Investments - Summary of investment (Detail) - GBP (£) £ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investments
Investments in joint ventures and associates	£ 178	£ 159	£ 105
Venture capital investments	97	127
Investments	£ 275	£ 286

The amount of investments accounted for using the equity method. The equity method is a method of accounting whereby the investment is initially recognised at cost and adjusted thereafter for the post-acquisition change in the investor's share of net assets of the investee. The investor's profit or loss includes its share of the profit or loss of the investee. The investor's other comprehensive income includes its share of the other comprehensive income of the investee. [Refer: At cost [member]]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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-IssueDate 2023-01-01
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