v3.25.4
Business Combinations - Schedule of Cash Flow on Acquisitions (Detail) - GBP (£)
£ in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Jul. 24, 2025
Disclosure of detailed information about business combination [line items]        
Net cash outflow £ (167) £ (39) £ (171)  
Intangible assets       £ 71
Goodwill 2,425 2,437    
Business combinations [member]        
Disclosure of detailed information about business combination [line items]        
Cash - current year acquisitions (168) (1) (152)  
Cash paid into escrow account (3) 0 0  
Cash and cash equivalents acquired 8 0 4  
Deferred payments for prior year acquisitions and other items (4) (38) (23)  
Net cash outflow (167) (39) (171)  
Intangible assets 71 1 117  
Trade and other receivables 7 0 8  
Cash and cash equivalents 8 0 4  
Trade and other liabilities (4) 0 (7)  
Provisions, including uncertain tax provisions (5) 0 0  
Deferred revenue (10) 0 0  
Deferred tax (1) 0 (31)  
Net assets acquired 66 1 91  
Goodwill 102 1 61  
Total 168 2 152  
Cash consideration 168 1 152  
Contingent or deferred consideration 0 1 0  
Total consideration £ 168 £ 2 £ 152