Leases - Additional information (Detail) - GBP (£) £ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Presentation Of Leases For Lessee [Line Items]
Contractual capital commitments	£ 8	£ 5
Finance lease receivable increased (decreased)	£ (21)	£ 6

The amount of capital commitments for which the entity has entered into a contract. [Refer: Capital commitments]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2023-01-01
-Paragraph 112
-Subparagraph c
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2023-en-r&anchor=para_112_c&doctype=Standard
-URIDate 2023-03-23

Name:	ifrs-full_ContractualCapitalCommitments
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant