Disposal of business (Narrative) (Details) £ in Millions	12 Months Ended
Dec. 31, 2022 GBP (£)
Capton Investments Limited \| Roder 1
Disclosure of operating segments [line items]
Gain on sale of direct ownership of subsidiaries	£ 43
Hawkins \| Roder 2
Disclosure of operating segments [line items]
Gain on sale of direct ownership of subsidiaries	£ 75

The profit (loss) on disposal of investments and changes in the value of investments. [Refer: Profit (loss)]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 26
-IssueDate 2022-03-24
-Paragraph 35
-Subparagraph b
-Clause ix
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=26&code=ifrs-tx-2022-en-r&anchor=para_35_b_ix&doctype=Standard
-URIDate 2022-03-24

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration