v3.26.1
Taxation (Details) - GBP (£)
£ in Millions
6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Major components of tax expense (income) [abstract]    
Average effective tax rate 20.30% 18.10%
Adjusting items included in taxation £ 100 £ (66)
Tax on adjusting items £ (179) £ (29)
Average effective tax rate for subsidiaries 23.80% 24.40%