v3.24.1.1.u2
Derivative financial instruments - Schedule of maturity profile of commodity contract derivatives (Details) - GBP (£)
£ in Millions
Mar. 31, 2024
Mar. 31, 2023
Disclosure of detailed information about financial instruments [line items]    
Derivative assets £ 368 £ 429
Derivative liabilities (1,244) (1,293)
Total (876) (864)
Commodity contract derivatives    
Disclosure of detailed information about financial instruments [line items]    
Derivative assets 35 66
Derivative liabilities (118) (174)
Total (83) (108)
Commodity contract derivatives | Less than 1 year    
Disclosure of detailed information about financial instruments [line items]    
Derivative assets 26 53
Derivative liabilities (86) (129)
Total (60) (76)
Commodity contract derivatives | Over 12 months past due    
Disclosure of detailed information about financial instruments [line items]    
Derivative assets 9 13
Derivative liabilities (32) (45)
Total (23) (32)
Commodity contract derivatives | In 1 to 2 years    
Disclosure of detailed information about financial instruments [line items]    
Derivative assets 3 11
Derivative liabilities (28) (29)
Total (25) (18)
Commodity contract derivatives | In 2 to 3 years    
Disclosure of detailed information about financial instruments [line items]    
Derivative assets 5 2
Derivative liabilities (4) (15)
Total 1 (13)
Commodity contract derivatives | In 3 to 4 years    
Disclosure of detailed information about financial instruments [line items]    
Derivative assets 1 0
Derivative liabilities 0 (1)
Total £ 1 £ (1)