EARNINGS FROM ASSOCIATES - Additional Information (Details) - GBP (£)	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disclosure of associates [line items]
Earnings from associates	£ 39,000,000	£ 36,000,000	£ 70,000,000
Interests in associates	231,000,000	253,000,000	287,000,000
Kantar
Disclosure of associates [line items]
Non-refundable distribution received	2,000,000	£ 2,000,000	£ 45,000,000
Interests in associates	£ 0

- Definition

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]]

+ References + Details