Current tax liabilities (Details) - GBP (£) £ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current tax liabilities
Uncertain tax provisions	£ 41	£ 54
Interest arising on tax provisions which is included within other payables	5	6
Income tax paid	£ 100	£ 77	£ 69

The cash flows from income taxes paid or refunded, classified as operating activities. [Refer: Income taxes paid (refund)]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2023-01-01
-Paragraph 35
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2023-en-r&anchor=para_35&doctype=Standard
-URIDate 2023-03-23

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Name IAS
-Number 7
-IssueDate 2023-01-01
-Paragraph 14
-Subparagraph f
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=7&code=ifrs-tx-2023-en-r&anchor=para_14_f&doctype=Standard
-URIDate 2023-03-23

Name:	ifrs-full_IncomeTaxesPaidRefundClassifiedAsOperatingActivities
Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration