Borrowing facilities - Schedule of undrawn committed borrowing facilities (Details) - GBP (£) £ in Millions |
Mar. 31, 2026 |
Mar. 31, 2025 |
|---|---|---|
| Disclosure of detailed information about borrowings [line items] | ||
| Undrawn borrowing facilities | £ 8,007 | £ 7,832 |
| Less than 1 year | ||
| Disclosure of detailed information about borrowings [line items] | ||
| Undrawn borrowing facilities | 0 | 0 |
| In 1 to 2 years | ||
| Disclosure of detailed information about borrowings [line items] | ||
| Undrawn borrowing facilities | 5,408 | 0 |
| In 2 to 3 years | ||
| Disclosure of detailed information about borrowings [line items] | ||
| Undrawn borrowing facilities | 604 | 5,982 |
| In 3 to 4 years | ||
| Disclosure of detailed information about borrowings [line items] | ||
| Undrawn borrowing facilities | 1,745 | 105 |
| In 4 to 5 years | ||
| Disclosure of detailed information about borrowings [line items] | ||
| Undrawn borrowing facilities | 0 | 1,745 |
| More than 5 years | ||
| Disclosure of detailed information about borrowings [line items] | ||
| Undrawn borrowing facilities | £ 250 | £ 0 |