v3.26.3
Basis of preparation and new accounting standards, interpretations and amendments (Details)
£ in Millions, $ in Millions
Sep. 30, 2026
GBP (£)
Sep. 30, 2026
USD ($)
Mar. 31, 2026
GBP (£)
Disclosure of detailed information about borrowings [line items]      
Financial assets £ 5,072   £ 3,587
Level 3      
Disclosure of detailed information about borrowings [line items]      
Financial assets 1,672   486
Investments held at fair value through profit and loss      
Disclosure of detailed information about borrowings [line items]      
Financial assets 3,978   2,364
Investments held at fair value through profit and loss | Level 3      
Disclosure of detailed information about borrowings [line items]      
Financial assets 1,637   £ 450
Joulent LLC | Investments held at fair value through profit and loss | Level 3      
Disclosure of detailed information about borrowings [line items]      
Financial assets 952 $ 1,263  
Fixed interest rate bonds      
Disclosure of detailed information about borrowings [line items]      
Notional amount £ 9,100