Statement Of Financial Position [Abstract]
| Concept |
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 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | |||||||||||||||||||||||||||
| Assets [abstract] | |||||||||||||||||||||||||||
| Non-current assets [abstract] | |||||||||||||||||||||||||||
| Property, plant and equipment | — |
3,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
3,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Right-of-use assets | — |
9,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
13,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill | — |
5,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
6,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Deferred tax assets | — |
–
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-current assets | — |
17,538,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
13,570,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | |||||||||||||||||||||||||||
| Cash and cash equivalents | — |
162,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
212,000,000
GBP
|
— | — | — | — | — | — |
216,000,000
GBP
|
— | — | — |
| Current assets | — |
281,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
378,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Assets | — |
17,819,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
13,948,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||||||||
| Issued capital | — |
719,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
719,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Retained earnings | — |
1,327,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,125,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Share premium | — |
790,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
789,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Treasury shares | — |
108,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
100,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity |
31,000,000
GBP
|
16,844,000,000
GBP
|
790,000,000
GBP
|
719,000,000
GBP
|
43,000,000
GBP
|
108,000,000
GBP
|
1,327,000,000
GBP
|
14,044,000,000
GBP
|
2,000,000
GBP
|
43,000,000
GBP
|
100,000,000
GBP
|
10,151,000,000
GBP
|
719,000,000
GBP
|
6,000,000
GBP
|
1,125,000,000
GBP
|
789,000,000
GBP
|
12,754,000,000
GBP
|
33,000,000
GBP
|
34,000,000
GBP
|
43,000,000
GBP
|
64,000,000
GBP
|
6,733,000,000
GBP
|
916,000,000
GBP
|
9,164,000,000
GBP
|
719,000,000
GBP
|
788,000,000
GBP
|
5,000,000
GBP
|
| Liabilities [abstract] | |||||||||||||||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||||||||||||||
| Non-current provisions [abstract] | |||||||||||||||||||||||||||
| Non-current provisions | — |
4,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
3,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Trade and other non-current payables | — |
4,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
14,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — |
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-current liabilities | — |
855,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
870,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | |||||||||||||||||||||||||||
| Trade and other current payables | — |
76,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
80,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current liabilities | — |
120,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
324,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Liabilities | — |
975,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,194,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |