OTHER FINANCIAL ASSETS AT AMORTISED COST (Details) - Other financial assets - GBP (£) £ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Financial Assets At Fair Value Through Profit Or Loss [Line Items] | ||
| Financial assets at amortised cost | £ 5,738 | £ 3,987 |
| Debt securities | ||
| Financial Assets At Fair Value Through Profit Or Loss [Line Items] | ||
| Financial assets at amortised cost | £ 5,738 | £ 3,987 |