Statement Of Financial Position [Abstract]
| Concept |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | |||||||||||||||||||||||||||
| Assets [abstract] | |||||||||||||||||||||||||||
| Non-current assets [abstract] | |||||||||||||||||||||||||||
| Property, plant and equipment | — |
18,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
4,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Right-of-use assets | — |
41,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
49,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill | — |
2,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
4,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Non-current assets | — |
25,469,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
21,108,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | |||||||||||||||||||||||||||
| Cash and cash equivalents | — |
412,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
358,000,000
GBP
|
— | — | — |
162,000,000
GBP
|
— | — | — | — | — | — | — |
| Current assets | — |
587,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
533,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Assets | — |
26,056,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
21,641,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||||||||
| Issued capital | — |
719,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
719,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Retained earnings | — |
1,845,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
1,519,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Share premium | — |
792,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
791,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Treasury shares | — |
81,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
92,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity |
35,000,000
GBP
|
24,611,000,000
GBP
|
43,000,000
GBP
|
792,000,000
GBP
|
81,000,000
GBP
|
719,000,000
GBP
|
1,845,000,000
GBP
|
1,000,000
GBP
|
21,257,000,000
GBP
|
42,000,000
GBP
|
1,519,000,000
GBP
|
791,000,000
GBP
|
719,000,000
GBP
|
92,000,000
GBP
|
43,000,000
GBP
|
20,170,000,000
GBP
|
6,000,000
GBP
|
17,154,000,000
GBP
|
31,000,000
GBP
|
16,844,000,000
GBP
|
790,000,000
GBP
|
719,000,000
GBP
|
108,000,000
GBP
|
43,000,000
GBP
|
1,327,000,000
GBP
|
14,044,000,000
GBP
|
2,000,000
GBP
|
| Liabilities [abstract] | |||||||||||||||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||||||||||||||
| Non-current provisions [abstract] | |||||||||||||||||||||||||||
| Non-current provisions | — |
2,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
2,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current payables | — |
6,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
5,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — |
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Non-current liabilities | — |
1,295,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
1,306,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | |||||||||||||||||||||||||||
| Current provisions [abstract] | |||||||||||||||||||||||||||
| Current provisions | — |
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
–
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other current payables | — |
133,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
134,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current liabilities | — |
150,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
165,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Liabilities | — |
1,445,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
1,471,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |