 — — 8.0 — — — — Foreign exchange and hedge accounting 1.6 — 0.1 — — 1.1 0.4 — Other 3.4 3.0 — — 0.4 — — — Balance sheet total 77.9 28.5 4.8 8.0 0.8 31.5 2.3 2.0 2021 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 — — 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 (1) This is included in our balance sheet total of £195,568m (2021: £192,926m). (2) Consists of £nil (2021: £nil ) fixed/floating rate non-cumulative callable preference shares, £0m (2021: £235m) Step-up Callable Perpetual Reserve Capital Instruments and £1,956m (2021: £1,956m) Perpetual Capital Securities. See Notes 44 and 33 to the Consolidated Financial Statements. (3) Other consists of items in the course of transmission and other deposits. 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. For details of the maturities of financial liabilities and off-balance sheet commitments, see Note 39 to the Consolidated Financial Statements. ≤ 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 2022 £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 0.7 — 0.6 0.8 2.9 1.6 6.4 1.6 12.5 – privately placed — — — — — — — 0.1 — 0.1 Subordinated liabilities and equity (incl. AT1) — — — — — — 0.5 1.2 1.0 2.7 0.8 0.7 — 0.6 0.8 2.9 2.1 7.7 2.6 15.3 Other Santander UK plc Deposits by banks 0.2 0.3 — — — 0.5 — — — 0.5 Certificates of deposit and commercial paper 1.2 3.2 0.3 — — 4.7 — — — 4.7 Senior unsecured – public benchmark 0.3 — — — — 0.3 0.9 0.3 0.3 1.8 – privately placed — — — — — — 0.1 0.2 0.2 0.5 Covered bonds — 1.0 0.1 0.9 — 2.0 3.4 8.4 1.1 14.9 Securitisation & structured issuance (2) 0.1 — 0.1 — — 0.2 0.1 0.6 0.1 1.0 TFSME — — — — — — — 25.0 — 25.0 Subordinated liabilities — — — — 0.4 0.4 — — 0.8 1.2 1.8 4.5 0.5 0.9 0.4 8.1 4.5 34.5 2.5 49.6 Other group entities Securitisation & structured issuance (3) — — — — — — — — — — Total at 2022 2.6 5.2 0.5 1.5 1.2 11.0 6.6 42.2 5.1 64.9 Of which: – Secured 0.1 1.0 0.2 0.9 — 2.2 3.5 34.0 1.2 40.9 – Unsecured 2.5 4.2 0.3 0.6 1.2 8.8 3.1 8.2 3.9 24.0 2021 Total at 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 (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 2022 and 31 December 2021. 2022 2021 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 18 58 24 — 9 59 32 — – privately placed — — — 100 — — — 100 Subordinated liabilities and equity (incl. AT1) 75 25 — — 73 27 — — 27 52 20 1 22 52 25 1 Other Santander UK plc Deposits by banks 29 71 — — 32 68 — — Certificates of deposit and commercial paper 56 42 2 — 45 53 2 — Senior unsecured – public benchmark 18 62 20 — 14 46 40 — – privately placed 95 — 5 — 92 — 6 2 Covered bonds 43 12 45 — 44 8 48 — Securitisation & structured issuance 100 — — — 74 26 — — TFSME 100 — — — 100 — — — Subordinated liabilities 48 52 — — 57 43 — — 74 12 14 — 77 10 13 — Total 63 21 16 — 66 18 15 1
Summary of External Term Issuance, Sterling Equivalent	In 31 December 2022, our external term issuance (sterling equivalent) was: Sterling US Dollar Euro Other 2022 2021 £bn £bn £bn £bn £bn £bn Downstreamed from Santander UK Group Holdings plc to Santander UK plc Senior unsecured – public benchmark 1.2 2.1 0.6 — 3.9 2.8 Subordinated debt and equity (inc. AT1) 0.8 — — — 0.8 0.2 2.0 2.1 0.6 — 4.7 3.0 Other Santander UK plc Securitisations and other secured funding 0.6 — — — 0.6 — Covered bonds 1.8 0.8 1.4 — 4.0 — Senior unsecured – public benchmark — — — — — — – privately placed 0.1 — — — 0.1 0.1 TFSME — — — — — 20.2 2.5 0.8 1.4 — 4.7 20.3 Total gross issuances 4.5 2.9 2.0 — 9.4 23.3
Summary of Balance Sheet Encumbered and Unencumbered Assets Explanatory	On-balance sheet encumbered and unencumbered assets (audited) Encumbered with counterparties other than central banks Assets positioned at central banks (3) Unencumbered assets not pre-positioned with central banks Covered Securitis- Other Total Readily Other Cannot be Total Total 2022 £m £m £m £m £m £m £m £m £m £m Cash and balances at central banks (1)(2) — 1,330 1,330 893 41,967 — — 42,860 44,190 Financial assets at FVTPL: – Derivative financial instruments — — — — — — — 2,407 2,407 2,407 – Other financial assets at FVTPL — — — — — — — 129 129 129 Financial assets at amortised cost: – Loans and advances to customers 21,304 2,851 56 24,211 68,535 91,761 18,284 16,925 195,505 219,716 – Loans and advances to banks — — 163 163 — — — 829 829 992 – Repurchase agreements – non trading — — — — — — — 7,348 7,348 7,348 – Other financial assets at amortised cost — — 48 48 — 108 — — 108 156 Financial assets at FVOCI — — 4,365 4,365 — 1,659 — — 1,659 6,024 Interests in other entities — — — — — — — 252 252 252 Intangible assets — — — — — — — 1,550 1,550 1,550 Property, plant and equipment — — — — — — 1,513 — 1,513 1,513 Current tax assets — — — — — — — 478 478 478 Retirement benefit assets — — — — — — — 1,050 1,050 1,050 Other assets — — — — — — — (592) (592) (592) Total assets 21,304 2,851 5,962 30,117 69,428 135,495 19,797 30,376 255,096 285,213 2021 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 (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, 2022
Disclosure Of Capital Risk Exposure [Abstract]
Summary of Regulatory Capital Resources	This table shows our qualifying regulatory capital: 2022 2021 £m £m CET1 capital 10,799 10,820 AT1 capital 1,956 2,119 Tier 1 capital 12,755 12,939 Tier 2 capital 1,548 1,816 Total regulatory capital (1) 14,303 14,755 (1) Capital resources include a transitional IFRS 9 benefit at 31 December 2022 of £19m(2021: £21m).

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2022
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 Shorter of the lease term or the useful life of the underlying asset Operating lease assets - vehicles 2 to 4 years
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 the need for any judgemental adjustments – Determining the need to assess corporate Stage 3 exposures individually Key estimates – Forward-looking multiple economic scenario assumptions – Probability weights assigned to multiple economic scenarios Key judgements – Determining whether a present obligation exists – Determining 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 testing methodology, including the need for planning assumptions and internal capital allocations 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, 2022
Disclosure of operating segments [abstract]
Summary of Results by Segment	Results by segment For the years ended 31 December Retail Banking Consumer Finance Corporate & Commercial Banking Corporate Centre Total 2022 £m £m £m £m £m Net interest income / (expense) 3,671 180 580 (6) 4,425 Non-interest income / (expense) 209 195 146 (19) 531 Total operating income 3,880 375 726 (25) 4,956 Operating expenses before credit impairment (charges)/write-backs, provisions and charges (1,682) (144) (342) (175) (2,343) Credit impairment (charges)/write-backs (262) (27) (31) — (320) Provisions for other liabilities and charges (394) (6) (8) (11) (419) Total operating credit impairment (charges)/write-backs, provisions and charges (656) (33) (39) (11) (739) Profit/(loss) from continuing operations before tax 1,542 198 345 (211) 1,874 Revenue from external customers 4,109 513 732 (398) 4,956 Inter-segment revenue (229) (138) (6) 373 — Total operating income 3,880 375 726 (25) 4,956 Revenue from external customers includes the following fee and commission income: (1) – Current account and debit card fees 502 — 60 — 562 – Insurance, protection and investments 78 — — — 78 – Credit cards 95 — — — 95 – Non-banking and other fees (2) 2 20 77 5 104 Total fee and commission income 677 20 137 5 839 Fee and commission expense (478) (5) (18) (8) (509) Net fee and commission income/(expense) 199 15 119 (3) 330 Customer loans 191,836 5,384 18,518 — 215,738 Total assets (3) 200,872 10,371 18,518 55,452 285,213 Of which assets held for sale — — — 49 49 Customer deposits 161,748 — 24,798 3,365 189,911 Total liabilities 161,821 1,223 24,473 83,289 270,806 Average number of full-time equivalent staff 15,212 531 2,336 44 18,123 (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 charge allowances. Retail Banking Consumer Finance Corporate & Commercial Banking Corporate & Investment Banking Corporate Centre Total 2021 £m £m £m £m £m £m Net interest income/(expense) 3,356 233 397 — (37) 3,949 Non-interest income 205 178 112 — 55 550 Total operating income 3,561 411 509 — 18 4,499 Operating expenses before credit impairment (charges)/write-backs, provisions and charges (1,701) (163) (365) — (281) (2,510) Credit impairment (charges)/write-backs 98 33 90 — 12 233 Provisions for other liabilities and charges (185) 4 (34) — (162) (377) Total operating credit impairment (charges)/write-backs, provisions and charges (87) 37 56 — (150) (144) Profit/(loss) from continuing operations before tax 1,773 285 200 — (413) 1,845 Revenue from external customers 4,010 489 619 — (619) 4,499 Inter-segment revenue (449) (78) (110) — 637 — Total operating income/(expense) 3,561 411 509 — 18 4,499 Revenue from external customers includes the following fee and commission income: (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 190 10 90 — (4) 286 Customer loans 183,023 4,984 19,281 — — 207,288 Total assets (3) 190,629 8,873 19,281 — 68,315 287,098 Customer deposits 156,991 — 26,466 — 2,758 186,215 Total liabilities 157,622 1,173 26,513 — 85,688 270,996 Average number of full-time equivalent staff 16,149 670 2,281 528 76 19,704 2020 Net interest income 2,753 264 355 — 16 3,388 Non-interest income 245 127 96 — (4) 464 Total operating income 2,998 391 451 — 12 3,852 Operating expenses before credit impairment (charges)/write-backs, provisions and charges (1,792) (166) (324) — (108) (2,390) Credit impairment (charges)/write-backs (264) (44) (294) — (36) (638) Provisions for other liabilities and charges (157) (8) (6) — (93) (264) Total operating credit impairment (charges)/write-backs, provisions and charges (421) (52) (300) — (129) (902) Profit/(loss) from continuing operations before tax 785 173 (173) (225) 560 Revenue from external customers 3,669 501 608 — (926) 3,852 Inter-segment revenue (671) (110) (157) — 938 — Total operating income 2,998 391 451 — 12 3,852 Revenue from external customers includes the following fee and commission income: (1) – Current account and debit card fees 442 — 42 — — 484 – Insurance, protection and investments 65 — — — — 65 – Credit card fees 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 20,822 2,784 0 207,011 Total assets (3) 183,154 11,143 20,820 2,784 74,431 292,332 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 (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 charge allowances. (4) CIB results presented as discontinued operations. See Note42.

Net Interest Income (Tables)

Net Interest Income (Tables)	12 Months Ended
	Dec. 31, 2022
Analysis of income and expense [abstract]
Summary of Net Interest Income	Group 2022 2021 2020 £m £m £m Interest and similar income: Loans and advances to customers 5,774 4,619 4,745 Loans and advances to banks 618 52 49 Reverse repurchase agreements – non trading 149 35 118 Other 167 56 119 Total interest and similar income (1) 6,708 4,762 5,031 Interest expense and similar charges: Deposits by customers (905) (430) (1,011) Deposits by banks (496) (25) (28) Repurchase agreements – non trading (120) (3) (43) Debt securities in issue (650) (252) (440) Subordinated liabilities (108) (92) (111) Other (4) (11) (10) Total interest expense and similar charges (2) (2,283) (813) (1,643) Net interest income 4,425 3,949 3,388 (1) Includes £87m (2021: £22m, 2020: £38m) of interest income on financial assets at FVOCI. (2) Includes £6m (2021: £317m, 2020: £451m) of interest expense on derivatives hedging debt issuances and £3m (2021: £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, 2022
Fee and commission income (expense) [abstract]
Summary of Net Fee and Commission Income	Group 2022 2021 2020 £m £m £m Fee and commission income: Current account and debit card fees 562 478 484 Insurance, protection and investments 78 67 65 Credit cards 95 73 66 Non-banking and other fees (1) 104 79 65 Total fee and commission income 839 697 680 Total fee and commission expense (509) (411) (361) Net fee and commission income 330 286 319 (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, 2022
Net Trading And Other Income [Abstract]
Summary of Net Trading and Other Income	Group 2022 2021 2020 £m £m £m Net gains/(losses) on financial instruments designated at fair value through profit or loss 62 (24) (77) Net (losses)/gains on financial instruments mandatorily at fair value through profit or loss (75) (2) 46 Hedge ineffectiveness 29 13 20 Net profit on sale of financial assets at fair value through other comprehensive income — 6 17 Income from operating lease assets 129 136 126 Other 56 135 13 201 264 145

Operating Expenses Before Cre_2

Operating Expenses Before Credit Impairment Charges, Provisions and Charges (Tables)	12 Months Ended
	Dec. 31, 2022
Expenses by nature [abstract]
Summary of Operating Expenses Before Credit Impairment Losses, Provisions and Charges	Group 2022 2021 2020 £m £m £m Staff costs: Wages and salaries 745 745 788 Performance-related payments 170 183 97 Social security costs 112 112 101 Pensions costs: – defined contribution plans 60 64 66 – defined benefit plans 28 38 38 Other share-based payments — — — Other personnel costs 44 41 33 1,159 1,183 1,123 Other administration expenses 888 826 706 Depreciation, amortisation and impairment 296 501 561 Total 2,343 2,510 2,390
Summary of Deferred Performance Awards	Costs recognised in 2022 Costs expected to be recognised in 2023 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 6 8 14 Shares 3 5 8 6 8 14 6 10 16 12 16 28
Disclosure of Amount of Bonus Awarded to Employees	Expenses charged in the year Expenses deferred to future periods Total 2022 2021 2022 2021 2022 2021 £m £m £m £m £m £m Cash award – not deferred 145 156 — — 145 156 – deferred 8 8 14 15 22 23 Shares award – not deferred 9 11 — — 9 11 – deferred 8 8 14 14 22 22 Total discretionary bonus 170 183 28 29 198 212

Audit and Other Services (Table

Audit and Other Services (Tables)	12 Months Ended
	Dec. 31, 2022
Audit And Other Services [Abstract]
Summary of Audit and Other Services	Group 2022 2021 2020 £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 11.8 11.2 10.0 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 0.7 0.9 1.4 Total audit fees (1) 12.5 12.1 11.4 Non-audit fees: Audit-related assurance services 0.6 0.8 0.8 Other assurance services 0.3 0.1 0.3 Other non-audit services — 0.2 — Total non-audit fees 0.9 1.1 1.1 (1) 2022 audit fees included £0.6m (2021: £1.2m, 2020: £0.8m) which related to the prior year.

Credit Impairment Charges and_2

Credit Impairment Charges and Provisions (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure Of Credit Impairment Loss And Provisions [Abstract]
Summary of Impairment Losses and Provisions	Group 2022 2021 2020 £m £m £m Credit impairment charges/(write-backs): Loans and advances to customers 248 (186) 665 Recoveries of loans and advances, net of collection costs 36 (17) (24) Off-balance sheet credit exposures (See Note 29) 36 (30) (3) 320 (233) 638 Provisions for other liabilities and charges (excluding off-balance sheet credit exposures) (See Note 29) 422 386 258 (Releases)/Provisions for residual value and voluntary termination (3) (9) 6 419 377 264 739 144 902

Taxation (Tables)

Taxation (Tables)	12 Months Ended
	Dec. 31, 2022
Major components of tax expense (income) [abstract]
Disclosure of Income Tax and Deferred Taxes Explanatory	Group 2022 2021 2020 £m £m £m Current tax: UK corporation tax on profit for the year 526 401 107 Adjustments in respect of prior years (81) (24) (24) Total current tax 445 377 83 Deferred tax: (Credit)/Charge for the year (29) 100 34 Adjustments in respect of prior years 64 15 4 Total deferred tax 35 115 38 Tax on profit from continuing operations 480 492 121
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 2022 was 25.6% (2021: 26.7%, 2020: 21.6%). The tax on profit from continuing operations before tax differs from the theoretical amount that would arise using the basic corporation tax rate as follows: For the years ended 31 December Group 2022 2021 2020 £m £m £m Profit from continuing operations before tax 1,874 1,845 560 Tax calculated at a tax rate of 19% (2021: 19%, 2020: 19%) 356 351 106 Bank surcharge on profits 121 104 27 Non-deductible preference dividends paid 9 9 8 Non-deductible UK Bank Levy 13 14 19 Non-deductible conduct remediation, fines and penalties 48 6 (4) Other non-deductible costs and non-taxable income 29 37 25 Effect of change in tax rate on deferred tax provision (29) 9 6 Tax relief on dividends in respect of other equity instruments (40) (40) (40) Adjustment to prior year provisions (27) 2 (26) Tax on profit from continuing operations 480 492 121
Disclosure of Movement in Current Tax Assets and Liabilities	Movements in current tax assets and liabilities during the year were as follows: Group 2022 2021 £m £m Assets 347 264 Liabilities — — At 1 January 347 264 Income statement charge (including discontinued operations) (445) (389) Other comprehensive income credit 159 33 Corporate income tax paid 405 427 Other movements 12 12 478 347 Assets 478 347 Liabilities — — At 31 December 478 347
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 2022 (123) (508) (7) (12) 8 68 (5) (579) Income statement (charge)/credit 150 (49) — — (7) (33) (96) (35) Transfers/reclassifications — — 2 — (1) — (1) — Credited/(charged) to other comprehensive income — 267 310 11 — — (9) 579 At 31 December 2022 27 (290) 305 (1) — 35 (111) (35) 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)

Dividends on Ordinary Shares (T

Dividends on Ordinary Shares (Tables)	12 Months Ended
	Dec. 31, 2022
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 2022 2021 2020 2022 2021 2020 Pence per share Pence per share Pence per share £m £m £m In respect of current year – first interim 1.25 0.90 0.42 389 281 129 – second interim 2.01 3.47 — 625 1,077 — 3.26 4.37 0.42 1,014 1,358 129

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure of nature and extent of risks arising from financial instruments [abstract]
Disclosure of Notional Amounts and Fair Values of Derivatives	Group 2022 2021 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 14,006 315 281 11,036 159 168 Interest rate contracts 31,135 465 754 25,148 463 485 Equity and credit contracts 902 130 25 1,056 161 54 Total derivatives held for trading 46,043 910 1,060 37,240 783 707 Derivatives held for hedging Designated as fair value hedges: Exchange rate contracts 538 12 4 590 39 — Interest rate contracts 77,748 1,777 403 80,514 904 737 78,286 1,789 407 81,104 943 737 Designated as cash flow hedges: Exchange rate contracts 26,035 1,717 186 22,239 996 338 Interest rate contracts 26,108 164 1,471 21,466 180 216 52,143 1,881 1,657 43,705 1,176 554 Total derivatives held for hedging 130,429 3,670 2,064 124,809 2,119 1,291 Derivative netting (1) — (2,173) (2,173) — (1,221) (1,221) Total derivatives 176,472 2,407 951 162,049 1,681 777 (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 £1,368m (2021: £189m) and the amount of cash collateral paid that had been offset against the gross derivative liabilities was £70m (2021: £202m).
Disclosure of Analysis of the Notional and Fair Values of Derivatives by Trading and Settlement Method	Notional Traded over the counter Asset Liability Settled by central counterparties Not settled by central counterparties Total Traded over the counter Traded over the counter 2022 £m £m £m £m £m Exchange rate contracts — 40,579 40,579 2,044 471 Interest rate contracts 124,638 10,353 134,991 233 455 Equity and credit contracts — 902 902 130 25 124,638 51,834 176,472 2,407 951 2021 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
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 2022 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) 2,210 4,468 21,678 45,314 3,808 77,478 Average fixed interest rate - GBP 2.58 % 0.88 % 0.56 % 2.07 % 3.78 % Average fixed interest rate - EUR 1.77 % 1.60 % 0.77 % 0.28 % 3.09 % Average fixed interest rate - USD 1.35 % 3.47 % 3.51 % 2.00 % 4.92 % Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) — — 66 465 7 538 Interest rate contracts - Nominal amount (£m) — — — 263 7 270 Average GBP - EUR exchange rate — — 1.20 1.16 1.10 Average GBP - USD exchange rate — — — 1.19 — Average fixed interest rate - EUR — — 3.42 % 2.06 % — Average fixed interest rate - USD — — — 4.63 % — Cash flow hedges: Interest rate risk Interest rate contracts – Nominal amount (£m) 1,042 2,191 1,940 13,197 1,076 19,446 Average fixed interest rate - GBP 1.77 % 2.29 % 1.98 % 2.35 % 1.84 % FX risk Exchange rate contracts - Nominal amount (£m) 2,301 3,135 2,381 10,606 1,163 19,586 Interest rate contracts - Nominal amount (£m) 415 — — 2,325 997 3,737 Average GBP - JPY exchange rate — 157.45 160.04 — — Average GBP - CHF exchange rate — 1.13 — — — Average GBP - EUR exchange rate — — 1.12 1.18 1.17 Average GBP - USD exchange rate 1.22 1.25 1.17 1.31 1.39 Interest rate/FX risk Exchange rate contracts - Nominal amount (£m) — — 1,173 4,626 650 6,449 Interest rate contracts - Nominal amount (£m) — — 585 2,132 208 2,925 Average GBP - EUR exchange rate 1.19 1.21 1.20 Average GBP - USD exchange rate 1.60 1.50 1.54 Average fixed interest rate – GBP — — 3.27 % 2.58 % 4.59 % 2021 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) — — 0 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 %
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 2022 2021 2020 £m £m £m Fair value hedging: Gains/(losses) on hedging instruments 2,381 852 (299) (Losses)/gains on hedged items attributable to hedged risks (2,316) (800) 365 Fair value hedging ineffectiveness 65 52 66 Cash flow hedging ineffectiveness (36) (39) (46) 29 13 20
Disclosure of Information about Hedging Ineffectiveness by Risk Category Explanatory	Hedge ineffectiveness can be analysed by risk category as follows: Group 2022 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 Change in FV of hedging instruments Change in FV of hedged items Recognised in income statement £m £m £m £m £m £m £m £m £m Fair value hedges: Interest rate risk 2,392 (2,333) 59 874 (834) 40 (358) 385 27 Interest rate/FX risk (11) 17 6 (22) 34 12 59 (20) 39 2,381 (2,316) 65 852 (800) 52 (299) 365 66 Group Hedging Instruments Income statement line item affected by reclassification Change in FV Recognised in OCI Recognised in Income Statement Reclassified from reserves to income £m £m £m £m Cash flow hedges: 2022 Interest rate risk Net interest income (1,161) 1,160 (1) (96) FX risk Net interest income/other operating income 1,604 (1,604) — 1,692 Interest rate/FX risk Net interest income/other operating income (54) 19 (35) 533 389 (425) (36) 2,129 2021 Interest rate risk Net interest income (317) 305 (12) 73 FX risk Net interest income/other operating income (54) 54 — (158) Interest rate/FX risk Net interest income/other operating income (541) 514 (27) (273) (912) 873 (39) (358) 2020 Interest rate risk Net interest income 185 (179) 6 33 FX risk Net interest income/other operating income (42) 38 (4) 2 Interest rate/FX risk Net interest income/other operating income 782 (830) (48) 773 925 (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 2022 2021 £m £m Balance at 1 January 129 644 Effective portion of changes in fair value: – Interest rate risk (1,160) (305) – Foreign currency risk 1,604 (54) – Equity risk — — – Interest rate/foreign currency risk (19) (514) 425 (873) Income statement transfers: – Interest rate risk 96 (73) – Foreign currency risk (1,692) 158 – Equity risk — – Interest rate/foreign currency risk (533) 273 (2,129) 358 Balance at 31 December (1,575) 129
Disclosure of detailed information about hedges [text block]	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 2022 2021 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 60,783 — (2,640) (653) (2,707) 58,455 — 80 491 (1,092) Other financial assets at amortised cost 156 — (12) 2 (14) 160 — 2 3 (12) Reverse repurchase agreements – non trading 4,045 — (5) (1) — 9,570 — (5) — (6) Other financial assets at FVOCI 2,325 (200) — 35 (227) 3,728 23 — 47 (112) Deposits by customers (1,739) 24 5 — 33 (1,665) (46) — (44) 104 Deposits by banks — — — — — — — — — — Debt securities in issue (4,735) 321 (94) (172) 528 (2,567) (140) (114) (185) 235 Subordinated liabilities (250) (27) (6) (63) 54 (293) (75) (8) (70) 49 Interest rate/FX risk: Other financial assets at FVOCI 237 (21) — 1 (9) 227 — — 1 (20) Debt securities in issue (290) (18) — (37) 27 (423) (55) — (47) 55 Subordinated liabilities 1 1 — 1 (1) 2 2 — 2 (1) 60,533 80 (2,752) (887) (2,316) 67,194 (291) (45) 198 (800) Group 2022 2021 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 935 (1,010) (1) 235 (135) (2) Cash and balances at central banks 233 (274) (106) 71 (79) — Reverse repurchase agreements - non trading — — — — — — Deposits by banks (8) 7 — (1) 1 — Debt securities in issue — — — — — — Repurchase agreements - non trading — — — — — — FX risk: Other financial assets at FVOCI — (6) — (195) (1) — Not applicable – highly probable forecast transactions (349) 2 — 149 1 — Deposits by customers (167) (2) — 9 9 10 Deposits by banks — — — — — — Debt securities in issue (1,051) (17) (2) 85 57 (4) Repurchase agreements - non trading (37) — — 6 — — Equity risk: Other liabilities — — — — — — Interest rate/FX risk: Debt securities in issue/loans and advances to customers 56 (170) (3) 410 105 (4) Deposits by customers — (74) — 93 38 — Subordinated liabilities/loans and advances to customers (37) (31) 77 11 133 80 (425) (1,575) (35) 873 129 80

Other Financial Assets at Fai_2

Other Financial Assets at Fair Value Through Profit or Loss (Tables)	12 Months Ended
	Dec. 31, 2022
Financial assets at fair value through profit or loss [abstract]
Summary of Other Financial Assets at Fair Value Through Profit or Loss	Group 2022 2021 £m £m Loans and advances to customers: Loans to housing associations 4 12 Other loans 41 62 45 74 Debt securities 84 111 129 185

Loans and Advances to Custome_2

Loans and Advances to Customers (Tables)	12 Months Ended
	Dec. 31, 2022
Net Loans And Advances To Customers [Abstract]
Summary of Net Loans and Advances to Customers	Group 2022 2021 £m £m Loans secured on residential properties 184,317 174,712 Corporate loans 19,057 19,282 Finance leases 4,645 3,916 Other unsecured loans 7,742 9,404 Accrued interest and other adjustments 688 452 Amounts due from fellow Banco Santander subsidiaries and joint ventures 4,220 3,175 Amounts due from Santander UK Group Holdings plc — 6 Loans and advances to customers 220,669 210,947 Credit impairment loss allowances on loans and advances to customers (931) (828) Residual value and voluntary termination provisions on finance leases (22) (25) Net loans and advances to customers 219,716 210,094
Disclosure of Finance Lease and Hire Purchase Contract Receivables	Finance lease and hire purchase contract receivables may be analysed as follows: Group 2022 2021 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 1,493 (182) 1,311 1,906 (5) 1,901 Later than one year and not later than two years 1,367 (168) 1,199 1,324 (200) 1,124 Later than two years and not later than three years 1,190 (147) 1,043 771 (141) 630 Later than three years and not later than four years 1,044 (129) 915 343 (82) 261 Later than four years and not later than five years 143 (18) 125 38 (38) — Later than five years 59 (7) 52 — — — 5,296 (651) 4,645 4,382 (466) 3,916
Disclosure of Maturity Analysis of Operating Lease Payments	At 31 December 2022 and 2021 , the Santander UK group had contracted with lessees for the following future undiscounted minimum lease payments receivable under operating leases. Group 2022 2021 £m £m No later than one year 31 31 Later than one year and not later than two years 27 27 Later than two years and not later than three years 22 21 Later than three years and not later than four years 13 15 Later than four years and not later than five years 11 11 Later than five years 21 28 125 133

Securitisations and Covered B_2

Securitisations and Covered Bonds (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure Of Securitisations And Covered Bonds [Abstract]
Disclosure of Analysis of Securitisations and Covered Bonds	Gross assets External notes in issue Notes issued to Santander UK plc/subsidiaries as collateral 2022 2021 2022 2021 2022 2021 £m £m £m £m £m £m Mortgage-backed master trust structures: - Holmes 1,646 2,294 790 430 176 183 - Fosse 2,028 2,154 100 288 1,365 1,402 3,674 4,448 890 718 1,541 1,585 Other asset-backed securitisation structures: - Motor 6 38 7 41 — — Total securitisation programmes 3,680 4,486 897 759 1,541 1,585 Covered bond programmes – Euro 35bn Global Covered Bond Programme 21,304 15,713 15,205 12,760 — — Total securitisation and covered bond programmes 24,984 20,199 16,102 13,519 1,541 1,585
Summary of Issuances and Redemptions of Securitisation and Covered Bond Programme	The following table sets out the internal and external issuances and redemptions in 2022 and 2021 for each securitisation and covered bond programme. Internal issuances External issuances Internal redemptions External redemptions 2022 2021 2022 2021 2022 2021 2022 2021 £bn £bn £bn £bn £bn £bn £bn £bn Mortgage-backed master trust structures: – Holmes — — 0.6 — 0.1 0.2 0.2 0.4 – Fosse — — — — — — 0.2 — – Langton — — — — — 2.4 — — Other asset-backed securitisation structures: – Motor — — — — — 0.1 — 0.1 – Auto ABS UK Loans — — 0.1 0.1 Covered bond programme — — 4.2 — 0.1 — 1.7 6.5 — — 4.8 — 0.2 2.8 2.1 7.1

Transfers of Financial Assets_2

Transfers of Financial Assets Not Qualifying for Derecognition (Tables)	12 Months Ended
	Dec. 31, 2022
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 2022 2021 Assets Liabilities Assets Liabilities Nature of transaction £m £m £m £m Sale and repurchase agreements 120 (128) 171 (172) Securities lending agreements 2,871 (2,509) 1,892 (1,742) Securitisations (See Notes 14 and 26) 3,680 (897) 4,486 (759) 6,671 (3,534) 6,549 (2,673)

Reverse Repurchase Agreements_2

Reverse Repurchase Agreements - Non Trading (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure Of Reserve Repurchase Agreements Non-Trading [Abstract]
Summary of Reverse Repurchase Agreements - Non Trading	Group 2022 2021 £m £m Agreements with banks 885 447 Agreements with customers 6,463 12,236 7,348 12,683

Other Financial Assets at Amo_2

Other Financial Assets at Amortised Cost (Tables)	12 Months Ended
	Dec. 31, 2022
Financial assets at fair value through profit or loss [abstract]
Summary of Other Financial Assets at Amortised Cost	Group 2022 2021 £m £m Asset backed securities 94 443 Debt securities 62 63 0 156 506

Financial Assets at Fair Valu_2

Financial Assets at Fair Value Through Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2022
Financial assets at fair value through other comprehensive income [abstract]
Summary of Financial Assets at Fair Value Through Other Comprehensive Income	Group 2022 2021 £m £m Debt securities 6,024 5,833 Loans and advances to customers — 18 6,024 5,851

Interests in Other Entities (Ta

Interests in Other Entities (Tables)	12 Months Ended
	Dec. 31, 2022
Investments accounted for using equity method [abstract]
Schedule of Interests in Other Entities	Group 2022 2021 £m £m Subsidiaries — — Joint Ventures 252 201 0 252 201

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure of detailed information about intangible assets [abstract]
Schedule of Goodwill	a) Goodwill Group Cost Accumulated impairment Carrying amount £m £m £m At 31 December 2021 and 1 January 2022 1,269 (66) 1,203 Movement in the period — (4) (4) At 31 December 2022 1,269 (70) 1,199
Schedule of Goodwill for Cash Generating Units	Basis of the recoverable amount The recoverable amount of all CGUs was determined based on its value in use (VIU) methodology at each testing date. For each CGU, the VIU is calculated by discounting management’s cash flow projections for the CGU. The cash flow projections also take account of increased internal capital allocations needed to achieve internal and regulatory capital targets including the leverage ratio. The key assumptions used in the VIU calculation for each CGU are set out below. The Retail Banking segment consists of the Private Banking CGU and the rest of Retail Banking, known as the Personal Financial Services CGU. Carrying amount of Goodwill by CGU and key assumptions in the VIU calculation Goodwill Discount rate Growth rate beyond initial cash flow projections 2022 2021 2022 2021 2022 2021 CGU £m £m % % % % Personal Financial Services 1,169 1,169 16.6 13.6 1.6 1.6 Private Banking 30 30 15.3 16.3 1.6 1.6 Other — 4 13.6 1.6 1,199 1,203
Disclosure of Reasonably Possible Changes in Key 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 – Higher interest rate environment impact on customer affordability – Customer remediation and regulatory action outcomes – Uncertain regulatory capital requirements. – Cash flow projections decrease by 5% (2021: 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 (2021: 100 basis points). At 31 December 2022 and 31 December 2021, 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 a reduction in headroom as follows. Reduction in headroom 2022 2021 CGU Reasonably possible change £m £m Personal Financial Services Cash flow projections decrease by 5% (2021: 5%) (538) (455) Discount rate increases by 100 basis points (2021: 100 basis points) (887) (943) 2022 Carrying value Value in use Headroom Increase in discount rate Decrease in cash flows CGU £m £m £m bps % Personal Financial Services 8,860 10,752 1,892 239 18 2021 Personal Financial Services 8,433 9,100 667 68 7
Disclosure of Intangible Assets	b) Other intangibles Group Cost Accumulated Carrying amount £m £m £m At 1 January 2022 1,334 (992) 342 Additions 112 — 112 Disposals (185) 185 — Charge — (100) (100) Impairment — (3) (3) At 31 December 2022 1,261 (910) 351 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

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2022
Property, plant and equipment [abstract]
Disclosure of Detailed Information about Property, Plant and Equipment	Group Property Office fixtures and equipment Computer software Operating lease assets Right-of-use assets Total (1) £m £m £m £m £m £m Cost: At 1 January 2022 978 1,049 434 755 254 3,470 Additions 61 86 — 185 38 370 Reclassification to assets held for sale (98) (13) — — — (111) Disposals (52) (299) (362) (218) (25) (956) At 31 December 2022 889 823 72 722 267 2,773 Accumulated depreciation: At 1 January 2022 334 857 434 160 137 1,922 Charge for the year (2) 18 68 1 73 19 179 Impairment during the year 8 2 — — — 10 Reclassification to assets held for sale (49) (13) — — — (62) Disposals (41) (296) (363) (88) (1) (789) At 31 December 2022 270 618 72 145 155 1,260 Carrying amount 619 205 — 577 112 1,513 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 (2) 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 Carrying amount 644 192 — 595 117 1,548

Other Financial Liabilities a_2

Other Financial Liabilities at Fair Value Through Profit or Loss (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure of financial liabilities [abstract]
Summary of Other Financial Liabilities at Fair Value Through Profit or Loss	Group 2022 2021 £m £m US$30bn Euro Medium Term Note Programme 3 5 Structured Notes Programmes 375 413 Eurobonds 102 142 Structured deposits 321 223 Collateral and associated financial guarantees 2 20 803 803

Deposits by Customers (Tables)

Deposits by Customers (Tables)	12 Months Ended
	Dec. 31, 2022
Deposits from customers [abstract]
Schedule of Deposits by Customers	Group 2022 2021 £m £m Demand and time deposits (1) 189,587 185,843 Amounts due to other Santander UK Group Holdings plc subsidiaries 67 59 Amounts due to Santander UK Group Holdings plc (2) 4,759 5,874 Amounts due to fellow Banco Santander subsidiaries and joint ventures 1,155 1,150 195,568 192,926 (1) Includes equity index-linked deposits of £408m (2021: £549m). The capital amount guaranteed/protected and the amount of return guaranteed in respect of the equity index-linked deposits were £408m and £2m (2021: £549m 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, 2022
Disclosure Of Deposits From Banks [Abstract]
Schedule of Deposits by Banks	Group 2022 2021 £m £m Items in the course of transmission 701 414 Deposits held as collateral 1,741 931 Other deposits (1) 26,082 32,507 Amounts due to Santander UK subsidiaries 1 3 28,525 33,855

Repurchase Agreements - Non T_2

Repurchase Agreements - Non Trading (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure Of Repurchase Agreements [Abstract]
Summary of Repurchase Agreements - Non Trading	Group 2022 2021 £m £m Agreements with banks (1) 50 43 Agreements with customers (1) 7,932 11,675 7,982 11,718 (1) In 2022, an administrative error was identified where some repurchase agreements had been incorrectly classified as 'agreements with banks, rather than 'agreements with customers'. As a result, the balance for 2021 has been restated to reclassify £4,102m from 'agreements with banks' to 'agreements with customers'.

Debt Securities in Issue (Table

Debt Securities in Issue (Tables)	12 Months Ended
	Dec. 31, 2022
Debt Securities In Issue [Abstract]
Summary of Debt Securities in Issue	Group 2022 2021 £m £m Medium-term notes: – US$30bn Euro Medium Term Note Programme 739 1,405 – Euro 30bn Euro Medium Term Note Programme 3,211 1,261 - US SEC-registered Debt Programme - Santander UK plc 6,694 4,185 10,644 6,851 Euro 35bn Global Covered Bond Programme 15,205 12,760 US$20bn Commercial Paper Programmes 1,851 2,704 Certificates of deposit 2,874 2,387 Credit linked notes 60 59 Securitisation programmes 897 759 31,531 25,520

Subordinated Liabilities (Table

Subordinated Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure Of Subordinated Liabilities [Abstract]
Schedule of Subordinated Liabilities	Group 2022 2021 £m £m £325m Sterling preference shares 344 344 Undated subordinated liabilities 219 240 Dated subordinated liabilities 1,769 1,644 2,332 2,228
Disclosure of Undated Subordinated Liabilities Explanatory	Group 2022 2021 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 14 35 219 240
Disclosure of Dated Subordinated Liabilities Explanatory	Group 2022 2021 Maturity £m £m 5% Subordinated notes (US$1,500m) 2023 591 548 4.75% Subordinated notes (US$1,000m) 2025 608 541 7.95% Subordinated notes (US$1,000m) 2029 207 221 6.50% Subordinated notes 2030 22 28 5.875%Subordinated notes 2031 7 9 5.625%Subordinated notes (US$500m) 2045 334 297 1,769 1,644

Other Liabilities (Tables)

Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Subclassifications of assets, liabilities and equities [abstract]
Disclosure Of Other Liabilities Explanatory	Group 2022 2021 £m £m Lease liabilities 125 132 Other (1) 2,456 1,935 2,581 2,067 (1) For more information on amounts restated see Note 44.

Provisions (Tables)

Provisions (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure of other provisions [abstract]
Summary of Provisions Reconciliation	Group Customer remediation Litigation and other regulatory Bank Levy Property ECL on undrawn facilities and guarantees Restructuring Other Total £m £m £m £m £m £m £m £m At 1 January 2022 44 166 1 74 38 28 13 364 Additional provisions (See Note 8) 77 137 47 — 36 23 196 516 Provisions released (See Note 8) (18) (18) (4) (7) — — (11) (58) Utilisation and other (13) (149) (59) (20) — (30) (191) (462) Recharge (1) — — 18 — — — — 18 At 31 December 2022 90 136 3 47 74 21 7 378

Retirement Benefit Plans (Table

Retirement Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure of net defined benefit liability (asset) [abstract]
Summary of Retirement Benefit Plans	The amounts recognised in the balance sheet were as follows: Group 2022 2021 £m £m Assets/(liabilities) Funded defined benefit pension scheme - surplus 1,050 1,572 Unfunded pension and post-retirement medical benefits (25) (37) Total net assets 1,025 1,535
Disclosure of Pension Remeasurements Included in Other Comprehensive income	Remeasurement losses/(gains) recognised in other comprehensive income in the year were as follows: Group 2022 2021 2020 £m £m £m Pension remeasurement 722 (1,264) 505
Disclosure of Total Defined Benefit Plan Amount Charged to the Income Statement	The total amount charged to the income statement was as follows: Group 2022 2021 2020 £m £m £m Net interest income (30) (5) (10) Current service cost 30 38 36 Past service and GMP costs — — 1 Past service curtailment costs 0 5 — Administration costs 9 8 8 9 46 35
Summary of Amounts Recognised in Other Comprehensive Income	The amounts recognised in other comprehensive income were as follows: Group 2022 2021 2020 £m £m £m Return on plan assets (excluding amounts included in net interest expense) 5,527 (454) (1,328) Actuarial (gains)/losses arising from changes in demographic assumptions (122) (17) 34 Actuarial (gains)/losses arising from experience adjustments 481 (19) (141) Actuarial (gains)/losses arising from changes in financial assumptions (5,164) (774) 1,940 Pension remeasurement 722 (1,264) 505
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 2022 2021 £m £m At 1 January (12,878) (13,887) Current service cost paid by Santander UK plc (29) (29) Current service cost paid by subsidiaries (1) (9) Current service cost paid by fellow Banco Santander subsidiaries — — Interest cost (241) (188) Employer salary sacrifice contributions (2) (9) Past service cost — — Past service curtailment costs — (5) GMP equalisation cost — — Remeasurement due to actuarial movements arising from: – Changes in demographic assumptions 122 17 – Experience adjustments (481) 19 – Changes in financial assumptions 5,164 774 Benefits paid 413 398 Derecognition of pension scheme liabilities arising from the sale of PSA — 41 At 31 December (7,933) (12,878)
Disclosure of Movements in Fair Value of Schemes' Assets	Movements in the fair value of the schemes’ assets were as follows: Group 2022 2021 £m £m At 1 January 14,413 13,979 Interest income 271 193 Contributions paid by employer and scheme members 223 246 Contributions paid by fellow Banco Santander subsidiaries — — Administration costs paid (9) (8) Return on plan assets (excluding amounts included in net interest expense) (5,527) 454 Benefits paid (413) (398) Derecognition of pension scheme assets arising from the sale of PSA — (53) At 31 December 8,958 14,413
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 2022 £m % £m % £m % technique Overseas equities 0 0 1,172 13 1,172 13 A,C Corporate bonds 1,991 22 244 3 2,235 25 A,C Government fixed interest bonds 1,138 13 — — 1,138 13 A Government index-linked bonds 5,525 62 — — 5,525 62 A Property — — 1,202 13 1,202 13 B Derivatives — — (78) (1) (78) (1) A Cash — — 1,340 15 1,340 15 A Repurchase agreements (1) — — (4,312) (48) (4,312) (48) A Infrastructure — — 426 5 426 5 B,C Annuities — — 293 3 293 3 D Longevity swap — (12) 0 (12) 0 D Other — — 29 0 29 0 C 8,654 97 304 3 8,958 100 2021 UK equities 38 0 — — 38 0 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 (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 Scheme were: Group 2022 2021 2020 % % % To determine benefit obligations (1) : – Discount rate for scheme liabilities 4.9 1.9 1.3 – General price inflation 3.1 3.4 3.0 – General salary increase 1.0 1.0 1.0 – Expected rate of pension increase 3.0 3.2 2.9 Years Years Years Longevity at 60 for current pensioners, on the valuation date: – Males 27.4 27.5 27.5 – Females 30.1 30.1 30.0 Longevity at 60 for future pensioners currently aged 40, on the valuation date: – Males 28.9 29.0 29.0 – Females 31.6 31.6 31.5 (1) The discount rate and inflation related assumptions set out in the table above 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. Change in pension obligation at year end from (Decrease)/increase 2022 2021 2022 2021 Assumption £m £m Discount rate 50 bps increase 25 bps increase (501) (571) General price inflation 50 bps increase 25 bps increase 374 392 Mortality Each additional year of longevity assumed Each additional year of longevity assumed 203 478
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 2023 416 2024 360 2025 382 2026 404 2027 425 Five years ending 2032 2,325

Contingent Liabilities and Co_2

Contingent Liabilities and Commitments (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure of contingent liabilities [abstract]
Summary of Contingent Liabilities and Commitments	Group 2022 2021 £m £m Guarantees given to third parties 448 363 Formal standby facilities, credit lines and other commitments 31,388 37,346 31,836 37,709

Share Capital (Tables)

Share Capital (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure of classes of share capital [abstract]
Schedule of Share Capital Issued and Fully Paid	Group Ordinary shares of £0.10 each Total Issued and fully paid share capital No. £m £m At 31 December 2021, 1 January 2022 and 31 December 2022 31,051,768,866 3,105 3,105
Summary of Share Premium	Group 2022 2021 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, 2022
Disclosure of classes of share capital [abstract]
Summary of Other Equity Instruments	Group Interest rate 2022 2021 % Next call date £m £m £300m Step-up Callable Perpetual Reserve Capital Instruments 7.037 February 2026 — 235 AT1 securities: - £500m Perpetual Capital Securities 6.75 June 2024 496 496 - £750m Perpetual Capital Securities 7.375 June 2022 — 750 - £500m Perpetual Capital Securities 6.30 March 2025 500 500 - £210m Perpetual Capital Securities 4.25 March 2026 210 210 - £750m Perpetual Capital Securities 6.50 June 2027 750 — 1,956 2,191

Notes to Cash Flows (Tables)

Notes to Cash Flows (Tables)	12 Months Ended
	Dec. 31, 2022
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 Balance sheet line item Debt securities in issue Subordinated liabilities Other equity instruments Lease liabilities Dividends paid Total 2022 £m £m £m £m £m £m At 1 January 25,520 2,228 2,191 132 — 30,071 Proceeds from issue of debt securities 4,778 — — — — 4,778 Repayment of debt securities (3,036) — — — — (3,036) Repayment of subordinated liabilities — (40) — — — (40) Issue of other equity instruments — — 750 — — 750 Repurchase of other equity instruments — — (985) — — (985) Principal elements of lease payments — — — (26) — (26) Dividends paid — — — — (1,164) (1,164) Liability-related other changes 3,155 2 — 19 — 3,176 Non-cash changes: – Unrealised foreign exchange 1,554 87 — — — 1,641 – Other changes (440) 55 — — 1,164 779 At 31 December 31,531 2,332 1,956 125 — 35,944 2021 At 1 January 35,566 2,556 2,191 97 — 40,410 Proceeds from issue of debt securities 2,872 — — — — 2,872 Repayment of debt securities (11,910) — — — — (11,910) Repayment of subordinated liabilities — (4) — — — (4) Issue of other equity instruments (2) — — 210 — — 210 Repurchase of other equity instruments (2) — — (210) — — (210) Principal elements of lease payments — — — (25) — (25) Dividends paid (1) — — — — (1,505) (1,505) Liability-related other changes (447) (4) — 60 — (391) Non-cash changes: – Unrealised foreign exchange (806) 6 — — — (800) – Other changes 245 (326) — — 1,505 1,424 At 31 December 25,520 2,228 2,191 132 — 30,071 2020 At 1 January 41,129 3,528 2,191 137 — 46,985 Proceeds from issue of debt securities 5,602 — — — — 5,602 Repayment of debt securities (11,378) — — — — (11,378) Repayment of subordinated liabilities — (659) — — — (659) Principal elements of lease payments — — — (45) — (45) Dividends paid — — — — (292) (292) Liability-related other changes (250) (10) — 5 — (255) Non-cash changes: – Unrealised foreign exchange 376 22 — — — 398 – Other changes 87 (325) — — 292 54 At 31 December 35,566 2,556 2,191 97 — 40,410 (1) Dividends paid have been restated for 2021 from the £1,494m previously disclosed to £1,505m due to an administrative error. (2) Issue and Repurchase of other equity instruments and Other Equity Instrument Other changes have been restated for 2021 from £450m, £500m and £50m previously disclosed to £210m for both Issue and Repurchase of Other equity instrument and £nil for Other changes due to an administrative error.

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, 2022
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 2022 2021 £m £m On-balance sheet: Cash and balances at central banks 1,330 1,580 Loans and advances to banks 130 284 Loans and advances to customers - securitisations and covered bonds (See Note 14) 24,155 19,432 Loans and advances to customers - other 32,001 41,936 Other financial assets at amortised cost 48 — Financial assets at fair value through other comprehensive income 4,365 4,363 Total on-balance sheet 62,029 67,595 Total off-balance sheet 9,146 14,449
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 2022 2021 £m £m On-balance sheet: Deposits by banks 1,741 931 Total on-balance sheet 1,741 931 Total off-balance sheet 10,141 17,781

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
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. 2022 2021 Number of options Weighted average exercise price Number of options Weighted average exercise price ‘000 £ ‘000 £ Outstanding at 1 January 25,993 2.25 21,162 2.32 Granted 13,068 1.89 9,414 2.43 Exercised (242) 1.69 (48) 1.86 Forfeited/expired (8,831) 2.59 (4,535) 2.95 Outstanding at 31 December 29,988 2.00 25,993 2.25 Exercisable at 31 December 3,439 3.22 1,321 2.75
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 2022 and 2021. 2022 2021 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 1.79 3 1.65 £2 to £3 2 2.56 3 2.81 £3 to £4 1 3.46 1 3.38 £4 to £5 0 4.02 1 4.02

Transactions with Directors a_2

Transactions with Directors and Other Key Management Personnel (Tables)	12 Months Ended
	Dec. 31, 2022
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 (KMP) of the Santander UK group is set out in aggregate below. 2022 2021 2020 Directors’ remuneration £ £ £ Salaries and fees (1) 4,696,699 5,488,388 5,361,444 Performance-related payments (2) 3,701,569 3,431,294 933,703 Other fixed remuneration (allowances and non-cash benefits) 906,201 929,935 1,107,348 Expenses 27,715 17,097 6,772 Total remuneration 9,332,184 9,866,714 7,409,267 Compensation for loss of office (3) 172,856 356,054 — 2022 2021 2020 Directors' and Other Key Management Personnel compensation £ £ £ Short-term employee benefits (2) 22,627,595 20,553,672 16,663,726 Post-employment benefits 1,026,848 988,829 1,821,548 Compensation for loss of office (3) 1,713,256 356,054 263,097 Total compensation 25,367,699 21,898,555 18,748,371 (1) 2021 and 2020 salaries and fees have been restated to reflect fees earned in respect of services rendered during the year. Fees of £7,463 have been reallocated from 2021 to 2020. (2) 2021 and 2020 Performance related payments have been restated to account for 36% of Directors and selected KMP awards being subject to long-term metrics. Performance against these metrics can decrease the award to 0% and may not increase the award value. Previously, the value of the Variable Pay Plan awards have been disclosed in full which has resulted in an overstatement post the application of performance conditions. The value of the 2021 and 2020 Variable Pay Plan awards subject to long-term performance conditions will be disclosed after the close of the performance period upon vesting. In addition to the remuneration in the table above, no grants of shares in Banco Santander SA were made to Directors and KMPs as part of buy-outs of deferred performance-related payments in connection with previous employment in 2022 (2021: one to a KMP with a value of £107,225, of which £25,413 vested in the year, 2020: one to a Director of £1,293,678 of which £242,605 vested in the year and one to a KMP of £924,133 of which £60,500 vested in the year). A payment of guaranteed variable remuneration of £660,648 was made to a Director in 2022 ( 2021 : £nil, 2020: £nil) part of which was awarded in Banco Santander SA shares. The element of the guaranteed remuneration which vested in respect of 2022 has been disclosed above, 40%, and the remaining 60% will be disclosed upon vesting. (3) Compensation for loss of office of £172,856 was paid in 2022 to two Directors (2021: £356,054 for two Directors, 2020: £nil). Compensation for loss of office was paid to three KMPs in 2022 totalling £1,540,400 (2021: £nil , 2020: one KMP: £263,097).
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. 2022 2021 No. £000 No. £000 Secured loans, unsecured loans and overdrafts At 1 January 6 360 12 3,640 Net movements 4 511 (6) (3,280) At 31 December 10 871 6 360 Deposit, bank and instant access accounts and investments At 1 January 21 6,552 23 8,195 Net movements 2 (2,419) (2) (1,643) At 31 December 23 4,133 21 6,552

Related Party Disclosures (Tabl

Related Party Disclosures (Tables)	12 Months Ended
	Dec. 31, 2022
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 2022 2021 2020 2022 2021 2020 2022 2021 2022 2021 £m £m £m £m £m £m £m £m £m £m Ultimate parent (710) (164) (119) 47 33 105 1,363 816 (1,673) (1,150) Immediate parent (6) (6) (7) 308 263 316 1 7 (14,390) (10,935) Fellow subsidiaries (69) (57) (58) 177 163 157 108 159 (348) (534) Associates & joint ventures (76) (34) (29) 17 4 — 4,151 3,075 (973) (918) (861) (261) (213) 549 463 578 5,623 4,057 (17,384) (13,537)

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure Of Fair Value Measurement Of Assets And Liabilities [Abstract]
Disclosure of Analysis of Fair Value of Financial Instruments Carried at Amortised Cost	Group 2022 2021 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 — — 212,479 212,479 219,716 — — 212,811 212,811 210,094 Loans and advances to banks — 992 — 992 992 — 1,169 — 1,169 1,169 Reverse repurchase agreements - non trading — 7,341 — 7,341 7,348 — 12,453 226 12,679 12,683 Other financial assets at amortised cost 144 — — 144 156 164 348 — 512 506 144 8,333 212,479 220,956 228,212 164 13,970 213,037 227,171 224,452 Liabilities Deposits by customers — 51 195,483 195,534 195,568 — 48 192,898 192,946 192,926 Deposits by banks — 27,979 55 28,034 28,525 — 33,770 85 33,855 33,855 Repurchase agreements - non trading — 7,982 — 7,982 7,982 — 11,718 — 11,718 11,718 Debt securities in issue 2,574 26,349 1,582 30,505 31,531 963 23,926 1,218 26,107 25,520 Subordinated liabilities 19 2,358 224 2,601 2,332 37 2,350 238 2,625 2,228 2,593 64,719 197,344 264,656 265,938 1,000 71,812 194,439 267,251 266,247
Disclosure of Analysis of Fair Value 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 2022 and 31 December 2021, analysed by their levels in the fair value hierarchy - Level 1, Level 2 and Level 3. Group 2022 2021 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 — 2,044 — 2,044 — 1,193 1 1,194 A Interest rate contracts — 2,399 7 2,406 — 1,547 — 1,547 A & C Equity and credit contracts — 100 30 130 — 116 45 161 B & D Netting — (2,173) — (2,173) — (1,221) — (1,221) — 2,370 37 2,407 — 1,635 46 1,681 Other financial assets at FVTPL Loans and advances to customers — — 45 45 — — 74 74 A Debt securities — 12 72 84 — — 111 111 A, B & D — 12 117 129 — — 185 185 Financial assets at FVOCI Debt securities 5,996 28 — 6,024 5,833 — — 5,833 D Loans and advances to customers — — — — — — 18 18 D 5,996 28 — 6,024 5,833 — 18 5,851 Total assets at fair value 5,996 2,410 154 8,560 5,833 1,635 249 7,717 Liabilities Derivative financial instruments Exchange rate contracts — 471 — 471 — 506 — 506 A Interest rate contracts — 2,624 4 2,628 — 1,436 2 1,438 A & C Equity and credit contracts — 17 8 25 — 24 30 54 B & D Netting — (2,173) — (2,173) — (1,221) — (1,221) — 939 12 951 — 745 32 777 Other financial liabilities at FVTPL Debt securities in issue — 477 3 480 — 555 5 560 A Structured deposits — 321 — 321 — 223 — 223 A Collateral and associated financial guarantees — 2 — 2 — 19 1 20 D — 800 3 803 — 797 6 803 Total liabilities at fair value — 1,739 15 1,754 — 1,542 38 1,580
Summary of Fair Value Adjustment	The fair value adjustments are set out in the following table: 2022 2021 £m £m Risk-related: - Bid-offer and trade specific adjustments (12) (9) - Uncertainty 12 20 - Credit risk adjustment 2 6 - Funding fair value adjustment 1 3 3 20 Day One profit 1 — 4 20
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) 2022 2021 2022 2021 2020 Balance sheet line item Category Financial instrument product type £m £m £m £m £m 1. Derivative assets Equity and credit contracts Reversionary property interests 30 45 (8) — 3 2. FVTPL assets Loans and advances to customers Roll-up mortgage portfolio 28 48 (18) (5) 6 3. FVTPL assets Loans and advances to customers Other loans 17 26 (4) (2) 3 4. FVTPL assets Debt securities Reversionary property securities 70 91 — 5 6 5. FVTPL assets Debt securities Credit linked notes 2 20 4 (5) (16) 6. FVOCI assets Loans and advances to customers Other loans — 18 — (3) (4) 7. Derivative liabilities Equity contracts Property options and forwards (8) (30) 4 (1) (3) 8. FVTPL liabilities Financial guarantees Credit protection guarantee — (1) 1 6 16 139 217 (21) (5) 11 Other Level 3 assets 7 1 6 (1) 7 Other Level 3 liabilities (7) (7) (2) 2 (1) Total net assets 139 211 Total income/(expense) (17) (4) 17
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 2022 and 2021: Assets Liabilities Derivatives Other financial assets at FVTPL Financial assets at FVOCI Total Derivatives Other financial liabilities at FVTPL Total £m £m £m £m £m £m £m At 1 January 2022 46 185 18 249 (32) (6) (38) Total (losses)/gains recognised: Fair value movements (2) (2) (18) — (20) 2 1 3 Foreign exchange and other movements — — — — — — — Transfers in — — — — (2) — (2) Transfers out — — — — — — — Netting (1) — (8) — (8) — — — Sales — (5) — (5) — — — Settlements (7) (37) (18) (62) 20 2 22 At 31 December 2022 37 117 — 154 (12) (3) (15) Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the year(2) (2) (18) — (20) 2 1 3 At 1 January 2021 68 208 21 297 (32) (8) (40) Total gains/(losses) recognised: - Fair value movements (1) (7) (3) (11) — 7 7 Netting (1) — 23 — 23 — (5) (5) 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 year (1) (7) (3) (11) — 7 7 (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.
Disclosure of 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 Weighted average Shift 2022 £m Assumption description £m £m 1. Derivative assets – Equity and credit contracts: 30 HPI Forward growth rate -5% to 5% 0.53 % 1 % 4 (4) – Reversionary property derivatives HPI Spot rate (2) n/a 513 10 % 4 (4) 2. FVTPL – Loans and advances to customers: 28 HPI Forward growth rate -5% to 5% 1.39 % 1 % 1 (1) – Roll-up mortgage portfolio 3. FVTPL – Loans and advances to customers: 17 Credit spreads 0.19% - 2.04% 0.98 % 20 % — — – Other loans 4. FVTPL – Debt securities: 70 HPI Forward growth rate -5% to 5% 0.53 % 1 % 1 (1) – Reversionary property securities HPI Spot rate (2) n/a 513 10 % 3 (3) 5. FVOCI - Loans and advances to customers: — Credit spreads 0.40% - 0.48% 0.48 % 20 % — — – Other loans 6. Derivative liabilities – Equity contracts: (8) HPI Forward growth rate -5% to 5% -0.92 % 1 % 1 (1) – Property options and forwards HPI Spot rate (2) n/a 491 10 % 2 (3) 2021 1. Derivative assets – Equity and credit contracts: 45 HPI Forward growth rate 0% - 5% 2.56 % 1 % 6 (6) – Reversionary property derivatives HPI Spot rate (2) n/a 483 10 % 6 (6) 2. FVTPL – Loans and advances to customers: 48 HPI Forward growth rate 0% - 5% 2.68 % 1 % 2 (2) – Roll-up mortgage portfolio 3. FVTPL – Loans and advances to customers: 26 Credit spreads 0.07% - 1.44% 0.50 % 20 % — — – Other loans 4. FVTPL – Debt securities: 91 HPI Forward growth rate 0% - 5% 2.56 % 1 % 1 (1) – Reversionary property securities HPI Spot rate (2) n/a 483 10 % 4 (4) 5. FVOCI - Loans and advances to customers: (1) 18 Credit spreads 0.15% - 0.19% 0.04 % 20 % — — – Other loans 6. 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) (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 2022 and 2021.
Disclosure of Maturity Analysis of Undiscounted Cash Flows for Financial Liabilities and Off Balance Sheet Commitments	Group On demand Not later than 3 months Later than 3 months and not later than 1 year Later than 1 year and not later than 5 years Later than 5 years Total 2022 £m £m £m £m £m £m Financial liabilities Derivative financial instruments — 206 120 496 255 1,077 Other financial liabilities at fair value through profit or loss — — 98 443 438 979 Deposits by customers 180,218 3,875 7,077 4,295 335 195,800 Deposits by banks 2,048 1,309 298 26,141 — 29,796 Repurchase agreements – non trading — 7,984 3 — — 7,987 Debt securities in issue — 5,814 1,485 16,672 9,921 33,892 Subordinated liabilities — 35 691 1,149 1,400 3,275 Lease liabilities — — 32 80 26 138 Total financial liabilities 182,266 19,223 9,804 49,276 12,375 272,944 Off-balance sheet commitments given 19,089 787 898 7,508 3,554 31,836 2021 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

Offsetting Financial Assets a_2

Offsetting Financial Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2022
Disclosure of offsetting of financial liabilities [abstract]
Summary of Information about Impact of Offsetting of Financial Assets and Liabilities	Group Amounts subject to enforceable netting arrangements 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) 2022 £m £m £m £m £m £m £m £m Assets Derivative financial assets 4,525 (2,173) 2,352 (515) (1,720) 117 55 2,407 Reverse repurchase, securities borrowing & similar agreements: – Amortised cost 8,826 (1,478) 7,348 (9) (7,339) — — 7,348 – Fair value — — — — — — — — Loans and advances to customers and banks⁽⁴⁾ 5,169 (908) 4,261 — — 4,261 216,447 220,708 18,520 (4,559) 13,961 (524) (9,059) 4,378 216,502 230,463 Liabilities Derivative financial liabilities 3,085 (2,173) 912 (515) (115) 282 39 951 Repurchase, securities lending & similar agreements: – Amortised cost 9,460 (1,478) 7,982 (9) (7,973) — — 7,982 – Fair value — — — — — — — — Deposits by customers and banks⁽⁴⁾ 8,077 (908) 7,169 — — 7,169 216,924 224,093 20,622 (4,559) 16,063 (524) (8,088) 7,451 216,963 233,026 2021 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 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 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 (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, 2022
Interest Rate Benchmark Reform [Abstract]
Schedule of Amounts Affected by IBOR Reform	Group 2022 GBP (2) LIBOR USD (2) LIBOR Other (2) Total £m £m £m £m Assets Derivatives (1) — 1,665 — 1,665 Financial assets at amortised cost 76 57 — 133 76 1,722 — 1,798 Liabilities Derivatives (1) 66 1,846 — 1,912 66 1,846 — 1,912 Off-balance sheet commitments given 2 — — 2 2021 Assets Derivatives (1) — 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) 338 1,831 — 2,169 Other financial liabilities at fair value through profit and loss — 5 — 5 Financial liabilities at amortised cost 34 185 — 219 372 2,021 — 2,393 Off-balance sheet commitments given 338 59 — 397
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 2022 2021 USD Total USD Total £m £m £m £m Total notional value of hedging instruments – Cash flow hedges 2,906 2,906 2,586 2,586 – Fair value hedges 178 178 160 160 3,084 3,084 2,746 2,746 Maturing after cessation date (1) – Cash flow hedges 2,906 2,906 2,586 2,586 – Fair value hedges 178 178 160 160 3,084 3,084 2,746 2,746

Discontinued Operations and A_2

Discontinued Operations and Assets and Liabilities Held for Sale (Tables)	12 Months Ended
	Dec. 31, 2022
Discontinued Operations and Assets and Liabilities Held for Sale [Abstract]
Disclosure of Financial Performance Relating to Discontinued Operations	The financial performance and cash flow information relating to the discontinued operations were as follows: For the years ended 31 December 2022 2021 2020 £m £m £m Net interest income — 32 55 Net fee and commission income — 35 66 Other operating income — 2 2 Total operating income — 69 123 Operating expenses before credit impairment (charges)/write-backs, provisions and charges — (33) (62) Credit impairment (charges)/write-backs — 11 (7) Provisions for other liabilities and charges — (4) (9) Total operating credit impairment (charges)/write-backs, provisions and charges — 7 (16) Profit from discontinued operations before tax — 43 45 Tax on profit from discontinued operations — (12) (13) Profit from discontinued operations after tax — 31 32
Disclosure of Assets Classified as Held for Sale	At 31 December 2022, assets held for sale comprised: 2022 2021 £m £m Assets Property, plant and equipment 49 — Total assets held for sale 49 —

Credit Risk - Disclosure of Exp

Credit Risk - Disclosure of Exposures to Credit Risk by Segment (Details) - Maximum £ in Millions	12 Months Ended
	Dec. 31, 2022 GBP (£)
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, 2022
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 or 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 CRD IV regulatory capital rules and gives us another view of credit risk. It is the product of the probability of default, exposure at default and loss given default, and we include direct and indirect costs. We base it on our risk models and our assessment of each customer’s credit quality. 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 impairment accounting policy, 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, 2022	Dec. 31, 2021
Upside 1
Disclosure of credit risk exposure [line items]
GDP growth, year 1	7.50%	(9.70%)
GDP growth, year 2	4.40%	7%
GDP growth, year 3	(1.00%)	4.80%
GDP growth, year 4	0.80%	2.20%
GDP growth, year 5	2%	1.90%
GDP growth, year 6	2%	2.10%
Bank of England base rate, year 1	0.25%	0.10%
Bank of England base rate, year 2	3.50%	0.25%
Bank of England base rate, year 3	3.75%	0.75%
Bank of England base rate, year 4	3%	0.75%
Bank of England base rate, year 5	2.50%	1.25%
Bank of England base rate, year 6	2.25%	1.75%
House price growth, year 1	8.70%	6.90%
House price growth, year 2	7.60%	5.40%
House price growth, year 3	(8.80%)	(0.80%)
House price growth, year 4	(4.30%)	(2.00%)
House price growth, year 5	0.60%	1%
House price growth, year 6	4.10%	3.80%
Unemployment rate, year 1	4%	5.20%
Unemployment rate, year 2	3.70%	4.40%
Unemployment rate, year 3	4.70%	4.40%
Unemployment rate, year 4	4.50%	4.20%
Unemployment rate, year 5	4.50%	3.90%
Unemployment rate, year 6	4.40%	3.70%
Base case
Disclosure of credit risk exposure [line items]
GDP growth, year 1	7.50%	(9.70%)
GDP growth, year 2	4.40%	6.90%
GDP growth, year 3	(1.30%)	4.60%
GDP growth, year 4	0.50%	1.70%
GDP growth, year 5	1.60%	1.50%
GDP growth, year 6	1.50%	1.60%
Bank of England base rate, year 1	0.25%	0.10%
Bank of England base rate, year 2	3.50%	0.25%
Bank of England base rate, year 3	4%	0.75%
Bank of England base rate, year 4	3.25%	0.75%
Bank of England base rate, year 5	2.75%	0.75%
Bank of England base rate, year 6	2.50%	0.75%
House price growth, year 1	8.70%	6.90%
House price growth, year 2	7%	5%
House price growth, year 3	(10.00%)	2%
House price growth, year 4	0%	2%
House price growth, year 5	2%	2%
House price growth, year 6	3%	2%
Unemployment rate, year 1	4%	5.20%
Unemployment rate, year 2	3.80%	4.70%
Unemployment rate, year 3	4.70%	4.50%
Unemployment rate, year 4	5.10%	4.40%
Unemployment rate, year 5	4.50%	4.30%
Unemployment rate, year 6	4.30%	4.30%
Downside 1
Disclosure of credit risk exposure [line items]
GDP growth, year 1	7.50%	(9.70%)
GDP growth, year 2	4.30%	6.80%
GDP growth, year 3	(1.90%)	4.10%
GDP growth, year 4	(0.30%)	0.90%
GDP growth, year 5	0.50%	0.50%
GDP growth, year 6	0.40%	0.50%
Bank of England base rate, year 1	0.25%	0.10%
Bank of England base rate, year 2	3.50%	0.25%
Bank of England base rate, year 3	3.50%	0.75%
Bank of England base rate, year 4	2.75%	0.75%
Bank of England base rate, year 5	2.50%	1%
Bank of England base rate, year 6	2.25%	1%
House price growth, year 1	8.70%	6.90%
House price growth, year 2	7.60%	5.40%
House price growth, year 3	(10.00%)	(1.80%)
House price growth, year 4	(6.70%)	(4.60%)
House price growth, year 5	(3.10%)	(3.10%)
House price growth, year 6	(0.20%)	(0.70%)
Unemployment rate, year 1	4%	5.20%
Unemployment rate, year 2	3.70%	4.40%
Unemployment rate, year 3	5.10%	4.80%
Unemployment rate, year 4	5.40%	5%
Unemployment rate, year 5	5.80%	5.10%
Unemployment rate, year 6	6.10%	5.40%
Downside 2
Disclosure of credit risk exposure [line items]
GDP growth, year 1	7.50%	(9.70%)
GDP growth, year 2	3.70%	6.20%
GDP growth, year 3	(6.40%)	(0.70%)
GDP growth, year 4	(0.70%)	0.50%
GDP growth, year 5	1.70%	1.60%
GDP growth, year 6	1.50%	1.70%
Bank of England base rate, year 1	0.25%	0.10%
Bank of England base rate, year 2	3.50%	0.25%
Bank of England base rate, year 3	3.75%	1%
Bank of England base rate, year 4	3%	2%
Bank of England base rate, year 5	2.75%	3%
Bank of England base rate, year 6	2.50%	2.75%
House price growth, year 1	8.70%	6.90%
House price growth, year 2	7.60%	5.40%
House price growth, year 3	(15.80%)	(8.30%)
House price growth, year 4	(14.30%)	(13.10%)
House price growth, year 5	(4.10%)	(4.80%)
House price growth, year 6	4.70%	4.30%
Unemployment rate, year 1	4%	5.20%
Unemployment rate, year 2	4.40%	4.40%
Unemployment rate, year 3	8.50%	6.90%
Unemployment rate, year 4	8%	6.90%
Unemployment rate, year 5	7.40%	6.40%
Unemployment rate, year 6	6.80%	6.10%
Stubborn Inflation
Disclosure of credit risk exposure [line items]
GDP growth, year 1	7.50%
GDP growth, year 2	4.20%
GDP growth, year 3	(2.70%)
GDP growth, year 4	(0.90%)
GDP growth, year 5	0.20%
GDP growth, year 6	0.60%
Bank of England base rate, year 1	0.25%
Bank of England base rate, year 2	3.50%
Bank of England base rate, year 3	6%
Bank of England base rate, year 4	5.50%
Bank of England base rate, year 5	3.50%
Bank of England base rate, year 6	3%
House price growth, year 1	8.70%
House price growth, year 2	7.60%
House price growth, year 3	(10.90%)
House price growth, year 4	(8.80%)
House price growth, year 5	(4.90%)
House price growth, year 6	(0.60%)
Unemployment rate, year 1	4%
Unemployment rate, year 2	3.70%
Unemployment rate, year 3	5.50%
Unemployment rate, year 4	5.90%
Unemployment rate, year 5	6.40%
Unemployment rate, year 6	6.60%
Downside 3
Disclosure of credit risk exposure [line items]
GDP growth, year 1		(9.70%)
GDP growth, year 2		5.60%
GDP growth, year 3		(7.50%)
GDP growth, year 4		3.10%
GDP growth, year 5		1.50%
GDP growth, year 6		1.50%
Bank of England base rate, year 1		0.10%
Bank of England base rate, year 2		0.25%
Bank of England base rate, year 3		(0.50%)
Bank of England base rate, year 4		0%
Bank of England base rate, year 5		0%
Bank of England base rate, year 6		0%
House price growth, year 1		6.90%
House price growth, year 2		(2.50%)
House price growth, year 3		(19.60%)
House price growth, year 4		(9.30%)
House price growth, year 5		2.40%
House price growth, year 6		3.30%
Unemployment rate, year 1		5.20%
Unemployment rate, year 2		6.80%
Unemployment rate, year 3		11.40%
Unemployment rate, year 4		8.70%
Unemployment rate, year 5		8%
Unemployment rate, year 6		7.40%
Weighted
Disclosure of credit risk exposure [line items]
GDP growth, year 1	7.50%	(9.70%)
GDP growth, year 2	4.30%	6.70%
GDP growth, year 3	(2.20%)	2.80%
GDP growth, year 4	0%	1.40%
GDP growth, year 5	1.20%	1.30%
GDP growth, year 6	1.20%	1.40%
Bank of England base rate, year 1	0.25%	0.10%
Bank of England base rate, year 2	3.50%	0.10%
Bank of England base rate, year 3	4.29%	0.55%
Bank of England base rate, year 4	3.59%	0.96%
Bank of England base rate, year 5	2.85%	1.24%
Bank of England base rate, year 6	2.55%	1.21%
House price growth, year 1	8.70%	6.90%
House price growth, year 2	7.30%	4.80%
House price growth, year 3	(10.70%)	(2.00%)
House price growth, year 4	(4.40%)	(3.10%)
House price growth, year 5	(0.80%)	(0.40%)
House price growth, year 6	2%	2.10%
Unemployment rate, year 1	4%	5.20%
Unemployment rate, year 2	3.80%	4.70%
Unemployment rate, year 3	5.30%	5.40%
Unemployment rate, year 4	5.60%	5.20%
Unemployment rate, year 5	5.40%	5%
Unemployment rate, year 6	5.30%	5%

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, 2022	Dec. 31, 2021
Upside 1
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease	(0.73%)	1.30%
House price growth, Peak/(trough) at	(12.79%)	(3.07%)
GDP, 5-year average increase/decrease	1.17%	2.33%
GDP, Cumulative growth/(fall) to peak/(trough)	5.98%	12.19%
Unemployment rate, 5-year end period	4.17%	3.60%
Unemployment rate, Peak/(trough) at	4.72%	4.45%
Bank of England bank rate, 5-year end period	2.25%	2%
Bank of England bank rate, Peak/(trough) at	3.75%	2%
Base case
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease	(0.62%)	2%
House price growth, Peak/(trough) at	(11.19%)	0%
GDP, 5-year average increase/decrease	0.75%	1.89%
GDP, Cumulative growth/(fall) to peak/(trough)	3.80%	9.83%
Unemployment rate, 5-year end period	4.28%	4.30%
Unemployment rate, Peak/(trough) at	5.10%	4.70%
Bank of England bank rate, 5-year end period	2.50%	0.75%
Bank of England bank rate, Peak/(trough) at	4%	0.75%
Downside 1
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease	(3.79%)	(1.78%)
House price growth, Peak/(trough) at	(19.00%)	(9.87%)
GDP, 5-year average increase/decrease	(0.17%)	0.93%
GDP, Cumulative growth/(fall) to peak/(trough)	(0.84%)	4.75%
Unemployment rate, 5-year end period	6.09%	5.65%
Unemployment rate, Peak/(trough) at	6.12%	5.65%
Bank of England bank rate, 5-year end period	2.25%	1%
Bank of England bank rate, Peak/(trough) at	3.50%	1%
Downside 2
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease	(4.82%)	(3.27%)
House price growth, Peak/(trough) at	(30.69%)	(24.03%)
GDP, 5-year average increase/decrease	(0.63%)	0.49%
GDP, Cumulative growth/(fall) to peak/(trough)	(3.12%)	2.48%
Unemployment rate, 5-year end period	6.23%	5.95%
Unemployment rate, Peak/(trough) at	8.50%	7.27%
Bank of England bank rate, 5-year end period	2.50%	2.25%
Bank of England bank rate, Peak/(trough) at	4%	3%
Stubborn Inflation
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease	(4.69%)
House price growth, Peak/(trough) at	(23.12%)
GDP, 5-year average increase/decrease	(0.45%)
GDP, Cumulative growth/(fall) to peak/(trough)	(2.23%)
Unemployment rate, 5-year end period	6.40%
Unemployment rate, Peak/(trough) at	6.64%
Bank of England bank rate, 5-year end period	3%
Bank of England bank rate, Peak/(trough) at	6%
Downside 3
Disclosure of credit risk exposure [line items]
House price growth, 5-year average increase/decrease		(6.00%)
House price growth, Peak/(trough) at		(32.12%)
GDP, 5-year average increase/decrease		(0.58%)
GDP, Cumulative growth/(fall) to peak/(trough)		(2.85%)
Unemployment rate, 5-year end period		6.80%
Unemployment rate, Peak/(trough) at		11.90%
Bank of England bank rate, 5-year end period		0.25%
Bank of England bank rate, Peak/(trough) at		(0.50%)

Credit Risk - Disclosure of Sce

Credit Risk - Disclosure of Scenario Weights Applied To Scenarios (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Upside 1
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	5%	5%
Base case
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	50%	45%
Downside 1
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	15%	25%
Downside 2
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	10%	20%
Stubborn Inflation
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	20%
Downside 3
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage		5%
Weighted
Disclosure of credit risk exposure [line items]
Probability weightings of scenarios, percentage	100%	100%

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, 2022
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%
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, 2022
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 - Group Level Credi

Credit Risk - Group Level Credit Risk Management, Additional Information (Details) £ in Millions	12 Months Ended
	Dec. 31, 2022 GBP (£) scenario	Dec. 31, 2021 GBP (£)	Dec. 31, 2020 GBP (£)
Disclosure of credit risk exposure [line items]
Minimum ECL to recognise judgemental adjustments	£ 1
Loss allowance	£ 1,005	£ 865
Climate change, period covered for ECL calculations	5 years
Stage 3
Disclosure of credit risk exposure [line items]
ECL individually assessed	£ 129	100
Minimum | Stage 3
Disclosure of credit risk exposure [line items]
ECL under reasonably possible judgements	68
Maximum | Stage 3
Disclosure of credit risk exposure [line items]
ECL under reasonably possible judgements	203
JAs
Disclosure of credit risk exposure [line items]
Loss allowance	166
JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
Increase in judgmental adjustments	13
Loss allowance	13
JAs | Long-term indeterminate arrears | No delay in repossession
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	12
JAs | Long-term indeterminate arrears | Three-year repossession delay
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	14
JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
Increase in judgmental adjustments	22
Loss allowance	22
JAs | 12+ months in arrears | No delay in repossession
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	7
JAs | 12+ months in arrears | Three-year repossession delay
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	28
JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
Increase in judgmental adjustments	15
Loss allowance	15
JAs | UPL loss floor | Increased PD stress factor
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	£ 12
Number of macroeconomic scenarios | scenario	5
JAs | Model underestimation
Disclosure of credit risk exposure [line items]
Increase in judgmental adjustments	£ 57
Loss allowance	57
JAs | Model underestimation | Corrected model underestimation
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	49
JAs | Model underestimation | Model uplift estimation
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	60
JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
Increase in judgmental adjustments		23
Loss allowance	23
ECL, minimum default amount			£ 10
JAs | Corporate single large exposure | One average losses
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements		12
JAs | Corporate single large exposure | Three average losses
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements		35
JAs | Other
Disclosure of credit risk exposure [line items]
Loss allowance	36
ECL, underlay amount	32
Affordability and cost of living JAs
Disclosure of credit risk exposure [line items]
Loss allowance	130	18
Affordability and cost of living JAs | Mortgages affordability
Disclosure of credit risk exposure [line items]
Increase in judgmental adjustments	9
Mortgages moved from stage 1 to stage 2	5,000
Loss allowance	27	18
Affordability and cost of living JAs | Retail Unsecured Affordability
Disclosure of credit risk exposure [line items]
Increase in judgmental adjustments	35
Loss allowance	35
Affordability and cost of living JAs | Retail Unsecured Affordability | Different sensitivities to PD uplifts | Minimum
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	49
Affordability and cost of living JAs | Retail Unsecured Affordability | Different sensitivities to PD uplifts | Maximum
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	82
Affordability and cost of living JAs | Corporate lending to segments affected by supply chain
Disclosure of credit risk exposure [line items]
Increase in judgmental adjustments	61
Loss allowance	61
Affordability and cost of living JAs | Corporate lending to segments affected by supply chain | Different sensitivities to PD uplifts | Minimum
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	26
Affordability and cost of living JAs | Corporate lending to segments affected by supply chain | Different sensitivities to PD uplifts | Maximum
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	187
Affordability and cost of living JAs | SME debt burden
Disclosure of credit risk exposure [line items]
Increase in judgmental adjustments	7
Loss allowance	7
Affordability and cost of living JAs | SME debt burden | Full lifetime losses
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	3
Affordability and cost of living JAs | SME debt burden | 50% coverage on all accounts
Disclosure of credit risk exposure [line items]
Judgemental adjustments under reasonably possible judgements	£ 15
Covid-19 JAs
Disclosure of credit risk exposure [line items]
Loss allowance		236
Covid-19 JAs | Model underestimation
Disclosure of credit risk exposure [line items]
Loss allowance		28
Covid-19 JAs | Corporate lending to segments affected by Covid-19
Disclosure of credit risk exposure [line items]
Loss allowance		176
Probation period	18 months
Covid-19 JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
Loss allowance		23
Covid-19 JAs | SME debt burden
Disclosure of credit risk exposure [line items]
Loss allowance		£ 9

Credit Risk - Disclosure of ECL

Credit Risk - Disclosure of ECL by Segment (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
ECL	£ 1,005	£ 865
ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	709	525
Modelled ECL | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	597	425
Individually assessed | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	112	100
Total JAs
Disclosure of credit risk exposure [line items]
ECL	296	340
Total JAs
Disclosure of credit risk exposure [line items]
ECL	166
Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL	13
Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL	22
Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL	15
Total JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL	57
Total JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL	23
Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL	36
Total JAs
Disclosure of credit risk exposure [line items]
ECL		86
Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL		14
Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL		29
Total JAs | Cladding Risk
Disclosure of credit risk exposure [line items]
ECL		15
Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL		21
Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL		7
Total Covid-19 JAs
Disclosure of credit risk exposure [line items]
ECL		236
Total Covid-19 JAs | Corporate lending to segments affected by Covid-19
Disclosure of credit risk exposure [line items]
ECL		176
Total Covid-19 JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL		28
Total Covid-19 JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL		23
Total Covid-19 JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL		9
Total Affordability and Cost of Living JAs
Disclosure of credit risk exposure [line items]
ECL	130	18
Total Affordability and Cost of Living JAs | Corporate lending to segments affected by supply chain
Disclosure of credit risk exposure [line items]
ECL	61
Total Affordability and Cost of Living JAs | Mortgages affordability
Disclosure of credit risk exposure [line items]
ECL	27	18
Total Affordability and Cost of Living JAs | Retail Unsecured Affordability
Disclosure of credit risk exposure [line items]
ECL	35
Total Affordability and Cost of Living JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL	7
Mortgages
Disclosure of credit risk exposure [line items]
ECL	251	190
Mortgages | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	133	120
Mortgages | Modelled ECL | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	133	120
Mortgages | Individually assessed | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	0	0
Mortgages | Total JAs
Disclosure of credit risk exposure [line items]
ECL	91
Mortgages | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL	13
Mortgages | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL	22
Mortgages | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL	0
Mortgages | Total JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL	36
Mortgages | Total JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL	0
Mortgages | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL	20
Mortgages | Total JAs
Disclosure of credit risk exposure [line items]
ECL		38
Mortgages | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL		14
Mortgages | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL		29
Mortgages | Total JAs | Cladding Risk
Disclosure of credit risk exposure [line items]
ECL		15
Mortgages | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL		0
Mortgages | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL		(20)
Mortgages | Total Covid-19 JAs
Disclosure of credit risk exposure [line items]
ECL		14
Mortgages | Total Covid-19 JAs | Corporate lending to segments affected by Covid-19
Disclosure of credit risk exposure [line items]
ECL		0
Mortgages | Total Covid-19 JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL		14
Mortgages | Total Covid-19 JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL		0
Mortgages | Total Covid-19 JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL		0
Mortgages | Total Affordability and Cost of Living JAs
Disclosure of credit risk exposure [line items]
ECL	27	18
Mortgages | Total Affordability and Cost of Living JAs | Corporate lending to segments affected by supply chain
Disclosure of credit risk exposure [line items]
ECL	0
Mortgages | Total Affordability and Cost of Living JAs | Mortgages affordability
Disclosure of credit risk exposure [line items]
ECL	27	18
Mortgages | Total Affordability and Cost of Living JAs | Retail Unsecured Affordability
Disclosure of credit risk exposure [line items]
ECL	0
Mortgages | Total Affordability and Cost of Living JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL	0
Credit cards
Disclosure of credit risk exposure [line items]
ECL	130	89
Credit cards | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	112	88
Credit cards | Modelled ECL | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	112	88
Credit cards | Individually assessed | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	0	0
Credit cards | Total JAs
Disclosure of credit risk exposure [line items]
ECL	3
Credit cards | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL	0
Credit cards | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL	0
Credit cards | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL	0
Credit cards | Total JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL	2
Credit cards | Total JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL	0
Credit cards | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL	1
Credit cards | Total JAs
Disclosure of credit risk exposure [line items]
ECL		1
Credit cards | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL		0
Credit cards | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL		0
Credit cards | Total JAs | Cladding Risk
Disclosure of credit risk exposure [line items]
ECL		0
Credit cards | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL		0
Credit cards | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL		1
Credit cards | Total Covid-19 JAs
Disclosure of credit risk exposure [line items]
ECL		0
Credit cards | Total Covid-19 JAs | Corporate lending to segments affected by Covid-19
Disclosure of credit risk exposure [line items]
ECL		0
Credit cards | Total Covid-19 JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL		0
Credit cards | Total Covid-19 JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL		0
Credit cards | Total Covid-19 JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL		0
Credit cards | Total Affordability and Cost of Living JAs
Disclosure of credit risk exposure [line items]
ECL	15	0
Credit cards | Total Affordability and Cost of Living JAs | Corporate lending to segments affected by supply chain
Disclosure of credit risk exposure [line items]
ECL	0
Credit cards | Total Affordability and Cost of Living JAs | Mortgages affordability
Disclosure of credit risk exposure [line items]
ECL	0	0
Credit cards | Total Affordability and Cost of Living JAs | Retail Unsecured Affordability
Disclosure of credit risk exposure [line items]
ECL	15
Credit cards | Total Affordability and Cost of Living JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL	0
Other
Disclosure of credit risk exposure [line items]
ECL	164	109
Other | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	93	57
Other | Modelled ECL | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	93	57
Other | Individually assessed | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	0	0
Other | Total JAs
Disclosure of credit risk exposure [line items]
ECL	44
Other | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL	0
Other | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL	0
Other | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL	15
Other | Total JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL	19
Other | Total JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL	0
Other | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL	10
Other | Total JAs
Disclosure of credit risk exposure [line items]
ECL		29
Other | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL		0
Other | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL		0
Other | Total JAs | Cladding Risk
Disclosure of credit risk exposure [line items]
ECL		0
Other | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL		21
Other | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL		8
Other | Total Covid-19 JAs
Disclosure of credit risk exposure [line items]
ECL		23
Other | Total Covid-19 JAs | Corporate lending to segments affected by Covid-19
Disclosure of credit risk exposure [line items]
ECL		0
Other | Total Covid-19 JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL		14
Other | Total Covid-19 JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL		0
Other | Total Covid-19 JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL		9
Other | Total Affordability and Cost of Living JAs
Disclosure of credit risk exposure [line items]
ECL	27	0
Other | Total Affordability and Cost of Living JAs | Corporate lending to segments affected by supply chain
Disclosure of credit risk exposure [line items]
ECL	0
Other | Total Affordability and Cost of Living JAs | Mortgages affordability
Disclosure of credit risk exposure [line items]
ECL	0	0
Other | Total Affordability and Cost of Living JAs | Retail Unsecured Affordability
Disclosure of credit risk exposure [line items]
ECL	20
Other | Total Affordability and Cost of Living JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL	7
Consumer Finance
Disclosure of credit risk exposure [line items]
ECL	67	52
Consumer Finance | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	65	52
Consumer Finance | Modelled ECL | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	65	52
Consumer Finance | Individually assessed | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	0	0
Consumer Finance | Total JAs
Disclosure of credit risk exposure [line items]
ECL	2
Consumer Finance | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL	0
Consumer Finance | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL	0
Consumer Finance | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL	0
Consumer Finance | Total JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL	0
Consumer Finance | Total JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL	0
Consumer Finance | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL	2
Consumer Finance | Total JAs
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total JAs | Cladding Risk
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total Covid-19 JAs
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total Covid-19 JAs | Corporate lending to segments affected by Covid-19
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total Covid-19 JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total Covid-19 JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total Covid-19 JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL		0
Consumer Finance | Total Affordability and Cost of Living JAs
Disclosure of credit risk exposure [line items]
ECL	0	0
Consumer Finance | Total Affordability and Cost of Living JAs | Corporate lending to segments affected by supply chain
Disclosure of credit risk exposure [line items]
ECL	0
Consumer Finance | Total Affordability and Cost of Living JAs | Mortgages affordability
Disclosure of credit risk exposure [line items]
ECL	0	0
Consumer Finance | Total Affordability and Cost of Living JAs | Retail Unsecured Affordability
Disclosure of credit risk exposure [line items]
ECL	0
Consumer Finance | Total Affordability and Cost of Living JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL	0
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
ECL	393	425
Corporate & Commercial Banking | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	306	208
Corporate & Commercial Banking | Modelled ECL | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	194	108
Corporate & Commercial Banking | Individually assessed | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	112	100
Corporate & Commercial Banking | Total JAs
Disclosure of credit risk exposure [line items]
ECL	26
Corporate & Commercial Banking | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL	0
Corporate & Commercial Banking | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL	0
Corporate & Commercial Banking | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL	0
Corporate & Commercial Banking | Total JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL	0
Corporate & Commercial Banking | Total JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL	23
Corporate & Commercial Banking | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL	3
Corporate & Commercial Banking | Total JAs
Disclosure of credit risk exposure [line items]
ECL		18
Corporate & Commercial Banking | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL		0
Corporate & Commercial Banking | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL		0
Corporate & Commercial Banking | Total JAs | Cladding Risk
Disclosure of credit risk exposure [line items]
ECL		0
Corporate & Commercial Banking | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL		0
Corporate & Commercial Banking | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL		18
Corporate & Commercial Banking | Total Covid-19 JAs
Disclosure of credit risk exposure [line items]
ECL		199
Corporate & Commercial Banking | Total Covid-19 JAs | Corporate lending to segments affected by Covid-19
Disclosure of credit risk exposure [line items]
ECL		176
Corporate & Commercial Banking | Total Covid-19 JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL		0
Corporate & Commercial Banking | Total Covid-19 JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL		23
Corporate & Commercial Banking | Total Covid-19 JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL		0
Corporate & Commercial Banking | Total Affordability and Cost of Living JAs
Disclosure of credit risk exposure [line items]
ECL	61	0
Corporate & Commercial Banking | Total Affordability and Cost of Living JAs | Corporate lending to segments affected by supply chain
Disclosure of credit risk exposure [line items]
ECL	61
Corporate & Commercial Banking | Total Affordability and Cost of Living JAs | Mortgages affordability
Disclosure of credit risk exposure [line items]
ECL	0	0
Corporate & Commercial Banking | Total Affordability and Cost of Living JAs | Retail Unsecured Affordability
Disclosure of credit risk exposure [line items]
ECL	0
Corporate & Commercial Banking | Total Affordability and Cost of Living JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre
Disclosure of credit risk exposure [line items]
ECL	0	0
Corporate Centre | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	0	0
Corporate Centre | Modelled ECL | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre | Individually assessed | ECL before JAs
Disclosure of credit risk exposure [line items]
ECL	0	0
Corporate Centre | Total JAs
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre | Total JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre | Total JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre | Total JAs
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total JAs | Long-term indeterminate arrears
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total JAs | 12+ months in arrears
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total JAs | Cladding Risk
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total JAs | UPL loss floor
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total JAs | Other
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total Covid-19 JAs
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total Covid-19 JAs | Corporate lending to segments affected by Covid-19
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total Covid-19 JAs | Model underestimation
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total Covid-19 JAs | Corporate single large exposure
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total Covid-19 JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL		0
Corporate Centre | Total Affordability and Cost of Living JAs
Disclosure of credit risk exposure [line items]
ECL	0	0
Corporate Centre | Total Affordability and Cost of Living JAs | Corporate lending to segments affected by supply chain
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre | Total Affordability and Cost of Living JAs | Mortgages affordability
Disclosure of credit risk exposure [line items]
ECL	0	£ 0
Corporate Centre | Total Affordability and Cost of Living JAs | Retail Unsecured Affordability
Disclosure of credit risk exposure [line items]
ECL	0
Corporate Centre | Total Affordability and Cost of Living JAs | SME debt burden
Disclosure of credit risk exposure [line items]
ECL	£ 0

Credit Risk - Disclosure of Bas

Credit Risk - Disclosure of Base Expected Credit Losses to Probability Weighted Estimated Credit Losses (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Exposure	£ 219,716	£ 210,094
ECL	1,005	865
Mortgages
Disclosure of credit risk exposure [line items]
ECL	251	190
Credit cards
Disclosure of credit risk exposure [line items]
ECL	130	89
Other
Disclosure of credit risk exposure [line items]
ECL	164	109
Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	5,384	4,984
ECL	67	52
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
ECL	393	425
Corporate Centre
Disclosure of credit risk exposure [line items]
ECL	0	0
Upside 1
Disclosure of credit risk exposure [line items]
Exposure	306,284	313,348
ECL	£ 930	£ 782
Proportion of assets in Stage 2	4%	5%
Proportion of assets in Stage 3	1%	1%
Upside 1 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 213,557	£ 212,396
ECL	£ 489	£ 307
Proportion of assets in Stage 2	4%	5%
Proportion of assets in Stage 3	1%	1%
Upside 1 | Mortgages
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 192,346	£ 190,663
ECL - of which: mortgages	£ 214	£ 134
Proportion of assets in Stage 2 - of which: mortgages	4%	6%
Proportion of assets in Stage 3 - of which: mortgages	1%	1%
Upside 1 | Credit cards
Disclosure of credit risk exposure [line items]
Exposure	£ 12,845	£ 12,301
ECL	£ 122	£ 78
Proportion of assets in Stage 2	3%	2%
Proportion of assets in Stage 3	0%	0%
Upside 1 | Other
Disclosure of credit risk exposure [line items]
Exposure	£ 8,366	£ 9,432
ECL	£ 153	£ 95
Proportion of assets in Stage 2	7%	3%
Proportion of assets in Stage 3	2%	2%
Upside 1 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,740	£ 5,298
ECL	£ 65	£ 50
Proportion of assets in Stage 2	6%	4%
Proportion of assets in Stage 3	1%	1%
Upside 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 28,277	£ 27,305
ECL	£ 376	£ 425
Proportion of assets in Stage 2	8%	16%
Proportion of assets in Stage 3	2%	2%
Upside 1 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 58,710	£ 68,349
ECL	£ 0	£ 0
Proportion of assets in Stage 2	0%	0%
Proportion of assets in Stage 3	0%	0%
Base case
Disclosure of credit risk exposure [line items]
Exposure	£ 306,284	£ 313,348
ECL	£ 932	£ 762
Proportion of assets in Stage 2	4%	5%
Proportion of assets in Stage 3	1%	1%
Base case | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 213,557	£ 212,396
ECL	£ 497	£ 286
Proportion of assets in Stage 2	4%	5%
Proportion of assets in Stage 3	1%	1%
Base case | Mortgages
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 192,346	£ 190,663
ECL - of which: mortgages	£ 218	£ 125
Proportion of assets in Stage 2 - of which: mortgages	4%	6%
Proportion of assets in Stage 3 - of which: mortgages	1%	1%
Base case | Credit cards
Disclosure of credit risk exposure [line items]
Exposure	£ 12,845	£ 12,301
ECL	£ 123	£ 72
Proportion of assets in Stage 2	3%	1%
Proportion of assets in Stage 3	0%	0%
Base case | Other
Disclosure of credit risk exposure [line items]
Exposure	£ 8,366	£ 9,432
ECL	£ 156	£ 89
Proportion of assets in Stage 2	7%	3%
Proportion of assets in Stage 3	2%	2%
Base case | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,740	£ 5,298
ECL	£ 66	£ 51
Proportion of assets in Stage 2	6%	4%
Proportion of assets in Stage 3	1%	1%
Base case | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 28,277	£ 27,305
ECL	£ 369	£ 425
Proportion of assets in Stage 2	9%	16%
Proportion of assets in Stage 3	2%	2%
Base case | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 58,710	£ 68,349
ECL	£ 0	£ 0
Proportion of assets in Stage 2	0%	0%
Proportion of assets in Stage 3	0%	0%
Downside 1
Disclosure of credit risk exposure [line items]
Exposure	£ 306,284	£ 313,348
ECL	£ 993	£ 851
Proportion of assets in Stage 2	5%	5%
Proportion of assets in Stage 3	1%	1%
Downside 1 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 213,557	£ 212,396
ECL	£ 529	£ 375
Proportion of assets in Stage 2	4%	5%
Proportion of assets in Stage 3	1%	1%
Downside 1 | Mortgages
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 192,346	£ 190,663
ECL - of which: mortgages	£ 244	£ 177
Proportion of assets in Stage 2 - of which: mortgages	4%	6%
Proportion of assets in Stage 3 - of which: mortgages	1%	1%
Downside 1 | Credit cards
Disclosure of credit risk exposure [line items]
Exposure	£ 12,845	£ 12,301
ECL	£ 127	£ 89
Proportion of assets in Stage 2	3%	2%
Proportion of assets in Stage 3	0%	0%
Downside 1 | Other
Disclosure of credit risk exposure [line items]
Exposure	£ 8,366	£ 9,432
ECL	£ 158	£ 109
Proportion of assets in Stage 2	7%	4%
Proportion of assets in Stage 3	2%	2%
Downside 1 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,740	£ 5,298
ECL	£ 65	£ 51
Proportion of assets in Stage 2	6%	4%
Proportion of assets in Stage 3	1%	1%
Downside 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 28,277	£ 27,305
ECL	£ 399	£ 425
Proportion of assets in Stage 2	9%	17%
Proportion of assets in Stage 3	2%	2%
Downside 1 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 58,710	£ 68,349
ECL	£ 0	£ 0
Proportion of assets in Stage 2	0%	0%
Proportion of assets in Stage 3	0%	0%
Downside 2
Disclosure of credit risk exposure [line items]
Exposure	£ 306,284	£ 313,348
ECL	£ 1,383	£ 988
Proportion of assets in Stage 2	11%	6%
Proportion of assets in Stage 3	1%	1%
Downside 2 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 213,557	£ 212,396
ECL	£ 830	£ 510
Proportion of assets in Stage 2	10%	7%
Proportion of assets in Stage 3	1%	1%
Downside 2 | Mortgages
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 192,346	£ 190,663
ECL - of which: mortgages	£ 501	£ 283
Proportion of assets in Stage 2 - of which: mortgages	11%	7%
Proportion of assets in Stage 3 - of which: mortgages	1%	1%
Downside 2 | Credit cards
Disclosure of credit risk exposure [line items]
Exposure	£ 12,845	£ 12,301
ECL	£ 142	£ 102
Proportion of assets in Stage 2	3%	2%
Proportion of assets in Stage 3	0%	0%
Downside 2 | Other
Disclosure of credit risk exposure [line items]
Exposure	£ 8,366	£ 9,432
ECL	£ 187	£ 125
Proportion of assets in Stage 2	9%	5%
Proportion of assets in Stage 3	2%	2%
Downside 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,740	£ 5,298
ECL	£ 69	£ 53
Proportion of assets in Stage 2	6%	4%
Proportion of assets in Stage 3	1%	1%
Downside 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 28,277	£ 27,305
ECL	£ 484	£ 425
Proportion of assets in Stage 2	18%	21%
Proportion of assets in Stage 3	2%	2%
Downside 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 58,710	£ 68,349
ECL	£ 0	£ 0
Proportion of assets in Stage 2	0%	0%
Proportion of assets in Stage 3	0%	0%
Stubborn Inflation
Disclosure of credit risk exposure [line items]
Exposure	£ 306,284
ECL	£ 1,149
Proportion of assets in Stage 2	7%
Proportion of assets in Stage 3	1%
Stubborn Inflation | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 213,557
ECL	£ 647
Proportion of assets in Stage 2	6%
Proportion of assets in Stage 3	1%
Stubborn Inflation | Mortgages
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 192,346
ECL - of which: mortgages	£ 324
Proportion of assets in Stage 2 - of which: mortgages	6%
Proportion of assets in Stage 3 - of which: mortgages	1%
Stubborn Inflation | Credit cards
Disclosure of credit risk exposure [line items]
Exposure	£ 12,845
ECL	£ 140
Proportion of assets in Stage 2	3%
Proportion of assets in Stage 3	0%
Stubborn Inflation | Other
Disclosure of credit risk exposure [line items]
Exposure	£ 8,366
ECL	£ 183
Proportion of assets in Stage 2	8%
Proportion of assets in Stage 3	2%
Stubborn Inflation | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,740
ECL	£ 68
Proportion of assets in Stage 2	6%
Proportion of assets in Stage 3	1%
Stubborn Inflation | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 28,277
ECL	£ 434
Proportion of assets in Stage 2	14%
Proportion of assets in Stage 3	2%
Stubborn Inflation | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 58,710
ECL	£ 0
Proportion of assets in Stage 2	0%
Proportion of assets in Stage 3	0%
Downside 3
Disclosure of credit risk exposure [line items]
Exposure		£ 313,348
ECL		£ 1,141
Proportion of assets in Stage 2		7%
Proportion of assets in Stage 3		1%
Downside 3 | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure		£ 212,396
ECL		£ 662
Proportion of assets in Stage 2		8%
Proportion of assets in Stage 3		1%
Downside 3 | Mortgages
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages		£ 190,663
ECL - of which: mortgages		£ 437
Proportion of assets in Stage 2 - of which: mortgages		8%
Proportion of assets in Stage 3 - of which: mortgages		1%
Downside 3 | Credit cards
Disclosure of credit risk exposure [line items]
Exposure		£ 12,301
ECL		£ 101
Proportion of assets in Stage 2		2%
Proportion of assets in Stage 3		0%
Downside 3 | Other
Disclosure of credit risk exposure [line items]
Exposure		£ 9,432
ECL		£ 124
Proportion of assets in Stage 2		4%
Proportion of assets in Stage 3		2%
Downside 3 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure		£ 5,298
ECL		£ 54
Proportion of assets in Stage 2		4%
Proportion of assets in Stage 3		1%
Downside 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure		£ 27,305
ECL		£ 425
Proportion of assets in Stage 2		21%
Proportion of assets in Stage 3		2%
Downside 3 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure		£ 68,349
ECL		£ 0
Proportion of assets in Stage 2		0%
Proportion of assets in Stage 3		0%
Weighted
Disclosure of credit risk exposure [line items]
Exposure	£ 306,284	£ 313,348
ECL	£ 1,005	£ 865
Proportion of assets in Stage 2	7%	5%
Proportion of assets in Stage 3	1%	1%
Weighted | Retail Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 213,557	£ 212,396
ECL	£ 544	£ 388
Proportion of assets in Stage 2	7%	6%
Proportion of assets in Stage 3	1%	1%
Weighted | Mortgages
Disclosure of credit risk exposure [line items]
Exposure - of which: mortgages	£ 192,346	£ 190,663
ECL - of which: mortgages	£ 251	£ 190
Proportion of assets in Stage 2 - of which: mortgages	7%	6%
Proportion of assets in Stage 3 - of which: mortgages	1%	1%
Weighted | Credit cards
Disclosure of credit risk exposure [line items]
Exposure	£ 12,845	£ 12,301
ECL	£ 130	£ 89
Proportion of assets in Stage 2	3%	2%
Proportion of assets in Stage 3	0%	0%
Weighted | Other
Disclosure of credit risk exposure [line items]
Exposure	£ 8,366	£ 9,432
ECL	£ 163	£ 109
Proportion of assets in Stage 2	8%	4%
Proportion of assets in Stage 3	2%	2%
Weighted | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposure	£ 5,740	£ 5,298
ECL	£ 67	£ 52
Proportion of assets in Stage 2	6%	4%
Proportion of assets in Stage 3	1%	1%
Weighted | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposure	£ 28,277	£ 27,305
ECL	£ 394	£ 425
Proportion of assets in Stage 2	12%	18%
Proportion of assets in Stage 3	2%	2%
Weighted | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposure	£ 58,710	£ 68,349
ECL	£ 0	£ 0
Proportion of assets in Stage 2	0%	0%
Proportion of assets in Stage 3	0%	0%

Credit Risk - Schedule of Impac

Credit Risk - 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 (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [abstract]
Increase in profit before tax due to 20 percentage increase in HPI rate	£ 48	£ 64
Increase in profit before tax due to 10 percentage increase in HPI rate	32	40
Decrease in profit before tax due to 10 percentage decrease in HPI rate	(61)	(69)
Decrease in profit before tax due to 20 percentage decrease in HPI rate	£ (176)	£ (197)

Credit Risk - Disclosure of Fac

Credit Risk - Disclosure of Factors to Measure ECL (Details) - Credit risk	12 Months Ended
	Dec. 31, 2022
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 occurs. We determine EAD for each month of the forecast period by the expected payment profile, which varies by product. 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 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, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Collateral cash	£ (8,088)	£ (11,224)
Netting	(524)	(1,189)
Net exposure	306,284	313,347
Credit risk
Disclosure of credit risk exposure [line items]
Collateral cash	(100)	(100)
Collateral non-cash	(216,000)	(211,500)
Netting	0	(400)
Net exposure	94,000	104,200
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	44,200	48,100
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	6,000	5,900
Balance sheet asset | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	278,400	278,500
Balance sheet asset | Credit risk | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	279,300	279,400
Balance sheet asset | Credit risk | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	900	900
Balance sheet asset | Credit risk | Cash and balances at central banks
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	44,200	48,100
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	44,200	48,100
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	6,000	5,900
Balance sheet asset | Credit risk | Financial assets at FVOCI | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	6,000	5,900
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	31,700	37,700
Off-balance sheet | Credit risk | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	31,800	37,700
Off-balance sheet | Credit risk | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(100)	0
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)	(100)
Collateral non-cash	(216,000)	(211,500)
Netting	0	(400)
Net exposure	43,800	50,200
Financial assets at amortised cost | Credit risk | Loans and advances to customers
Disclosure of credit risk exposure [line items]
Collateral cash	(100)	(100)
Collateral non-cash	(208,700)	(199,300)
Netting	0	0
Net exposure	42,200	48,000
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	(187,400)	(177,800)
Netting	0	0
Net exposure	4,700	12,700
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	(16,500)	(16,800)
Netting	0	0
Net exposure	11,400	9,600
Financial assets at amortised cost | Credit risk | Loans and advances to customers | Accrued interest and other adjustments
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	0	0
Netting	0	0
Net exposure	700	500
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
Collateral non-cash		0
Netting		0
Net exposure	21,100	22,600
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	4,200	3,200
Financial assets at amortised cost | Credit risk | Loans and advances to customers | Finance leases
Disclosure of credit risk exposure [line items]
Collateral cash	0	0
Collateral non-cash	(4,800)	(4,700)
Netting	0	0
Net exposure	100	(600)
Financial assets at amortised cost | Credit risk | Loans and advances to banks
Disclosure of credit risk exposure [line items]
Collateral cash		0
Collateral non-cash		0
Netting		0
Net exposure	1,400	1,600
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	(7,300)	(12,200)
Netting	0	(400)
Net exposure	0	100
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	200	500
Financial assets at amortised cost | Balance sheet asset | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	228,200	224,500
Financial assets at amortised cost | Balance sheet asset | Credit risk | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	229,100	225,400
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	900
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	219,700	210,100
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	184,100	174,500
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	18,700	18,900
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	700	500
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	7,500	9,200
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	4,200	3,200
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	220,600	211,000
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	184,300	174,700
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	19,100	19,300
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	700	500
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	7,700	9,400
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	4,200	3,200
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	900
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	200
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	400
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	200
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 customers | Finance leases
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	4,500	3,800
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	4,600	3,900
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 banks
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	1,000	1,200
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	1,000	1,200
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
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	7,300	12,700
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	7,300	12,700
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	200	500
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	200	500
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	31,700	37,700
Financial assets at amortised cost | Off-balance sheet | Credit risk | Gross amounts
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	31,800	37,700
Financial assets at amortised cost | Off-balance sheet | Credit risk | Loss allowance
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	(100)	0
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	31,300	37,300
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	8,000	16,000
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	9,300	7,600
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	13,600	13,400
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	31,400	37,300
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	8,000	16,000
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	9,300	7,600
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	13,700	13,400
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	(100)	0
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	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	(100)	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 customers | Finance leases
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	400	300
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	400	300
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
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	400
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	400
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
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	6,000	5,900
Debt securities | Balance sheet asset | Credit risk | Financial assets at FVOCI
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	6,000	5,900
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	6,000	5,900
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, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Collateral cash	£ (8,088)	£ (11,224)
Netting	(524)	(1,189)
Exposures	306,284	313,347
Credit risk
Disclosure of credit risk exposure [line items]
Collateral cash	(100)	(100)
Collateral non-cash	(216,000)	(211,500)
Netting	0	(400)
Exposures	94,000	104,200
Financial assets at fair value through profit loss | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	2,500	1,900
Collateral cash	0	0
Collateral non-cash	(1,700)	(700)
Netting	(500)	(800)
Exposures	300	400
Derivative financial instruments | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	2,400	1,700
Collateral cash		0
Collateral non-cash	(1,700)	(700)
Netting	(500)	(800)
Exposures	200	200
Other financial assets at FVTPL | Credit risk
Disclosure of credit risk exposure [line items]
Maximum exposure to balance sheet	100	200
Collateral cash		0
Collateral non-cash	0	0
Netting	0	0
Exposures	£ 100	£ 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, 2022
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%
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%
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%
Lower | Santander UK risk grade 9
Disclosure of credit risk exposure [line items]
Standard and poors rating probability of default percent	0%
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%
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%

Credit Risk - Disclosure of Cre

Credit Risk - Disclosure of Credit Rating of Financial Assets Subject to Credit Risk (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of internal credit grades [line items]
Credit impairment loss allowances on loans and advances to customers	£ (1,005)	£ (865)
Coverage ratio	0.30%	0.30%
Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 310,100	£ 316,200
Credit impairment loss allowances on loans and advances to customers	£ (1,000)	£ (900)
Coverage ratio	0.30%	0.30%
Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 1,000	£ 900
Internal grade 9 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 63,000	£ 71,200
Coverage ratio	0%	0%
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	£ 45,800	£ 42,100
Coverage ratio	0%	0%
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	£ 92,900	£ 93,600
Coverage ratio	0%	0%
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	£ 59,700	£ 55,400
Coverage ratio	0%	0%
Internal grade 6 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Internal grade 5 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 20,100	£ 17,300
Coverage ratio	1%	1.20%
Internal grade 5 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 200
Internal grade 4 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 11,300	£ 11,500
Coverage ratio	1.80%	0.90%
Internal grade 4 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
Internal grade 3 to 1 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 5,800	£ 6,500
Coverage ratio	10.30%	9.20%
Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 600	£ 600
Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 12,500	£ 19,500
Coverage ratio	0%	0%
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	278,400	278,500
Credit impairment loss allowances on loans and advances to customers	£ (900)	£ (900)
Coverage ratio	0.30%	0.30%
Balance sheet asset | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 900	£ 900
Balance sheet asset | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	228,200	224,500
Credit impairment loss allowances on loans and advances to customers	£ (900)	£ (900)
Coverage ratio	0.40%	0.40%
Balance sheet asset | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 184,100	£ 174,500
Credit impairment loss allowances on loans and advances to customers	£ (200)	£ (200)
Coverage ratio	0.10%	0.10%
Balance sheet asset | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 900	£ 900
Balance sheet asset | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	200	200
Balance sheet asset | Cash and balances at central banks | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	44,200	48,100
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	219,700	210,100
Credit impairment loss allowances on loans and advances to customers	£ (900)	£ (900)
Coverage ratio	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	£ 900
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	1,000	1,200
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	7,300	12,700
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	200	500
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	6,000	5,900
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	£ 62,900	£ 71,100
Coverage ratio	0%	0%
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	£ 15,200	£ 19,400
Coverage ratio	0%	0%
Balance sheet asset | Internal grade 9 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 9,500	£ 9,000
Coverage ratio	0%	0%
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	£ 44,200	£ 48,100
Coverage ratio	0%	0%
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	£ 9,500	£ 9,000
Coverage ratio	0%	0%
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	£ 100	£ 200
Coverage ratio	0%	0%
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	£ 5,400	£ 9,700
Coverage ratio	0%	0%
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	£ 200	£ 500
Coverage ratio	0%	0%
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	£ 3,500	£ 3,600
Coverage ratio	0%	0%
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	£ 38,600	£ 34,900
Coverage ratio	0%	0%
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	£ 36,400	£ 32,800
Coverage ratio	0%	0%
Balance sheet asset | Internal grade 8 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 33,400	£ 29,700
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 35,900	£ 32,500
Coverage ratio	0%	0%
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	£ (100)	£ 200
Coverage ratio	0%	0%
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	£ 600	£ 100
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 2,200	£ 2,100
Coverage ratio	0%	0%
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	£ 86,000	£ 86,600
Coverage ratio	0%	0%
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	£ 85,700	£ 86,400
Coverage ratio	0%	0%
Balance sheet asset | Internal grade 7 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 82,300	£ 79,300
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 85,600	£ 84,500
Coverage ratio	0%	0%
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	£ 0	£ 800
Coverage ratio	0%	0%
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	£ 100	£ 1,100
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 300	£ 200
Coverage ratio	0%	0%
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	£ 53,200	£ 48,600
Coverage ratio	0%	0%
Balance sheet asset | Internal grade 6 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Balance sheet asset | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 53,200	£ 48,600
Coverage ratio	0%	0%
Balance sheet asset | Internal grade 6 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 45,000	£ 42,500
Coverage ratio	0%	0%
Balance sheet asset | Internal grade 6 | 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 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 ratio	0%	0%
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	£ 52,100	£ 48,000
Coverage ratio	0%	0%
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
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 ratio	0%	0%
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	£ 1,100	£ 600
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 0
Coverage ratio	0%	0%
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	£ 15,200	£ 12,800
Coverage ratio	1.30%	1.60%
Balance sheet asset | Internal grade 5 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 200
Balance sheet asset | Internal grade 5 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 15,200	£ 12,800
Coverage ratio	1.30%	1.60%
Balance sheet asset | Internal grade 5 | Financial assets at amortised cost | Credit risk | Exposures | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	£ 7,200	£ 6,400
Coverage ratio	1.40%	0%
Balance sheet asset | Internal grade 5 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 200
Balance sheet asset | Internal grade 5 | Financial assets at amortised cost | Credit risk | ECL | Mortgages
Disclosure of internal credit grades [line items]
Financial assets	100	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 ratio	0%	0%
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	£ 15,200	£ 12,800
Coverage ratio	1.30%	1.60%
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	£ 200
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 ratio	0%	0%
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
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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	£ 9,200	£ 10,200
Coverage ratio	2.20%	1%
Balance sheet asset | Internal grade 4 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
Balance sheet asset | Internal grade 4 | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 9,200	£ 10,200
Coverage ratio	2.20%	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	£ 3,800	£ 4,700
Coverage ratio	2.60%	2.10%
Balance sheet asset | Internal grade 4 | Financial assets at amortised cost | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 200	£ 100
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 ratio	0%	0%
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	£ 9,200	£ 10,200
Coverage ratio	2.20%	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	£ 200	£ 100
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 ratio	0%	0%
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
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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	£ 5,400	£ 6,000
Coverage ratio	9.30%	10%
Balance sheet asset | Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 500	£ 600
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	£ 5,400	£ 6,000
Coverage ratio	9.30%	10%
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	£ 3,100
Coverage ratio	0%	3.20%
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	£ 500	£ 600
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
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 ratio	0%	0%
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	£ 5,400	£ 6,000
Coverage ratio	9.30%	10%
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	£ 500	£ 600
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 ratio	0%	0%
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
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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	£ 8,800	£ 9,200
Coverage ratio	0%	0%
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	£ 8,800	£ 9,200
Coverage ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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	£ 7,700	£ 8,000
Coverage ratio	0%	0%
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	£ 1,000	£ 0
Coverage ratio	0%	0%
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	£ 100	£ 1,200
Coverage ratio	0%	0%
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
Coverage ratio	0%	0%
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 ratio	0%	0%
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	31,700	37,700
Credit impairment loss allowances on loans and advances to customers	£ (100)	£ 0
Coverage ratio	0.30%	0%
Off-balance sheet | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 0
Off-balance sheet | Internal grade 9 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 100
Coverage ratio	0%	0%
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	£ 7,200
Coverage ratio	0%	0%
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	£ 6,900	£ 7,000
Coverage ratio	0%	0%
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	£ 6,500	£ 6,800
Coverage ratio	0%	0%
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	£ 4,900	£ 4,500
Coverage ratio	0%	0%
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	£ 2,100	£ 1,300
Coverage ratio	0%	0%
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	£ 400	£ 500
Coverage ratio	25%	0%
Off-balance sheet | Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 0
Off-balance sheet | Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 3,700	£ 10,300
Coverage ratio	0%	0%
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	169,100	161,800
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	44,200	48,100
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	199,600	191,600
Credit impairment loss allowances on loans and advances to customers	£ (100)	£ (100)
Coverage ratio	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	£ 100
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	1,000	1,200
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	7,300	12,700
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	200	500
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	6,000	5,900
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	£ 9,500	£ 9,000
Coverage ratio	0%	0%
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	£ 44,200	£ 48,100
Coverage ratio	0%	0%
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	£ 9,500	£ 9,000
Coverage ratio	0%	0%
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	£ 100	£ 200
Coverage ratio	0%	0%
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	£ 5,400	£ 9,700
Coverage ratio	0%	0%
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	£ 200	£ 500
Coverage ratio	0%	0%
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	£ 3,500	£ 3,600
Coverage ratio	0%	0%
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	£ 33,100	£ 29,500
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 35,600	£ 31,700
Coverage ratio	0%	0%
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	£ (100)	£ 200
Coverage ratio	0%	0%
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	£ 600	£ 100
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 2,200	£ 2,100
Coverage ratio	0%	0%
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	£ 80,700	£ 78,000
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 83,900	£ 83,100
Coverage ratio	0%	0%
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	£ 0	£ 800
Coverage ratio	0%	0%
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	£ 100	£ 1,100
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 300	£ 200
Coverage ratio	0%	0%
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	£ 41,100	£ 39,600
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 47,900	£ 44,900
Coverage ratio	0%	0%
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	£ 0
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 ratio	0%	0%
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	£ 1,100	£ 600
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 0
Coverage ratio	0%	0%
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	£ 4,100
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 11,100	£ 10,000
Coverage ratio	0.90%	1%
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	£ 100
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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	£ 500	£ 1,600
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 3,900	£ 5,000
Coverage ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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	£ 100	£ 0
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 500	£ 600
Coverage ratio	0%	0%
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	£ 0
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	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 | 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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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	£ 7,300	£ 7,400
Coverage ratio	0%	0%
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	£ 1,000	£ 0
Coverage ratio	0%	0%
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	£ 100	£ 1,200
Coverage ratio	0%	0%
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
Coverage ratio	0%	0%
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 ratio	0%	0%
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	30,800	36,100
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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	£ 100
Coverage ratio	0%	0%
Stage 1 | Off-balance sheet | Internal grade 9 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Stage 1 | Off-balance sheet | Internal grade 8 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 7,200	£ 6,900
Coverage ratio	0%	0%
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	£ 6,800	£ 6,700
Coverage ratio	0%	0%
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	£ 6,400	£ 6,600
Coverage ratio	0%	0%
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	£ 4,700	£ 4,300
Coverage ratio	0%	0%
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	£ 1,700	£ 1,000
Coverage ratio	0%	0%
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 ratio	0%	0%
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	£ 3,700	£ 10,300
Coverage ratio	0%	0%
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	13,300	11,000
Credit impairment loss allowances on loans and advances to customers	£ (100)	£ (100)
Coverage ratio	0.80%	0.90%
Stage 2 | Balance sheet asset | 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 | Loans and advances to customers | Financial assets at amortised cost | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	17,800	16,000
Credit impairment loss allowances on loans and advances to customers	£ (500)	£ (400)
Coverage ratio	2.80%	2.50%
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	£ 500	£ 400
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 ratio	0%	0%
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 ratio	0%	0%
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	£ 300	£ 200
Coverage ratio	0%	0%
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	£ 300	£ 800
Coverage ratio	0%	0%
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	£ 1,600	£ 1,300
Coverage ratio	0%	0%
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	£ 1,700	£ 1,400
Coverage ratio	0%	0%
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	£ 3,900	£ 2,900
Coverage ratio	0%	0%
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	£ 4,200	£ 3,100
Coverage ratio	0%	0%
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	£ 3,100	£ 2,300
Coverage ratio	3.20%	0%
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	£ 100	£ 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	£ 4,100	£ 2,800
Coverage ratio	2.40%	3.60%
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	£ 3,200	£ 3,100
Coverage ratio	0%	3.20%
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	£ 0	£ 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	£ 5,200
Coverage ratio	3.80%	1.90%
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	£ 200	£ 100
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	£ 1,300
Coverage ratio	0%	0%
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	£ 0
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	£ 2,600	£ 2,800
Coverage ratio	7.70%	7.10%
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 ratio	0%	0%
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	£ 200	£ 300
Coverage ratio	0%	0%
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	800	1,500
Credit impairment loss allowances on loans and advances to customers	£ (100)	£ 0
Coverage ratio	12.50%	0%
Stage 2 | Off-balance sheet | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 0
Stage 2 | Off-balance sheet | Internal grade 9 | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage ratio	0%	0%
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	£ 0	£ 300
Coverage ratio	0%	0%
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	£ 100	£ 300
Coverage ratio	0%	0%
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	£ 100	£ 200
Coverage ratio	0%	0%
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	£ 200
Coverage ratio	0%	0%
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	£ 400	£ 300
Coverage ratio	0%	0%
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	£ 100	£ 200
Coverage ratio	100%	0%
Stage 2 | Off-balance sheet | Internal grade 3 to 1 | Credit risk | ECL
Disclosure of internal credit grades [line items]
Financial assets	£ 100	£ 0
Stage 2 | Off-balance sheet | Other | Credit risk | Exposures
Disclosure of internal credit grades [line items]
Financial assets	£ 0	£ 0
Coverage ratio	0%	0%
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
Credit impairment loss allowances on loans and advances to customers	£ (100)	£ (100)
Coverage ratio	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	2,300	2,500
Credit impairment loss allowances on loans and advances to customers	£ (300)	£ (400)
Coverage ratio	13%	16%
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	£ 300	£ 400
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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	£ 100	£ 0
Coverage ratio	100%	0%
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	£ 100	£ 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	£ 100	£ 0
Coverage ratio	0%	0%
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	£ 1,700	£ 1,800
Coverage ratio	0%	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	£ 0	£ 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	£ 2,300	£ 2,600
Coverage ratio	13%	15.40%
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	£ 300	£ 400
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 ratio	0%	0%
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	£ 200	£ 300
Coverage ratio	0%	0%
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
Credit impairment loss allowances on loans and advances to customers	£ 0	£ 0
Coverage ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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 ratio	0%	0%
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, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 219,716	£ 210,094
Loss allowance	1,005	865
Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers	247,500	245,000
Gross write- offs	156	190
Loss allowance	1,005	865
Loans to customers | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	215,700	207,300
Gross write- offs	156	190
Loss allowance	931	827
Loans to customers | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	31,800	37,700
Gross write- offs	0	0
Loss allowance	74	38
Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 225,700	£ 224,100
Exposure ratio
Loans to customers | Stage 1 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 194,900	£ 187,900
Exposure ratio	90.40%	90.60%
Loans to customers | Stage 1 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 30,800	£ 36,200
Exposure ratio
Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 19,200	£ 18,000
Exposure ratio
Loans to customers | Stage 2 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 18,300	£ 16,500
Exposure ratio	8.50%	7.90%
Loans to customers | Stage 2 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 900	£ 1,500
Exposure ratio
Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 2,600	£ 2,900
Exposure ratio
Loans to customers | Stage 3 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 2,500	£ 2,900
Exposure ratio	1.26%	1.45%
Loans to customers | Stage 3 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 100	£ 0
Exposure ratio
Retail Banking | Loans to customers | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 191,800	£ 183,000
Gross write- offs	113	107
Loss allowance	502	367
Retail Banking | Loans to customers | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	21,700	29,400
Gross write- offs	0	0
Loss allowance	42	21
Retail Banking | Loans to customers | Stage 1 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 175,400	£ 169,200
Exposure ratio	91.40%	92.50%
Retail Banking | Loans to customers | Stage 1 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 21,100	£ 29,200
Exposure ratio
Retail Banking | Loans to customers | Stage 2 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 14,400	£ 11,700
Exposure ratio	7.50%	6.40%
Retail Banking | Loans to customers | Stage 2 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 500	£ 200
Exposure ratio
Retail Banking | Loans to customers | Stage 3 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 2,000	£ 2,100
Exposure ratio	1.10%	1.10%
Retail Banking | Loans to customers | Stage 3 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 100	£ 0
Exposure ratio
Mortgages
Disclosure of credit risk exposure [line items]
Loss allowance	£ 251	£ 190
Mortgages | Loans to customers | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	184,300	174,700
Gross write- offs	3	5
Loss allowance	248	185
Mortgages | Loans to customers | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	8,000	16,000
Gross write- offs	0	0
Loss allowance	3	5
Mortgages | Loans to customers | Stage 1 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 169,100	£ 161,800
Exposure ratio	91.70%	92.60%
Mortgages | Loans to customers | Stage 1 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 7,900	£ 15,900
Exposure ratio
Mortgages | Loans to customers | Stage 2 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 13,400	£ 11,100
Exposure ratio	7.30%	6.40%
Mortgages | Loans to customers | Stage 2 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 100	£ 100
Exposure ratio
Mortgages | Loans to customers | Stage 3 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 1,800	£ 1,800
Exposure ratio	1%	1%
Mortgages | Loans to customers | Stage 3 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio
Credit cards
Disclosure of credit risk exposure [line items]
Loss allowance	£ 130	£ 89
Credit cards | Loans to customers | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,500	2,400
Gross write- offs	40	39
Loss allowance	120	82
Credit cards | Loans to customers | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	10,200	9,900
Gross write- offs	0	0
Loss allowance	10	7
Credit cards | Loans to customers | Stage 1 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 2,100	£ 2,200
Exposure ratio	85.70%	91.70%
Credit cards | Loans to customers | Stage 1 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 10,100	£ 9,900
Exposure ratio
Credit cards | Loans to customers | Stage 2 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 300	£ 200
Exposure ratio	12.90%	7.70%
Credit cards | Loans to customers | Stage 2 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 100	£ 0
Exposure ratio
Credit cards | Loans to customers | Stage 3 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 100	£ 0
Exposure ratio	2.53%	2.54%
Credit cards | Loans to customers | Stage 3 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio
Other
Disclosure of credit risk exposure [line items]
Loss allowance	£ 164	£ 109
Other | Loans to customers | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	5,000	5,900
Gross write- offs	70	63
Loss allowance	134	100
Other | Loans to customers | Total Drawn | BBLS
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,500
Other | Loans to customers | Total Drawn | BBLS 100% Government Guarantee
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 2,400
Government Guarantee, percentage	100%
Other | Loans to customers | Total Drawn | Unsecured personal loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 2,000
Other | Loans to customers | Total Drawn | Overdrafts
Disclosure of credit risk exposure [line items]
Loans and advances to customers	500
Other | Loans to customers | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	3,500	3,500
Gross write- offs	0	0
Loss allowance	29	9
Other | Loans to customers | Stage 1 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 4,200	£ 5,200
Exposure ratio	82.80%	88.10%
Other | Loans to customers | Stage 1 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 3,100	£ 3,400
Exposure ratio
Other | Loans to customers | Stage 2 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 700	£ 400
Exposure ratio	13%	6.60%
Other | Loans to customers | Stage 2 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 300	£ 100
Exposure ratio
Other | Loans to customers | Stage 3 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 100	£ 300
Exposure ratio	4.30%	4.90%
Other | Loans to customers | Stage 3 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 100	£ 0
Exposure ratio
Consumer Finance
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 5,384	£ 4,984
Gross write- offs	19	25
Loss allowance	67	52
Consumer Finance | Loans to customers | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	5,400	5,000
Gross write- offs	19	25
Loss allowance	£ 67	52
Lending, percentage collateralised on vehicle	84%
Consumer Finance | Loans to customers | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 400	300
Gross write- offs	0	0
Loss allowance	0	0
Consumer Finance | Loans to customers | Stage 1 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 5,000	£ 4,800
Exposure ratio	93%	96%
Consumer Finance | Loans to customers | Stage 1 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 400	£ 300
Exposure ratio
Consumer Finance | Loans to customers | Stage 2 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 400	£ 200
Exposure ratio	6.50%	4%
Consumer Finance | Loans to customers | Stage 2 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio
Consumer Finance | Loans to customers | Stage 3 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio	0.54%	0.48%
Consumer Finance | Loans to customers | Stage 3 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Loss allowance	£ 393	£ 425
Corporate & Commercial Banking | Loans to customers
Disclosure of credit risk exposure [line items]
Loans and advances to customers		19,300
Gross write- offs		58
Loss allowance		408
Corporate & Commercial Banking | Loans to customers | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	18,500
Gross write- offs	24
Loss allowance	362
Corporate & Commercial Banking | Loans to customers | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	9,700	8,000
Gross write- offs	0	0
Loss allowance	32	£ 17
Corporate & Commercial Banking | Loans to customers | Stage 1
Disclosure of credit risk exposure [line items]
Exposure ratio		72%
Corporate & Commercial Banking | Loans to customers | Stage 1 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 14,500	£ 13,900
Exposure ratio	78.30%
Corporate & Commercial Banking | Loans to customers | Stage 1 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 9,300	£ 6,700
Exposure ratio
Corporate & Commercial Banking | Loans to customers | Stage 2
Disclosure of credit risk exposure [line items]
Exposure ratio		23.90%
Corporate & Commercial Banking | Loans to customers | Stage 2 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 3,500	£ 4,600
Exposure ratio	18.80%
Corporate & Commercial Banking | Loans to customers | Stage 2 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 400	£ 1,300
Exposure ratio
Corporate & Commercial Banking | Loans to customers | Stage 3
Disclosure of credit risk exposure [line items]
Exposure ratio		4.28%
Corporate & Commercial Banking | Loans to customers | Stage 3 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 500	£ 800
Exposure ratio	3.08%
Corporate & Commercial Banking | Loans to customers | Stage 3 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio
Corporate Centre
Disclosure of credit risk exposure [line items]
Loss allowance	£ 0	£ 0
Corporate Centre | Loans to customers | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	0	0
Gross write- offs	0	0
Loss allowance	0	0
Corporate Centre | Loans to customers | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	0	0
Gross write- offs	0	0
Loss allowance	0	0
Corporate Centre | Loans to customers | Stage 1 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio	0%	0%
Corporate Centre | Loans to customers | Stage 1 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio
Corporate Centre | Loans to customers | Stage 2 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio	0%	0%
Corporate Centre | Loans to customers | Stage 2 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio
Corporate Centre | Loans to customers | Stage 3 | Total Drawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio	0%	0%
Corporate Centre | Loans to customers | Stage 3 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 0	£ 0
Exposure ratio

Credit Risk - Disclosure of IFR

Credit Risk - Disclosure of IFRS 9 Credit Quality (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Exposures	£ 306,284	£ 313,347
Loss allowance	1,005	865
Provisions	378	364
Total ECL	£ 1,005	£ 865
Coverage ratio	0.30%	0.30%
Retail mortgage offers in pipeline	£ 2,800	£ 10,600
Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	274,448	275,638
Loss allowance	£ 931	£ 827
Coverage ratio	0.30%	0.30%
Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 31,836	£ 37,709
Provisions	£ 74	£ 38
Coverage ratio	0.20%	0.10%
Customer loans | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 215,700	£ 207,300
Loans and advances to banks | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	1,000	1,200
Sovereign assets measured at amortized cost | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	7,500	13,200
Financial assets measured at fair value through other comprehensive income | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	6,000	5,900
Cash and balances at central banks | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	44,200	48,100
Retail Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	191,836	183,023
Loss allowance	£ 502	£ 367
Coverage ratio	0.30%	0.20%
Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 21,721	£ 29,372
Provisions	£ 42	£ 21
Coverage ratio	0.20%	0.10%
Mortgages
Disclosure of credit risk exposure [line items]
Loss allowance	£ 251	£ 190
Mortgages | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	184,317	174,712
Loss allowance	£ 248	£ 185
Coverage ratio	0.10%	0.10%
Mortgages | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 8,029	£ 15,951
Provisions	£ 3	£ 5
Coverage ratio	0%	0%
Credit cards
Disclosure of credit risk exposure [line items]
Loss allowance	£ 130	£ 89
Credit cards | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	2,557	2,341
Loss allowance	£ 120	£ 82
Coverage ratio	4.70%	3.50%
Credit cards | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 10,288	£ 9,960
Provisions	£ 10	£ 7
Coverage ratio	0.10%	0.10%
Other
Disclosure of credit risk exposure [line items]
Loss allowance	£ 164	£ 109
Other | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	4,962	5,970
Loss allowance	£ 134	£ 100
Coverage ratio	2.70%	1.70%
Other | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 3,404	£ 3,461
Provisions	£ 29	£ 9
Coverage ratio	0.90%	0.30%
Consumer Finance
Disclosure of credit risk exposure [line items]
Loss allowance	£ 67	£ 52
Consumer Finance | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	5,384	4,984
Loss allowance	£ 67	£ 52
Coverage ratio	1.20%	1%
Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 356	£ 314
Provisions	£ 0	£ 0
Coverage ratio	0%	0%
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Loss allowance	£ 393	£ 425
Corporate & Commercial Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	18,518	19,282
Loss allowance	£ 362	£ 408
Coverage ratio	2%	2.10%
Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 9,759	£ 8,023
Provisions	£ 32	£ 17
Coverage ratio	0.30%	0.20%
Corporate Centre
Disclosure of credit risk exposure [line items]
Loss allowance	£ 0	£ 0
Corporate Centre | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	58,710	68,349
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Provisions	£ 0
Coverage ratio	0%
Stage 1
Disclosure of credit risk exposure [line items]
Exposures	£ 284,428	292,366
Total ECL	£ 170	£ 132
Coverage ratio	0.10%	0%
Stage 1 | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 253,587	£ 256,254
Loss allowance	£ 144	£ 115
Coverage ratio	0.10%	0%
Stage 1 | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 30,841	£ 36,112
Provisions	£ 26	£ 17
Coverage ratio	0.10%	0%
Stage 1 | Retail Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 175,365	£ 169,255
Loss allowance	£ 56	£ 52
Coverage ratio	0%	0%
Stage 1 | Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 21,175	£ 29,123
Provisions	£ 12	£ 12
Coverage ratio	0.10%	0%
Stage 1 | Mortgages | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 169,066	£ 161,845
Loss allowance	£ 23	£ 8
Coverage ratio	0%	0%
Stage 1 | Mortgages | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 7,899	£ 15,851
Provisions	£ 2	£ 5
Coverage ratio	0%	0%
Stage 1 | Credit cards | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 2,192	£ 2,125
Loss allowance	£ 14	£ 15
Coverage ratio	0.60%	0.70%
Stage 1 | Credit cards | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 10,137	£ 9,887
Provisions	£ 3	£ 3
Coverage ratio	0%	0%
Stage 1 | Other | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 4,107	£ 5,285
Loss allowance	£ 19	£ 29
Coverage ratio	0.50%	0.50%
Stage 1 | Other | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 3,139	£ 3,385
Provisions	£ 7	£ 4
Coverage ratio	0.20%	0.10%
Stage 1 | Consumer Finance | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 5,005	£ 4,760
Loss allowance	£ 19	£ 18
Coverage ratio	0.40%	0.40%
Stage 1 | Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 356	£ 314
Provisions	£ 0	£ 0
Coverage ratio	0%	0%
Stage 1 | Corporate & Commercial Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 14,507	£ 13,890
Loss allowance	£ 69	£ 45
Coverage ratio	0.50%	0.30%
Stage 1 | Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 9,310	£ 6,675
Provisions	£ 14	£ 5
Coverage ratio	0.20%	0.10%
Stage 1 | Corporate Centre | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 58,710	£ 68,349
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 1 | Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Provisions	£ 0
Coverage ratio	0%
Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 19,127	17,964
Loss allowance	516	330
Total ECL	£ 516	£ 330
Coverage ratio	2.70%	1.80%
Stage 2 | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 18,225	£ 16,448
Loss allowance	£ 477	£ 314
Coverage ratio	2.60%	1.90%
Stage 2 | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 902	£ 1,516
Provisions	£ 39	£ 16
Coverage ratio	4.30%	1.10%
Stage 2 | Retail Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 14,399	£ 11,646
Loss allowance	£ 295	£ 178
Coverage ratio	2%	1.50%
Stage 2 | Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 490	£ 204
Provisions	£ 28	£ 8
Coverage ratio	5.70%	3.90%
Stage 2 | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	£ 13,424	£ 11,071
Loss allowance	£ 130	£ 88
Coverage ratio	1%	0.80%
Stage 2 | Mortgages | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 13,424	£ 11,071
Loss allowance	£ 130	£ 88
Coverage ratio	1%	0.80%
Stage 2 | Mortgages | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 109	£ 81
Provisions	£ 1	£ 0
Coverage ratio	0.90%	0%
Stage 2 | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	£ 328	£ 180
Loss allowance	£ 85	£ 47
Coverage ratio	25.90%	26.10%
Stage 2 | Credit cards | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 328	£ 181
Loss allowance	£ 85	£ 47
Coverage ratio	25.90%	26%
Stage 2 | Credit cards | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 122	£ 49
Provisions	£ 6	£ 3
Coverage ratio	4.90%	6.10%
Stage 2 | Other
Disclosure of credit risk exposure [line items]
Exposures	£ 647	£ 395
Loss allowance	£ 80	£ 43
Coverage ratio	12.40%	10.90%
Stage 2 | Other | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 647	£ 394
Loss allowance	£ 80	£ 43
Coverage ratio	12.40%	10.90%
Stage 2 | Other | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 259	£ 74
Provisions	£ 21	£ 5
Coverage ratio	8.10%	6.80%
Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 350	£ 200
Loss allowance	£ 27	£ 17
Coverage ratio	7.70%	8.50%
Stage 2 | Consumer Finance | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 350	£ 200
Loss allowance	£ 27	£ 17
Coverage ratio	7.70%	8.50%
Stage 2 | Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Provisions	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 3,476	£ 4,602
Loss allowance	£ 155	£ 119
Coverage ratio	4.50%	2.60%
Stage 2 | Corporate & Commercial Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 3,476	£ 4,602
Loss allowance	£ 155	£ 119
Coverage ratio	4.50%	2.60%
Stage 2 | Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 412	£ 1,312
Provisions	£ 11	£ 8
Coverage ratio	2.70%	0.60%
Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Corporate Centre | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Provisions	£ 0
Coverage ratio	0%
Stage 3
Disclosure of credit risk exposure [line items]
Exposures	£ 2,729	3,017
Total ECL	£ 319	£ 403
Coverage ratio	11.70%	13.40%
Stage 3 | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 2,636	£ 2,936
Loss allowance	£ 310	£ 398
Coverage ratio	11.80%	13.60%
Stage 3 | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 93	£ 81
Provisions	£ 9	£ 5
Coverage ratio	9.70%	6.20%
Stage 3 | Retail Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 2,072	£ 2,122
Loss allowance	£ 151	£ 137
Coverage ratio	7.30%	6.50%
Stage 3 | Retail Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 56	£ 45
Provisions	£ 2	£ 1
Coverage ratio	3.60%	2.20%
Stage 3 | Mortgages | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 1,827	£ 1,796
Loss allowance	£ 95	£ 89
Coverage ratio	5.20%	5%
Stage 3 | Mortgages | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 21	£ 19
Provisions	£ 0	£ 0
Coverage ratio	0%	0%
Stage 3 | Credit cards | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 37	£ 35
Loss allowance	£ 21	£ 20
Coverage ratio	56.80%	57.10%
Stage 3 | Credit cards | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 29	£ 24
Provisions	£ 1	£ 1
Coverage ratio	3.40%	4.20%
Stage 3 | Other | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 208	£ 291
Loss allowance	£ 35	£ 28
Coverage ratio	16.80%	9.60%
Stage 3 | Other | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 6	£ 2
Provisions	£ 1	£ 0
Coverage ratio	16.70%	0%
Stage 3 | Consumer Finance | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 29	£ 24
Loss allowance	£ 21	£ 17
Coverage ratio	72.40%	70.80%
Stage 3 | Consumer Finance | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Provisions	£ 0	£ 0
Coverage ratio	0%	0%
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 572	£ 828
Stage 3 | Corporate & Commercial Banking | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	535	790
Loss allowance	£ 138	£ 244
Coverage ratio	25.80%	30.90%
Stage 3 | Corporate & Commercial Banking | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 37	£ 36
Provisions	£ 7	£ 4
Coverage ratio	18.90%	11.10%
Stage 3 | Corporate Centre | Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 3 | Corporate Centre | Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Provisions	£ 0
Coverage ratio	0%

Credit Risk - Disclosure of Sta

Credit Risk - Disclosure of Stage 2 Exposures by Classification (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Exposures	£ 306,284	£ 313,347
Loss allowance	£ 1,005	£ 865
Coverage ratio	0.30%	0.30%
Mortgages
Disclosure of credit risk exposure [line items]
Loss allowance	£ 251	£ 190
Credit cards
Disclosure of credit risk exposure [line items]
Loss allowance	130	89
Other
Disclosure of credit risk exposure [line items]
Loss allowance	164	109
Consumer Finance
Disclosure of credit risk exposure [line items]
Loss allowance	67	52
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Loss allowance	393	425
Corporate Centre
Disclosure of credit risk exposure [line items]
Loss allowance	0	0
Stage 2
Disclosure of credit risk exposure [line items]
Exposures	19,127	17,964
Loss allowance	£ 516	£ 330
Coverage ratio	2.70%	1.80%
Stage 2 | Total Drawn
Disclosure of credit risk exposure [line items]
Exposures	£ 18,225	£ 16,448
Loss allowance	£ 477	£ 314
Coverage ratio	2.60%	1.90%
Stage 2 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loss allowance	£ 39	£ 16
Stage 2 | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	13,424	11,071
Loss allowance	£ 130	£ 88
Coverage ratio	1%	0.80%
Stage 2 | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	£ 328	£ 180
Loss allowance	£ 85	£ 47
Coverage ratio	25.90%	26.10%
Stage 2 | Other
Disclosure of credit risk exposure [line items]
Exposures	£ 647	£ 395
Loss allowance	£ 80	£ 43
Coverage ratio	12.40%	10.90%
Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 350	£ 200
Loss allowance	£ 27	£ 17
Coverage ratio	7.70%	8.50%
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 3,476	£ 4,602
Loss allowance	£ 155	£ 119
Coverage ratio	4.50%	2.60%
Stage 2 | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | PD deterioration
Disclosure of credit risk exposure [line items]
Exposures	£ 10,323	£ 6,373
Loss allowance	303	153
Stage 2 | PD deterioration | Total Drawn
Disclosure of credit risk exposure [line items]
Exposures	9,560	5,906
Loss allowance	£ 284	£ 145
Coverage ratio	3%	2.50%
Stage 2 | PD deterioration | Total Undrawn
Disclosure of credit risk exposure [line items]
Loss allowance	£ 19	£ 8
Stage 2 | PD deterioration | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	7,310	5,091
Loss allowance	£ 86	£ 57
Coverage ratio	1.20%	1.10%
Stage 2 | PD deterioration | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	£ 239	£ 160
Loss allowance	£ 63	£ 41
Coverage ratio	26.40%	25.60%
Stage 2 | PD deterioration | Other
Disclosure of credit risk exposure [line items]
Exposures	£ 304	£ 150
Loss allowance	£ 43	£ 22
Coverage ratio	14.10%	14.70%
Stage 2 | PD deterioration | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 159	£ 42
Loss allowance	£ 11	£ 6
Coverage ratio	6.90%	14.30%
Stage 2 | PD deterioration | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 1,548	£ 463
Loss allowance	£ 81	£ 19
Coverage ratio	5.20%	4.10%
Stage 2 | PD deterioration | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%
Stage 2 | Forbearance
Disclosure of credit risk exposure [line items]
Exposures	£ 625	£ 1,004
Loss allowance	6	15
Stage 2 | Forbearance | Total Drawn
Disclosure of credit risk exposure [line items]
Exposures	513	933
Loss allowance	£ 6	£ 14
Coverage ratio	1.20%	1.50%
Stage 2 | Forbearance | Total Undrawn
Disclosure of credit risk exposure [line items]
Loss allowance	£ 0	£ 1
Stage 2 | Forbearance | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	449	650
Loss allowance	£ 2	£ 4
Coverage ratio	0.40%	0.60%
Stage 2 | Forbearance | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Forbearance | Other
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Forbearance | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 11
Loss allowance	£ 0	£ 2
Coverage ratio	0%	18.20%
Stage 2 | Forbearance | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 64	£ 272
Loss allowance	£ 4	£ 8
Coverage ratio	6.30%	2.90%
Stage 2 | Forbearance | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%
Stage 2 | Other
Disclosure of credit risk exposure [line items]
Exposures	£ 1,116	£ 1,302
Loss allowance	30	27
Stage 2 | Other | Total Drawn
Disclosure of credit risk exposure [line items]
Exposures	1,137	1,194
Loss allowance	£ 22	£ 26
Coverage ratio	1.90%	2.20%
Stage 2 | Other | Total Undrawn
Disclosure of credit risk exposure [line items]
Loss allowance	£ 8	£ 1
Stage 2 | Other | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	241	600
Loss allowance	£ 5	£ 2
Coverage ratio	2.10%	0.30%
Stage 2 | Other | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	£ 22	£ 13
Loss allowance	£ 4	£ 2
Coverage ratio	18.20%	15.40%
Stage 2 | Other | Other
Disclosure of credit risk exposure [line items]
Exposures	£ 26	£ 6
Loss allowance	£ 6	£ 1
Coverage ratio	23.10%	16.70%
Stage 2 | Other | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 164	£ 130
Loss allowance	£ 6	£ 4
Coverage ratio	3.70%	3.10%
Stage 2 | Other | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 684	£ 445
Loss allowance	£ 1	£ 17
Coverage ratio	0.10%	3.80%
Stage 2 | Other | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%
Stage 2 | 30 DPD
Disclosure of credit risk exposure [line items]
Exposures	£ 937	£ 1,183
Loss allowance	54	39
Stage 2 | 30 DPD | Total Drawn
Disclosure of credit risk exposure [line items]
Exposures	890	1,065
Loss allowance	£ 48	£ 37
Coverage ratio	5.40%	3.50%
Stage 2 | 30 DPD | Total Undrawn
Disclosure of credit risk exposure [line items]
Loss allowance	£ 6	£ 2
Stage 2 | 30 DPD | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	463	489
Loss allowance	£ 10	£ 7
Coverage ratio	2.20%	1.40%
Stage 2 | 30 DPD | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	£ 8	£ 7
Loss allowance	£ 4	£ 4
Coverage ratio	50%	57.10%
Stage 2 | 30 DPD | Other
Disclosure of credit risk exposure [line items]
Exposures	£ 178	£ 239
Loss allowance	£ 14	£ 20
Coverage ratio	7.90%	8.40%
Stage 2 | 30 DPD | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 27	£ 17
Loss allowance	£ 10	£ 5
Coverage ratio	37%	29.40%
Stage 2 | 30 DPD | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 214	£ 313
Loss allowance	£ 10	£ 1
Coverage ratio	4.70%	0.30%
Stage 2 | 30 DPD | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%
Stage 2 | Mortgages affordability
Disclosure of credit risk exposure [line items]
Exposures	£ 4,961	£ 4,272
Loss allowance	27	18
Stage 2 | Mortgages affordability | Total Drawn
Disclosure of credit risk exposure [line items]
Exposures	4,961	4,241
Loss allowance	£ 27	£ 18
Coverage ratio	0.50%	0.40%
Stage 2 | Mortgages affordability | Total Undrawn
Disclosure of credit risk exposure [line items]
Loss allowance	£ 0	£ 0
Stage 2 | Mortgages affordability | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	4,961	4,241
Loss allowance	£ 27	£ 18
Coverage ratio	0.50%	0.40%
Stage 2 | Mortgages affordability | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Mortgages affordability | Other
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Mortgages affordability | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Mortgages affordability | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Mortgages affordability | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%
Stage 2 | Retail Unsecured affordability
Disclosure of credit risk exposure [line items]
Exposures	£ 199	£ 0
Loss allowance	35	0
Stage 2 | Retail Unsecured affordability | Total Drawn
Disclosure of credit risk exposure [line items]
Exposures	198	0
Loss allowance	£ 31	£ 0
Coverage ratio	15.70%	0%
Stage 2 | Retail Unsecured affordability | Total Undrawn
Disclosure of credit risk exposure [line items]
Loss allowance	£ 4	£ 0
Stage 2 | Retail Unsecured affordability | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	0	0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Retail Unsecured affordability | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	£ 59	£ 0
Loss allowance	£ 14	£ 0
Coverage ratio	23.70%	0%
Stage 2 | Retail Unsecured affordability | Other
Disclosure of credit risk exposure [line items]
Exposures	£ 139	£ 0
Loss allowance	£ 17	£ 0
Coverage ratio	12.20%	0%
Stage 2 | Retail Unsecured affordability | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Retail Unsecured affordability | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | Retail Unsecured affordability | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%
Stage 2 | High risk corporate
Disclosure of credit risk exposure [line items]
Exposures	£ 966	£ 3,830
Loss allowance	61	78
Stage 2 | High risk corporate | Total Drawn
Disclosure of credit risk exposure [line items]
Exposures	966	3,109
Loss allowance	£ 59	£ 74
Coverage ratio	6.10%	2.40%
Stage 2 | High risk corporate | Total Undrawn
Disclosure of credit risk exposure [line items]
Loss allowance	£ 2	£ 4
Stage 2 | High risk corporate | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	0	0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | High risk corporate | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | High risk corporate | Other
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | High risk corporate | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%	0%
Stage 2 | High risk corporate | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	£ 966	£ 3,109
Loss allowance	£ 59	£ 74
Coverage ratio	6.10%	2.40%
Stage 2 | High risk corporate | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	£ 0	£ 0
Loss allowance	£ 0	£ 0
Coverage ratio	0%

Credit Risk - Disclosure of S_2

Credit Risk - Disclosure of Stage 2 Decomposition Cure and Not Cure Explanatory (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Exposures	£ 306,284	£ 313,347
Loss allowance	£ 1,005	£ 865
Coverage ratio	0.30%	0.30%
Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 19,127	£ 17,964
Loss allowance	£ 516	£ 330
Coverage ratio	2.70%	1.80%
Stage 2 not in cure period | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 13,001	£ 13,302
Loss allowance	£ 439	£ 286
Coverage ratio	3.40%	2.20%
Stage 2 in cure period (for transfer to Stage 1) | Stage 2
Disclosure of credit risk exposure [line items]
Exposures	£ 6,126	£ 4,662
Loss allowance	£ 77	£ 44
Coverage ratio	1.30%	0.90%

Credit Risk - Disclosure of S_3

Credit Risk - Disclosure of Stage 3 Decomposition Cure and Not Cure Explanatory (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Exposures	£ 306,284	£ 313,347
Loss allowance	£ 1,005	£ 865
Coverage ratio	0.30%	0.30%
Stage 3
Disclosure of credit risk exposure [line items]
Exposures	£ 2,729	£ 3,017
Loss allowance	£ 319	£ 403
Coverage ratio	11.70%	13.40%
Stage 3 | Stage 3 not in cure period
Disclosure of credit risk exposure [line items]
Exposures	£ 2,415
Loss allowance	£ 285
Coverage ratio	11.80%
Stage 3 | Stage 3 in cure period (for transfer to Stage 2)
Disclosure of credit risk exposure [line items]
Exposures	£ 314
Loss allowance	£ 34
Coverage ratio	10.80%

Credit Risk - Disclosure of Rec

Credit Risk - Disclosure of Reconciliation of Exposures, ECL and Net Carrying Amounts (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of credit risk exposure [line items]
Exposures	£ 306,284	£ 313,347
Loss allowance	1,005	865
Assets classified at FVTPL	113	173
Total assets	285,213	287,098	£ 292,332
Loss allowance	378	364
Macro hedge of interest rate risk	(2,657)	77
Retail Banking
Disclosure of credit risk exposure [line items]
Total assets	200,872	190,629	183,154
Mortgages
Disclosure of credit risk exposure [line items]
Loss allowance	251	190
Credit cards
Disclosure of credit risk exposure [line items]
Loss allowance	130	89
Other
Disclosure of credit risk exposure [line items]
Loss allowance	164	109
Consumer Finance
Disclosure of credit risk exposure [line items]
Loss allowance	67	52
Total assets	10,371	8,873	11,143
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Loss allowance	393	425
Total assets	18,518	19,281	20,820
Corporate Centre
Disclosure of credit risk exposure [line items]
Loss allowance	0	0
Total assets	55,452	68,315	£ 74,431
Balance sheet asset
Disclosure of credit risk exposure [line items]
Exposures	274,448	275,638
Loss allowance	931	827
Net carrying amount	273,517	274,810
Joint ventures	4,164	3,079
Other items	745	553
Adjusted net carrying amount	278,426	278,442
Assets classified at FVTPL	2,536	1,866
Non-financial assets	4,251	6,790
Total assets	285,213	287,098
Balance sheet asset | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	191,836	183,023
Loss allowance	502	367
Net carrying amount	191,334	182,656
Balance sheet asset | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	184,317	174,712
Loss allowance	248	185
Net carrying amount	184,069	174,527
Balance sheet asset | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	2,557	2,341
Loss allowance	120	82
Net carrying amount	2,437	2,259
Balance sheet asset | Other
Disclosure of credit risk exposure [line items]
Exposures	4,962	5,970
Loss allowance	134	100
Net carrying amount	4,828	5,870
Balance sheet asset | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	5,384	4,984
Loss allowance	67	52
Net carrying amount	5,317	4,932
Balance sheet asset | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	18,518	19,282
Loss allowance	362	408
Net carrying amount	18,156	18,874
Balance sheet asset | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	58,710	68,349
Loss allowance	0	0
Net carrying amount	58,710	68,349
Off-balance sheet
Disclosure of credit risk exposure [line items]
Exposures	31,836	37,709
Loss allowance	74	38
Off-balance sheet | Retail Banking
Disclosure of credit risk exposure [line items]
Exposures	21,721	29,372
Loss allowance	42	21
Off-balance sheet | Mortgages
Disclosure of credit risk exposure [line items]
Exposures	8,029	15,951
Loss allowance	3	5
Off-balance sheet | Credit cards
Disclosure of credit risk exposure [line items]
Exposures	10,288	9,960
Loss allowance	10	7
Off-balance sheet | Other
Disclosure of credit risk exposure [line items]
Exposures	3,404	3,461
Loss allowance	29	9
Off-balance sheet | Consumer Finance
Disclosure of credit risk exposure [line items]
Exposures	356	314
Loss allowance	0	0
Off-balance sheet | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	9,759	8,023
Loss allowance	32	17
Off-balance sheet | Corporate Centre
Disclosure of credit risk exposure [line items]
Exposures	0	0
Loss allowance	£ 0	£ 0

Credit Risk - Disclosure of E_2

Credit Risk - Disclosure of ECL Reconciliation (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	£ 865
Ending balance	1,005	£ 865
Less: Recoveries net of collection costs	(36)	17	£ 24
ECL charge/(release) to the Income Statement from continued operations	320	(233)	638
ECL
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	865	1,377
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	98	(43)
Change in economic scenarios	163	(170)
Changes to model	0
New lending and assets purchased	142	76
Redemptions, repayments and assets sold	(130)	(205)
Changes in risk parameters and other movements	24	21
Assets written off	(157)	(191)
Ending balance	1,005	865	1,377
Net movement in the period	140	(512)
ECL charge/(release) to the Income Statement	297	(321)
Less: Discount unwind	(13)	(11)
Less: Recoveries net of collection costs	36	88
Total ECL charge/(release) to the Income Statement	320	(244)
Discontinued operations ECL adjustment	0	11
ECL charge/(release) to the Income Statement from continued operations	320	(233)
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	132
Ending balance	170	132
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	330
Ending balance	516	330
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	403
Ending balance	319	403
Exposures
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	313,347	322,745
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	49,377	51,823
Redemptions, repayments and assets sold	(57,561)	(67,619)
Changes in risk parameters and other movements	1,375	6,695
Assets written off	(254)	(297)
Ending balance	306,284	313,347	322,745
Net movement in the period	(7,063)	(9,398)
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	132	216
Transfers from Stage 1 to Stage 2	(25)	(9)
Transfers from Stage 2 to Stage 1	133	167
Transfers to Stage 3	(4)	(3)
Transfers from Stage 3	1	2
Transfers of financial instruments	105	157
Net ECL remeasurement on stage transfer	(110)	(133)
Change in economic scenarios	37	(7)
Changes to model	0
New lending and assets purchased	42	31
Redemptions, repayments and assets sold	(35)	(70)
Changes in risk parameters and other movements	(1)	(62)
Assets written off	0	0
Ending balance	170	132	216
Net movement in the period	38	(84)
ECL charge/(release) to the Income Statement	38	(84)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	38	(84)
Discontinued operations ECL adjustment	0	11
ECL charge/(release) to the Income Statement from continued operations	38	(73)
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	292,366	301,413
Transfers from Stage 1 to Stage 2	(9,100)	(6,805)
Transfers from Stage 2 to Stage 1	7,207	5,883
Transfers to Stage 3	(621)	(571)
Transfers from Stage 3	10	14
Transfers of financial instruments	(2,504)	(1,479)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	48,194	50,862
Redemptions, repayments and assets sold	(54,546)	(63,658)
Changes in risk parameters and other movements	918	5,228
Assets written off	0	0
Ending balance	284,428	292,366	301,413
Net movement in the period	(7,938)	(9,047)
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	330	592
Transfers from Stage 1 to Stage 2	25	9
Transfers from Stage 2 to Stage 1	(133)	(167)
Transfers to Stage 3	(32)	(20)
Transfers from Stage 3	150	62
Transfers of financial instruments	10	(116)
Net ECL remeasurement on stage transfer	98	26
Change in economic scenarios	123	(151)
Changes to model	0
New lending and assets purchased	76	26
Redemptions, repayments and assets sold	(60)	(67)
Changes in risk parameters and other movements	(61)	20
Assets written off	0	0
Ending balance	516	330	592
Net movement in the period	186	(262)
ECL charge/(release) to the Income Statement	186	(262)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
Total ECL charge/(release) to the Income Statement	186	(262)
Discontinued operations ECL adjustment	0	0
ECL charge/(release) to the Income Statement from continued operations	186	(262)
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	17,964	18,336
Transfers from Stage 1 to Stage 2	9,100	6,805
Transfers from Stage 2 to Stage 1	(7,207)	(5,883)
Transfers to Stage 3	(624)	(532)
Transfers from Stage 3	758	456
Transfers of financial instruments	2,027	846
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	1,119	936
Redemptions, repayments and assets sold	(2,065)	(3,442)
Changes in risk parameters and other movements	82	1,288
Assets written off	0	0
Ending balance	19,127	17,964	18,336
Net movement in the period	1,163	(372)
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	403	569
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	36	23
Transfers from Stage 3	(151)	(64)
Transfers of financial instruments	(115)	(41)
Net ECL remeasurement on stage transfer	110	64
Change in economic scenarios	3	(12)
Changes to model	0
New lending and assets purchased	24	19
Redemptions, repayments and assets sold	(35)	(68)
Changes in risk parameters and other movements	86	63
Assets written off	(157)	(191)
Ending balance	319	403	569
Net movement in the period	(84)	(166)
ECL charge/(release) to the Income Statement	73	25
Less: Discount unwind	(13)	(11)
Less: Recoveries net of collection costs	36	88
Total ECL charge/(release) to the Income Statement	96	102
Discontinued operations ECL adjustment	0	0
ECL charge/(release) to the Income Statement from continued operations	96	102
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	3,017	2,996
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	1,245	1,103
Transfers from Stage 3	(768)	(470)
Transfers of financial instruments	477	633
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	64	25
Redemptions, repayments and assets sold	(950)	(519)
Changes in risk parameters and other movements	375	179
Assets written off	(254)	(297)
Ending balance	2,729	3,017	£ 2,996
Net movement in the period	£ (288)	£ 21

Credit Risk - Disclosure of Cou

Credit Risk - Disclosure of Country Risk Exposure (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Exposures	£ 306,284	£ 313,347
Total
Disclosure of credit risk exposure [line items]
Exposures	306,100	313,800
Governments
Disclosure of credit risk exposure [line items]
Exposures	47,000	50,100
Banks
Disclosure of credit risk exposure [line items]
Exposures	5,300	4,700
Other
Disclosure of credit risk exposure [line items]
Exposures	8,900	15,000
Retail
Disclosure of credit risk exposure [line items]
Exposures	217,300	215,100
Corporate
Disclosure of credit risk exposure [line items]
Exposures	27,600	28,900
Eurozone | Netherlands
Disclosure of credit risk exposure [line items]
Exposures	100	200
Eurozone | Belgium
Disclosure of credit risk exposure [line items]
Exposures	600	700
Eurozone | Finland
Disclosure of credit risk exposure [line items]
Exposures	100	0
Eurozone | Total
Disclosure of credit risk exposure [line items]
Exposures	5,000	7,600
Eurozone | Total | Ireland
Disclosure of credit risk exposure [line items]
Exposures	2,400	5,300
Eurozone | Total | Spain
Disclosure of credit risk exposure [line items]
Exposures	0	100
Eurozone | Total | France
Disclosure of credit risk exposure [line items]
Exposures	1,400	600
Eurozone | Total | Germany
Disclosure of credit risk exposure [line items]
Exposures	400	400
Eurozone | Total | Luxembourg
Disclosure of credit risk exposure [line items]
Exposures	0	100
Eurozone | Total | Other
Disclosure of credit risk exposure [line items]
Exposures	800	1,100
Eurozone | Governments
Disclosure of credit risk exposure [line items]
Exposures	400	400
Eurozone | Governments | Ireland
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	300
Eurozone | Banks
Disclosure of credit risk exposure [line items]
Exposures	1,600	1,500
Eurozone | Banks | Ireland
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	800	300
Eurozone | Banks | Germany
Disclosure of credit risk exposure [line items]
Exposures	300	400
Eurozone | Banks | Luxembourg
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Banks | Other
Disclosure of credit risk exposure [line items]
Exposures	500	800
Eurozone | Other
Disclosure of credit risk exposure [line items]
Exposures	2,800	5,600
Eurozone | Other | Ireland
Disclosure of credit risk exposure [line items]
Exposures	2,300	5,300
Eurozone | Other | Spain
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Other | France
Disclosure of credit risk exposure [line items]
Exposures	500	200
Eurozone | Other | Germany
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Other | Luxembourg
Disclosure of credit risk exposure [line items]
Exposures	0	100
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 | 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	200	100
Eurozone | Corporate | Ireland
Disclosure of credit risk exposure [line items]
Exposures	100	0
Eurozone | Corporate | Spain
Disclosure of credit risk exposure [line items]
Exposures	0	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	100	0
Eurozone | Corporate | Luxembourg
Disclosure of credit risk exposure [line items]
Exposures	0	0
Eurozone | Corporate | Other
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Total | UK
Disclosure of credit risk exposure [line items]
Exposures	295,900	303,000
Other countries | Total | US
Disclosure of credit risk exposure [line items]
Exposures	1,100	1,300
Other countries | Total | Japan
Disclosure of credit risk exposure [line items]
Exposures	1,400	1,200
Other countries | Total | Switzerland
Disclosure of credit risk exposure [line items]
Exposures	1,200	0
Other countries | Total | Other
Disclosure of credit risk exposure [line items]
Exposures	1,500	700
Other countries | Governments | UK
Disclosure of credit risk exposure [line items]
Exposures	44,100	47,900
Other countries | Governments | US
Disclosure of credit risk exposure [line items]
Exposures	100	500
Other countries | Governments | Japan
Disclosure of credit risk exposure [line items]
Exposures	1,100	1,000
Other countries | Governments | Switzerland
Disclosure of credit risk exposure [line items]
Exposures	1,200	0
Other countries | Governments | Other
Disclosure of credit risk exposure [line items]
Exposures	100	300
Other countries | Banks | UK
Disclosure of credit risk exposure [line items]
Exposures	1,800	2,000
Other countries | Banks | US
Disclosure of credit risk exposure [line items]
Exposures	900	800
Other countries | Banks | Japan
Disclosure of credit risk exposure [line items]
Exposures	300	200
Other countries | Banks | Switzerland
Disclosure of credit risk exposure [line items]
Exposures	0	0
Other countries | Banks | Other
Disclosure of credit risk exposure [line items]
Exposures	700	200
Other countries | Other | UK
Disclosure of credit risk exposure [line items]
Exposures	5,800	9,300
Other countries | Other | US
Disclosure of credit risk exposure [line items]
Exposures	100	0
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 | Other
Disclosure of credit risk exposure [line items]
Exposures	200	100
Other countries | Retail | UK
Disclosure of credit risk exposure [line items]
Exposures	217,300	215,100
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 | Other
Disclosure of credit risk exposure [line items]
Exposures		0
Other countries | Corporate | UK
Disclosure of credit risk exposure [line items]
Exposures	26,900	28,700
Other countries | Corporate | US
Disclosure of credit risk exposure [line items]
Exposures	0	0
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 | Other
Disclosure of credit risk exposure [line items]
Exposures	500	100
All countries excluding Eurozone countries | Total
Disclosure of credit risk exposure [line items]
Exposures	301,100	306,200
All countries excluding Eurozone countries | Governments
Disclosure of credit risk exposure [line items]
Exposures	46,600	49,700
All countries excluding Eurozone countries | Banks
Disclosure of credit risk exposure [line items]
Exposures	3,700	3,200
All countries excluding Eurozone countries | Other
Disclosure of credit risk exposure [line items]
Exposures	6,100	9,400
All countries excluding Eurozone countries | Retail
Disclosure of credit risk exposure [line items]
Exposures	217,300	215,100
All countries excluding Eurozone countries | Corporate
Disclosure of credit risk exposure [line items]
Exposures	£ 27,400	£ 28,800

Credit Risk - Disclosure of Bal

Credit Risk - Disclosure of Balances with Other Banco Santander Companies (Details) - Santander UK Group Holdings plc - GBP (£) £ in Billions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of detailed information about financial instruments [line items]
Financial assets	£ 5.6	£ 4.1
Financial liabilities	17.4	13.5
Spain
Disclosure of detailed information about financial instruments [line items]
Financial assets	1.4	0.8
Financial liabilities	1.8	1.3
UK
Disclosure of detailed information about financial instruments [line items]
Financial assets	4.2	3.3
Financial liabilities	15.6	12.1
Uruguay
Disclosure of detailed information about financial instruments [line items]
Financial liabilities	0	0.1
Banks
Disclosure of detailed information about financial instruments [line items]
Financial assets	1.4	0.8
Financial liabilities	1.7	1.3
Banks | Spain
Disclosure of detailed information about financial instruments [line items]
Financial assets	1.4	0.8
Financial liabilities	1.7	1.2
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	0.1
Other
Disclosure of detailed information about financial instruments [line items]
Financial assets	4.2	3.3
Financial liabilities	15.7	12.2
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	4.2	3.3
Financial liabilities	15.6	12.1
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 Bor

Credit Risk - Disclosure of Borrower Profile (Details) - Credit risk - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 184,317	£ 174,712
Percentage of residential mortgage loans	100%	100%
New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 34,127	£ 32,013
Percentage of residential mortgage loans	100%	100%
Home movers | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 76,357	£ 74,657
Percentage of residential mortgage loans	41%	42%
Home movers | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 12,221	£ 13,537
Percentage of residential mortgage loans	36%	43%
Remortgagers | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 53,190	£ 50,645
Percentage of residential mortgage loans	29%	29%
Remortgagers | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 10,644	£ 8,031
Percentage of residential mortgage loans	31%	25%
First-time buyers | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 37,971	£ 34,517
Percentage of residential mortgage loans	21%	20%
First-time buyers | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 8,129	£ 6,206
Percentage of residential mortgage loans	24%	19%
Buy-to-let | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 16,799	£ 14,893
Percentage of residential mortgage loans	9%	9%
Buy-to-let | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 3,133	£ 4,239
Percentage of residential mortgage loans	9%	13%

Credit Risk - Homes Credit Risk

Credit Risk - Homes Credit Risk Review, Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Advances and flexible mortgage drawdowns	£ 1,200	£ 1,400
Percentage of customers with a maturing mortgage retained	81%	83%
Part of loans in negative equity, uncollateralized	£ 48	£ 75
Average LTV of mortgage total new lending, in London	66%	64%
Internal remortgages
Disclosure of credit risk exposure [line items]
Internal remortgages	£ 24,900	£ 29,800

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, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 184,317	£ 174,712
Percentage of residential mortgage loans	100%	100%
Fixed rate
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 163,622	£ 147,147
Percentage of residential mortgage loans	89%	84%
Fixed rate | No later than one year
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 38,233	£ 29,644
Percentage of residential mortgage loans	21%	17%
Fixed rate | Later than 1 year but no later than 3 years
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 38,213	£ 40,967
Percentage of residential mortgage loans	21%	23%
Fixed rate | Later than 3 years but no later than 4 years
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 24,310	£ 24,074
Percentage of residential mortgage loans	13%	14%
Fixed rate | Later than 4 years but no later than 5 years
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 24,888	£ 21,140
Percentage of residential mortgage loans	14%	12%
Fixed rate | Later than five years
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 37,978	£ 31,322
Percentage of residential mortgage loans	21%	18%
Variable rate
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 12,430	£ 17,010
Percentage of residential mortgage loans	7%	10%
Standard Variable Rate (SVR)
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 5,645	£ 7,836
Percentage of residential mortgage loans	3%	4%
Follow on Rate (FoR)
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 2,620	£ 2,719
Percentage of residential mortgage loans	1%	2%

Credit Risk - Disclosure of Geo

Credit Risk - Disclosure of Geographic Distribution of Mortgage Assets Stock (Details) - Credit risk - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 184,317	£ 174,712
New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	34,127	32,013
London | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	47,000	44,600
London | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	8,300	8,300
Midlands and East Anglia | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	25,600	23,800
Midlands and East Anglia | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	5,300	4,700
North | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	24,400	23,100
North | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	4,700	3,800
Northern Ireland | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	2,900	3,000
Northern Ireland | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	300	300
Scotland | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	6,800	6,600
Scotland | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	1,200	1,000
South East excluding London | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	58,400	55,500
South East excluding London | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	10,600	10,500
South West, Wales and other | Stock
Disclosure of credit risk exposure [line items]
Residential mortgage loans	19,200	18,100
South West, Wales and other | New business
Disclosure of credit risk exposure [line items]
Residential mortgage loans	£ 3,700	£ 3,400

Credit Risk - Disclosure of Mor

Credit Risk - Disclosure of Mortgage Loan Size (Details) - Credit risk - GBP (£) £ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Stock
Disclosure of credit risk exposure [line items]
Mortgage loans average size	£ 183	£ 174
New business
Disclosure of credit risk exposure [line items]
Mortgage loans average size	£ 237	£ 234
Over £1.0m
Disclosure of credit risk exposure [line items]
Mortgage loan size, percentage	2%	2%
£0.5m to £1.0m
Disclosure of credit risk exposure [line items]
Mortgage loan size, percentage	10%	9%
£0.25m to £0.5m
Disclosure of credit risk exposure [line items]
Mortgage loan size, percentage	31%	30%
Below £0.25m
Disclosure of credit risk exposure [line items]
Mortgage loan size, percentage	57%	59%

Credit Risk - Disclosure of LTV

Credit Risk - Disclosure of LTV Distribution of Mortgage Assets Stock (Details) - Credit risk - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	£ 184,317	£ 174,712
Collateral value, stock	184,269	174,637
Loan-to-value, stage 3	1,827	1,796
Collateral value, stage 3	1,818	1,784
Loan-to-value, new business	34,127	32,013
Collateral value, new business	34,126	32,012
Collateral against loans in negative equity	323	455
ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	252	190
Loan-to-value, stage 3	95	89
Up to 50%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	87,379	78,911
Loan-to-value, stage 3	1,111	942
Loan-to-value, new business	4,890	4,997
Up to 50% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	37	25
Loan-to-value, stage 3	14	9
>50-60%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	35,664	30,328
Loan-to-value, stage 3	283	301
Loan-to-value, new business	4,014	4,379
>50-60% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	29	22
Loan-to-value, stage 3	11	10
>60-70%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	33,868	32,803
Loan-to-value, stage 3	197	227
Loan-to-value, new business	6,104	6,517
>60-70% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	50	25
Loan-to-value, stage 3	16	11
>70-80%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	17,824	24,217
Loan-to-value, stage 3	110	154
Loan-to-value, new business	10,094	10,242
>70-80% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	45	30
Loan-to-value, stage 3	15	14
>80-90%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	7,339	6,565
Loan-to-value, stage 3	42	68
Loan-to-value, new business	6,002	4,558
>80-90% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	29	21
Loan-to-value, stage 3	9	10
>90-100%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	1,873	1,360
Loan-to-value, stage 3	32	39
Loan-to-value, new business	2,999	1,270
>90-100% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	17	16
Loan-to-value, stage 3	9	9
>100%
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	370	528
Loan-to-value, stage 3	52	65
Loan-to-value, new business	24	50
>100% | ECL
Disclosure of credit risk exposure [line items]
Loan-to-value, stock	45	51
Loan-to-value, stage 3	£ 21	£ 26
Average LTV - Balance weighted
Disclosure of credit risk exposure [line items]
Percentage of loan to value, stock	50%	52%
Percentage of loan to value, stage 3	47%	51%
Percentage of loan to value, new business	69%	66%
Average LTV - Simple
Disclosure of credit risk exposure [line items]
Percentage of loan to value, stock	39%	41%

Credit Risk - Disclosure of C_3

Credit Risk - Disclosure of Credit Performance by Segment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 219,716	£ 210,094
Loss allowance	1,005	865
Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	184,317	174,712
Everyday Banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	7,520	8,311
Loss allowance	£ 293	£ 198
Stage 3 ratio	3.71%	4.23%
Gross write- offs	£ 110	£ 103
Everyday Banking | Business banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,519	3,532
Loss allowance	£ 19	£ 22
Stage 3 ratio	6.58%	7.20%
Gross write- offs	£ 11	£ 6
Everyday Banking | Other unsecured loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	5,001	4,779
Loss allowance	£ 274	£ 176
Stage 3 ratio	2.27%	2.03%
Gross write- offs	£ 99	£ 97
Everyday Banking | Personal loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	1,982	2,000
Loss allowance	62	47
Everyday Banking | Credit cards
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,558	2,341
Loss allowance	130	89
Everyday Banking | Overdrafts
Disclosure of credit risk exposure [line items]
Loans and advances to customers	461	438
Loss allowance	82	40
Everyday Banking | Total Undrawn
Disclosure of credit risk exposure [line items]
Stage 3 undrawn exposures	35	26
Everyday Banking | Total Undrawn | Business banking
Disclosure of credit risk exposure [line items]
Stage 3 undrawn exposures	3	0
Everyday Banking | Total Undrawn | Other unsecured loans
Disclosure of credit risk exposure [line items]
Stage 3 undrawn exposures	32	26
Consumer Finance
Disclosure of credit risk exposure [line items]
Loans and advances to customers	5,384	4,984
Loss allowance	£ 67	£ 52
Stage 3 ratio	0.54%	0.49%
Gross write- offs	£ 19	£ 25
Consumer Finance | Total Undrawn
Disclosure of credit risk exposure [line items]
Stage 3 undrawn exposures	0	0
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Loss allowance	393	425
Maximum exposure to credit risk	27,564	27,443
Loss allowances	394	425
Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	14,123	14,655
Loss allowances	355	376
Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,407	4,849
Loss allowances	38	46
Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	8,034	7,939
Loss allowances	1	3
Corporate & Commercial Banking | Fully performing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	24,539	23,370
Corporate & Commercial Banking | Fully performing | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	11,796	11,227
Corporate & Commercial Banking | Fully performing | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,765	4,344
Corporate & Commercial Banking | Fully performing | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	7,978	7,799
Corporate & Commercial Banking | Enhanced monitoring
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	580	724
Corporate & Commercial Banking | Enhanced monitoring | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	431	520
Corporate & Commercial Banking | Enhanced monitoring | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	103	204
Corporate & Commercial Banking | Enhanced monitoring | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	46
Corporate & Commercial Banking | Proactive management
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,873	2,521
Corporate & Commercial Banking | Proactive management | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,383	2,161
Corporate & Commercial Banking | Proactive management | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	480	220
Corporate & Commercial Banking | Proactive management | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	10	140
Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	572	828
Corporate & Commercial Banking | Stage 3 | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	513	747
Corporate & Commercial Banking | Stage 3 | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	59	81
Corporate & Commercial Banking | Stage 3 | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0
Stage 1 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	169,066	161,845
Stage 1 | Everyday Banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	6,300	7,410
Stage 1 | Everyday Banking | Business banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,223	3,076
Stage 1 | Everyday Banking | Other unsecured loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	4,077	4,334
Stage 1 | Everyday Banking | Personal loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	1,730	1,910
Stage 1 | Everyday Banking | Credit cards
Disclosure of credit risk exposure [line items]
Loans and advances to customers	2,192	2,125
Stage 1 | Everyday Banking | Overdrafts
Disclosure of credit risk exposure [line items]
Loans and advances to customers	155	299
Stage 1 | Consumer Finance
Disclosure of credit risk exposure [line items]
Loans and advances to customers	5,005	4,760
Stage 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	23,104	20,702
Stage 2
Disclosure of credit risk exposure [line items]
Loss allowance	516	330
Stage 2 | Total Undrawn
Disclosure of credit risk exposure [line items]
Loss allowance	39	16
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	13,424	11,071
Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	975	575
Stage 2 | Everyday Banking | Business banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	133	201
Stage 2 | Everyday Banking | Other unsecured loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	842	374
Stage 2 | Everyday Banking | Personal loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	231	73
Stage 2 | Everyday Banking | Credit cards
Disclosure of credit risk exposure [line items]
Loans and advances to customers	329	181
Stage 2 | Everyday Banking | Overdrafts
Disclosure of credit risk exposure [line items]
Loans and advances to customers	282	120
Stage 2 | Consumer Finance
Disclosure of credit risk exposure [line items]
Loans and advances to customers	350	200
Loss allowance	27	17
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Loss allowance	155	119
Maximum exposure to credit risk	3,888	5,913
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 1,827	£ 1,796
Stage 3 ratio	1%	1.04%
Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 245	£ 326
Stage 3 | Everyday Banking | Business banking
Disclosure of credit risk exposure [line items]
Loans and advances to customers	163	255
Stage 3 | Everyday Banking | Other unsecured loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	82	71
Stage 3 | Everyday Banking | Personal loans
Disclosure of credit risk exposure [line items]
Loans and advances to customers	21	17
Stage 3 | Everyday Banking | Credit cards
Disclosure of credit risk exposure [line items]
Loans and advances to customers	37	35
Stage 3 | Everyday Banking | Overdrafts
Disclosure of credit risk exposure [line items]
Loans and advances to customers	24	19
Stage 3 | Consumer Finance
Disclosure of credit risk exposure [line items]
Loans and advances to customers	29	24
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	572	828
Credit risk | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	184,317	174,712
Loss allowance	£ 251	£ 190
Stage 1 ratio	91.73%	92.64%
Stage 2 ratio	7.28%	6.34%
Stage 3 ratio	1%	1.04%
Credit risk | Stage 1 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 169,066	£ 161,845
Credit risk | Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	13,424	11,071
Credit risk | Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 1,827	£ 1,796

Credit Risk - Disclosure of E_3

Credit Risk - Disclosure of ECL Reconciliation by Segment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	£ 865
Ending balance	1,005	£ 865
Less: Recoveries net of collection costs	(36)	17	£ 24
ECL charge/(release) to the Income Statement from continued operations	320	(233)	638
Consumer Finance
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
ECL charge/(release) to the Income Statement from continued operations	27	(33)	44
Corporate & Commercial Banking
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
ECL charge/(release) to the Income Statement from continued operations	31	(90)	294
Corporate Centre
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
ECL charge/(release) to the Income Statement from continued operations	0	(12)	36
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	132
Ending balance	170	132
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	292,366	301,413
Transfers from Stage 1 to Stage 2	(9,100)	(6,805)
Transfers from Stage 2 to Stage 1	7,207	5,883
Transfers to Stage 3	(621)	(571)
Transfers from Stage 3	10	14
Transfers of financial instruments	(2,504)	(1,479)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	48,194	50,862
Redemptions, repayments and assets sold	(54,546)	(63,658)
Changes in risk parameters and other movements	918	5,228
Assets written off	0	0
Ending balance	284,428	292,366	301,413
Net movement in the period	(7,938)	(9,047)
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	177,696	167,766
Transfers from Stage 1 to Stage 2	(5,834)	(5,439)
Transfers from Stage 2 to Stage 1	2,961	3,782
Transfers to Stage 3	(278)	(242)
Transfers from Stage 3	4	3
Transfers of financial instruments	(3,147)	(1,896)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	35,028	33,292
Redemptions, repayments and assets sold	(32,565)	(25,072)
Changes in risk parameters and other movements	(47)	3,606
Assets written off	0	0
Ending balance	176,965	177,696	167,766
Net movement in the period	(731)	9,930
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	20,682	21,089
Transfers from Stage 1 to Stage 2	(841)	(214)
Transfers from Stage 2 to Stage 1	155	418
Transfers to Stage 3	(158)	(284)
Transfers from Stage 3	7	5
Transfers of financial instruments	(837)	(75)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	2,312	2,150
Redemptions, repayments and assets sold	(2,829)	3,023
Changes in risk parameters and other movements	249	541
Assets written off	0	0
Ending balance	19,577	20,682	21,089
Net movement in the period	(1,105)	(407)
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	5,074	7,824
Transfers from Stage 1 to Stage 2	(232)	(98)
Transfers from Stage 2 to Stage 1	68	105
Transfers to Stage 3	(13)	(8)
Transfers from Stage 3	0	5
Transfers of financial instruments	(177)	4
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	2,225	2,212
Redemptions, repayments and assets sold	(1,232)	(4,063)
Changes in risk parameters and other movements	(529)	(903)
Assets written off	0	0
Ending balance	5,361	5,074	7,824
Net movement in the period	287	(2,750)
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	20,604	20,952
Transfers from Stage 1 to Stage 2	(2,195)	(1,055)
Transfers from Stage 2 to Stage 1	4,023	1,579
Transfers to Stage 3	(172)	(38)
Transfers from Stage 3	0	1
Transfers of financial instruments	1,656	487
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	8,629	13,208
Redemptions, repayments and assets sold	(9,019)	(16,644)
Changes in risk parameters and other movements	1,968	2,601
Assets written off	0	0
Ending balance	23,838	20,604	20,952
Net movement in the period	3,234	(348)
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	68,349	72,575
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	0	0
Redemptions, repayments and assets sold	(8,901)	(3,749)
Changes in risk parameters and other movements	(738)	(477)
Assets written off	0	0
Ending balance	58,710	68,349	72,575
Net movement in the period	(9,639)	(4,226)
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	330
Ending balance	516	330
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	17,964	18,336
Transfers from Stage 1 to Stage 2	9,100	6,805
Transfers from Stage 2 to Stage 1	(7,207)	(5,883)
Transfers to Stage 3	(624)	(532)
Transfers from Stage 3	758	456
Transfers of financial instruments	2,027	846
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	1,119	936
Redemptions, repayments and assets sold	(2,065)	(3,442)
Changes in risk parameters and other movements	82	1,288
Assets written off	0	0
Ending balance	19,127	17,964	18,336
Net movement in the period	1,163	(372)
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	11,152	10,427
Transfers from Stage 1 to Stage 2	5,834	5,439
Transfers from Stage 2 to Stage 1	(2,961)	(3,782)
Transfers to Stage 3	(448)	(451)
Transfers from Stage 3	279	353
Transfers of financial instruments	2,704	1,559
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	529	332
Redemptions, repayments and assets sold	(1,229)	(1,436)
Changes in risk parameters and other movements	377	270
Assets written off	0	0
Ending balance	13,533	11,152	10,427
Net movement in the period	2,381	725
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	698	791
Transfers from Stage 1 to Stage 2	840	214
Transfers from Stage 2 to Stage 1	(155)	(418)
Transfers to Stage 3	(56)	(36)
Transfers from Stage 3	14	11
Transfers of financial instruments	643	(229)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	253	84
Redemptions, repayments and assets sold	(176)	101
Changes in risk parameters and other movements	(62)	153
Assets written off	0	0
Ending balance	1,356	698	791
Net movement in the period	658	(93)
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	200	379
Transfers from Stage 1 to Stage 2	232	98
Transfers from Stage 2 to Stage 1	(68)	(105)
Transfers to Stage 3	(10)	(8)
Transfers from Stage 3	1	3
Transfers of financial instruments	155	(12)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	110	70
Redemptions, repayments and assets sold	(77)	(142)
Changes in risk parameters and other movements	(38)	(95)
Assets written off	0	0
Ending balance	350	200	379
Net movement in the period	150	(179)
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	5,914	6,311
Transfers from Stage 1 to Stage 2	2,195	1,055
Transfers from Stage 2 to Stage 1	(4,023)	(1,579)
Transfers to Stage 3	(111)	(37)
Transfers from Stage 3	463	88
Transfers of financial instruments	(1,476)	(473)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	228	450
Redemptions, repayments and assets sold	(584)	(1,357)
Changes in risk parameters and other movements	(194)	983
Assets written off	0	0
Ending balance	3,888	5,914	6,311
Net movement in the period	(2,026)	(397)
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	0
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	0	0
Redemptions, repayments and assets sold	0	0
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
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	403
Ending balance	319	403
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	3,017	2,996
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	1,245	1,103
Transfers from Stage 3	(768)	(470)
Transfers of financial instruments	477	633
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	64	25
Redemptions, repayments and assets sold	(950)	(519)
Changes in risk parameters and other movements	375	179
Assets written off	(254)	(297)
Ending balance	2,729	3,017	2,996
Net movement in the period	(288)	21
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	1,815	1,813
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	726	693
Transfers from Stage 3	(283)	(356)
Transfers of financial instruments	443	337
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	(415)	(331)
Changes in risk parameters and other movements	14	11
Assets written off	(10)	(16)
Ending balance	1,848	1,815	1,813
Net movement in the period	33	2
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	352	105
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	214	320
Transfers from Stage 3	(21)	(16)
Transfers of financial instruments	193	304
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	16	9
Redemptions, repayments and assets sold	(483)	29
Changes in risk parameters and other movements	324	77
Assets written off	(122)	114
Ending balance	280	352	105
Net movement in the period	(72)	247
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	24	58
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	22	16
Transfers from Stage 3	(1)	(8)
Transfers of financial instruments	21	8
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	3
Redemptions, repayments and assets sold	0	(19)
Changes in risk parameters and other movements	18	11
Assets written off	(37)	(37)
Ending balance	29	24	58
Net movement in the period	5	(34)
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	827	1,020
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	283	75
Transfers from Stage 3	(463)	(89)
Transfers of financial instruments	(180)	(14)
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	43	12
Redemptions, repayments and assets sold	(53)	(139)
Changes in risk parameters and other movements	21	54
Assets written off	(86)	(106)
Ending balance	572	827	1,020
Net movement in the period	(255)	(193)
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	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	0	0
Redemptions, repayments and assets sold	0	0
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
Exposures
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	313,347	322,745
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	0
Net ECL remeasurement on stage transfer	0	0
Change in economic scenarios	0	0
Changes to model	0
New lending and assets purchased	49,377	51,823
Redemptions, repayments and assets sold	(57,561)	(67,619)
Changes in risk parameters and other movements	1,375	6,695
Assets written off	(254)	(297)
Ending balance	306,284	313,347	322,745
Net movement in the period	(7,063)	(9,398)
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	190,663	180,006
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	35,558	33,625
Redemptions, repayments and assets sold	(34,209)	(26,839)
Changes in risk parameters and other movements	344	3,887
Assets written off	(10)	(16)
Ending balance	192,346	190,663	180,006
Net movement in the period	1,683	10,657
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	21,732	21,985
Transfers from Stage 1 to Stage 2	(1)	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	(1)	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	2,581	2,243
Redemptions, repayments and assets sold	(3,488)	3,153
Changes in risk parameters and other movements	511	771
Assets written off	(122)	114
Ending balance	21,213	21,732	21,985
Net movement in the period	(519)	(253)
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	5,298	8,261
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	(1)	0
Transfers from Stage 3	0	0
Transfers of financial instruments	(1)	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	2,338	2,285
Redemptions, repayments and assets sold	(1,309)	(4,224)
Changes in risk parameters and other movements	(549)	(987)
Assets written off	(37)	(37)
Ending balance	5,740	5,298	8,261
Net movement in the period	442	(2,963)
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	27,345	28,283
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	8,900	13,670
Redemptions, repayments and assets sold	(9,656)	(18,140)
Changes in risk parameters and other movements	1,795	3,638
Assets written off	(86)	(106)
Ending balance	28,298	27,345	28,283
Net movement in the period	953	(938)
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	68,349	72,575
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	0	0
Redemptions, repayments and assets sold	(8,901)	(3,749)
Changes in risk parameters and other movements	(738)	(477)
Assets written off	0	0
Ending balance	58,710	68,349	72,575
Net movement in the period	(9,639)	(4,226)
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	132	216
Transfers from Stage 1 to Stage 2	(25)	(9)
Transfers from Stage 2 to Stage 1	133	167
Transfers to Stage 3	(4)	(3)
Transfers from Stage 3	1	2
Transfers of financial instruments	105	157
Net ECL remeasurement on stage transfer	(110)	(133)
Change in economic scenarios	37	(7)
Changes to model	0
New lending and assets purchased	42	31
Redemptions, repayments and assets sold	(35)	(70)
Changes in risk parameters and other movements	(1)	(62)
Assets written off	0	0
Ending balance	170	132	216
Net movement in the period	38	(84)
ECL charge/(release) to the Income Statement	38	(84)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	38	(73)
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	13	17
Transfers from Stage 1 to Stage 2	(1)	(2)
Transfers from Stage 2 to Stage 1	16	21
Transfers to Stage 3	(2)	(2)
Transfers from Stage 3	0	0
Transfers of financial instruments	13	17
Net ECL remeasurement on stage transfer	(15)	(19)
Change in economic scenarios	1	(1)
Changes to model	0	0
New lending and assets purchased	7	6
Redemptions, repayments and assets sold	(3)	(3)
Changes in risk parameters and other movements	9	(4)
Assets written off	0	0
Ending balance	25	13	17
Net movement in the period	12	(4)
ECL charge/(release) to the Income Statement	12	(4)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	12	(4)
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	51	57
Transfers from Stage 1 to Stage 2	(7)	(2)
Transfers from Stage 2 to Stage 1	22	81
Transfers to Stage 3	(1)	(1)
Transfers from Stage 3	0	1
Transfers of financial instruments	14	79
Net ECL remeasurement on stage transfer	(22)	(78)
Change in economic scenarios	(2)	(4)
Changes to model	0	0
New lending and assets purchased	12	13
Redemptions, repayments and assets sold	(11)	11
Changes in risk parameters and other movements	1	(6)
Assets written off	0	(1)
Ending balance	43	51	57
Net movement in the period	(8)	(6)
ECL charge/(release) to the Income Statement	(8)	(7)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	(8)	(7)
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	18	44
Transfers from Stage 1 to Stage 2	(2)	(1)
Transfers from Stage 2 to Stage 1	2	6
Transfers to Stage 3	0	0
Transfers from Stage 3	0	0
Transfers of financial instruments	0	5
Net ECL remeasurement on stage transfer	(2)	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	7	6
Redemptions, repayments and assets sold	(5)	(19)
Changes in risk parameters and other movements	1	(18)
Assets written off	0	0
Ending balance	19	18	44
Net movement in the period	1	(26)
ECL charge/(release) to the Income Statement	1	(26)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	1	(26)
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	50	77
Transfers from Stage 1 to Stage 2	(14)	(4)
Transfers from Stage 2 to Stage 1	92	60
Transfers to Stage 3	(1)	0
Transfers from Stage 3	0	0
Transfers of financial instruments	77	56
Net ECL remeasurement on stage transfer	(72)	(39)
Change in economic scenarios	38	(2)
Changes to model	0	0
New lending and assets purchased	16	6
Redemptions, repayments and assets sold	(15)	(15)
Changes in risk parameters and other movements	(11)	(33)
Assets written off	0	0
Ending balance	83	50	77
Net movement in the period	33	(27)
ECL charge/(release) to the Income Statement	33	(27)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	33	(27)
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	0	35
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	0	0
Redemptions, repayments and assets sold	0	(18)
Changes in risk parameters and other movements	0	(17)
Assets written off	0	0
Ending balance	0	0	35
Net movement in the period	0	(35)
ECL charge/(release) to the Income Statement		(35)
Less: Discount unwind		0
Less: Recoveries net of collection costs		0
ECL charge/(release) to the Income Statement from continued operations	0	(35)
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	330	592
Transfers from Stage 1 to Stage 2	25	9
Transfers from Stage 2 to Stage 1	(133)	(167)
Transfers to Stage 3	(32)	(20)
Transfers from Stage 3	150	62
Transfers of financial instruments	10	(116)
Net ECL remeasurement on stage transfer	98	26
Change in economic scenarios	123	(151)
Changes to model	0
New lending and assets purchased	76	26
Redemptions, repayments and assets sold	(60)	(67)
Changes in risk parameters and other movements	(61)	20
Assets written off	0	0
Ending balance	516	330	592
Net movement in the period	186	(262)
ECL charge/(release) to the Income Statement	186	(262)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	186	(262)
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	88	131
Transfers from Stage 1 to Stage 2	1	2
Transfers from Stage 2 to Stage 1	(16)	(21)
Transfers to Stage 3	(11)	(4)
Transfers from Stage 3	9	15
Transfers of financial instruments	(17)	(8)
Net ECL remeasurement on stage transfer	40	10
Change in economic scenarios	21	(67)
Changes to model	0	0
New lending and assets purchased	11	2
Redemptions, repayments and assets sold	(11)	(6)
Changes in risk parameters and other movements	(1)	26
Assets written off	0	0
Ending balance	131	88	131
Net movement in the period	43	(43)
ECL charge/(release) to the Income Statement	43	(43)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	43	(43)
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	98	201
Transfers from Stage 1 to Stage 2	8	2
Transfers from Stage 2 to Stage 1	(22)	(81)
Transfers to Stage 3	(7)	(10)
Transfers from Stage 3	4	5
Transfers of financial instruments	(17)	(84)
Net ECL remeasurement on stage transfer	91	39
Change in economic scenarios	26	(19)
Changes to model	0	0
New lending and assets purchased	38	12
Redemptions, repayments and assets sold	(10)	16
Changes in risk parameters and other movements	(35)	(34)
Assets written off	0	1
Ending balance	191	98	201
Net movement in the period	93	(103)
ECL charge/(release) to the Income Statement	93	(102)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	93	(102)
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	17	37
Transfers from Stage 1 to Stage 2	2	1
Transfers from Stage 2 to Stage 1	(2)	(6)
Transfers to Stage 3	(2)	(2)
Transfers from Stage 3	1	2
Transfers of financial instruments	(1)	(5)
Net ECL remeasurement on stage transfer	9	0
Change in economic scenarios	0	(2)
Changes to model	0	0
New lending and assets purchased	8	4
Redemptions, repayments and assets sold	(7)	(6)
Changes in risk parameters and other movements	1	(12)
Assets written off	0	1
Ending balance	27	17	37
Net movement in the period	10	(20)
ECL charge/(release) to the Income Statement	10	(21)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	10	(21)
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	127	199
Transfers from Stage 1 to Stage 2	14	4
Transfers from Stage 2 to Stage 1	(92)	(60)
Transfers to Stage 3	(13)	(3)
Transfers from Stage 3	135	40
Transfers of financial instruments	44	(19)
Net ECL remeasurement on stage transfer	(41)	(22)
Change in economic scenarios	76	(62)
Changes to model	0	0
New lending and assets purchased	19	8
Redemptions, repayments and assets sold	(32)	(17)
Changes in risk parameters and other movements	(27)	40
Assets written off	0	0
Ending balance	166	127	199
Net movement in the period	39	(72)
ECL charge/(release) to the Income Statement	39	(72)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	39	(72)
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	0
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	0	0
Redemptions, repayments and assets sold	0	0
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
Less: Discount unwind		0
Less: Recoveries net of collection costs		0
ECL charge/(release) to the Income Statement from continued operations	0	0
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	403	569
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	36	23
Transfers from Stage 3	(151)	(64)
Transfers of financial instruments	(115)	(41)
Net ECL remeasurement on stage transfer	110	64
Change in economic scenarios	3	(12)
Changes to model	0
New lending and assets purchased	24	19
Redemptions, repayments and assets sold	(35)	(68)
Changes in risk parameters and other movements	86	63
Assets written off	(157)	(191)
Ending balance	319	403	569
Net movement in the period	(84)	(166)
ECL charge/(release) to the Income Statement	73	25
Less: Discount unwind	(13)	(11)
Less: Recoveries net of collection costs	36	88
ECL charge/(release) to the Income Statement from continued operations	96	102
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	89	132
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	13	6
Transfers from Stage 3	(9)	(15)
Transfers of financial instruments	4	(9)
Net ECL remeasurement on stage transfer	8	9
Change in economic scenarios	2	(12)
Changes to model	0	0
New lending and assets purchased	0	0
Redemptions, repayments and assets sold	(12)	(16)
Changes in risk parameters and other movements	7	(10)
Assets written off	(3)	(5)
Ending balance	95	89	132
Net movement in the period	6	(43)
ECL charge/(release) to the Income Statement	9	(38)
Less: Discount unwind	(2)	(2)
Less: Recoveries net of collection costs	(1)	(1)
ECL charge/(release) to the Income Statement from continued operations	6	(41)
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	49	50
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	7	11
Transfers from Stage 3	(5)	(6)
Transfers of financial instruments	2	5
Net ECL remeasurement on stage transfer	30	23
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	10	4
Redemptions, repayments and assets sold	(5)	5
Changes in risk parameters and other movements	83	74
Assets written off	(110)	102
Ending balance	59	49	50
Net movement in the period	10	(1)
ECL charge/(release) to the Income Statement	120	101
Less: Discount unwind	(4)	(4)
Less: Recoveries net of collection costs	1	(51)
ECL charge/(release) to the Income Statement from continued operations	117	46
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	17	37
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	2	2
Transfers from Stage 3	(1)	(2)
Transfers of financial instruments	1	0
Net ECL remeasurement on stage transfer	10	0
Change in economic scenarios	0	0
Changes to model	0	0
New lending and assets purchased	2	2
Redemptions, repayments and assets sold	0	(3)
Changes in risk parameters and other movements	10	6
Assets written off	(19)	(25)
Ending balance	21	17	37
Net movement in the period	4	(20)
ECL charge/(release) to the Income Statement	23	5
Less: Discount unwind	(2)	0
Less: Recoveries net of collection costs	(5)	9
ECL charge/(release) to the Income Statement from continued operations	16	14
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	248	350
Transfers from Stage 1 to Stage 2	0	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	14	3
Transfers from Stage 3	(135)	(40)
Transfers of financial instruments	(121)	(37)
Net ECL remeasurement on stage transfer	61	31
Change in economic scenarios	0	(1)
Changes to model	0	0
New lending and assets purchased	12	13
Redemptions, repayments and assets sold	(17)	(42)
Changes in risk parameters and other movements	(14)	(7)
Assets written off	(24)	(59)
Ending balance	145	248	350
Net movement in the period	(103)	(102)
ECL charge/(release) to the Income Statement	(79)	(43)
Less: Discount unwind	(3)	(4)
Less: Recoveries net of collection costs	42	56
ECL charge/(release) to the Income Statement from continued operations	(40)	9
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	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	0	0
Redemptions, repayments and assets sold	0	0
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	0	0
ECL charge/(release) to the Income Statement from continued operations	0	0
ECL
Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items]
Beginning balance	865	1,377
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	98	(43)
Change in economic scenarios	163	(170)
Changes to model	0
New lending and assets purchased	142	76
Redemptions, repayments and assets sold	(130)	(205)
Changes in risk parameters and other movements	24	21
Assets written off	(157)	(191)
Ending balance	1,005	865	1,377
Net movement in the period	140	(512)
ECL charge/(release) to the Income Statement	297	(321)
Less: Discount unwind	(13)	(11)
Less: Recoveries net of collection costs	36	88
ECL charge/(release) to the Income Statement from continued operations	320	(233)
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	190	280
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	33	0
Change in economic scenarios	24	(80)
Changes to model	0	0
New lending and assets purchased	18	8
Redemptions, repayments and assets sold	(26)	(25)
Changes in risk parameters and other movements	15	12
Assets written off	(3)	(5)
Ending balance	251	190	280
Net movement in the period	61	(90)
ECL charge/(release) to the Income Statement	64	(85)
Less: Discount unwind	(2)	(2)
Less: Recoveries net of collection costs	(1)	(1)
ECL charge/(release) to the Income Statement from continued operations	61	(88)
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	198	308
Transfers from Stage 1 to Stage 2	1	0
Transfers from Stage 2 to Stage 1	0	0
Transfers to Stage 3	(1)	0
Transfers from Stage 3	(1)	0
Transfers of financial instruments	(1)	0
Net ECL remeasurement on stage transfer	99	(16)
Change in economic scenarios	24	(23)
Changes to model	0	0
New lending and assets purchased	60	29
Redemptions, repayments and assets sold	(26)	32
Changes in risk parameters and other movements	49	34
Assets written off	(110)	102
Ending balance	293	198	308
Net movement in the period	95	(110)
ECL charge/(release) to the Income Statement	205	(8)
Less: Discount unwind	(4)	(4)
Less: Recoveries net of collection costs	1	(51)
ECL charge/(release) to the Income Statement from continued operations	202	(63)
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	52	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	17	0
Change in economic scenarios	0	(2)
Changes to model	0	0
New lending and assets purchased	17	12
Redemptions, repayments and assets sold	(12)	(28)
Changes in risk parameters and other movements	12	(24)
Assets written off	(19)	(24)
Ending balance	67	52	118
Net movement in the period	15	(66)
ECL charge/(release) to the Income Statement	34	(42)
Less: Discount unwind	(2)	0
Less: Recoveries net of collection costs	(5)	9
ECL charge/(release) to the Income Statement from continued operations	27	(33)
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	425	626
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	(52)	(30)
Change in economic scenarios	114	(65)
Changes to model	0	0
New lending and assets purchased	47	27
Redemptions, repayments and assets sold	(64)	(74)
Changes in risk parameters and other movements	(52)	0
Assets written off	(24)	(59)
Ending balance	394	425	626
Net movement in the period	(31)	(201)
ECL charge/(release) to the Income Statement	(7)	(142)
Less: Discount unwind	(3)	(4)
Less: Recoveries net of collection costs	42	56
ECL charge/(release) to the Income Statement from continued operations	32	(90)
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	0	35
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	0	0
Redemptions, repayments and assets sold	0	(18)
Changes in risk parameters and other movements	0	(17)
Assets written off	0	0
Ending balance	0	0	£ 35
Net movement in the period	0	(35)
ECL charge/(release) to the Income Statement	0	(35)
Less: Discount unwind	0	0
Less: Recoveries net of collection costs	0	0
ECL charge/(release) to the Income Statement from continued operations	£ 0	£ (35)

Credit Risk - Disclosure of Loa

Credit Risk - Disclosure of Loan Modification by Segment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Homes
Disclosure of credit risk exposure [line items]
Amortised cost before modification	£ 315	£ 422
Net modification loss	7	9
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	91	152
Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	14	22
Net modification loss	13	9
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	4	6
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	240	243
Net modification loss	8	(5)
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	15	29
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	7	13
Net modification loss	7	5
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	3	4
Overdrafts | Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	7	9
Net modification loss	6	4
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	£ 1	£ 2

Credit Risk - Disclosure of For

Credit Risk - Disclosure of Forbearance Balances by Segment (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Homes
Disclosure of credit risk exposure [line items]
Capitalisation	£ 607	£ 604
Term extension	459	518
Interest-only	305	346
Concessionary interest rate	196	115
Forbearance	1,567	1,583
Loss allowances	£ 42	£ 38
Loans capitalisation forbearance percentage	0.30%	0.30%
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%	0.10%
Loans forbearance percentage	0.90%	0.90%
Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	£ 54	£ 56
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Capitalisation	219	204
Term extension	98	150
Interest-only	238	239
Forbearance	£ 555	£ 593
Proportion of portfolio	2%	2.40%
Stage 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Forbearance	£ 17	£ 20
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Capitalisation	309	387
Term extension	319	444
Interest-only	240	273
Concessionary interest rate	6	4
Forbearance	874	1,108
Loss allowances	11	12
Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	9	10
Stage 2 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Forbearance	173	303
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Capitalisation	298	217
Term extension	140	74
Interest-only	65	73
Concessionary interest rate	190	111
Forbearance	693	475
Loss allowances	31	26
Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	45	46
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Forbearance	365	270
Business banking | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	3	2
Business banking | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	0	0
Business banking | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	3	2
Total other unsecured | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	51	54
Total other unsecured | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	9	10
Total other unsecured | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	42	44
Personal loans | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	1	1
Personal loans | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	1	0
Personal loans | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	0	1
Credit cards | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	34	38
Credit cards | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	6	7
Credit cards | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	28	31
Overdrafts | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	16	15
Overdrafts | Stage 2 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	2	3
Overdrafts | Stage 3 | Everyday Banking
Disclosure of credit risk exposure [line items]
Forbearance	£ 14	£ 12

Credit Risk - Disclosure of Oth

Credit Risk - Disclosure of Other Loan Modification by Segment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Homes
Disclosure of credit risk exposure [line items]
Amortised cost before modification	£ 315	£ 422
Net modification loss	7	9
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	91	152
Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	14	22
Net modification loss	13	9
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	4	6
Other loans | Homes
Disclosure of credit risk exposure [line items]
Amortised cost before modification	0	647
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	0	8
Other loans | Everyday Banking
Disclosure of credit risk exposure [line items]
Amortised cost before modification	0	9
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	1
Other loans | Consumer Finance
Disclosure of credit risk exposure [line items]
Amortised cost before modification	0	54
Net modification loss	0	0
Gross carrying amount of financial assets for which the loss allowance changed to 12 months ECL in the period	95	226
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	0	9
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	£ 1

Credit Risk - Disclosure of Hom

Credit Risk - Disclosure of Homes Portfolios of Particular Interest by Credit Performance (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 219,716	£ 210,094
Properties in possession	£ 47	£ 2
Balance weighted LTV (indexed)	50%	52%
Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 184,317	£ 174,712
Interest-only
Disclosure of credit risk exposure [line items]
Properties in possession	£ 18	£ 1
Balance weighted LTV (indexed)	47%	49%
Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 40,825	£ 40,654
Part interest-only, part repayment
Disclosure of credit risk exposure [line items]
Properties in possession	£ 8	£ 1
Balance weighted LTV (indexed)	49%	52%
Mortgage loan including interest-only part	£ 10,010	£ 10,106
Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	13,510	13,638
Flexible
Disclosure of credit risk exposure [line items]
Properties in possession	£ 3	£ 0
Balance weighted LTV (indexed)	36%	39%
Flexible | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 6,765	£ 8,549
LTV >100%
Disclosure of credit risk exposure [line items]
Properties in possession	£ 7	£ 1
Balance weighted LTV (indexed)	117%	118%
LTV >100% | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 370	£ 528
Buy-to-Let
Disclosure of credit risk exposure [line items]
Properties in possession	£ 1	£ 0
Balance weighted LTV (indexed)	58%	61%
Buy-to-Let | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 16,799	£ 14,893
Other portfolio
Disclosure of credit risk exposure [line items]
Properties in possession	£ 16	£ 0
Balance weighted LTV (indexed)	52%	53%
Other portfolio | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 126,996	£ 116,767
Stage 1 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	169,066	161,845
Stage 1 | Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	35,702	36,212
Stage 1 | Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	12,143	12,391
Stage 1 | Flexible | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	5,713	7,509
Stage 1 | LTV >100% | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	217	354
Stage 1 | Buy-to-Let | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	15,884	14,363
Stage 1 | Other portfolio | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	118,507	109,878
Stage 2 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	13,424	11,071
Stage 2 | Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	4,250	3,626
Stage 2 | Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	1,149	1,020
Stage 2 | Flexible | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	839	796
Stage 2 | LTV >100% | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	101	109
Stage 2 | Buy-to-Let | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	876	489
Stage 2 | Other portfolio | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	7,791	6,188
Stage 3 | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 1,827	£ 1,796
Stage 3 ratio	1%	1.04%
Stage 3 | Interest-only | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 873	£ 816
Stage 3 ratio	2.16%	2.03%
Stage 3 | Part interest-only, part repayment | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 218	£ 227
Stage 3 ratio	1.62%	1.66%
Stage 3 | Flexible | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 213	£ 244
Stage 3 ratio	3.45%	3.06%
Stage 3 | LTV >100% | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 52	£ 65
Stage 3 ratio	13.94%	12.34%
Stage 3 | Buy-to-Let | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 39	£ 41
Stage 3 ratio	0.23%	0.27%
Stage 3 | Other portfolio | Homes
Disclosure of credit risk exposure [line items]
Loans and advances to customers	£ 698	£ 701
Stage 3 ratio	0.55%	0.60%

Credit Risk - Disclosure of H_2

Credit Risk - Disclosure of Homes Portfolios of Particular Interest by Forbearance Balances (Details) - Homes - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Forbearance	£ 1,567	£ 1,583
Stage 2
Disclosure of credit risk exposure [line items]
Forbearance	874	1,108
Stage 3
Disclosure of credit risk exposure [line items]
Forbearance	693	475
Interest-only
Disclosure of credit risk exposure [line items]
Forbearance	290	419
Interest-only | Stage 2
Disclosure of credit risk exposure [line items]
Forbearance	111	280
Interest-only | Stage 3
Disclosure of credit risk exposure [line items]
Forbearance	179	139
Flexible
Disclosure of credit risk exposure [line items]
Forbearance	36	35
Flexible | Stage 2
Disclosure of credit risk exposure [line items]
Forbearance	19	24
Flexible | Stage 3
Disclosure of credit risk exposure [line items]
Forbearance	17	11
LTV >100%
Disclosure of credit risk exposure [line items]
Forbearance	9	13
LTV >100% | Stage 2
Disclosure of credit risk exposure [line items]
Forbearance	0	3
LTV >100% | Stage 3
Disclosure of credit risk exposure [line items]
Forbearance	9	10
Buy-to-Let
Disclosure of credit risk exposure [line items]
Forbearance	15	11
Buy-to-Let | Stage 2
Disclosure of credit risk exposure [line items]
Forbearance	11	8
Buy-to-Let | Stage 3
Disclosure of credit risk exposure [line items]
Forbearance	£ 4	£ 3

Credit Risk - Disclosure of Seg

Credit Risk - Disclosure of Segments Exposure by Credit Rating (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	£ 27,564	£ 27,443
Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	23,104	20,702
Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,888	5,913
Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	572	828
Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	14,123	14,655
Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,407	4,849
Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	8,034	7,939
Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	52,700	59,351
Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	52,700	59,349
Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	2
Corporate Centre | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	48,117	56,112
Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,173	1,875
Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,410	1,364
Internal grade 9 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	44	52
Internal grade 9 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	39	52
Internal grade 9 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5	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	44	52
Internal grade 9 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	48,367	56,113
Internal grade 9 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	48,367	56,113
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 | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	47,040	55,061
Internal grade 9 | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	136	573
Internal grade 9 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,191	479
Internal grade 8 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,366	4,746
Internal grade 8 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,364	3,809
Internal grade 8 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2	937
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	336	659
Internal grade 8 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2	126
Internal grade 8 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,028	3,961
Internal grade 8 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,911	2,648
Internal grade 8 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,911	2,648
Internal grade 8 | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
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 | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,077	1,051
Internal grade 8 | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,162	1,064
Internal grade 8 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	672	533
Internal grade 7 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,990	4,610
Internal grade 7 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,944	4,359
Internal grade 7 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	46	251
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	923	714
Internal grade 7 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	111	137
Internal grade 7 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,956	3,759
Internal grade 7 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,396	542
Internal grade 7 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,396	542
Internal grade 7 | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	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 | 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	875	197
Internal grade 7 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	521	345
Internal grade 6 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,391	3,877
Internal grade 6 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,202	3,604
Internal grade 6 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	189	239
Internal grade 6 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	34
Internal grade 6 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,341	2,397
Internal grade 6 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,044	1,471
Internal grade 6 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	6	9
Internal grade 6 | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	26	48
Internal grade 6 | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	26	46
Internal grade 6 | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	2
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 | 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	0	41
Internal grade 6 | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	26	7
Internal grade 5 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,427	5,295
Internal grade 5 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,773	4,192
Internal grade 5 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	654	1,086
Internal grade 5 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	17
Internal grade 5 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	3,299	3,067
Internal grade 5 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,128	2,228
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 | 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 4 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	6,263	6,236
Internal grade 4 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4,289	4,138
Internal grade 4 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,974	2,005
Internal grade 4 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	93
Internal grade 4 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,327	5,545
Internal grade 4 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	936	638
Internal grade 4 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	53
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 | 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 3 to 1 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,976	2,456
Internal grade 3 to 1 | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	386	380
Internal grade 3 to 1 | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,018	1,509
Internal grade 3 to 1 | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	572	567
Internal grade 3 to 1 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,791	2,207
Internal grade 3 to 1 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	185	249
Internal grade 3 to 1 | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	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 | 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
Other | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	107	171
Other | Corporate & Commercial Banking | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	107	168
Other | Corporate & Commercial Banking | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	(114)
Other | Corporate & Commercial Banking | Stage 3
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	117
Other | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	106	66
Other | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1	0
Other | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	105
Other | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Other | Corporate Centre | Stage 1
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Other | Corporate Centre | Stage 2
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
Other | Corporate Centre | Stage 3
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

Credit Risk - Disclosure of S_4

Credit Risk - Disclosure of Segments Exposure by Geographical Distribution (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	£ 27,564	£ 27,443
Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	14,123	14,655
Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,407	4,849
Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	8,034	7,939
Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	52,700	59,351
Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	48,117	56,112
Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,173	1,875
Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,410	1,364
UK | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	27,532	27,400
UK | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	14,091	14,612
UK | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	5,407	4,849
UK | Corporate & Commercial Banking | Social Housing
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	8,034	7,939
UK | Corporate Centre
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	46,303	54,020
UK | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	43,936	52,297
UK | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,379	1,219
UK | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	988	504
Europe | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	32	43
Europe | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	32	43
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	3,313	2,171
Europe | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,886	950
Europe | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	422	656
Europe | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	1,005	565
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	317	550
US | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	83	469
US | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	4	0
US | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	230	81
Rest of World | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	0	0
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	0
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	2,767	2,610
Rest of World | Corporate Centre | Sovereign and Supranational
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	2,212	2,396
Rest of World | Corporate Centre | Structured Products
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	368	0
Rest of World | Corporate Centre | Financial Institutions
Disclosure of credit risk exposure [line items]
Maximum exposure to credit risk	£ 187	£ 214

Credit Risk - Disclosure of S_5

Credit Risk - Disclosure of Segments Exposure by Gross and Net Credit Exposure (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of credit risk exposure [line items]
Exposures	£ 306,284	£ 313,347
Stage 3
Disclosure of credit risk exposure [line items]
Exposures	2,729	3,017
Stage 3 | Corporate & Commercial Banking
Disclosure of credit risk exposure [line items]
Exposures	572	828
Collateral	199	344
Net exposure	373	484
Stage 3 | Corporate & Commercial Banking | SME and mid corporate
Disclosure of credit risk exposure [line items]
Exposures	513	747
Collateral	169	307
Net exposure	344	440
Stage 3 | Corporate & Commercial Banking | Commercial Real Estate
Disclosure of credit risk exposure [line items]
Exposures	59	81
Collateral	30	37
Net exposure	£ 29	£ 44

Market Risk - Summary of NII an

Market Risk - Summary of NII and EVE Sensitivities Measurement (Details)	12 Months Ended
	Dec. 31, 2022 yield_curve nII_total
Disclosure Of Sensitivity Limit Of Risk [line items]
NII sensitivity, number of NII totals | nII_total	2
NII sensitivity, number of yield curves | yield_curve	2
Minimum
Disclosure Of Sensitivity Limit Of Risk [line items]
NII sensitivity, period	12 months
Maximum
Disclosure Of Sensitivity Limit Of Risk [line items]
NII sensitivity, period	36 months

Market Risk - Summary of Detail

Market Risk - Summary of Detailed Information about VaR (Details)	Dec. 31, 2022
Disclosure Of Market Risk Exposure [Abstract]
VaR, confidence level	99%

Market Risk - Additional Inform

Market Risk - Additional Information (Details)	Dec. 31, 2022
Disclosure Of Market Risk Exposure [Abstract]
VaR, losses greater than VaR estimate, percentage of trading days	1%

Liquidity Risk - Summary of Rec

Liquidity Risk - Summary of Reconciliation of Wholesale Funding to Balance Sheet (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Deposits by banks	£ 28,525	£ 33,855
Deposits by customers	195,568	192,926
Repurchase agreements - non trading	7,982	11,718
Debt securities in issue	31,531	25,520
Subordinated liabilities	2,332	2,228
Other equity interest	1,956	2,191
Liquidity risk
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	77,900	82,300
Deposits by banks	28,500	33,900
Deposits by customers	4,800	6,000
Repurchase agreements - non trading	8,000	11,700
Financial liabilities designated at fair value	800	800
Debt securities in issue	31,500	25,500
Subordinated liabilities	2,300	2,200
Other equity instruments	2,000	2,200
Liquidity risk | Repos
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	8,000	11,700
Deposits by banks	0	0
Deposits by customers	0	0
Repurchase agreements - non trading	8,000	11,700
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	1,600	1,100
Deposits by banks	0	0
Deposits by customers	100	100
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	1,100	700
Subordinated liabilities	400	300
Other equity instruments	0	0
Liquidity risk | Other
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	3,400	2,100
Deposits by banks	3,000	1,800
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	400	300
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	64,900	67,400
Deposits by banks	25,500	32,100
Deposits by customers	4,700	5,900
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	400	500
Debt securities in issue	30,400	24,800
Subordinated liabilities	1,900	1,900
Other equity instruments	2,000	2,200
Liquidity risk | Wholesale funding | Deposits by banks
Reconciliation Of Wholesale Funding To Balance Sheet [line items]
Funding analysis	500	200
Deposits by banks	500	200
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	4,700	5,100
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	4,700	5,100
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	14,300	12,300
Deposits by banks	0	0
Deposits by customers	4,600	5,800
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	9,700	6,500
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	600
Deposits by banks	0	0
Deposits by customers	100	100
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	400	500
Debt securities in issue	100	0
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	14,900	12,500
Deposits by banks	0	0
Deposits by customers	0	0
Repurchase agreements - non trading	0	0
Financial liabilities designated at fair value	0	0
Debt securities in issue	14,900	12,500
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	1,000	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	1,000	700
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	25,000	31,900
Deposits by banks	25,000	31,900
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	3,900	4,100
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	1,900
Other equity instruments	2,000	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	0	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, 2022	Dec. 31, 2021
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	£ 64,900	£ 67,400
Deposits by banks	28,525	33,855
Subordinated liabilities	2,332	2,228
Of which secured	40,900	45,100
Of which unsecured	£ 24,000	22,300
Unsecured debt issued	95%
Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	£ 12,500
Senior unsecured – privately placed	100
Subordinated liabilities and equity (incl. AT1)	2,700
Wholesale fund amount	15,300
Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	1,800
Senior unsecured – privately placed	500
Wholesale fund amount	49,600
Deposits by banks	500
Certificates of deposit and commercial paper	4,700
Covered bonds	14,900
Securitisation and structured issuance	1,000
TFSME	25,000
Subordinated liabilities	1,200
Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
≤ 1 month
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	2,600	3,100
Of which secured	100	200
Of which unsecured	2,500	2,900
≤ 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	300
Senior unsecured – privately placed	0
Wholesale fund amount	1,800
Deposits by banks	200
Certificates of deposit and commercial paper	1,200
Covered bonds	0
Securitisation and structured issuance	100
TFSME	0
Subordinated liabilities	0
≤ 1 month | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>1 and ≤ 3 months
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	5,200	3,200
Of which secured	1,000	0
Of which unsecured	4,200	3,200
>1 and ≤ 3 months | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	700
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	0
Wholesale fund amount	700
>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
Wholesale fund amount	4,500
Deposits by banks	300
Certificates of deposit and commercial paper	3,200
Covered bonds	1,000
Securitisation and structured issuance	0
TFSME	0
Subordinated liabilities	0
>1 and ≤ 3 months | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>3 and ≤ 6 months
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	500	2,800
Of which secured	200	900
Of which unsecured	300	1,900
>3 and ≤ 6 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
>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
Wholesale fund amount	500
Deposits by banks	0
Certificates of deposit and commercial paper	300
Covered bonds	100
Securitisation and structured issuance	100
TFSME	0
Subordinated liabilities	0
>3 and ≤ 6 months | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>6 and ≤ 9 months
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	1,500	200
Of which secured	900	100
Of which unsecured	600	100
>6 and ≤ 9 months | Santander UK Group Holdings 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)	0
Wholesale fund amount	600
>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
Wholesale fund amount	900
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	900
Securitisation and structured issuance	0
TFSME	0
Subordinated liabilities	0
>6 and ≤ 9 months | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>9 and ≤ 12 months
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	1,200	900
Of which secured	0	900
Of which unsecured	1,200	0
>9 and ≤ 12 months | 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
>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
Wholesale fund amount	400
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	0
Securitisation and structured issuance	0
TFSME	0
Subordinated liabilities	400
>9 and ≤ 12 months | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
No later than one year
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	11,000	10,200
Of which secured	2,200	2,100
Of which unsecured	8,800	8,100
No later than one year | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	2,900
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	0
Wholesale fund amount	2,900
No later than one year | Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	300
Senior unsecured – privately placed	0
Wholesale fund amount	8,100
Deposits by banks	500
Certificates of deposit and commercial paper	4,700
Covered bonds	2,000
Securitisation and structured issuance	200
TFSME	0
Subordinated liabilities	400
No later than one year | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
Later than 1 year but no later than 3 years
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	6,600	5,900
Of which secured	3,500	2,100
Of which unsecured	3,100	3,800
Later than 1 year but no later than 3 years | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	1,600
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	500
Wholesale fund amount	2,100
Later than 1 year but no later than 3 years | Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	900
Senior unsecured – privately placed	100
Wholesale fund amount	4,500
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	3,400
Securitisation and structured issuance	100
TFSME	0
Subordinated liabilities	0
Later than 1 year but no later than 3 years | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>2 and ≤ 5 years
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	42,200	40,700
Of which secured	34,000	33,700
Of which unsecured	8,200	7,000
>2 and ≤ 5 years | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	6,400
Senior unsecured – privately placed	100
Subordinated liabilities and equity (incl. AT1)	1,200
Wholesale fund amount	7,700
>2 and ≤ 5 years | Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	300
Senior unsecured – privately placed	200
Wholesale fund amount	34,500
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	8,400
Securitisation and structured issuance	600
TFSME	25,000
Subordinated liabilities	0
>2 and ≤ 5 years | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	0
>5 years
Disclosure Of Sources Of Wholesale Funding [Line Items]
Wholesale fund amount	5,100	10,600
Of which secured	1,200	7,200
Of which unsecured	3,900	£ 3,400
>5 years | Santander UK Group Holdings plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	1,600
Senior unsecured – privately placed	0
Subordinated liabilities and equity (incl. AT1)	1,000
Wholesale fund amount	2,600
>5 years | Other Santander UK plc
Disclosure Of Sources Of Wholesale Funding [Line Items]
Senior unsecured – public benchmark	300
Senior unsecured – privately placed	200
Wholesale fund amount	2,500
Deposits by banks	0
Certificates of deposit and commercial paper	0
Covered bonds	1,100
Securitisation and structured issuance	100
TFSME	0
Subordinated liabilities	800
>5 years | Other group entities
Disclosure Of Sources Of Wholesale Funding [Line Items]
Securitisation and structured issuance	£ 0

Liquidity Risk - Summary of Who

Liquidity Risk - Summary of Wholesale Funding by Currency (Details) - Liquidity risk	Dec. 31, 2022	Dec. 31, 2021
Sterling
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	63%	66%
Sterling | Santander UK Group Holdings plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	27%	22%
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	18%	9%
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%	0%
Sterling | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	75%	73%
Sterling | Other Santander UK plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	74%	77%
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	18%	14%
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	95%	92%
Sterling | Other Santander UK plc | Deposits by banks
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	29%	32%
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	56%	45%
Sterling | Other Santander UK plc | Covered bonds
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	43%	44%
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	100%	74%
Sterling | Other Santander UK plc | TFSME
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	100%	100%
Sterling | Other Santander UK plc | Subordinated liabilities
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	48%	57%
US Dollar
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	21%	18%
US Dollar | Santander UK Group Holdings plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	52%	52%
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	58%	59%
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%	0%
US Dollar | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	25%	27%
US Dollar | Other Santander UK plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	12%	10%
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	62%	46%
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%	0%
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	71%	68%
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	42%	53%
US Dollar | Other Santander UK plc | Covered bonds
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	12%	8%
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	0%	26%
US Dollar | Other Santander UK plc | TFSME
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0%	0%
US Dollar | Other Santander UK plc | Subordinated liabilities
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	52%	43%
Euro
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	16%	15%
Euro | Santander UK Group Holdings plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	20%	25%
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	24%	32%
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%	0%
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%	0%
Euro | Other Santander UK plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	14%	13%
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	20%	40%
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	5%	6%
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%	0%
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%	2%
Euro | Other Santander UK plc | Covered bonds
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	45%	48%
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%	0%
Euro | Other Santander UK plc | TFSME
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0%	0%
Euro | Other Santander UK plc | Subordinated liabilities
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0%	0%
Other
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0%	1%
Other | Santander UK Group Holdings plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	1%	1%
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%	0%
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%	100%
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%	0%
Other | Other Santander UK plc
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0%	0%
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%	0%
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	0%	2%
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%	0%
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%	0%
Other | Other Santander UK plc | Covered bonds
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0%	0%
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%	0%
Other | Other Santander UK plc | TFSME
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0%	0%
Other | Other Santander UK plc | Subordinated liabilities
Disclosure Of Currency Composition Of Wholesale Funds [Line Items]
Percentage of wholesale funding by major currencies	0%	0%

Liquidity Risk - Summary of Ext

Liquidity Risk - Summary of External Term Issuance, Sterling Equivalent (Details) - Liquidity risk - GBP (£) £ in Billions	Dec. 31, 2022	Dec. 31, 2021
Santander UK Group Holdings plc
Disclosure of detailed information about borrowings [line items]
Borrowings	£ 4.7	£ 3
Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	3.9	2.8
Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure of detailed information about borrowings [line items]
Borrowings	0.8	0.2
Other Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	4.7	20.3
Other Santander UK plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	0	0
Other Santander UK plc | Securitisations and other secured funding
Disclosure of detailed information about borrowings [line items]
Borrowings	0.6	0
Other Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	4	0
Other Santander UK plc | Senior unsecured – privately placed
Disclosure of detailed information about borrowings [line items]
Borrowings	0.1	0.1
Other Santander UK plc | TFSME
Disclosure of detailed information about borrowings [line items]
Borrowings	0	20.2
Other group entities
Disclosure of detailed information about borrowings [line items]
Borrowings	9.4	£ 23.3
Sterling | Santander UK Group Holdings plc
Disclosure of detailed information about borrowings [line items]
Borrowings	2
Sterling | Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	1.2
Sterling | Santander UK Group Holdings plc | Subordinated liabilities and equity
Disclosure of detailed information about borrowings [line items]
Borrowings	0.8
Sterling | Other Santander UK plc
Disclosure of detailed information about borrowings [line items]
Borrowings	2.5
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	0.6
Sterling | Other Santander UK plc | Covered bonds
Disclosure of detailed information about borrowings [line items]
Borrowings	1.8
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	0
Sterling | Other group entities
Disclosure of detailed information about borrowings [line items]
Borrowings	4.5
US Dollar | Santander UK Group Holdings plc
Disclosure of detailed information about borrowings [line items]
Borrowings	2.1
US Dollar | Santander UK Group Holdings plc | Senior unsecured – public benchmark
Disclosure of detailed information about borrowings [line items]
Borrowings	2.1
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	0.8
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	0.8
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	2.9
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	1.4
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	1.4
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	2
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

Liquidity Risk - Summary of Bal

Liquidity Risk - Summary of Balance Sheet Encumbered and Unencumbered Assets Explanatory (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	£ 44,190	£ 48,139	£ 41,250
Financial assets at fair value through profit or loss [abstract]
Derivative financial instruments	2,407	1,681
Other financial assets at FVTPL	129	185
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	219,716	210,094
Loans and advances to banks	992	1,169
Repurchase agreements – non trading	7,348	12,683
Financial assets at fair value through other comprehensive income	6,024	5,851
Interests in other entities	252	201
Intangible assets	1,550	1,545
Property, plant and equipment	1,513	1,548
Current tax assets	478	347	264
Retirement benefit assets	1,050	1,572
Other assets	2,016	1,500
Total assets	285,213	287,098	£ 292,332
Liquidity risk
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	44,190	48,139
Financial assets at fair value through profit or loss [abstract]
Derivative financial instruments	2,407	1,681
Other financial assets at FVTPL	129	185
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	219,716	210,094
Loans and advances to banks	992	1,169
Repurchase agreements – non trading	7,348	12,683
Other financial assets at amortised cost	156	506
Financial assets at fair value through other comprehensive income	6,024	5,851
Interests in other entities	252	201
Intangible assets	1,550	1,545
Property, plant and equipment	1,513	1,548
Current tax assets	478	347
Retirement benefit assets	1,050	1,572
Total assets	285,213	287,098
Liquidity risk | Other assets
Financial Assets At Amortised Cost [Abstract]
Other assets	(592)	1,577
Liquidity risk | Total
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	42,860	46,559
Financial assets at fair value through profit or loss [abstract]
Derivative financial instruments	2,407	1,681
Other financial assets at FVTPL	129	185
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	195,505	190,561
Loans and advances to banks	829	691
Repurchase agreements – non trading	7,348	12,683
Other financial assets at amortised cost	108	506
Financial assets at fair value through other comprehensive income	1,659	1,488
Interests in other entities	252	201
Intangible assets	1,550	1,545
Property, plant and equipment	1,513	1,548
Current tax assets	478	347
Retirement benefit assets	1,050	1,572
Total assets	255,096	261,144
Liquidity risk | Total | Other assets
Financial Assets At Amortised Cost [Abstract]
Other assets	(592)	1,577
Liquidity risk | Assets positioned at central banks
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	893	918
Financial assets at fair value through profit or loss [abstract]
Derivative financial instruments	0	0
Other financial assets at FVTPL	0	0
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	68,535	80,624
Loans and advances to banks	0	0
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at fair value through other comprehensive income	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Retirement benefit assets	0	0
Total assets	69,428	81,542
Liquidity risk | Assets positioned at central banks | Other assets
Financial Assets At Amortised Cost [Abstract]
Other assets	0	0
Liquidity risk | Readily available
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	41,967	45,641
Financial assets at fair value through profit or loss [abstract]
Derivative financial instruments	0	0
Other financial assets at FVTPL	0	0
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	91,761	74,890
Loans and advances to banks	0	0
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	108	506
Financial assets at fair value through other comprehensive income	1,659	1,488
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
Total assets	135,495	122,525
Liquidity risk | Readily available | Other assets
Financial Assets At Amortised Cost [Abstract]
Other assets	0	0
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 [abstract]
Derivative financial instruments	0	0
Other financial assets at FVTPL	0	0
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	18,284	18,893
Loans and advances to banks	0	0
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at fair value through other comprehensive income	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	1,513	1,548
Current tax assets	0	0
Retirement benefit assets	0	0
Total assets	19,797	20,441
Liquidity risk | Other available assets | Other assets
Financial Assets At Amortised Cost [Abstract]
Other assets	0	0
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 [abstract]
Derivative financial instruments	2,407	1,681
Other financial assets at FVTPL	129	185
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	16,925	16,154
Loans and advances to banks	829	691
Repurchase agreements – non trading	7,348	12,683
Other financial assets at amortised cost	0	0
Financial assets at fair value through other comprehensive income	0	0
Interests in other entities	252	201
Intangible assets	1,550	1,545
Property, plant and equipment	0	0
Current tax assets	478	347
Retirement benefit assets	1,050	1,572
Total assets	30,376	36,636
Liquidity risk | Cannot be encumbered | Other assets
Financial Assets At Amortised Cost [Abstract]
Other assets	(592)	1,577
Total | Liquidity risk
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	1,330	1,580
Financial assets at fair value through profit or loss [abstract]
Derivative financial instruments	0	0
Other financial assets at FVTPL	0	0
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	24,211	19,533
Loans and advances to banks	163	478
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	48	0
Financial assets at fair value through other comprehensive income	4,365	4,363
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
Total assets	30,117	25,954
Total | Liquidity risk | Other assets
Financial Assets At Amortised Cost [Abstract]
Other assets	0	0
Covered bonds | Liquidity risk
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks		0
Financial assets at fair value through profit or loss [abstract]
Derivative financial instruments	0	0
Other financial assets at FVTPL	0	0
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	21,304	15,713
Loans and advances to banks	0	0
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at fair value through other comprehensive income	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Retirement benefit assets	0	0
Total assets	21,304	15,713
Covered bonds | Liquidity risk | Other assets
Financial Assets At Amortised Cost [Abstract]
Other assets	0	0
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 [abstract]
Derivative financial instruments	0	0
Other financial assets at FVTPL	0	0
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	2,851	3,720
Loans and advances to banks	0	0
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	0	0
Financial assets at fair value through other comprehensive income	0	0
Interests in other entities	0	0
Intangible assets	0	0
Property, plant and equipment	0	0
Current tax assets	0	0
Retirement benefit assets	0	0
Total assets	2,851	3,720
Securitis- ations | Liquidity risk | Other assets
Financial Assets At Amortised Cost [Abstract]
Other assets	0	0
Other | Liquidity risk
Disclosure Of Encumbered And Unencumbered Assets [Line Items]
Cash and balances at central banks	1,330	1,580
Financial assets at fair value through profit or loss [abstract]
Derivative financial instruments	0	0
Other financial assets at FVTPL	0	0
Financial Assets At Amortised Cost [Abstract]
Loans and advances to customers	56	100
Loans and advances to banks	163	478
Repurchase agreements – non trading	0	0
Other financial assets at amortised cost	48	0
Financial assets at fair value through other comprehensive income	4,365	4,363
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
Total assets	5,962	6,521
Other | Liquidity risk | Other assets
Financial Assets At Amortised Cost [Abstract]
Other assets	£ 0	£ 0

Capital Risk - Additional Infor

Capital Risk - Additional Information (Details)	12 Months Ended
	Dec. 31, 2022
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, 2022	Dec. 31, 2021
Disclosure Of Capital Risk Exposure [Abstract]
CET1 capital	£ 10,799	£ 10,820
AT1 capital	1,956	2,119
Tier 1 capital	12,755	12,939
Tier 2 capital	1,548	1,816
Total regulatory capital	14,303	14,755
Transitional IFRS 9 Benefit	£ 19	£ 21

Accounting Policies - Additiona

Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2022 area
Disclosure of detailed information about financial instruments [line items]
Climate change objective, number of main focus areas	3
Climate change, period covered for ECL calculations	5 years
180 Days | Unsecured Debt
Disclosure of detailed information about financial instruments [line items]
Written off period for past due	180 days

Accounting Policies - Summary o

Accounting Policies - Summary of Useful Lives or Depreciation Rates Used for Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2022
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, 2022
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
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
Minimum | Operating lease assets
Disclosure of detailed information about property, plant and equipment [line items]
Useful lives or depreciation rates, property, plant and equipment	2 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
Maximum | Operating lease assets
Disclosure of detailed information about property, plant and equipment [line items]
Useful lives or depreciation rates, property, plant and equipment	4 years

Segments - Additional Informati

Segments - Additional Information (Details) £ in Millions	12 Months Ended
	Dec. 31, 2022 GBP (£) business_unit segment	Dec. 31, 2021 GBP (£)	Dec. 31, 2020 GBP (£)
Disclosure of operating segments [line items]
Number of segments | segment	4
Profit (loss) before tax	£ 1,874	£ 1,888	£ 605
Retail Banking
Disclosure of operating segments [line items]
Number of business units | business_unit	2
Corporate & Commercial Banking | Reclassified amounts
Disclosure of operating segments [line items]
Social housing loans	£ (1,500)	(2,300)	(3,200)
Non-core liabilities	(400)	(900)	0
Profit (loss) before tax	2.9	(2.7)	(6.3)
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
Corporate Centre | Reclassified amounts
Disclosure of operating segments [line items]
Social housing loans	1,500	2,300	3,200
Non-core liabilities	400	900	0
Profit (loss) before tax	£ (2.9)	£ 2.7	£ 6.3

Segments - Summary of Results b

Segments - Summary of Results by Segment (Details) £ in Millions	12 Months Ended
	Dec. 31, 2022 GBP (£) employee	Dec. 31, 2021 GBP (£) employee	Dec. 31, 2020 GBP (£) employee
Disclosure of operating segments [line items]
Net interest income / (expense)	£ 4,425	£ 3,949	£ 3,388
Non-interest income / (expense)	531	550	464
Total operating income	4,956	4,499	3,852
Operating expenses before credit impairment (charges)/write-backs, provisions and charges	(2,343)	(2,510)	(2,390)
Credit impairment (charges)/write-backs	(320)	233	(638)
Provisions for other liabilities and charges	(419)	(377)	(264)
Total operating credit impairment (charges)/write-backs, provisions and charges	(739)	(144)	(902)
Profit from continuing operations before tax	1,874	1,845	560
Revenue from external customers	4,956	4,499	3,852
Inter-segment revenue	4,956	4,499	3,852
Revenue from external customers includes the following fee and commission income disaggregated by income type
Current account and debit card fees	562	478	484
Insurance, protection and investments	78	67	65
Credit cards	95	73	66
Non-banking and other fees	104	79	65
Total fee and commission income	839	697	680
Fee and commission expense	(509)	(411)	(361)
Net fee and commission income	330	286	319
Customer loans	215,738	207,288	207,011
Total assets	285,213	287,098	292,332
Assets held for sale	49	0
Customer deposits	189,911	186,215	185,707
Total liabilities	£ 270,806	£ 270,996	£ 276,396
Average number of full-time equivalent staff | employee	18,123	19,704	21,998
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)	3,671	3,356	2,753
Non-interest income / (expense)	209	205	245
Total operating income	3,880	3,561	2,998
Operating expenses before credit impairment (charges)/write-backs, provisions and charges	(1,682)	(1,701)	(1,792)
Credit impairment (charges)/write-backs	(262)	98	(264)
Provisions for other liabilities and charges	(394)	(185)	(157)
Total operating credit impairment (charges)/write-backs, provisions and charges	(656)	(87)	(421)
Profit from continuing operations before tax	1,542	1,773	785
Revenue from external customers	4,109	4,010	3,669
Revenue from external customers includes the following fee and commission income disaggregated by income type
Current account and debit card fees	502	428	442
Insurance, protection and investments	78	67	65
Credit cards	95	73	66
Non-banking and other fees	2	2	3
Total fee and commission income	677	570	576
Fee and commission expense	(478)	(380)	(335)
Net fee and commission income	199	190	241
Customer loans	191,836	183,023	175,380
Total assets	200,872	190,629	183,154
Assets held for sale	0
Customer deposits	161,748	156,991	152,167
Total liabilities	£ 161,821	£ 157,622	£ 152,687
Average number of full-time equivalent staff | employee	15,212	16,149	18,198
Retail Banking | Inter-segment revenue
Disclosure of operating segments [line items]
Inter-segment revenue	£ (229)	£ (449)	£ (671)
Consumer Finance
Disclosure of operating segments [line items]
Net interest income / (expense)	180	233	264
Non-interest income / (expense)	195	178	127
Total operating income	375	411	391
Operating expenses before credit impairment (charges)/write-backs, provisions and charges	(144)	(163)	(166)
Credit impairment (charges)/write-backs	(27)	33	(44)
Provisions for other liabilities and charges	(6)	4	(8)
Total operating credit impairment (charges)/write-backs, provisions and charges	(33)	37	(52)
Profit from continuing operations before tax	198	285	173
Revenue from external customers	513	489	501
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	20	10	10
Total fee and commission income	20	10	10
Fee and commission expense	(5)	0	0
Net fee and commission income	15	10	10
Customer loans	5,384	4,984	8,025
Total assets	10,371	8,873	11,143
Assets held for sale	0
Customer deposits	0	0	0
Total liabilities	£ 1,223	£ 1,173	£ 2,397
Average number of full-time equivalent staff | employee	531	670	640
Consumer Finance | Inter-segment revenue
Disclosure of operating segments [line items]
Inter-segment revenue	£ (138)	£ (78)	£ (110)
Corporate & Commercial Banking
Disclosure of operating segments [line items]
Net interest income / (expense)	580	397	355
Non-interest income / (expense)	146	112	96
Total operating income	726	509	451
Operating expenses before credit impairment (charges)/write-backs, provisions and charges	(342)	(365)	(324)
Credit impairment (charges)/write-backs	(31)	90	(294)
Provisions for other liabilities and charges	(8)	(34)	(6)
Total operating credit impairment (charges)/write-backs, provisions and charges	(39)	56	(300)
Profit from continuing operations before tax	345	200	(173)
Revenue from external customers	732	619	608
Revenue from external customers includes the following fee and commission income disaggregated by income type
Current account and debit card fees	60	50	42
Insurance, protection and investments	0	0	0
Credit cards	0	0	0
Non-banking and other fees	77	62	50
Total fee and commission income	137	112	92
Fee and commission expense	(18)	(22)	(22)
Net fee and commission income	119	90	70
Customer loans	18,518	19,281	20,822
Total assets	18,518	19,281	20,820
Assets held for sale	0
Customer deposits	24,798	26,466	24,985
Total liabilities	£ 24,473	£ 26,513	£ 25,011
Average number of full-time equivalent staff | employee	2,336	2,281	2,405
Corporate & Commercial Banking | Inter-segment revenue
Disclosure of operating segments [line items]
Inter-segment revenue	£ (6)	£ (110)	£ (157)
Corporate & Investment Banking
Disclosure of operating segments [line items]
Net interest income / (expense)		0	0
Non-interest income / (expense)		0	0
Total operating income		0	0
Operating expenses before credit impairment (charges)/write-backs, provisions and charges		0	0
Credit impairment (charges)/write-backs		0	0
Provisions for other liabilities and charges		0	0
Total operating credit impairment (charges)/write-backs, provisions and charges		0	0
Profit from continuing operations before tax		0
Revenue from external customers		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
Insurance, protection and investments		0	0
Credit cards		0	0
Non-banking and other fees		0	0
Total fee and commission income		0	0
Fee and commission expense		0	0
Net fee and commission income		0	0
Customer loans		0	2,784
Total assets		0	2,784
Customer deposits		0	6,506
Total liabilities		£ 0	£ 6,517
Average number of full-time equivalent staff | employee		528	716
Corporate & Investment Banking | Inter-segment revenue
Disclosure of operating segments [line items]
Inter-segment revenue		£ 0	£ 0
Corporate Centre
Disclosure of operating segments [line items]
Net interest income / (expense)	(6)	(37)	16
Non-interest income / (expense)	(19)	55	(4)
Total operating income	(25)	18	12
Operating expenses before credit impairment (charges)/write-backs, provisions and charges	(175)	(281)	(108)
Credit impairment (charges)/write-backs	0	12	(36)
Provisions for other liabilities and charges	(11)	(162)	(93)
Total operating credit impairment (charges)/write-backs, provisions and charges	(11)	(150)	(129)
Profit from continuing operations before tax	(211)	(413)	(225)
Revenue from external customers	(398)	(619)	(926)
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	5	2
Total fee and commission income	5	5	2
Fee and commission expense	(8)	(9)	(4)
Net fee and commission income	(3)	(4)	(2)
Customer loans	0	0	0
Total assets	55,452	68,315	74,431
Assets held for sale	49
Customer deposits	3,365	2,758	2,049
Total liabilities	£ 83,289	£ 85,688	£ 89,784
Average number of full-time equivalent staff | employee	44	76	39
Corporate Centre | Inter-segment revenue
Disclosure of operating segments [line items]
Inter-segment revenue	£ 373	£ 637	£ 938

Net Interest Income (Details)

Net Interest Income (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Interest and similar income:
Loans and advances to customers	£ 5,774	£ 4,619	£ 4,745
Loans and advances to banks	618	52	49
Reverse repurchase agreements – non trading	149	35	118
Other	167	56	119
Total interest and similar income	6,708	4,762	5,031
Interest expense and similar charges:
Deposits by customers	(905)	(430)	(1,011)
Deposits by banks	(496)	(25)	(28)
Repurchase agreements – non trading	(120)	(3)	(43)
Debt securities in issue	(650)	(252)	(440)
Subordinated liabilities	(108)	(92)	(111)
Other	(4)	(11)	(10)
Total interest expense and similar charges	(2,283)	(813)	(1,643)
Net interest income	4,425	3,949	3,388
Interest income on financial assets at fair value through other comprehensive income	87	22	38
Interest expense on derivatives hedging debt issuances	6	317	451
Interest expense on lease liabilities	£ 3	£ 3	£ 3

Net Fee and Commission Income_2

Net Fee and Commission Income (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Fee And Commission Income [Line Items]
Total fee and commission income	£ 839	£ 697	£ 680
Total fee and commission expense	(509)	(411)	(361)
Net fee and commission income	330	286	319
Current account and debit card fees
Net Fee And Commission Income [Line Items]
Total fee and commission income	562	478	484
Insurance, protection and investments
Net Fee And Commission Income [Line Items]
Total fee and commission income	78	67	65
Credit cards
Net Fee And Commission Income [Line Items]
Total fee and commission income	95	73	66
Non-banking and other fees
Net Fee And Commission Income [Line Items]
Total fee and commission income	£ 104	£ 79	£ 65

Other Operating Income - Summar

Other Operating Income - Summary of Net Trading and Other Income (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Trading And Other Income [Abstract]
Net gains/(losses) on financial instruments designated at fair value through profit or loss	£ 62	£ (24)	£ (77)
Net (losses)/gains on financial instruments mandatorily at fair value through profit or loss	(75)	(2)	46
Hedge ineffectiveness	29	13	20
Net profit on sale of financial assets at fair value through other comprehensive income	0	6	17
Income from operating lease assets	129	136	126
Other	56	135	13
Other operating income (expense)	£ 201	£ 264	£ 145

Other Operating Income - Additi

Other Operating Income - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Trading And Other Income [Abstract]
Gains (losses) on embedded derivatives bifurcated from certain equity index-linked deposits	£ 14	£ (15)	£ 89
Gains (losses) on economic hedging of embedded derivatives bifurcated from certain equity index-linked deposits	(14)	15	(88)
Net gain on equity index-linked deposits and the related economic hedges	0	0	1
Exchange rate differences recognised	(2,163)	242	(751)
Principally offset from cash flow hedge reserve	2,129	(358)	809
Loss on repurchase of debt securities and subordinated liabilities	(5)	(1)	£ (24)
Losses on disposals of property, plant and equipment	£ 7
Gains on disposals of property, plant and equipment		£ 73

Operating Expenses Before Cre_3

Operating Expenses Before Credit Impairment Charges, Provisions and Charges - Summary of Operating Expenses Before Credit Impairment Losses, Provisions and Charges (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Staff costs:
Wages and salaries	£ 745	£ 745	£ 788
Performance-related payments	170	183	97
Social security costs	112	112	101
Pension costs, defined contribution plans	60	64	66
Pension costs, defined benefit plans	28	38	38
Other share-based payments	0	0	0
Other personnel costs	44	41	33
Staff costs	1,159	1,183	1,123
Other administration expenses	888	826	706
Depreciation, amortisation and impairment	296	501	561
Total operating expenses before impairment losses, provisions and charges	£ 2,343	£ 2,510	£ 2,390

Operating Expenses Before Cre_4

Operating Expenses Before Credit Impairment Charges, Provisions and Charges - Summary of Deferred Performance Awards (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Deferred Performance Awards [Line Items]
Cash	£ 22	£ 23
Shares	22	22
Expenses charged in the year
Disclosure Of Deferred Performance Awards [Line Items]
Cash	8	8
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	14	15
Shares	14	£ 14
Deferred performance awards	28
Expenses deferred to future periods | Arising from awards in current year
Disclosure Of Deferred Performance Awards [Line Items]
Cash	6
Shares	6
Deferred performance awards	12
Expenses deferred to future periods | Arising from awards in prior year
Disclosure Of Deferred Performance Awards [Line Items]
Cash	8
Shares	8
Deferred performance awards	£ 16

Operating Expenses Before Cre_5

Operating Expenses Before Credit Impairment Charges, Provisions and Charges - Summary of Amount of Bonus Awarded to Employees (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Amount Of Bonus Awarded To Employees [Line Items]
Cash award – not deferred	£ 145	£ 156
Cash award – deferred	22	23
Shares award – not deferred	9	11
Shares award – deferred	22	22
Total discretionary bonus	198	212
Expenses charged in the year
Disclosure Of Amount Of Bonus Awarded To Employees [Line Items]
Cash award – not deferred	145	156
Cash award – deferred	8	8
Shares award – not deferred	9	11
Shares award – deferred	8	8
Total discretionary bonus	170	183
Expenses deferred to future periods
Disclosure Of Amount Of Bonus Awarded To Employees [Line Items]
Cash award – not deferred	0	0
Cash award – deferred	14	15
Shares award – not deferred	0	0
Shares award – deferred	14	14
Total discretionary bonus	£ 28	£ 29

Operating Expenses Before Cre_6

Operating Expenses Before Credit Impairment Charges, Provisions and Charges - Additional Information (Details) £ in Millions	12 Months Ended
	Dec. 31, 2022 GBP (£) employee	Dec. 31, 2021 GBP (£) employee	Dec. 31, 2020 GBP (£) employee
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Average number of full-time equivalent staff | employee	18,123	19,704	21,998
Property, plant and equipment	£ 1,513	£ 1,548
Expense relating to short-term leases	21	23	£ 10
Right-of-use assets
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Property, plant and equipment	112	117
Depreciation for lease assets	19	19	58
Operating lease assets	112	117	100
Accumulated depreciation
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Property, plant and equipment	(1,260)	(1,922)	(2,287)
Impairment during the year	(10)	(97)
Accumulated depreciation | Right-of-use assets
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Property, plant and equipment	(155)	(137)	(118)
Impairment during the year	0	(23)
Accumulated depreciation | Branch and head office site closures
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Impairment during the year	10	88	0
Operating lease assets
Operating Expenses Before Credit Impairment Losses Provision And Charges [Line Items]
Depreciation, property, plant and equipment	73	81	92
Property, plant and equipment	£ 577	£ 595	£ 542

Audit and Other Services - Summ

Audit and Other Services - Summary of Audit and Other Services (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Audit fees:
Fees payable to the Company’s auditor and its associates for the audit of the Santander UK group’s annual accounts	£ 11.8	£ 11.2	£ 10
Audit of the Santander UK group's subsidiaries	0.7	0.9	1.4
Total audit fees	12.5	12.1	11.4
Non-audit fees:
Audit-related assurance services	0.6	0.8	0.8
Other assurance services	0.3	0.1	0.3
Other non-audit services	0	0.2	0
Total non-audit fees	0.9	1.1	1.1
Prior year audit services
Non-audit fees:
Auditors fee	£ 0.6	£ 1.2	£ 0.8

Audit and Other Services - Addi

Audit and Other Services - Additional Information (Details) - GBP (£) £ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Audit Fees And Non Audit Fees [Line Items]
Non-audit fees - Audit fees per US Securities and Exchange Commission guidance	£ 200	£ 400	£ 400
Non-audit fees - Audit related fees per US Securities and Exchange Commission guidance	700	700	700
Non-audit fees - All other fees per US Securities and Exchange Commission guidance	0	0	0
Audit fees payable for statutory audit	12,500	12,100	11,400
Incremental work, audit of Banco Santander
Disclosure Of Audit Fees And Non Audit Fees [Line Items]
Audit fees payable for statutory audit	1,600	1,400	1,500
Corporate and other borrowers
Disclosure Of Audit Fees And Non Audit Fees [Line Items]
Audit fees payable for statutory audit	£ 0	£ 27	£ 24

Credit Impairment Charges and_3

Credit Impairment Charges and Provisions - Summary of Impairment Losses and Provisions (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Credit Impairment Loss And Provisions [Abstract]
Loans and advances to customers	£ 248	£ (186)	£ 665
Recoveries of loans and advances, net of collection costs	36	(17)	(24)
Off-balance sheet credit exposures (See Note 29)	36	(30)	(3)
Impairment loss on financial assets	320	(233)	638
Provisions for other liabilities and charges (excluding off-balance sheet credit exposures) (See Note 29)	422	386	258
(Releases)/Provisions for residual value and voluntary termination	(3)	(9)	6
Provisions for other liabilities and charges	419	377	264
Total operating credit impairment (charges)/write-backs, provisions and charges	£ 739	£ 144	£ 902

Credit Impairment Charges and_4

Credit Impairment Charges and Provisions - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Credit Impairment Loss And Provisions [Abstract]
Impairment losses on loans and advances to banks	£ 0	£ 0	£ 0
Impairment losses on non-trading reverse repurchase agreements	0	0	0
Impairment losses on other financial assets at amortised cost	0	0	0
Impairment losses on financial assets at FVOCI	£ 0	£ 0	£ 0

Taxation - Disclosure of Income

Taxation - Disclosure of Income Tax and Deferred Taxes Explanatory (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Current tax:
UK corporation tax on profit for the year	£ 526	£ 401	£ 107
Adjustments in respect of prior years	(81)	(24)	(24)
Total current tax	445	377	83
Deferred tax:
(Credit)/Charge for the year	(29)	100	34
Adjustments in respect of prior years	64	15	4
Total deferred tax	35	115	38
Tax on profit from continuing operations	£ 480	£ 492	£ 121

Taxation - Additional Informati

Taxation - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Expense Benefits [Line Items]
Increase in applicable tax rate			2%
Bank corporation tax surcharge	8%
Unrecognised capital losses carried forward	£ 0	£ 0
At 1 April 2023
Income Tax Expense Benefits [Line Items]
Applicable tax rate (percentage)	25%
Increase in applicable tax rate	6%
Bank Surcharge, Q1 2022
Income Tax Expense Benefits [Line Items]
Bank corporation tax surcharge	3%
Banking entities
Income Tax Expense Benefits [Line Items]
Applicable tax rate (percentage)	27%	27%	27%
Non-banking entities
Income Tax Expense Benefits [Line Items]
Applicable tax rate (percentage)	19%	19%	19%
Deferred tax assets
Income Tax Expense Benefits [Line Items]
Recognised capital losses carried forward	£ 0	£ 5

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Major components of tax expense (income) [abstract]
Effective tax rate (percentage)	25.60%	26.70%	21.60%
Profit from continuing operations before tax	£ 1,874	£ 1,845	£ 560
Tax calculated at a tax rate of 19% (2021: 19%, 2020: 19%)	356	351	106
Bank surcharge on profits	121	104	27
Non-deductible preference dividends paid	9	9	8
Non-deductible UK Bank Levy	13	14	19
Non-deductible conduct remediation, fines and penalties	48	6	(4)
Other non-deductible costs and non-taxable income	29	37	25
Effect of change in tax rate on deferred tax provision	(29)	9	6
Tax relief on dividends in respect of other equity instruments	(40)	(40)	(40)
Adjustment to prior year provisions	(27)	2	(26)
Tax on profit from continuing operations	£ 480	£ 492	£ 121

Taxation - Disclosure of Moveme

Taxation - Disclosure of Movements in Current Tax Assets and Liabilities (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Major components of tax expense (income) [abstract]
Assets	£ 347	£ 264
Liabilities	0	0
Beginning balance	347	264
Income statement charge (including discontinued operations)	(445)	(389)
Other comprehensive income credit	159	33
Corporate income tax paid	405	427
Other movements	12	12
Ending balance	478	347
Assets	478	347
Liabilities	£ 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, 2022	Dec. 31, 2021
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	£ (579)	£ (111)
Income statement (charge)/credit	(35)	(115)
Transfers/reclassifications	0	(40)
Credited/(charged) to other comprehensive income	579	(313)
Ending balance	(35)	(579)
Fair value of financial instruments
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(123)	(65)
Income statement (charge)/credit	150	(58)
Transfers/reclassifications	0	0
Credited/(charged) to other comprehensive income	0	0
Ending balance	27	(123)
Pension remeasurement
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(508)	(26)
Income statement (charge)/credit	(49)	(67)
Transfers/reclassifications	0	4
Credited/(charged) to other comprehensive income	267	(419)
Ending balance	(290)	(508)
Cash flow hedges
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(7)	(99)
Income statement (charge)/credit	0	0
Transfers/reclassifications	2	(16)
Credited/(charged) to other comprehensive income	310	108
Ending balance	305	(7)
Fair value reserve
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(12)	(11)
Income statement (charge)/credit	0	0
Transfers/reclassifications	0	1
Credited/(charged) to other comprehensive income	11	(2)
Ending balance	(1)	(12)
Tax losses carried forward
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	8	15
Income statement (charge)/credit	(7)	(7)
Transfers/reclassifications	(1)	0
Credited/(charged) to other comprehensive income	0	0
Ending balance	0	8
Accelerated tax depreciation
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	68	38
Income statement (charge)/credit	(33)	40
Transfers/reclassifications	0	(10)
Credited/(charged) to other comprehensive income	0	0
Ending balance	35	68
Other temporary differences
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Beginning balance	(5)	37
Income statement (charge)/credit	(96)	(23)
Transfers/reclassifications	(1)	(19)
Credited/(charged) to other comprehensive income	(9)	0
Ending balance	£ (111)	£ (5)

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividend per share	£ 3.26	£ 4.37	£ 0.42
Dividends	£ 1,014	£ 1,358	£ 129
First interim
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividend per share	£ 1.25	£ 0.90	£ 0.42
Dividends	£ 389	£ 281	£ 129
Second interim
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividend per share	£ 2.01	£ 3.47	£ 0
Dividends	£ 625	£ 1,077	£ 0

Dividends on Ordinary Shares _2

Dividends on Ordinary Shares - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividends declared and paid	£ 1,014	£ 1,358	£ 129
Special Dividend
Disclosure Of Dividends On Ordinary Shares [Line Items]
Dividends declared and paid	£ 300

Derivative Financial Instrume_3

Derivative Financial Instruments - Notional Amounts of Transactions Outstanding (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of detailed information about hedges
Notional amount	£ 176,472	£ 162,049
Assets	2,407	1,681
Liabilities	951	777
Cash collateral received subject to enforceable master netting arrangement or similar agreement not set off against financial assets	9,059	12,941
Collateral cash	8,088	11,224
Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	46,043	37,240
Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	130,429	124,809
Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	78,286	81,104
Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	52,143	43,705
Exchange rate contracts
Disclosure of detailed information about hedges
Notional amount	40,579	33,865
Exchange rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	14,006	11,036
Exchange rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	538	590
Exchange rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	26,035	22,239
Interest rate contracts
Disclosure of detailed information about hedges
Notional amount	134,991	127,128
Interest rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	31,135	25,148
Interest rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	77,748	80,514
Interest rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Notional amount	26,108	21,466
Equity and credit contracts
Disclosure of detailed information about hedges
Notional amount	902	1,056
Equity and credit contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Notional amount	902	1,056
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	1,368	189
Derivative liabilities
Disclosure of detailed information about hedges
Collateral cash	70	202
Fair value
Disclosure of detailed information about hedges
Assets	2,407	1,681
Liabilities	951	777
Fair value | Derivatives held for trading:
Disclosure of detailed information about hedges
Assets	910	783
Liabilities	1,060	707
Fair value | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	3,670	2,119
Liabilities	2,064	1,291
Fair value | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	1,789	943
Liabilities	407	737
Fair value | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	1,881	1,176
Liabilities	1,657	554
Fair value | Exchange rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Assets	315	159
Liabilities	281	168
Fair value | Exchange rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	12	39
Liabilities	4	0
Fair value | Exchange rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	1,717	996
Liabilities	186	338
Fair value | Interest rate contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Assets	465	463
Liabilities	754	485
Fair value | Interest rate contracts | Fair value hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	1,777	904
Liabilities	403	737
Fair value | Interest rate contracts | Cash flow hedges | Derivatives held for hedging
Disclosure of detailed information about hedges
Assets	164	180
Liabilities	1,471	216
Fair value | Equity and credit contracts | Derivatives held for trading:
Disclosure of detailed information about hedges
Assets	130	161
Liabilities	25	54
Fair value | Derivative netting
Disclosure of detailed information about hedges
Assets	(2,173)	(1,221)
Liabilities	£ (2,173)	£ (1,221)

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, 2022	Dec. 31, 2021
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	£ 176,472	£ 162,049
Exchange rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	40,579	33,865
Interest rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	134,991	127,128
Equity and credit contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	902	1,056
Settled by central counterparties
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	124,638	117,559
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	124,638	117,559
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	51,834	44,490
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	40,579	33,865
Not settled by central counterparties | Interest rate contracts
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional amount	10,353	9,569
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	902	1,056
Traded over the counter
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Asset	2,407	1,681
Liability	951	777
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	2,044	1,194
Liability	471	507
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	233	326
Liability	455	216
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	130	161
Liability	£ 25	£ 54

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, 2022 GBP (£)	Dec. 31, 2021 GBP (£)
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 176,472	£ 162,049
Exchange rate contracts
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	40,579	33,865
Exchange rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	19,586	14,535
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	538	590
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	6,449	7,704
Interest rate contracts
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	134,991	127,128
Interest rate contracts | Interest rate risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	77,478	80,284
Interest rate contracts | Interest rate risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	19,446	15,168
Interest rate contracts | FX risk | Cash flow hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	3,737	3,325
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	270	230
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	2,925	2,973
≤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	£ 2,301	£ 2,703
Average GBP - JPY exchange rate	0	0
Average GBP - CHF exchange rate	0
Average GBP - EUR exchange rate	0	1.17
Average GBP - USD exchange rate	1.22	1.34
≤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
Average GBP - USD exchange rate	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	£ 0	£ 620
Average GBP - EUR exchange rate		1.28
Average GBP - USD exchange rate		0
≤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	£ 2,210	£ 3,121
≤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	0.0258	0.0059
≤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	0.0177	0.0051
≤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	0.0135	0.0191
≤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	£ 1,042	£ 1,010
≤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	0.0177	0.0197
≤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	£ 415	£ 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 | Fair value hedges | US Dollar
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	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	£ 0
≤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	0.0226
>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	£ 3,135	£ 936
Average GBP - JPY exchange rate	157.45	142.91
Average GBP - CHF exchange rate	1.13
Average GBP - EUR exchange rate	0	0
Average GBP - USD exchange rate	1.25	1.34
>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
Average GBP - USD exchange rate	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
Average GBP - USD exchange rate		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	£ 4,468	£ 6,223
>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	0.0088	0.0042
>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	0.0160	0.0174
>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	0.0347	0.0096
>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	£ 2,191	£ 481
>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	0.0229	0.0044
>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 | 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 | Fair value hedges | US Dollar
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	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
>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	£ 2,381	£ 2,057
Average GBP - JPY exchange rate	160.04	148.86
Average GBP - CHF exchange rate	0
Average GBP - EUR exchange rate	1.12	1.18
Average GBP - USD exchange rate	1.17	1.33
>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	£ 66	£ 107
Average GBP - EUR exchange rate	1.20	1.21
Average GBP - USD exchange rate	0
>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	£ 1,173	£ 840
Average GBP - EUR exchange rate	1.19	1.39
Average GBP - USD exchange rate	1.60	0
>3 and ≤12 months | Interest rate contracts | Interest rate risk | Fair value hedges
Disclosure of nature and extent of risks arising from financial instruments [line items]
Notional amount	£ 21,678	£ 21,442
>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	0.0056	0.0009
>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	0.0077	0.0108
>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	0.0351	0.0144
>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	£ 1,940	£ 871
>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	0.0198	0.0008
>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 | 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	0.0342	0.0329
>3 and ≤12 months | Interest rate contracts | Interest rate/FX risk | Fair value hedges | US Dollar
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0
>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	£ 585	£ 0
>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	0.0327	0.0117
>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	£ 10,606	£ 6,715
Average GBP - JPY exchange rate	0	0
Average GBP - CHF exchange rate	0
Average GBP - EUR exchange rate	1.18	1.16
Average GBP - USD exchange rate	1.31	1.34
>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	£ 465	£ 381
Average GBP - EUR exchange rate	1.16	1.16
Average GBP - USD exchange rate	1.19
>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	£ 4,626	£ 4,765
Average GBP - EUR exchange rate	1.21	1.20
Average GBP - USD exchange rate	1.50	1.61
>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	£ 45,314	£ 44,507
>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	0.0207	0.0088
>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	0.0028	0.0081
>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	0.0200	0.0276
>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	£ 13,197	£ 7,669
>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	0.0235	0.0139
>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	£ 2,325	£ 2,438
>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	£ 263	£ 193
>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	0.0206	0.0203
>1 and ≤5 years | Interest rate contracts | Interest rate/FX risk | Fair value hedges | US Dollar
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0.0463
>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	£ 2,132	£ 2,049
>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	0.0258	0.0272
>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	£ 1,163	£ 2,124
Average GBP - JPY exchange rate	0	0
Average GBP - CHF exchange rate	0
Average GBP - EUR exchange rate	1.17	1.17
Average GBP - USD exchange rate	1.39	1.39
>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	£ 7	£ 102
Average GBP - EUR exchange rate	1.10	1.17
Average GBP - USD exchange rate	0
>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	£ 650	£ 1,479
Average GBP - EUR exchange rate	1.20	1.20
Average GBP - USD exchange rate	1.54	1.38
>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	£ 3,808	£ 4,991
>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	0.0378	0.0313
>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	0.0309	0.0261
>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	0.0492	0.0405
>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	£ 1,076	£ 5,137
>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	0.0184	0.0097
>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	£ 997	£ 887
>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	£ 7	£ 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	0.0262
>5 years | Interest rate contracts | Interest rate/FX risk | Fair value hedges | US Dollar
Disclosure of nature and extent of risks arising from financial instruments [line items]
Average fixed interest rate	0
>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	£ 208	£ 924
>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	0.0459	0.0341

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of detailed information about hedges
Hedge ineffectiveness	£ 29	£ 13	£ 20
Fair Value and Cash Flow Hedges
Disclosure of detailed information about hedges
Gains/(losses) on hedging instruments	2,381	852	(299)
(Losses)/gains on hedged items attributable to hedged risks	(2,316)	(800)	365
Fair value hedging ineffectiveness	65	52	66
Cash flow hedging ineffectiveness	(36)	(39)	(46)
Hedge ineffectiveness	£ 29	£ 13	£ 20

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair value hedges
Disclosure of detailed information about hedges
Change in FV of hedging instruments	£ 2,381	£ 852	£ (299)
Change in FV of hedged items	(2,316)	(800)	365
Recognised in income statement	65	52	66
Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	2,392	874	(358)
Change in FV of hedged items	(2,333)	(834)	385
Recognised in income statement	59	40	27
Fair value hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(11)	(22)	59
Change in FV of hedged items	17	34	(20)
Recognised in income statement	6	12	39
Cash flow hedges
Disclosure of detailed information about hedges
Change in FV of hedging instruments	389	(912)	925
Change in FV of hedged items	(425)	873
Recognised in OCI	(425)	873	(971)
Recognised in income statement	(36)	(39)	(46)
Reclassified from reserves to income	2,129	(358)	808
Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(1,161)	(317)	185
Recognised in OCI	1,160	305	(179)
Recognised in income statement	(1)	(12)	6
Reclassified from reserves to income	(96)	73	33
Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	1,604	(54)	(42)
Recognised in OCI	(1,604)	54	38
Recognised in income statement	0	0	(4)
Reclassified from reserves to income	1,692	(158)	2
Cash flow hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Change in FV of hedging instruments	(54)	(541)	782
Recognised in OCI	19	514	(830)
Recognised in income statement	(35)	(27)	(48)
Reclassified from reserves to income	£ 533	£ (273)	£ 773

Derivative Financial Instrume_8

Derivative Financial Instruments - Additional Information (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of nature and extent of risks arising from financial instruments [abstract]
Ceased cash flow hedge accounting	£ 0	£ 14

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) - Cash flow hedges - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of detailed information about hedges
Beginning Balance	£ 129	£ 644
Effective portion of changes in fair value:	425	(873)
Income statement transfers:	(2,129)	358
Ending Balance	(1,575)	129
Interest rate risk
Disclosure of detailed information about hedges
Effective portion of changes in fair value:	(1,160)	(305)
Income statement transfers:	96	(73)
Foreign currency risk
Disclosure of detailed information about hedges
Effective portion of changes in fair value:	1,604	(54)
Income statement transfers:	(1,692)	158
Equity risk
Disclosure of detailed information about hedges
Effective portion of changes in fair value:	0	0
Income statement transfers:		0
Interest rate/FX risk
Disclosure of detailed information about hedges
Effective portion of changes in fair value:	(19)	(514)
Income statement transfers:	£ (533)	£ 273

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair value hedges
Disclosure of detailed information about hedges
Carrying value of assets	£ 60,533	£ 67,194
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	80	(291)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks assets	(2,752)	(45)
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	(887)	198
Change in value to calculate hedge ineffectiveness	(2,316)	(800)	£ 365
Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	(2,333)	(834)	385
Fair value hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	17	34	(20)
Cash flow hedges
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	(425)	873
Cash flow hedge reserve	(1,575)	129	£ 644
Balances on cash flow hedge reserve for discontinued hedges	(35)	80
Deposits by customers | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of liabilities	(1,739)	(1,665)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	24	(46)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks liabilities	5	0
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	0	(44)
Change in value to calculate hedge ineffectiveness	33	104
Deposits by customers | Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	(167)	9
Cash flow hedge reserve	(2)	9
Balances on cash flow hedge reserve for discontinued hedges	0	10
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	(8)	(1)
Cash flow hedge reserve	7	1
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	(4,735)	(2,567)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	321	(140)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks liabilities	(94)	(114)
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	(172)	(185)
Change in value to calculate hedge ineffectiveness	528	235
Debt securities in issue | Fair value hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Carrying value of liabilities	(290)	(423)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	(18)	(55)
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	(37)	(47)
Change in value to calculate hedge ineffectiveness	27	55
Debt securities in issue | Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	(1,051)	85
Cash flow hedge reserve	(17)	57
Balances on cash flow hedge reserve for discontinued hedges	(2)	(4)
Subordinated liabilities | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of liabilities	(250)	(293)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	(27)	(75)
Accumulated amount of FV hedge adjustments for portfolio hedge of interest rate risks liabilities	(6)	(8)
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	(63)	(70)
Change in value to calculate hedge ineffectiveness	54	49
Subordinated liabilities | Fair value hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Carrying value of liabilities	(1)	(2)
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item liabilities	1	2
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	1	2
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	0
Cash flow hedge reserve	0	0
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	(37)	6
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	60,783	58,455
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	(2,640)	80
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	(653)	491
Change in value to calculate hedge ineffectiveness	(2,707)	(1,092)
Loans and advances to customers | Cash flow hedges | Interest rate risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	935	235
Cash flow hedge reserve	(1,010)	(135)
Balances on cash flow hedge reserve for discontinued hedges	(1)	(2)
Other financial assets at amortised cost | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of assets	156	160
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	(12)	2
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	2	3
Change in value to calculate hedge ineffectiveness	(14)	(12)
Reverse repurchase agreements – non trading | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of assets	4,045	9,570
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)	(5)
Accumulated amount of FV hedge adjustments on balance sheet for discontinued hedges	(1)	0
Change in value to calculate hedge ineffectiveness	0	(6)
Other financial assets at FVOCI | Fair value hedges | Interest rate risk
Disclosure of detailed information about hedges
Carrying value of assets	2,325	3,728
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item assets	(200)	23
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	35	47
Change in value to calculate hedge ineffectiveness	(227)	(112)
Other financial assets at FVOCI | Fair value hedges | Interest rate/FX risk
Disclosure of detailed information about hedges
Carrying value of assets	237	227
Accumulated amount of FV hedge adjustments on hedged item in carrying value of hedged item assets	(21)	0
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	1
Change in value to calculate hedge ineffectiveness	(9)	(20)
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	233	71
Cash flow hedge reserve	(274)	(79)
Balances on cash flow hedge reserve for discontinued hedges	(106)	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	0
Cash flow hedge reserve	0	0
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
Other financial assets at FVOCI | Cash flow hedges | FX risk
Disclosure of detailed information about hedges
Change in value to calculate hedge ineffectiveness	0	(195)
Cash flow hedge reserve	(6)	(1)
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	(349)	149
Cash flow hedge reserve	2	1
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	56	410
Cash flow hedge reserve	(170)	105
Balances on cash flow hedge reserve for discontinued hedges	(3)	(4)
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	0	93
Cash flow hedge reserve	(74)	38
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	(37)	11
Cash flow hedge reserve	(31)	133
Balances on cash flow hedge reserve for discontinued hedges	£ 77	£ 80

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, 2022	Dec. 31, 2021
Disclosure Of Other Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at fair value through profit or loss	£ 129	£ 185
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	45	74
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	4	12
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	41	62
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	£ 84	£ 111

Other Financial Assets at Fai_4

Other Financial Assets at Fair Value Through Profit or Loss - Additional Information (Details) - GBP (£) £ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financial assets at fair value through profit or loss [abstract]
Financial assets designated at FVTPL	£ 16,000	£ 12,000
Financial assets mandatorily at FVTPL	113,000	173,000
Net (loss)/gain attributable to changes in credit risk for loans and advances at fair value through profit or loss	(1,000)	0	£ 0
Cumulative net loss attributable to changes in credit risk for loans and advances at fair value through profit or loss	£ (3,000)	£ (2,000)

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, 2022	Dec. 31, 2021
Net Loans And Advances To Customers [Abstract]
Loans secured on residential properties	£ 184,317	£ 174,712
Corporate loans	19,057	19,282
Finance leases	4,645	3,916
Other unsecured loans	7,742	9,404
Accrued interest and other adjustments	688	452
Amounts due from fellow Banco Santander subsidiaries and joint ventures	4,220	3,175
Amounts due from Santander UK Group Holdings plc	0	6
Loans and advances to customers	220,669	210,947
Credit impairment loss allowances on loans and advances to customers	(931)	(828)
Residual value and voluntary termination provisions on finance leases	(22)	(25)
Net loans and advances to customers	£ 219,716	£ 210,094

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, 2022	Dec. 31, 2021
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	£ 5,296	£ 4,382
Unearned finance income	(651)	(466)
Net investment	4,645	3,916
No later than one year
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	1,493	1,906
Unearned finance income	(182)	(5)
Net investment	1,311	1,901
Later than one year and not later than two years
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	1,367	1,324
Unearned finance income	(168)	(200)
Net investment	1,199	1,124
Later than two years and not later than three years
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	1,190	771
Unearned finance income	(147)	(141)
Net investment	1,043	630
Later than three years and not later than four years
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	1,044	343
Unearned finance income	(129)	(82)
Net investment	915	261
Later than four years and not later than five years
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	143	38
Unearned finance income	(18)	(38)
Net investment	125	0
Later than five years
Disclosure Of Finance Lease And Hire Purchase Contract Receivables [Line Items]
Gross investment	59	0
Unearned finance income	(7)	0
Net investment	£ 52	£ 0

Loans and Advances to Custome_5

Loans and Advances to Customers - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Loans And Advances To Customers [Abstract]
Unguaranteed residual value of leases	£ 1,761	£ 1,510
Contingent rent income	0	0	£ 0
Finance income on the net investment in finance leases	£ 230	£ 243	£ 308

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, 2022	Dec. 31, 2021
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	£ 125	£ 133
No later than one year
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	31	31
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	27
Later than two years and not later than three years
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	22	21
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	13	15
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	11
Later than five years
Disclosure of maturity analysis of operating lease payments [line items]
Undiscounted operating lease payments to be received	£ 21	£ 28

Securitisations and Covered B_3

Securitisations and Covered Bonds - Analysis of Securitisations and Covered Bonds (Details) £ in Millions	Dec. 31, 2022 GBP (£)	Dec. 31, 2022 EUR (€)	Dec. 31, 2021 GBP (£)	Dec. 31, 2021 EUR (€)
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	£ 24,984		£ 20,199
External notes in issue	16,102		13,519
Notes issued to Santander UK plc/subsidiaries as collateral	1,541		1,585
Notional amount	176,472		162,049
Euro 35bn Global Covered Bond Programme
Disclosure Of Securitisations And Covered Bonds [Line Items]
Notional amount | €		€ 35,000,000,000		€ 35,000,000,000
Securitisation programmes
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	3,680		4,486
External notes in issue	897		759
Notes issued to Santander UK plc/subsidiaries as collateral	1,541		1,585
Securitisation programmes | Mortgage-backed master trust structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	3,674		4,448
External notes in issue	890		718
Notes issued to Santander UK plc/subsidiaries as collateral	1,541		1,585
Holmes | Securitisation programmes | Mortgage-backed master trust structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	1,646		2,294
External notes in issue	790		430
Notes issued to Santander UK plc/subsidiaries as collateral	176		183
Fosse | Securitisation programmes | Mortgage-backed master trust structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	2,028		2,154
External notes in issue	100		288
Notes issued to Santander UK plc/subsidiaries as collateral	1,365		1,402
Motor | Securitisation programmes | Other asset-backed securitisation structures:
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	6		38
External notes in issue	7		41
Notes issued to Santander UK plc/subsidiaries as collateral	0		0
Euro 35bn Global Covered Bond Programme | Covered bond programmes
Disclosure Of Securitisations And Covered Bonds [Line Items]
Gross assets	21,304		15,713
External notes in issue	15,205		12,760
Notes issued to Santander UK plc/subsidiaries as collateral	£ 0		£ 0

Securitisations and Covered B_4

Securitisations and Covered Bonds - Summary of Issuances and Redemptions of Securitisation and Covered Bond Programme (Details) - GBP (£) £ in Billions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Internal issuances
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	£ 0	£ 0
Internal and external redemptions	0.2	2.8
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	0.1	0.2
Internal issuances | Mortgage-backed master trust structures: | Fosse
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0
Internal and external redemptions	0	0
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	0	2.4
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	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
Internal and external redemptions		0.1
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	0.1	0
External issuances
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	4.8	0
Internal and external redemptions	2.1	7.1
External issuances | Mortgage-backed master trust structures: | Holmes
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0.6	0
Internal and external redemptions	0.2	0.4
External issuances | Mortgage-backed master trust structures: | Fosse
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	0	0
Internal and external redemptions	0.2	0
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	0.1
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
Internal and external redemptions		0.1
External issuances | Covered bond programmes
Issuances And Redemptions Of Securitisation And Covered Bond [Line items]
Internal and external issuances	4.2	0
Internal and external redemptions	£ 1.7	£ 6.5

Securitisations and Covered B_5

Securitisations and Covered Bonds - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2022
Langton
Disclosure Of Gross Asset Securitised [Line Items]
Gain or loss on covered bonds programme redemption	£ 0
Holmes
Disclosure Of Gross Asset Securitised [Line Items]
Beneficial interest in residential mortgage loans	500	£ 800
Cash deposits	60	112
Fosse
Disclosure Of Gross Asset Securitised [Line Items]
Beneficial interest in residential mortgage loans	1,600	1,500
Cash deposits	£ 185	£ 108

Transfers of Financial Assets_3

Transfers of Financial Assets Not Qualifying for Derecognition (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of continuing involvement in derecognised financial assets [line items]
Carrying amount of financial assets not derecognised in their entirety	£ 6,671	£ 6,549
Carrying amount of associated financial liabilities	(3,534)	(2,673)
Sale and repurchase agreements
Disclosure of continuing involvement in derecognised financial assets [line items]
Carrying amount of financial assets not derecognised in their entirety	120	171
Carrying amount of associated financial liabilities	(128)	(172)
Securities lending agreements
Disclosure of continuing involvement in derecognised financial assets [line items]
Carrying amount of financial assets not derecognised in their entirety	2,871	1,892
Carrying amount of associated financial liabilities	(2,509)	(1,742)
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	3,680	4,486
Carrying amount of associated financial liabilities	£ (897)	£ (759)

Reverse Repurchase Agreements_3

Reverse Repurchase Agreements - Non Trading (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Reserve Repurchase Agreements Non-Trading [Line Items]
Repurchase agreements – non trading	£ 7,348	£ 12,683
Agreements with banks
Disclosure Of Reserve Repurchase Agreements Non-Trading [Line Items]
Repurchase agreements – non trading	885	447
Agreements with customers
Disclosure Of Reserve Repurchase Agreements Non-Trading [Line Items]
Repurchase agreements – non trading	£ 6,463	£ 12,236

Other Financial Assets at Amo_3

Other Financial Assets at Amortised Cost (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at amortised cost	£ 156	£ 506
Other financial assets
Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at amortised cost	156	506
Other financial assets | Asset backed securities
Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at amortised cost	94	443
Other financial assets | Debt securities
Financial Assets At Fair Value Through Profit Or Loss [Line Items]
Financial assets at amortised cost	£ 62	£ 63

Financial Assets at Fair Valu_3

Financial Assets at Fair Value Through Other Comprehensive Income (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Financial Assets At Fair Value Through Other Comprehensive Income [Line Items]
Financial assets at fair value through other comprehensive income	£ 6,024	£ 5,851
Debt securities
Disclosure Of Financial Assets At Fair Value Through Other Comprehensive Income [Line Items]
Financial assets at fair value through other comprehensive income	6,024	5,833
Loans and advances to customers
Disclosure Of Financial Assets At Fair Value Through Other Comprehensive Income [Line Items]
Financial assets at fair value through other comprehensive income	£ 0	£ 18

Interests in Other Entities - S

Interests in Other Entities - Schedule of Interests in Other Entities (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Investments accounted for using equity method [abstract]
Subsidiaries	£ 0	£ 0
Joint Ventures	£ 252	£ 201

Interests In Other Entities - A

Interests In Other Entities - Additional Information (Details)	12 Months Ended
	Dec. 31, 2022 GBP (£)	Dec. 31, 2021 GBP (£)
Disclosure of subsidiaries [line items]
Ownership interest in share capital	100%
Joint Ventures	£ 252,000,000	£ 201,000,000
Number of credit protection vehicles	4	3
Senior credit linked notes issued	£ 180,000,000	£ 1,184,000,000
Junior credit linked notes issued	465,000,000	619,000,000
Santander (UK) Common Investment Fund
Disclosure of subsidiaries [line items]
Defined benefit assets and obligations	8,646,000,000	14,100,000,000
Joint ventures
Disclosure of subsidiaries [line items]
Profit after tax	36,000,000	22,000,000
Joint Ventures	252,000,000	201,000,000
Commitments and contingent liabilities	£ 0	£ 0

Intangible Assets - Schedule of

Intangible Assets - Schedule of Goodwill (Details) £ in Millions	12 Months Ended
	Dec. 31, 2022 GBP (£)
Disclosure Of Goodwill [Line Items]
Goodwill at beginning of period	£ 1,203
Increase (decrease) in goodwill	(4)
Goodwill at end of period	1,199
Cost
Disclosure Of Goodwill [Line Items]
Goodwill at beginning of period	1,269
Increase (decrease) in goodwill	0
Goodwill at end of period	1,269
Accumulated impairment
Disclosure Of Goodwill [Line Items]
Goodwill at beginning of period	(66)
Increase (decrease) in goodwill	(4)
Goodwill at end of period	£ (70)

Intangible Assets - Additional

Intangible Assets - Additional Information (Details) - GBP (£)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of detailed information about intangible assets [abstract]
Goodwill impairment recognised	£ 0	£ 0
Computer software	149,000,000	83,000,000
Internally generated computer software	33,000,000	31,000,000
Impairment charge	£ 3,000,000	£ 26,000,000

Intangible Assets - Schedule _2

Intangible Assets - Schedule of Goodwill for Cash Generating Units (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of information for cash-generating units [line items]
Goodwill	£ 1,199	£ 1,203
Personal Financial Services
Disclosure of information for cash-generating units [line items]
Goodwill	£ 1,169	£ 1,169
Discount rate	16.60%	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	15.30%	16.30%
Growth rate beyond initial cash flow projections	1.60%	1.60%
Other
Disclosure of information for cash-generating units [line items]
Goodwill	£ 0	£ 4
Discount rate		13.60%
Growth rate beyond initial cash flow projections		1.60%

Intangible Assets - Disclosure

Intangible Assets - Disclosure of Reasonably Possible Changes in Key Assumptions (Details) - Personal Financial Services - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Goodwill [Line Items]
Value in use estimate, increase (decrease) in cash flows	5%	5%
Increase (decrease) in discount rate applied to cash flow projections	1%	1%
Value in use estimate, impairment increase sensitivity for cash flows adjustment	£ (538)	£ (455)
Value in use estimate, impairment increase sensitivity for discount rate adjustment	£ (887)	£ (943)

Intangible Assets - Sensitivity

Intangible Assets - Sensitivity of VIU Changes to Current Assumptions (Details) - Personal Financial Services - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Goodwill [Line Items]
Carrying value	£ 8,860	£ 8,433
Value in use	10,752	9,100
Headroom	£ 1,892	£ 667
Increase in discount rate	2.39%	0.68%
Decrease in cash flows	18%	7%

Intangible Assets - Schedule _3

Intangible Assets - Schedule of Other Intangibles (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of detailed information about intangible assets [line items]
Other intangibles at beginning of period	£ 342	£ 443
Additions	112	84
Disposals	0	(1)
Charge	(100)	(158)
Impairment	(3)	(26)
Other intangibles at end of period	351	342
Cost
Disclosure of detailed information about intangible assets [line items]
Other intangibles at beginning of period	1,334	1,304
Additions	112	84
Disposals	(185)	(54)
Charge	0	0
Impairment	0	0
Other intangibles at end of period	1,261	1,334
Accumulated amortisation/ impairment
Disclosure of detailed information about intangible assets [line items]
Other intangibles at beginning of period	(992)	(861)
Additions	0	0
Disposals	185	53
Charge	(100)	(158)
Impairment	(3)	(26)
Other intangibles at end of period	£ (910)	£ (992)

Property, Plant and Equipment -

Property, Plant and Equipment - Disclosure of Detailed Information about Property, Plant and Equipment (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	£ 1,548
Property, plant and equipment at end of period	1,513	£ 1,548
Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	3,470	4,021
Additions	370	501
Reclassification to assets held for sale	(111)
Disposals	(956)	(1,052)
Property, plant and equipment at end of period	2,773	3,470
Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(1,922)	(2,287)
Additions	(179)	(219)
Impairment during the year	10	97
Reclassification to assets held for sale	62
Disposals	789	681
Property, plant and equipment at end of period	(1,260)	(1,922)
Property
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	644
Property, plant and equipment at end of period	619	644
Property | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	978	1,272
Additions	61	126
Reclassification to assets held for sale	(98)
Disposals	(52)	(420)
Property, plant and equipment at end of period	889	978
Property | Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(334)	(489)
Additions	(18)	(32)
Impairment during the year	8	46
Reclassification to assets held for sale	49
Disposals	41	233
Property, plant and equipment at end of period	(270)	(334)
Office fixtures and equipment
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	192
Property, plant and equipment at end of period	205	192
Office fixtures and equipment | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	1,049	1,375
Additions	86	26
Reclassification to assets held for sale	(13)
Disposals	(299)	(352)
Property, plant and equipment at end of period	823	1,049
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	(857)	(1,068)
Additions	(68)	(86)
Impairment during the year	2	28
Reclassification to assets held for sale	13
Disposals	296	325
Property, plant and equipment at end of period	(618)	(857)
Computer software
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	0
Property, plant and equipment at end of period	0	0
Computer software | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	434	436
Additions	0	0
Reclassification to assets held for sale	0
Disposals	(362)	(2)
Property, plant and equipment at end of period	72	434
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)	(1)
Impairment during the year	0	0
Reclassification to assets held for sale	0
Disposals	363	1
Property, plant and equipment at end of period	(72)	(434)
Operating lease assets
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	595
Property, plant and equipment at end of period	577	595
Operating lease assets | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	755	720
Additions	185	284
Reclassification to assets held for sale	0
Disposals	(218)	(249)
Property, plant and equipment at end of period	722	755
Operating lease assets | Accumulated depreciation
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	(160)	(178)
Additions	(73)	(81)
Impairment during the year	0	0
Reclassification to assets held for sale	0
Disposals	88	99
Property, plant and equipment at end of period	(145)	(160)
Right-of-use assets
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	117
Property, plant and equipment at end of period	112	117
Right-of-use assets | Cost
Disclosure of detailed information about property, plant and equipment [line items]
Property, plant and equipment at beginning of period	254	218
Additions	38	65
Reclassification to assets held for sale	0
Disposals	(25)	(29)
Property, plant and equipment at end of period	267	254
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	(137)	(118)
Additions	(19)	(19)
Impairment during the year	0	23
Reclassification to assets held for sale	0
Disposals	1	23
Property, plant and equipment at end of period	£ (155)	£ (137)

Property, Plant and Equipment_2

Property, Plant and Equipment - Additional Information (Details) - Head Office, Milton Keynes £ in Millions	Dec. 31, 2022 GBP (£)
Disclosure of detailed information about property, plant and equipment [line items]
Planned investment	£ 200
Expenditures	£ 204

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, 2022 GBP (£)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2021 USD ($)
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		£ 803
Notional amount	176,472		162,049
– 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	3		5
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	375		413
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	102		142
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	321		223
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	£ 2		£ 20

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of financial liabilities [abstract]
Increase (decrease) in fair value of financial liability, attributable to changes in credit risk of liability	£ 25	£ (12)	£ (3)
Accumulated increase (decrease) in fair value of financial liability, attributable to changes in credit risk of liability	15	(10)	£ (3)
Difference between carrying amount of financial liability and amount contractually required to pay at maturity to holder of obligation	£ 138	£ 0

Deposits by Customers (Details)

Deposits by Customers (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	£ 195,568	£ 192,926
Demand and time deposits
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	189,587	185,843
Amounts due to other Santander UK Group Holdings plc subsidiaries
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	67	59
Amounts due to Santander UK Group Holdings plc
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	4,759	5,874
Amounts due to fellow Banco Santander subsidiaries and joint ventures
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	1,155	1,150
Equity Index Linked Deposits
Disclosure Of Deposits From Customers [Line Items]
Deposits by customers	408	549
Capital amount guaranteed or protected	408	549
Capital amount of return guaranteed	£ 2	£ 2

Deposits by Banks (Details)

Deposits by Banks (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	£ 28,525	£ 33,855
Drawdown from TFSME	25,000	31,900
Items in the course of transmission
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	701	414
Deposits held as collateral
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	1,741	931
Other deposits
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	26,082	32,507
Amounts due to Santander UK subsidiaries
Disclosure Of Deposits From Banks [Line Items]
Deposits by banks	£ 1	£ 3

Repurchase Agreements - Non T_3

Repurchase Agreements - Non Trading (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Repurchase Agreements [Line Items]
Repurchase agreements - non trading	£ 7,982	£ 11,718
Agreements with banks
Disclosure Of Repurchase Agreements [Line Items]
Repurchase agreements - non trading	50	43
Agreements with banks | Increase (decrease) due to corrections of prior period errors
Disclosure Of Repurchase Agreements [Line Items]
Repurchase agreements - non trading		(4,102)
Agreements with customers
Disclosure Of Repurchase Agreements [Line Items]
Repurchase agreements - non trading	£ 7,932	11,675
Agreements with customers | Increase (decrease) due to corrections of prior period errors
Disclosure Of Repurchase Agreements [Line Items]
Repurchase agreements - non trading		£ 4,102

Debt Securities In Issue (Detai

Debt Securities In Issue (Details) £ in Millions	Dec. 31, 2022 GBP (£)	Dec. 31, 2022 EUR (€)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 GBP (£)	Dec. 31, 2021 EUR (€)	Dec. 31, 2021 USD ($)
Debt Securities In Issue [Line Items]
Debt securities	£ 31,531			£ 25,520
Notional amount	176,472			162,049
Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities	10,644			6,851
Euro 35bn Global Covered Bond Programme
Debt Securities In Issue [Line Items]
Debt securities	15,205			12,760
Notional amount | €		€ 35,000,000,000			€ 35,000,000,000
US$20bn Commercial Paper Programmes
Debt Securities In Issue [Line Items]
Debt securities	1,851			2,704
Notional amount | $			$ 20,000,000,000			$ 20,000,000,000
Certificates of deposit
Debt Securities In Issue [Line Items]
Debt securities	2,874			2,387
Credit linked notes
Debt Securities In Issue [Line Items]
Credit linked notes	60			59
Securitisation programmes
Debt Securities In Issue [Line Items]
Debt securities	897			759
– US$30bn Euro Medium Term Note Programme | Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities	739			1,405
Notional amount | $			$ 30,000,000,000			$ 30,000,000,000
– Euro 30bn Euro Medium Term Note Programme | Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities	3,211			1,261
Notional amount | €		€ 30,000,000,000			€ 30,000,000,000
- US SEC-registered Debt Programme - Santander UK plc | Medium-term notes
Debt Securities In Issue [Line Items]
Debt securities	£ 6,694			£ 4,185

Subordinated Liabilities - Sche

Subordinated Liabilities - Schedule of Subordinated Liabilities (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Subordinated liabilities [abstract]
£325m Sterling preference shares	£ 344	£ 344
Undated subordinated liabilities	219	240
Dated subordinated liabilities	1,769	1,644
Subordinated liabilities	2,332	2,228
£325m Sterling preference shares, notional amount	£ 325	£ 325

Subordinated Liabilities - Addi

Subordinated Liabilities - Additional Information (Details) - GBP (£)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Subordinated Liabilities [Line Items]
Loss on repurchase of debt securities and subordinated liabilities	£ (5,000,000)	£ (1,000,000)	£ (24,000,000)
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)	£ 0.10	£ 0.10	£ 0.10
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, 2022	Dec. 31, 2021
Disclosure Of Subordinated Liabilities [Line Items]
Undated subordinated liabilities	£ 219	£ 240
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	£ 14	£ 35

Subordinated Liabilities - Su_2

Subordinated Liabilities - Summary of Dated Subordinated Liabilities (Details) £ in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2022 GBP (£)	Dec. 31, 2021 GBP (£)
Disclosure Of Subordinated Liabilities [Line Items]
Dated subordinated liabilities			£ 1,769	£ 1,644
5% Subordinated notes (US$1,500m)
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	5%	5%	5%	5%
Notional amount | $	$ 1,500	$ 1,500
Maturity	2023	2023
Dated subordinated liabilities			£ 591	£ 548
4.75% Subordinated notes (US$1,000m)
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	4.75%	4.75%	4.75%	4.75%
Notional amount | $	$ 1,000	$ 1,000
Maturity	2025	2025
Dated subordinated liabilities			£ 608	£ 541
7.95% Subordinated notes (US$1,000m)
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	7.95%	7.95%	7.95%	7.95%
Notional amount | $	$ 1,000	$ 1,000
Maturity	2029	2029
Dated subordinated liabilities			£ 207	£ 221
6.50% Subordinated notes
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	6.50%	6.50%	6.50%	6.50%
Maturity	2030	2030
Dated subordinated liabilities			£ 22	£ 28
5.875%Subordinated notes
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	5.875%	5.875%	5.875%	5.875%
Maturity	2031	2031
Dated subordinated liabilities			£ 7	£ 9
5.625%Subordinated notes (US$500m)
Disclosure Of Subordinated Liabilities [Line Items]
Interest rate	5.625%	5.625%	5.625%	5.625%
Notional amount | $	$ 500	$ 500
Maturity	2045	2045
Dated subordinated liabilities			£ 334	£ 297

Other Liabilities (Details)

Other Liabilities (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Subclassifications of assets, liabilities and equities [abstract]
Lease liabilities	£ 125	£ 132
Other	2,456	1,935
Other liabilities	£ 2,581	£ 2,067

Provisions - Summary of Provisi

Provisions - Summary of Provisions Reconciliation (Details) £ in Millions	12 Months Ended
	Dec. 31, 2022 GBP (£)
Disclosure of other provisions [line items]
Beginning balance	£ 364
Additional provisions	516
Provision releaseds	(58)
Utilisation and other	(462)
Recharge	18
Ending balance	378
Customer remediation
Disclosure of other provisions [line items]
Beginning balance	44
Additional provisions	77
Provision releaseds	(18)
Utilisation and other	(13)
Recharge	0
Ending balance	90
Litigation and other regulatory
Disclosure of other provisions [line items]
Beginning balance	166
Additional provisions	137
Provision releaseds	(18)
Utilisation and other	(149)
Recharge	0
Ending balance	136
Bank Levy
Disclosure of other provisions [line items]
Beginning balance	1
Additional provisions	47
Provision releaseds	(4)
Utilisation and other	(59)
Recharge	18
Ending balance	3
Property
Disclosure of other provisions [line items]
Beginning balance	74
Additional provisions	0
Provision releaseds	(7)
Utilisation and other	(20)
Recharge	0
Ending balance	47
ECL on undrawn facilities and guarantees
Disclosure of other provisions [line items]
Beginning balance	38
Additional provisions	36
Provision releaseds	0
Utilisation and other	0
Recharge	0
Ending balance	74
Restructuring
Disclosure of other provisions [line items]
Beginning balance	28
Additional provisions	23
Provision releaseds	0
Utilisation and other	(30)
Recharge	0
Ending balance	21
Other
Disclosure of other provisions [line items]
Beginning balance	13
Additional provisions	196
Provision releaseds	(11)
Utilisation and other	(191)
Recharge	0
Ending balance	£ 7

Provisions - Additional Informa

Provisions - Additional Information (Details) £ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2022 GBP (£)	Dec. 31, 2022 GBP (£) exercise	Dec. 31, 2021 GBP (£)
Disclosure of other provisions [line items]
Loss allowance	£ 378	£ 378	£ 364
Additional provisions		£ 516
Number of customer remediation exercises | exercise		2
Financial Conduct Authority Civil Regulatory Investigation, Money Laundering Regulations 2007
Disclosure of other provisions [line items]
Losses on litigation settlements	108
No later than one year
Disclosure of other provisions [line items]
Loss allowance	130	£ 130	180
Customer remediation
Disclosure of other provisions [line items]
Loss allowance	90	90	44
Additional provisions		77
Consumer remediation, Consumer Credit Act Compliance
Disclosure of other provisions [line items]
Loss allowance	0	0	£ 6
PPI, current stock and estimated future claim
Disclosure of other provisions [line items]
Additional provisions		£ 24
Regulatory related UK Bank Levy
Disclosure of other provisions [line items]
Bank Levy rate		0.10%	0.10%
Restructuring
Disclosure of other provisions [line items]
Loss allowance	£ 21	£ 21	£ 28
Additional provisions		23
Provisions for costs related to transformation programs		19
Operational risk provisions
Disclosure of other provisions [line items]
Additional provisions		186
Fraud losses
Disclosure of other provisions [line items]
Additional provisions		£ 153

Retirement Benefit Plans - Summ

Retirement Benefit Plans - Summary of Retirement Benefit Plans (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets/(liabilities)
Total net assets	£ 1,025	£ 1,535
Unfunded pension and post-retirement medical benefits
Assets/(liabilities)
Surplus (deficit) in plan	(25)	(37)
Surplus | Funded defined benefit pension scheme
Assets/(liabilities)
Surplus (deficit) in plan	£ 1,050	£ 1,572

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of net defined benefit liability (asset) [abstract]
Pension remeasurement	£ 722	£ (1,264)	£ 505

Retirement Benefit Plans - Addi

Retirement Benefit Plans - Additional Information (Details) £ in Millions	12 Months Ended
	Dec. 31, 2022 GBP (£) section director	Dec. 31, 2021 GBP (£) director	Dec. 31, 2020 GBP (£)	Mar. 31, 2021	May 31, 2020	Aug. 31, 2019 GBP (£)	Mar. 01, 2015
Disclosure of defined benefit plans [line items]
Defined contribution expense	£ 60	£ 64	£ 66
Number of legally segregated sections | section	7
Percentage of employee covered defined benefit pension schemes	10%	11%
Number of directors selected | director	6	5
Number of directors nominated | director	4	5
Actuarial valuation deficit						£ 183
Percentage of the SMA section pensioner liabilities insured					100%
Percentage of the SPI section pensioner liabilities insured					50%
Contribution to scheme based on agreement	£ 218	£ 241
Period over which the spot rate remain constant	50 years
Percentage of pension pay increase	3%	3.20%	2.90%				1%
Percentage improvements in membership profile retirement benefits plan	0.25%
Improvements to life expectancy of female employees	1.25%
Improvements to life expectancy of male employees	1.25%
Weight percentage applied in data model	10%
Average duration of defined benefit obligation	14.2 years	18.3 years
Minimum
Disclosure of defined benefit plans [line items]
Forward curve term	30 years
Maximum
Disclosure of defined benefit plans [line items]
Forward curve term	50 years
General price inflation
Disclosure of defined benefit plans [line items]
Percentage of reasonably possible increase in actuarial assumption	0.50%	0.25%
Deficit Repair Contributions
Disclosure of defined benefit plans [line items]
Contribution to scheme based on agreement	£ 178	£ 194
Equity collar
Disclosure of defined benefit plans [line items]
Gross notional value	3	1,259
Currency futures
Disclosure of defined benefit plans [line items]
Gross notional value	£ 985	£ 2,296
Longevity swap
Disclosure of defined benefit plans [line items]
Percentage of pensioner liabilities covered by longevity swap				85%
Santander CF Trustee Limited
Disclosure of defined benefit plans [line items]
Number of trustee directors | director	10

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of net defined benefit liability (asset) [abstract]
Net interest income	£ (30)	£ (5)	£ (10)
Current service cost	30	38	36
Past service and GMP costs	0	0	1
Past service curtailment costs	0	5	0
Administration costs	9	8	8
Total	£ 9	£ 46	£ 35

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of net defined benefit liability (asset) [abstract]
Return on plan assets (excluding amounts included in net interest expense)	£ 5,527	£ (454)	£ (1,328)
Actuarial (gains)/losses arising from changes in demographic assumptions	(122)	(17)	34
Actuarial (gains)/losses arising from experience adjustments	481	(19)	(141)
Actuarial (gains)/losses arising from changes in financial assumptions	(5,164)	(774)	1,940
Pension remeasurement	£ 722	£ (1,264)	£ 505

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	£ (1,535)
Current service cost paid by Santander UK plc	30	£ 38	£ 36
Interest cost	(30)	(5)	(10)
Past service curtailment costs	0	5	0
Remeasurement due to actuarial movements arising from:
Changes in demographic assumptions	(122)	(17)	34
– Experience adjustments	481	(19)	(141)
Changes in financial assumptions	(5,164)	(774)	1,940
Ending balance	(1,025)	(1,535)
Present value of defined benefit obligations
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	(12,878)	(13,887)
Current service cost paid by Santander UK plc	(29)	(29)
Current service cost paid by subsidiaries	(1)	(9)
Current service cost paid by fellow Banco Santander subsidiaries	0	0
Interest cost	(241)	(188)
Employer salary sacrifice contributions	(2)	(9)
Past service cost	0	0
Past service curtailment costs	0	(5)
GMP equalisation cost	0	0
Remeasurement due to actuarial movements arising from:
Changes in demographic assumptions	122	17
– Experience adjustments	(481)	19
Changes in financial assumptions	5,164	774
Benefits paid	413	398
Derecognition of pension scheme liabilities arising from the sale of PSA	0	41
Ending balance	£ (7,933)	£ (12,878)	£ (13,887)

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	£ (1,535)
Interest income	(30)	£ (5)	£ (10)
Return on plan assets (excluding amounts included in net interest expense)	5,527	(454)	(1,328)
Ending balance	(1,025)	(1,535)
Fair value of scheme assets
Disclosure of net defined benefit liability (asset) [line items]
Beginning balance	14,413	13,979
Interest income	271	193
Contributions paid by employer and scheme members	223	246
Contributions paid by fellow Banco Santander subsidiaries	0	0
Administration costs paid	(9)	(8)
Return on plan assets (excluding amounts included in net interest expense)	(5,527)	454
Benefits paid	(413)	(398)
Derecognition of pension scheme liabilities arising from the sale of PSA	0	(53)
Ending balance	£ 8,958	£ 14,413	£ 13,979

Retirement Benefit Plans - Su_4

Retirement Benefit Plans - Summary of Composition and Fair Value of Plan Assets (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of net defined benefit liability (asset) [line items]
UK equities		£ 38
Overseas equities	£ 1,172	2,466
Corporate bonds	2,235	1,919
Government fixed interest bonds	1,138	2,788
Government index-linked bonds	5,525	9,159
Property	1,202	1,409
Derivatives	(78)	(83)
Cash	1,340	2,290
Repurchase agreements	(4,312)	(6,582)
Infrastructure	426	390
Annuities	293	291
Longevity swap	(12)	(8)
Other	29	336
Total	£ 8,958	£ 14,413
UK equities, percentage		0%
Overseas equities, percentage	13%	17%
Corporate bonds, percentage	25%	13%
Government fixed interest bonds, percentage	13%	19%
Government index-linked bonds, percentage	62%	64%
Property, percentage	13%	10%
Derivatives, percentage	(1.00%)	(1.00%)
Cash, percentage	15%	16%
Repurchase agreements, percentage	(48.00%)	(45.00%)
Infrastructure, percentage	5%	3%
Annuities, percentage	3%	2%
Longevity swap, percentage	0%	0%
Other, percentage	0%	2%
Total, percentage	100%	100%
Quoted prices in active markets
Disclosure of net defined benefit liability (asset) [line items]
UK equities		£ 38
Overseas equities	£ 0	1,401
Corporate bonds	1,991	1,607
Government fixed interest bonds	1,138	2,788
Government index-linked bonds	5,525	9,159
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	£ 8,654	£ 14,993
UK equities, percentage		0%
Overseas equities, percentage	0%	10%
Corporate bonds, percentage	22%	11%
Government fixed interest bonds, percentage	13%	19%
Government index-linked bonds, percentage	62%	64%
Property, percentage	0%	0%
Derivatives, percentage	0%	0%
Cash, percentage	0%	0%
Repurchase agreements, percentage	0%	0%
Infrastructure, percentage	0%	0%
Annuities, percentage	0%	0%
Longevity swap, percentage		0%
Other, percentage	0%	0%
Total, percentage	97%	104%
Prices not quoted in active markets
Disclosure of net defined benefit liability (asset) [line items]
UK equities		£ 0
Overseas equities	£ 1,172	1,065
Corporate bonds	244	312
Government fixed interest bonds	0	0
Government index-linked bonds	0	0
Property	1,202	1,409
Derivatives	(78)	(83)
Cash	1,340	2,290
Repurchase agreements	(4,312)	(6,582)
Infrastructure	426	390
Annuities	293	291
Longevity swap	(12)	(8)
Other	29	336
Total	£ 304	£ (580)
UK equities, percentage		0%
Overseas equities, percentage	13%	7%
Corporate bonds, percentage	3%	2%
Government fixed interest bonds, percentage	0%	0%
Government index-linked bonds, percentage	0%	0%
Property, percentage	13%	10%
Derivatives, percentage	(1.00%)	(1.00%)
Cash, percentage	15%	16%
Repurchase agreements, percentage	(48.00%)	(45.00%)
Infrastructure, percentage	5%	3%
Annuities, percentage	3%	2%
Longevity swap, percentage	0%	0%
Other, percentage	0%	2%
Total, percentage	3%	(4.00%)

Retirement Benefit Plans - Su_5

Retirement Benefit Plans - Summary of Principal Actuarial Assumptions Used for Defined Benefit Schemes (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Mar. 01, 2015
Disclosure of net defined benefit liability (asset) [abstract]
Discount rate for scheme liabilities	4.90%	1.90%	1.30%
General price inflation	3.10%	3.40%	3%
General salary increase	1%	1%	1%
Expected rate of pension increase	3%	3.20%	2.90%	1%
Longevity at 60 for current pensioners, on the valuation date:
Males	27 years 4 months 24 days	27 years 6 months	27 years 6 months
Females	30 years 1 month 6 days	30 years 1 month 6 days	30 years
Longevity at 60 for future pensioners currently aged 40, on the valuation date:
Males	28 years 10 months 24 days	29 years	29 years
Females	31 years 7 months 6 days	31 years 7 months 6 days	31 years 6 months

Retirement Benefit Plans - Su_6

Retirement Benefit Plans - Summary of Actuarial Assumption Sensitivities (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Discount rate
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Percentage of reasonably possible increase in actuarial assumption	0.50%	0.25%
Description of changes in methods and assumptions	bps increase	bps increase
Increase (decrease) in defined benefit obligation	£ (501)	£ (571)
General price inflation
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Percentage of reasonably possible increase in actuarial assumption	0.50%	0.25%
Description of changes in methods and assumptions	bps increase	bps increase
Increase (decrease) in defined benefit obligation	£ 374	£ 392
Mortality
Disclosure of sensitivity analysis for actuarial assumptions [line items]
Description of changes in methods and assumptions	Each additional year of longevity assumed	Each additional year of longevity assumed
Increase (decrease) in defined benefit obligation	£ 203	£ 478

Retirement Benefit Plans - Di_3

Retirement Benefit Plans - Disclosure of Benefits Expected To Be Paid (Details) £ in Millions	Dec. 31, 2022 GBP (£)
2023
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	£ 416
2024
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	360
2025
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	382
2026
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	404
2027
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	425
Five years ending 2032
Disclosure of net defined benefit liability (asset) [line items]
Benefits expected to be paid	£ 2,325

Contingent Liabilities and Co_3

Contingent Liabilities and Commitments - Summary of Contingent Liabilities and Commitments (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure of contingent liabilities [line items]
Guarantees and formal standby facilities, credit lines and other commitments	£ 31,836	£ 37,709
Contingent liability for guarantees
Disclosure of contingent liabilities [line items]
Guarantees given to third parties	448	363
Loan commitments
Disclosure of contingent liabilities [line items]
Formal standby facilities, credit lines and other commitments	£ 31,388	£ 37,346

Contingent Liabilities and Co_4

Contingent Liabilities and Commitments - Additional Information (Details) £ in Millions		1 Months Ended	12 Months Ended
	Nov. 02, 2015	Dec. 31, 2022 GBP (£)	Dec. 31, 2022 EUR (€)	Dec. 31, 2022 EUR (€)	Oct. 21, 2022 GBP (£)	Dec. 31, 2021 GBP (£)	Jul. 31, 2020 GBP (£)
Disclosure of contingent liabilities [line items]
Capital support arrangements, risk-weighted exposures of regulated entities		0%		0%
Provisions		£ 378				£ 364
Financial Conduct Authority Civil Regulatory Investigation, Money Laundering Regulations 2007
Disclosure of contingent liabilities [line items]
Losses on litigation settlements		£ 108
AXA France
Disclosure of contingent liabilities [line items]
Amount claimed by other party					£ 670	£ 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%
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

Share Capital - Schedule of Sha

Share Capital - Schedule of Share Capital Issued and Fully Paid (Details) - GBP (£) £ / shares in Units, £ in Millions	Dec. 31, 2022	Jan. 01, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of classes of share capital [line items]
Ordinary shares, price per share (in GBP per share)	£ 0.10		£ 0.10	£ 0.10
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, 2022	Jan. 01, 2022	Dec. 31, 2021	Jan. 01, 2021
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
	Jun. 30, 2022 GBP (£)	Dec. 31, 2022 GBP (£)	Dec. 31, 2021 GBP (£)
Disclosure Of Other Equity Instruments [Line Items]
Other equity instruments		£ 1,956,000,000	£ 2,191,000,000
£300m Step-up Callable Perpetual Reserve Capital Instruments
Disclosure Of Other Equity Instruments [Line Items]
Capital securities		£ 300,000,000	£ 300,000,000
Interest rate		0.07037	0.07037
Other equity interest maturity period		2026-02	2026-02
Other equity instruments		£ 0	£ 235,000,000
- £500m Perpetual 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 Perpetual Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities		£ 750,000,000	£ 750,000,000
Interest rate	0.07375	0.07375	0.07375
Other equity interest maturity period		2022-06	2022-06
Other equity instruments		£ 0	£ 750,000,000
- £500m Perpetual Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities		£ 500,000,000	£ 500,000,000
Interest rate		0.0630	0.0630
Other equity interest maturity period		2025-03	2025-03
Other equity instruments		£ 500,000,000	£ 500,000,000
- £210m Perpetual Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities		£ 210,000,000	£ 210,000,000
Interest rate		0.0425	0.0425
Other equity interest maturity period		2026-03	2026-03
Other equity instruments		£ 210,000,000	£ 210,000,000
- £750m Perpetual Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities	£ 750,000,000	£ 750,000,000	£ 750,000,000
Interest rate	0.0650	0.0650	0.0650
Other equity interest maturity period		2027-06	2027-06
Other equity instruments		£ 750,000,000	£ 0

Other Equity Instruments - Addi

Other Equity Instruments - Additional Information (Details)		1 Months Ended	12 Months Ended
	Feb. 14, 2022 GBP (£)	Jun. 30, 2022 GBP (£)	Dec. 31, 2022 GBP (£)	Dec. 31, 2021 GBP (£)
Disclosure Of Other Equity Instruments [Line Items]
Repurchase of other equity instruments			£ 985,000,000	£ 210,000,000
£300m Step-up Callable Perpetual Reserve Capital Instruments
Disclosure Of Other Equity Instruments [Line Items]
Repurchase of other equity instruments	£ 300,000,000
Interest rate			0.07037	0.07037
Capital securities issued			£ 300,000,000	£ 300,000,000
AT1 Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Distribution rate reset, period			5 years
Common equity tier 1 capital ratio minimum			7%
- £750m Perpetual Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Capital securities purchased and redeemed		£ 750,000,000
Interest rate		0.07375	0.07375	0.07375
Capital securities issued			£ 750,000,000	£ 750,000,000
- £750m Perpetual Capital Securities
Disclosure Of Other Equity Instruments [Line Items]
Interest rate		0.0650	0.0650	0.0650
Capital securities issued		£ 750,000,000	£ 750,000,000	£ 750,000,000

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	£ 30,071	£ 40,410	£ 46,985
Proceeds from issue of debt securities	4,778	2,872	5,602
Repayment of debt securities	(3,036)	(11,910)	(11,378)
Repayment of subordinated liabilities	(40)	(4)	(659)
Issue of other equity instruments	750	210
Repurchase of other equity instruments	(985)	(210)
Principal elements of lease payments	(26)	(25)	(45)
Dividends paid	(1,164)	(1,505)	(292)
Liability-related other changes	3,176	(391)	(255)
Non-cash changes:
– Unrealised foreign exchange	1,641	(800)	398
– Other changes	779	1,424	54
Ending Balance	35,944	30,071	40,410
Previously stated
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Issue of other equity instruments		450
Repurchase of other equity instruments		(500)
Dividends paid		(1,494)
Debt securities in issue
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	25,520	35,566	41,129
Proceeds from issue of debt securities	4,778	2,872	5,602
Repayment of debt securities	(3,036)	(11,910)	(11,378)
Liability-related other changes	3,155	(447)	(250)
Non-cash changes:
– Unrealised foreign exchange	1,554	(806)	376
– Other changes	(440)	245	87
Ending Balance	31,531	25,520	35,566
Subordinated liabilities
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	2,228	2,556	3,528
Repayment of subordinated liabilities	(40)	(4)	(659)
Liability-related other changes	2	(4)	(10)
Non-cash changes:
– Unrealised foreign exchange	87	6	22
– Other changes	55	(326)	(325)
Ending Balance	2,332	2,228	2,556
Other equity instruments
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	2,191	2,191	2,191
Issue of other equity instruments	750	210
Repurchase of other equity instruments	(985)	(210)
Non-cash changes:
– Other changes		0
Ending Balance	1,956	2,191	2,191
Other equity instruments | Previously stated
Non-cash changes:
– Other changes		50
Lease liabilities
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	132	97	137
Principal elements of lease payments	(26)	(25)	(45)
Liability-related other changes	19	60	5
Non-cash changes:
Ending Balance	125	132	97
Dividends paid
Disclosure of reconciliation of liabilities arising from financing activities [line items]
Beginning Balance	0	0	0
Dividends paid	(1,164)	(1,505)	(292)
Non-cash changes:
– Other changes	1,164	1,505	292
Ending Balance	£ 0	£ 0	£ 0

Notes to Cash Flows - Additiona

Notes to Cash Flows - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure Of Cash Flows Explanatory Notes [Line Items]
Interest received	£ 6,508	£ 4,806	£ 5,139
Interest paid	2,089	1,064	1,857
Dividends received	0	0	0
Cash outflow for leases	28	28	48
Cash and cash equivalents restated	(46,484)	(49,254)	(46,697)	£ (27,871)
Restricted balances restated	2,223	2,498	1,839
Disposal of non-controlling interests		181
Net cash flows from operating activities	£ (2,970)	10,251	18,918
Increase (decrease) due to voluntary changes in accounting policy
Disclosure Of Cash Flows Explanatory Notes [Line Items]
Non-cash items included in profit restated		504	134
Increase (decrease) due to changes in accounting policy required by IFRSs
Disclosure Of Cash Flows Explanatory Notes [Line Items]
Cash and cash equivalents restated		1,580	985
Restricted balances restated		1,580	985
Net cash flows from operating activities		£ 595	£ 95

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, 2022	Dec. 31, 2021
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	£ 1,541	£ 1,585
On-balance sheet:
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	62,029	67,595
On-balance sheet: | Cash and balances at central banks
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	1,330	1,580
On-balance sheet: | Loans and advances to banks
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	130	284
On-balance sheet: | Loans and advances to customers | Securitisations and covered bonds
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	24,155	19,432
On-balance sheet: | Loans and advances to customers | Other
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	32,001	41,936
On-balance sheet: | Other financial assets at amortised cost
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	48	0
On-balance sheet: | Financial assets at fair value through other comprehensive income
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	4,365	4,363
Off-balance sheet
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	£ 9,146	£ 14,449

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, 2022	Dec. 31, 2021
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	£ 1,541	£ 1,585
Gross assets charged as security for liabilities	24,984	20,199
Notes issued under securitisation and covered bond programmes retained internally	16,102	13,519
Purchase and resale agreements
Disclosure Of Assets Pledged As Security [Line Items]
Collateral accepted as security for assets	8,628	14,562
Securitisations and covered bonds | Internally retained
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued under securitisation and covered bond programmes retained internally	1,725	1,855
Securitisations and covered bonds | Third party bilateral secured funding transactions
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	500	500
Securities lending
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	34,861	45,936
Collateral accepted as security for assets	1,513	3,219
Derivatives | Cash
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	1,506	1,947
Collateral accepted as security for assets	1,741	931
Fellow subsidiaries | Sale and repurchase agreements
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	11,553	15,368
Fellow subsidiaries | Loans and advances to customers securitisations and covered bonds
Disclosure Of Assets Pledged As Security [Line Items]
Notes issued as collateral	900	639
Santander UK Plc | Securitisations and covered bonds | Internally retained
Disclosure Of Assets Pledged As Security [Line Items]
Internally retained securitisation and covered bond issuances available for creating collateral	£ 829	£ 767

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, 2022	Dec. 31, 2021
On-balance sheet:
Disclosure Of Assets Pledged As Security [Line Items]
Total on-balance sheet/ off-balance sheet	£ 1,741	£ 931
On-balance sheet: | Deposits by banks
Disclosure Of Assets Pledged As Security [Line Items]
Total on-balance sheet/ off-balance sheet	1,741	931
Off-balance sheet
Disclosure Of Assets Pledged As Security [Line Items]
Total on-balance sheet/ off-balance sheet	£ 10,141	£ 17,781

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details)	12 Months Ended		180 Months Ended
	Dec. 31, 2022 GBP (£) £ / shares shares	Dec. 31, 2021 GBP (£) £ / shares shares	Dec. 31, 2022 GBP (£) invitation
Disclosure of terms and conditions of share-based payment arrangement [line items]
Liabilities arising from share-based payment transactions	£ 6,600,000	£ 3,700,000	£ 6,600,000
Liabilities arising from share-based payment transactions, vested liabilities	100,000	£ 400,000	£ 100,000
Number of sharesave schemes launched | invitation			15
Employee saving on share based compensation	£ 500,000		£ 500,000
Price determination period for options	3 days
Maximum discount applicable	20%
Actual discount applied	10%
Expiration term of vested options	6 months
Weighted average share price (GBP per share) | £ / shares	£ 2.34	£ 2.65
Weighted average grant-date fair value (GBP per share)	£ 0.23	£ 0.20	0.23
Number of shares outstanding | shares	3,974,698	3,618,796
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%
Transformation Incentive Plan
Disclosure of terms and conditions of share-based payment arrangement [line items]
Liabilities arising from share-based payment transactions	£ 1,800,000		1,800,000
Value of awards granted	£ 1,000,000
Shares | Material Risk Takers
Disclosure of terms and conditions of share-based payment arrangement [line items]
Annual bonus percentage	50%
Cash | Material Risk Takers
Disclosure of terms and conditions of share-based payment arrangement [line items]
Annual bonus percentage	50%
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
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
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%
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%
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

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Movement in Share Options (Details) - Sharesave Schemes number in Thousands	12 Months Ended
	Dec. 31, 2022 £ / shares	Dec. 31, 2021 £ / shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of options outstanding, beginning balance (in shares)	25,993	21,162
Number of options granted (in shares)	13,068	9,414
Number of options exercised (in shares)	(242)	(48)
Number of options forfeited/expired (in shares)	(8,831)	(4,535)
Number of options outstanding, ending balance (in shares)	29,988	25,993
Number of options exercisable (in shares)	3,439	1,321
Weighted average exercise price outstanding, beginning balance	£ 2.25	£ 2.32
Weighted average exercise price granted	1.89	2.43
Weighted average exercise price exercised	1.69	1.86
Weighted average exercise price forfeited/expired	2.59	2.95
Weighted average exercise price outstanding, ending balance	2	2.25
Weighted average exercise price exercisable	£ 3.22	£ 2.75

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, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of number and weighted average remaining contractual life of outstanding share options [line items]
Weighted average exercise price (in GBP per share)	£ 2	£ 2.25	£ 2.32
£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	3 years
Weighted average exercise price (in GBP per share)	£ 1.79	£ 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	2 years	3 years
Weighted average exercise price (in GBP per share)	£ 2.56	£ 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)	£ 3.46	£ 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	0 years	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, 2022 GBP (£) individual director	Dec. 31, 2021 GBP (£) director individual	Dec. 31, 2020 GBP (£) individual
Disclosure Of Directors And Key Management Remuneration [Line Items]
Salaries and fees	£ 4,696,699	£ 5,488,388	£ 5,361,444
Performance-related payments	3,701,569	3,431,294	933,703
Other fixed remuneration (allowances and non-cash benefits)	906,201	929,935	1,107,348
Expenses	27,715	17,097	6,772
Total remuneration	9,332,184	9,866,714	7,409,267
Short-term employee benefits	22,627,595	20,553,672	16,663,726
Post-employment benefits	1,026,848	988,829	1,821,548
Compensation for loss of office	1,713,256	356,054	263,097
Total compensation	£ 25,367,699	£ 21,898,555	£ 18,748,371
Long-term metrics, percentage achieved		36%
Guaranteed variable remuneration, percentage vested	40%
Guaranteed variable remuneration, percentage unvested	60%
Number of Directors who received termination payment | director	2	2
Number key management persons who receives termination benefit | individual	3		1
Increase (decrease) due to voluntary changes in accounting policy
Disclosure Of Directors And Key Management Remuneration [Line Items]
Salaries and fees		£ (7,463)	£ 7,463
Minimum
Disclosure Of Directors And Key Management Remuneration [Line Items]
Long-term metrics, minimum percentage		0%
Director
Disclosure Of Directors And Key Management Remuneration [Line Items]
Compensation for loss of office	£ 172,856	£ 356,054	0
Deferred performance related payments of shares	0		£ 1,293,678
Number of previously employed individuals for buy-out of deferred performance related payment | individual			1
Deferred performance related payments of shares vested			£ 242,605
Guaranteed variable remuneration expense	660,648	0	0
Key Management Personnel
Disclosure Of Directors And Key Management Remuneration [Line Items]
Compensation for loss of office	1,540,400	0	263,097
Deferred performance related payments of shares	£ 0	£ 107,225	£ 924,133
Number of previously employed individuals for buy-out of deferred performance related payment | individual		1	1
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, 2022 GBP (£) director transaction	Dec. 31, 2021 GBP (£) director transaction	Dec. 31, 2020 GBP (£)
Disclosure Of Directors And Key Management Remuneration [Line Items]
Remuneration excluding pension contribution | £	£ 3,510,441	£ 3,740,810	£ 2,093,149
Remuneration excluding pension contribution performance related | £	1,900,506	1,864,320	0
Accrued defined benefit pension related highest paid director | £	£ 0	22,119	21,309
Directors with a deferred pension benefit accruing under a defined benefit scheme	1
Ex gratia pensions paid to former Directors | £	£ 379,945	£ 370,668	£ 366,248
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	6	4
Loans made to directors | £	£ 540,450	£ 348,306
Number of other transactions, arrangements or agreements with material interest | transaction	0	0
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	4	2
Loans made to key management personnel | £	£ 330,972	£ 11,678

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, 2022 GBP (£) loans deposits	Dec. 31, 2021 GBP (£) loans deposits
Disclosure Of Directors And Key Management Remuneration [Line Items]
Number of secured loans, unsecured loans and overdrafts, beginning balance | loans	6	12
Number of secured loans, unsecured loans and overdrafts, net movements | loans	4	(6)
Number of secured loans, unsecured loans and overdrafts, ending balance | loans	10	6
Beginning balance	£ 360	£ 3,640
Net movements	511	(3,280)
Ending balance	£ 871	£ 360
Number of deposit, bank and instant access accounts and investments, beginning balance | deposits	21	23
Number of deposit, bank and instant access accounts and investments, net movements | deposits	2	(2)
Number of deposit, bank and instant access accounts and investments, ending balance | deposits	23	21
Beginning balance	£ 6,552	£ 8,195
Net movements	(2,419)	(1,643)
Ending balance	£ 4,133	£ 6,552

Related Party Disclosures - Sum

Related Party Disclosures - Summary of Transactions With Related Parties (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	£ (861)	£ (261)	£ (213)
Interest, fees and other expenses paid	549	463	578
Amounts owed by related parties	5,623	4,057
Amounts owed to related parties	(17,384)	(13,537)
Ultimate parent
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	(710)	(164)	(119)
Interest, fees and other expenses paid	47	33	105
Amounts owed by related parties	1,363	816
Amounts owed to related parties	(1,673)	(1,150)
Immediate parent
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	(6)	(6)	(7)
Interest, fees and other expenses paid	308	263	316
Amounts owed by related parties	1	7
Amounts owed to related parties	(14,390)	(10,935)
Fellow subsidiaries
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	(69)	(57)	(58)
Interest, fees and other expenses paid	177	163	157
Amounts owed by related parties	108	159
Amounts owed to related parties	(348)	(534)
Associates & joint ventures
Disclosure of transactions between related parties [line items]
Interest, fees and other income received	(76)	(34)	(29)
Interest, fees and other expenses paid	17	4	£ 0
Amounts owed by related parties	4,151	3,075
Amounts owed to related parties	£ (973)	£ (918)

Related Party Disclosures - Add

Related Party Disclosures - Additional Information (Details) - GBP (£) £ in Millions	1 Months Ended		12 Months Ended
	May 31, 2022	Oct. 31, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Nov. 30, 2022	Jul. 30, 2021
Unsecured committed liquidity facility
Disclosure of transactions between related parties [line items]
Borrowings						£ 600
Santander Financial Services PLC | Mortgages
Disclosure of transactions between related parties [line items]
Book value of financial assets transferred	£ 624	£ 3,163
Proceeds from transfer of financial assets	631	3,174
Price premium on transfer of financial assets	£ 7	£ 11
Santander UK Investments
Disclosure of transactions between related parties [line items]
Rental expense			£ 6	£ 4
Santander Consumer (UK) | PSA Finance UK Limited
Disclosure of transactions between related parties [line items]
Proportion of ownership interest in subsidiary sold							50%
Volvo Car Financial Services UK Limited
Disclosure of transactions between related parties [line items]
Proportion of ownership interest in joint venture					50%
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 - Disclos

Financial Instruments - Disclosure of Analysis of Fair Value of Financial Instruments Carried at Amortised Cost (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Loans and advances to customers	£ 219,716	£ 210,094
Loans and advances to banks	992	1,169
Reverse repurchase agreements - non trading	7,348	12,683
Other financial assets at amortised cost	156	506
Deposits by customers	195,568	192,926
Deposits by banks	28,525	33,855
Repurchase agreements - non trading	7,982	11,718
Debt securities in issue	31,531	25,520
Subordinated liabilities	2,332	2,228
Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Total financial liabilities	265,938	266,247
Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	228,212	224,452
Deposits by customers | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by customers	195,568	192,926
Deposits by banks | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Deposits by banks	28,525	33,855
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	7,982	11,718
Debt securities in issue | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Debt securities in issue	31,531	25,520
Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	2,332	2,228
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	219,716	210,094
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	992	1,169
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	7,348	12,683
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	156	506
Level 1 | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Total financial liabilities	2,593	1,000
Level 1 | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	144	164
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	2,574	963
Level 1 | Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	19	37
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	144	164
Level 2 | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Total financial liabilities	64,719	71,812
Level 2 | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	8,333	13,970
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	51	48
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	27,979	33,770
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	7,982	11,718
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	26,349	23,926
Level 2 | Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	2,358	2,350
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	992	1,169
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	7,341	12,453
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	0	348
Level 3 | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Total financial liabilities	197,344	194,439
Level 3 | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	212,479	213,037
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	195,483	192,898
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	55	85
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	1,582	1,218
Level 3 | Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	224	238
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	212,479	212,811
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	0	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	264,656	267,251
Fair value | Financial assets at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Financial assets	220,956	227,171
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	195,534	192,946
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	28,034	33,855
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	7,982	11,718
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	30,505	26,107
Fair value | Subordinated liabilities | Financial liabilities at amortised cost
Disclosure Of Fair Values Of Financial Instruments Carried At Amortised Cost [Line Items]
Subordinated liabilities	2,601	2,625
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	212,479	212,811
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	992	1,169
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	7,341	12,679
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	£ 144	£ 512

Financial Instruments - Discl_2

Financial Instruments - Disclosure of Analysis of Fair Value of Financial Instruments Measured at Fair Value on a Recurring Basis (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 8,560	£ 7,717
Liabilities at fair value	1,754	1,580
Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	951	777
Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	803	803
Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	2,407	1,681
Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	129	185
Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	6,024	5,851
Level 1
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	5,996	5,833
Liabilities at fair value	0	0
Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Level 1 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Level 1 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	5,996	5,833
Level 2
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	2,410	1,635
Liabilities at fair value	1,739	1,542
Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	939	745
Level 2 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	800	797
Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	2,370	1,635
Level 2 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	12	0
Level 2 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	28	0
Level 3
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	154	249
Liabilities at fair value	15	38
Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	12	32
Level 3 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	3	6
Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	37	46
Level 3 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	117	185
Level 3 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	18
Exchange rate contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 471	506
Valuation technique	A
Exchange rate contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 2,044	1,194
Valuation technique	A
Exchange rate contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Exchange rate contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Exchange rate contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	471	506
Exchange rate contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	2,044	1,193
Exchange rate contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Exchange rate contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	1
Interest rate contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 2,628	1,438
Valuation technique	A & C
Interest rate contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 2,406	1,547
Valuation technique	A & C
Interest rate contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Interest rate contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Interest rate contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	2,624	1,436
Interest rate contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	2,399	1,547
Interest rate contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	4	2
Interest rate contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	7	0
Equity and credit contracts
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	30	45
Equity and credit contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 25	54
Valuation technique	B & D
Equity and credit contracts | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 130	161
Valuation technique	B & D
Equity and credit contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Equity and credit contracts | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Equity and credit contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	17	24
Equity and credit contracts | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	100	116
Equity and credit contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	8	30
Equity and credit contracts | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	30	45
Netting | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	(2,173)	(1,221)
Netting | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	(2,173)	(1,221)
Netting | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Netting | Level 1 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Netting | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	(2,173)	(1,221)
Netting | Level 2 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	(2,173)	(1,221)
Netting | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Netting | Level 3 | Derivative financial instruments
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	0	0
Loans and advances to customers | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 45	74
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	£ 0	18
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	45	74
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	0	18
Debt securities | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	£ 84	111
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	£ 6,024	5,833
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	5,996	5,833
Debt securities | Level 2 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	12	0
Debt securities | Level 2 | Financial assets at FVOCI
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	28	0
Debt securities | Level 3 | Other financial assets at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Assets at fair value	72	111
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
Debt securities in issue | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 480	560
Valuation technique	A
Debt securities in issue | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Debt securities in issue | Level 2 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	477	555
Debt securities in issue | Level 3 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	3	5
Structured deposits | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 321	223
Valuation technique	A
Structured deposits | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Structured deposits | Level 2 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	321	223
Structured deposits | Level 3 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	0	0
Collateral and associated financial guarantees | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 2	20
Valuation technique	D
Collateral and associated financial guarantees | Level 1 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	0
Collateral and associated financial guarantees | Level 2 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	2	19
Collateral and associated financial guarantees | Level 3 | Other financial liabilities at FVTPL
Disclosure Of Fair Value Measurements Of Assets And Liabilities [Line Items]
Liabilities at fair value	£ 0	£ 1

Financial Instruments - Additio

Financial Instruments - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
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, 2022	Dec. 31, 2021
Disclosure of financial assets [line items]
Fair value adjustments	£ 4	£ 20
Risk-related
Disclosure of financial assets [line items]
Fair value adjustments	3	20
Day One profit
Disclosure of financial assets [line items]
Fair value adjustments	1	0
- Bid-offer and trade specific adjustments | Risk-related
Disclosure of financial assets [line items]
Fair value adjustments	(12)	(9)
- Uncertainty | Risk-related
Disclosure of financial assets [line items]
Fair value adjustments	12	20
- Credit risk adjustment | Risk-related
Disclosure of financial assets [line items]
Fair value adjustments	2	6
- Funding fair value adjustment | Risk-related
Disclosure of financial assets [line items]
Fair value adjustments	£ 1	£ 3

Financial Instruments - Discl_3

Financial Instruments - Disclosure of Analysis of Financial Instruments Valued Using Internal Models Based on Information Other than Market Data (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	£ 129	£ 185
Financial assets at fair value through other comprehensive income	6,024	5,851
Total net assets	139	211
Total income/(expense)	(17)	(4)	£ 17
Level 3
Disclosure Of Financial Assets And Liabilities [Line Items]
Financial assets and liabilities	139	217
Financial asset liabilities	(21)	(5)	11
Loans and advances to customers
Disclosure Of Financial Assets And Liabilities [Line Items]
Financial assets at fair value through other comprehensive income	0	18
Other Level 3 assets | Level 3
Disclosure Of Financial Assets And Liabilities [Line Items]
Other Level 3 assets	7	1
Other Level 3 liabilities	(7)	(7)
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	6	(1)	7
Derivative liabilities and other Level 3 liabilities, fair value movements recognised in profit/(loss)	(2)	2	(1)
Reversionary property interests | Equity and credit contracts
Disclosure Of Financial Assets And Liabilities [Line Items]
Derivative assets	30	45
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	(8)	0	3
Reversionary property interests | Debt securities
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	70	91
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	0	5	6
Roll-up mortgage portfolio | Loans and advances to customers
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	28	48
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	(18)	(5)	6
Other loans | Loans and advances to customers
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	17	26
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	(4)	(2)	3
Other loans | Loans and advances to customers | Financial assets at FVOCI
Disclosure Of Financial Assets And Liabilities [Line Items]
Financial assets at fair value through other comprehensive income	0	18
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	0	(3)	(4)
Credit linked notes | Debt securities
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL assets	2	20
Derivative assets and other Level 3 assets, fair value movements recognised in profit/(loss)	4	(5)	(16)
Property options and forwards | Equity contracts
Disclosure Of Financial Assets And Liabilities [Line Items]
Derivative liabilities	(8)	(30)
Derivative liabilities and other Level 3 liabilities, fair value movements recognised in profit/(loss)	4	(1)	(3)
Credit protection guarantee | Financial guarantees
Disclosure Of Financial Assets And Liabilities [Line Items]
FVTPL liabilities	0	(1)
Derivative liabilities and other Level 3 liabilities, fair value movements recognised in profit/(loss)	£ 1	£ 6	£ 16

Financial Instruments - Summa_2

Financial Instruments - Summary of Reconciliation of Fair Value Measurement in Level 3 of the Fair Value Hierarchy (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disclosure of fair value measurement of assets [line items]
Beginning balance	£ 287,098	£ 292,332
Beginning balance	(270,996)	(276,396)
Transfers in	0	0
Transfers in	0	0
Transfers out	0	0
Transfers out	0	0
Ending Balance	285,213	287,098
Ending Balance	(270,806)	(270,996)
Level 3 | Other financial assets at FVTPL
Disclosure of fair value measurement of assets [line items]
Beginning balance	185	208
Fair value movements	(18)	(7)
Foreign exchange and other movements	0
Transfers in	0
Transfers out	0
Netting	8	23
Sales	(5)	(16)
Settlements	(37)	(23)
Ending Balance	117	185
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period	(18)	(7)
Level 3 | Financial assets at FVOCI
Disclosure of fair value measurement of assets [line items]
Beginning balance	18	21
Fair value movements	0	(3)
Foreign exchange and other movements	0
Transfers in	0
Transfers out	0
Netting	0	0
Sales	0	0
Settlements	(18)	0
Ending Balance	0	18
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period	0	(3)
Level 3 | Financial assets at fair value
Disclosure of fair value measurement of assets [line items]
Beginning balance	249	297
Fair value movements	(20)	(11)
Foreign exchange and other movements	0
Transfers in	0
Transfers out	0
Netting	8	23
Sales	(5)	(16)
Settlements	(62)	(44)
Ending Balance	154	249
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period	(20)	(11)
Level 3 | Derivatives
Disclosure of fair value measurement of assets [line items]
Beginning balance	46	68
Fair value movements	(2)	(1)
Foreign exchange and other movements	0
Transfers in	0
Transfers out	0
Netting	0	0
Sales	0	0
Settlements	(7)	(21)
Ending Balance	37	46
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period	(2)	(1)
Derivatives | Level 3
Disclosure of fair value measurement of assets [line items]
Beginning balance	(32)	(32)
Fair value movements	2	0
Foreign exchange and other movements	0
Transfers in	(2)
Transfers out	0
Netting	0	0
Sales	0	0
Settlements	20	0
Ending Balance	(12)	(32)
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period	2	0
Other financial liabilities at FVTPL | Level 3
Disclosure of fair value measurement of assets [line items]
Beginning balance	(6)	(8)
Fair value movements	1	7
Foreign exchange and other movements	0
Transfers in	0
Transfers out	0
Netting	0	(5)
Sales	0	0
Settlements	2	0
Ending Balance	(3)	(6)
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period	1	7
Financial liabilities at fair value | Level 3
Disclosure of fair value measurement of assets [line items]
Beginning balance	(38)	(40)
Fair value movements	3	7
Foreign exchange and other movements	0
Transfers in	(2)
Transfers out	0
Netting	0	(5)
Sales	0	0
Settlements	22	0
Ending Balance	(15)	(38)
Gains/(losses) recognised in profit or loss/other comprehensive income relating to assets and liabilities held at the end of the period	£ 3	£ 7

Financial Instruments - Discl_4

Financial Instruments - Disclosure of Effects of Changes in Significant Unobservable Assumptions to Reasonably Possible Alternatives Level Three (Details) £ in Millions	12 Months Ended
	Dec. 31, 2022 GBP (£) index	Dec. 31, 2021 GBP (£) index
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 8,560	£ 7,717
Liabilities at fair value	(1,754)	(1,580)
Equity and credit contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 30	£ 45
Assumption description	HPI Forward growth rate	HPI Forward growth rate
Shift	1%	1%
Favourable changes	£ 4	£ 6
Unfavourable changes	£ (4)	£ (6)
Equity and credit contracts | Reversionary property derivatives
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Shift	10%	10%
Favourable changes	£ 4	£ 6
Unfavourable changes	(4)	(6)
Equity contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Liabilities at fair value	£ (8)	£ (30)
Assumption description	HPI Forward growth rate	HPI Forward growth rate
Shift	1%	1%
Favourable changes	£ 1	£ 2
Unfavourable changes	£ (1)	£ (2)
Equity contracts | Property options and forwards
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Shift	10%	10%
Favourable changes	£ 2	£ 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	0.53%	2.56%
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	513	483
Weighted average | Equity contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	(0.92%)	2.39%
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	491	469
Minimum | Equity and credit contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	(5.00%)	0%
Minimum | 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%)	0%
Maximum | Equity and credit contracts
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assumption value	5%	5%
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%	5%
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	£ 28	£ 48
Assumption description	HPI Forward growth rate	HPI Forward growth rate
Shift	1%	1%
Favourable changes	£ 1	£ 2
Unfavourable changes	(1)	(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	£ 17	£ 26
Assumption description	Credit spreads	Credit spreads
Shift	20%	20%
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	£ 70	£ 91
Assumption description	HPI Forward growth rate	HPI Forward growth rate
Shift	1%	1%
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%	10%
Favourable changes	£ 3	£ 4
Unfavourable changes	£ (3)	£ (4)
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	1.39%	2.68%
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	0.98%	0.50%
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	0.53%	2.56%
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	513	483
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	(5.00%)	0%
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	0.19%	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	(5.00%)	0%
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%	5%
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	2.04%	1.44%
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%	5%
Financial assets at FVOCI
Effect Of Changes In Significant Unobservable Assumptions To Reasonably Possible Alternatives - Level 3 [Line Items]
Assets at fair value	£ 6,024	£ 5,851
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	0	18
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	£ 0	£ 18
Assumption description	Credit spreads	Credit spreads
Shift	20%	20%
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	0.48%	0.04%
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	0.40%	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	0.48%	0.19%

Financial Instruments - Discl_5

Financial Instruments - Disclosure of Maturity Analysis of Undiscounted Cash Flows for Financial Liabilities and Off Balance Sheet Commitments (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Other financial liabilities at fair value through profit or loss	£ 803	£ 803
Deposits by customers	195,568	192,926
Deposits by banks	28,525	33,855
Repurchase agreements - non trading	7,982	11,718
Debt securities in issue	31,531	25,520
Subordinated liabilities	2,332	2,228
Lease liabilities	125	132
Undiscounted Cash Flow
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	1,077	809
Other financial liabilities at fair value through profit or loss	979	803
Deposits by customers	195,800	193,057
Deposits by banks	29,796	33,955
Repurchase agreements - non trading	7,987	11,718
Debt securities in issue	33,892	26,191
Subordinated liabilities	3,275	3,697
Lease liabilities	138	141
Total financial liabilities	272,944	270,371
Off-balance sheet commitments given	31,836	37,709
Undiscounted Cash Flow | On demand
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	0	0
Other financial liabilities at fair value through profit or loss	0	0
Deposits by customers	180,218	177,926
Deposits by banks	2,048	1,377
Repurchase agreements - non trading	0	0
Debt securities in issue	0	0
Subordinated liabilities	0	0
Lease liabilities	0	0
Total financial liabilities	182,266	179,303
Off-balance sheet commitments given	19,089	20,519
Undiscounted Cash Flow | Not later than 3 months
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	206	74
Other financial liabilities at fair value through profit or loss	0	6
Deposits by customers	3,875	3,107
Deposits by banks	1,309	551
Repurchase agreements - non trading	7,984	11,419
Debt securities in issue	5,814	4,993
Subordinated liabilities	35	32
Lease liabilities	0	0
Total financial liabilities	19,223	20,182
Off-balance sheet commitments given	787	5,359
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	120	58
Other financial liabilities at fair value through profit or loss	98	8
Deposits by customers	7,077	4,691
Deposits by banks	298	41
Repurchase agreements - non trading	3	299
Debt securities in issue	1,485	2,725
Subordinated liabilities	691	98
Lease liabilities	32	32
Total financial liabilities	9,804	7,952
Off-balance sheet commitments given	898	5,734
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	496	389
Other financial liabilities at fair value through profit or loss	443	553
Deposits by customers	4,295	5,750
Deposits by banks	26,141	31,986
Repurchase agreements - non trading	0	0
Debt securities in issue	16,672	11,921
Subordinated liabilities	1,149	1,547
Lease liabilities	80	78
Total financial liabilities	49,276	52,224
Off-balance sheet commitments given	7,508	5,523
Undiscounted Cash Flow | Later than five years
Disclosure Of Maturity Analysis For Financial Liabilities [Line Items]
Derivative financial instruments	255	288
Other financial liabilities at fair value through profit or loss	438	236
Deposits by customers	335	1,583
Deposits by banks	0	0
Repurchase agreements - non trading	0	0
Debt securities in issue	9,921	6,552
Subordinated liabilities	1,400	2,020
Lease liabilities	26	31
Total financial liabilities	12,375	10,710
Off-balance sheet commitments given	£ 3,554	£ 574

Offsetting Financial Assets a_3

Offsetting Financial Assets and Liabilities (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	£ 18,520	£ 21,965
Amounts offset, Assets	(4,559)	(4,343)
Net amounts reported on the balance sheet, Assets	13,961	17,622
Financial instruments, Assets	(524)	(1,189)
Financial collateral, Assets	(9,059)	(12,941)
Net amount, Assets	4,378	3,492
Assets not subject to enforceable netting arrangements, Assets	216,502	208,007
Balance sheet total, Assets	230,463	225,629
Gross amounts, Liabilities	20,622	24,481
Amounts offset, Liabilities	(4,559)	(4,343)
Net amounts reported on the balance sheet, Liabilities	16,063	20,138
Financial instruments, Liabilities	(524)	(1,189)
Financial collateral, Liabilities	(8,088)	(11,224)
Net amount, Liabilities	7,451	7,725
Assets not subject to enforceable netting arrangements, Liabilities	216,963	219,138
Balance sheet total, Liabilities	233,026	239,276
Derivative financial instruments
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	4,525	2,832
Amounts offset, Assets	(2,173)	(1,221)
Net amounts reported on the balance sheet, Assets	2,352	1,611
Financial instruments, Assets	(515)	(754)
Financial collateral, Assets	(1,720)	(693)
Net amount, Assets	117	164
Assets not subject to enforceable netting arrangements, Assets	55	72
Balance sheet total, Assets	2,407	1,683
Amortised cost
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	8,826	14,882
Amounts offset, Assets	(1,478)	(2,199)
Net amounts reported on the balance sheet, Assets	7,348	12,683
Financial instruments, Assets	(9)	(435)
Financial collateral, Assets	(7,339)	(12,248)
Net amount, Assets	0	0
Assets not subject to enforceable netting arrangements, Assets	0	0
Balance sheet total, Assets	7,348	12,683
Gross amounts, Liabilities	9,460	13,917
Amounts offset, Liabilities	(1,478)	(2,199)
Net amounts reported on the balance sheet, Liabilities	7,982	11,718
Financial instruments, Liabilities	(9)	(435)
Financial collateral, Liabilities	(7,973)	(11,283)
Net amount, Liabilities	0	0
Assets not subject to enforceable netting arrangements, Liabilities	0	0
Balance sheet total, Liabilities	7,982	11,718
Fair value
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	0
Amounts offset, Assets	0
Net amounts reported on the balance sheet, Assets	0
Financial instruments, Assets	0
Financial collateral, Assets	0
Net amount, Assets	0
Assets not subject to enforceable netting arrangements, Assets	0
Balance sheet total, Assets	0
Gross amounts, Liabilities	0
Amounts offset, Liabilities	0
Net amounts reported on the balance sheet, Liabilities	0
Financial instruments, Liabilities	0
Financial collateral, Liabilities	0
Net amount, Liabilities	0
Assets not subject to enforceable netting arrangements, Liabilities	0
Balance sheet total, Liabilities	0
Loans and advances to customers
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Assets	5,169	4,251
Amounts offset, Assets	(908)	(923)
Net amounts reported on the balance sheet, Assets	4,261	3,328
Financial instruments, Assets	0	0
Financial collateral, Assets	0	0
Net amount, Assets	4,261	3,328
Assets not subject to enforceable netting arrangements, Assets	216,447	207,935
Balance sheet total, Assets	220,708	211,263
Derivative financial liabilities
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Liabilities	3,085	1,955
Amounts offset, Liabilities	(2,173)	(1,221)
Net amounts reported on the balance sheet, Liabilities	912	734
Financial instruments, Liabilities	(515)	(754)
Financial collateral, Liabilities	(115)	59
Net amount, Liabilities	282	39
Assets not subject to enforceable netting arrangements, Liabilities	39	43
Balance sheet total, Liabilities	951	777
Deposits by customers and banks
Disclosure Of Offsetting Of Financial Assets And Liabilities [Line Items]
Gross amounts, Liabilities	8,077	8,609
Amounts offset, Liabilities	(908)	(923)
Net amounts reported on the balance sheet, Liabilities	7,169	7,686
Financial instruments, Liabilities	0	0
Financial collateral, Liabilities	0	0
Net amount, Liabilities	7,169	7,686
Assets not subject to enforceable netting arrangements, Liabilities	216,924	219,095
Balance sheet total, Liabilities	£ 224,093	£ 226,781

Interest Rate Benchmark Refor_2

Interest Rate Benchmark Reform - Schedule of Amounts Affected by IBOR Reform (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Assets
Derivative financial instruments	£ 2,407	£ 1,681
Other financial assets at fair value through profit or loss	129	185
Total assets	285,213	287,098	£ 292,332
Liabilities
Derivative financial instruments	951	777
Other financial liabilities at fair value through profit or loss	803	803
Total liabilities	270,806	270,996	£ 276,396
Total
Assets
Derivative financial instruments	1,665	1,480
Other financial assets at fair value through profit or loss		8
Financial assets at amortised cost	133	1,455
Total assets	1,798	2,943
Liabilities
Derivative financial instruments	1,912	2,169
Other financial liabilities at fair value through profit or loss		5
Financial liabilities at amortised cost		219
Total liabilities	1,912	2,393
Off-balance sheet commitments given	2	397
GBP LIBOR
Assets
Derivative financial instruments	0	0
Other financial assets at fair value through profit or loss		8
Financial assets at amortised cost	76	1,373
Total assets	76	1,381
Liabilities
Derivative financial instruments	66	338
Other financial liabilities at fair value through profit or loss		0
Financial liabilities at amortised cost		34
Total liabilities	66	372
Off-balance sheet commitments given	2	338
USD LIBOR
Assets
Derivative financial instruments	1,665	1,480
Other financial assets at fair value through profit or loss		0
Financial assets at amortised cost	57	81
Total assets	1,722	1,561
Liabilities
Derivative financial instruments	1,846	1,831
Other financial liabilities at fair value through profit or loss		5
Financial liabilities at amortised cost		185
Total liabilities	1,846	2,021
Off-balance sheet commitments given	0	59
Other
Assets
Derivative financial instruments	0	0
Other financial assets at fair value through profit or loss		0
Financial assets at amortised cost	0	1
Total assets	0	1
Liabilities
Derivative financial instruments	0	0
Other financial liabilities at fair value through profit or loss		0
Financial liabilities at amortised cost		0
Total liabilities	0	0
Off-balance sheet commitments given	£ 0	£ 0

Interest Rate Benchmark Refor_3

Interest Rate Benchmark Reform - Schedule of Derivatives Directly Affected by IBOR Reform Uncertainties (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Total
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	3,084	2,746
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	3,084	2,746
USD LIBOR
Disclosure Of Analysis Of Notional And Fair Values Of Derivatives By Trading And Settlement Method [Line Items]
Notional value of hedging instruments	3,084	2,746
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	3,084	2,746
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	2,906	2,586
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	2,906	2,586
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	2,906	2,586
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	2,906	2,586
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	178	160
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	178	160
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	178	160
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	178	160

Discontinued Operations and A_3

Discontinued Operations and Assets and Liabilities Held for Sale - Disclosure of Financial Performance Relating to Discontinued Operations (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of analysis of single amount of discontinued operations [line items]
Net interest income	£ 4,425	£ 3,949	£ 3,388
Net fee and commission income	330	286	319
Other operating income	201	264	145
Total operating income	4,956	4,499	3,852
Operating expenses before credit impairment (charges)/write-backs, provisions and charges	(2,343)	(2,510)	(2,390)
Credit impairment (charges)/write-backs	(320)	233	(638)
Provisions for other liabilities and charges	(419)	(377)	(264)
Total operating credit impairment (charges)/write-backs, provisions and charges	(739)	(144)	(902)
Profit from discontinued operations before tax	0	43	45
Tax on profit from discontinued operations	0	(12)	(13)
Profit from discontinued operations after tax	0	31	32
Discontinued operations
Disclosure of analysis of single amount of discontinued operations [line items]
Net interest income	0	32	55
Net fee and commission income	0	35	66
Other operating income	0	2	2
Total operating income	0	69	123
Operating expenses before credit impairment (charges)/write-backs, provisions and charges	0	(33)	(62)
Credit impairment (charges)/write-backs	0	11	(7)
Provisions for other liabilities and charges	0	(4)	(9)
Total operating credit impairment (charges)/write-backs, provisions and charges	£ 0	£ 7	£ (16)

Discontinued Operations and A_4

Discontinued Operations and Assets and Liabilities Held for Sale - Additional Information (Details) - GBP (£) £ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Discontinued Operations and Assets and Liabilities Held for Sale [Abstract]
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	£ 0	£ 3,612	£ 1,815

Discontinued Operations and A_5

Discontinued Operations and Assets and Liabilities Held for Sale - Disclosure of Assets and Liabilities Held for Sale (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Disclosure Of Assets And Liabilities Classified As Held For Sale [Line Items]
Assets held for sale	£ 49	£ 0
Property, plant and equipment
Disclosure Of Assets And Liabilities Classified As Held For Sale [Line Items]
Assets held for sale	£ 49	£ 0

Events After the Balance Shee_2

Events After the Balance Sheet Date (Details)	12 Months Ended
	Dec. 31, 2022
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 2022 and the date of approval of these financial statements which would require a change to or additional disclosure in the financial statements.

Notes to the Balance Sheet (Det

Notes to the Balance Sheet (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disclosure of reclassifications or changes in presentation [line items]
Other assets	£ (2,016)	£ (1,500)
Other liabilities	(2,581)	(2,067)
Macro hedge of interest rate risk	(2,657)	77
Macro hedge of interest rate risk	£ 95	122
Increase (decrease) due to changes in accounting policy
Disclosure of reclassifications or changes in presentation [line items]
Other assets		77	£ 1,226
Other liabilities		122	188
Macro hedge of interest rate risk		77	1,226
Macro hedge of interest rate risk		£ 122	£ 188