Statement Of Financial Position [Abstract]
| Concept |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2020-04-30 |
As at 2020-04-30 |
As at 2020-04-30 |
As at 2020-04-30 |
As at 2020-04-30 |
As at 2020-04-30 |
As at 2020-04-30 |
As at 2020-04-30 |
As at 2020-04-30 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | |||||||||||||||||||||||||||
| Assets [abstract] | |||||||||||||||||||||||||||
| Property, plant and equipment | — | — | — | — | — | — | — |
3,128,000,000
GBP
|
— | — |
3,050,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Right-of-use assets | — | — | — | — | — | — | — |
199,000,000
GBP
|
— | — |
226,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Investments accounted for using equity method | — | — | — | — | — | — | — |
17,000,000
GBP
|
— | — |
38,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Current tax assets | — | — | — | — | — | — | — |
34,000,000
GBP
|
— | — |
41,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax assets | — | — | — | — | — | — | — |
7,000,000
GBP
|
— | — |
37,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — | — | — | — | — | — |
819,000,000
GBP
|
— | — |
813,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Assets | — | — | — | — | — | — | — |
9,886,000,000
GBP
|
— | — |
8,700,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||||||||
| Issued capital | — | — | — | — | — | — | — |
137,000,000
GBP
|
— | — |
137,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Share premium | — | — | — | — | — | — | — |
2,248,000,000
GBP
|
— | — |
2,241,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent | — | — | — | — | — | — | — |
4,232,000,000
GBP
|
— | — |
3,533,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-controlling interests | — | — | — | — | — | — | — |
2,000,000
GBP
|
— | — |
2,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity |
1,352,000,000
GBP
|
105,000,000
GBP
|
2, 248
GBP
|
4,23 2
GBP
|
2,000,000
GBP
|
137,000,000
GBP
|
9,000,000
GBP
|
4,234,000,000
GBP
|
6 09
GBP
|
3,000,000
GBP
|
3,535,000,000
GBP
|
84,000,000
GBP
|
2,241,000,000
GBP
|
53,000,000
GBP
|
1,189,000,000
GBP
|
2,000,000
GBP
|
3,533,000,000
GBP
|
137,000,000
GBP
|
3,000,000
GBP
|
2,238,000,000
GBP
|
14,000,000
GBP
|
137,000,000
GBP
|
39,000,000
GBP
|
1,003,000,000
GBP
|
3,350,000,000
GBP
|
1,000,000
GBP
|
3,351,000,000
GBP
|
| Liabilities [abstract] | |||||||||||||||||||||||||||
| Current tax liabilities | — | — | — | — | — | — | — |
143,000,000
GBP
|
— | — |
133,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — | — | — | — | — | — | — |
396,000,000
GBP
|
— | — |
271,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Liabilities | — | — | — | — | — | — | — |
5,652,000,000
GBP
|
— | — |
5,165,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |