v3.26.1
Borrowings - Narrative (Details) - GBP (£)
£ in Millions
Mar. 31, 2026
Mar. 31, 2025
Mar. 31, 2024
Disclosure of fair value measurement of liabilities [line items]      
Borrowings £ 46,755 £ 47,539 £ 47,072
Collateral received 47 49  
Borrowings      
Disclosure of fair value measurement of liabilities [line items]      
Notional amount 46,113 46,739  
At fair value      
Disclosure of fair value measurement of liabilities [line items]      
Borrowings 42,505 43,137  
At fair value | Level 1      
Disclosure of fair value measurement of liabilities [line items]      
Borrowings 35,727 34,639  
At fair value | Level 2      
Disclosure of fair value measurement of liabilities [line items]      
Borrowings £ 6,778 £ 8,498