Statement Of Changes In Equity [Abstract]
| Concept |
2021-05-01 to 2022-04-30 |
2021-05-01 to 2022-04-30 |
2021-05-01 to 2022-04-30 |
2021-05-01 to 2022-04-30 |
2021-05-01 to 2022-04-30 |
2021-05-01 to 2022-04-30 |
2020-05-01 to 2021-04-30 |
2020-05-01 to 2021-04-30 |
2020-05-01 to 2021-04-30 |
2020-05-01 to 2021-04-30 |
2020-05-01 to 2021-04-30 |
2020-05-01 to 2021-04-30 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | ||||||||||||
| Statement of changes in equity [line items] | ||||||||||||
| Purchase of treasury shares |
63,700,000
GBP
|
0. 1
GBP
|
-
GBP
|
63. 7
GBP
|
–
GBP
|
100,000
GBP
|
–
GBP
|
188,600,000
GBP
|
188,600,000
GBP
|
200,000
GBP
|
200,000
GBP
|
–
GBP
|