Assets pledged, collateral received and assets transferred - Fair value at the balance sheet date of collateral accepted and re-pledged to others (Details) - GBP (£) £ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets pledged, collateral received and assets transferred
Fair value of securities accepted as collateral	£ 989,211	£ 934,363
Of which fair value of securities re-pledged/transferred to others	£ 892,760	£ 819,169

The fair value of collateral held that is permitted to be sold or repledged in the absence of default by the owner of the collateral. [Refer: At fair value [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 7
-IssueDate 2022-03-24
-Paragraph 15
-Subparagraph a
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2022-en-r&anchor=para_15_a&doctype=Standard
-URIDate 2022-03-24

Name:	ifrs-full_AssetsHeldAsCollateralPermittedToBeSoldOrRepledgedAtFairValue
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant