Statement Of Changes In Equity [Abstract]
| Concept |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | ||||||||||||
| Statement of changes in equity [line items] | ||||||||||||
| Increase (decrease) through transactions with owners, equity |
3,900,000
GBP
|
2 .1
GBP
|
–
GBP
|
20. 1
GBP
|
24. 0
GBP
|
22,200,000
GBP
|
2 4.3
GBP
|
–
GBP
|
25,500,000
GBP
|
1,900,000
GBP
|
23,600,000
GBP
|
700,000
GBP
|