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 |
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 |
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 |
–
GBP
|
200,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
132,400,000
GBP
|
132,400,000
GBP
|
132,200,000
GBP
|
75,700,000
GBP
|
100,000
GBP
|
1,900,000
GBP
|
168,400,000
GBP
|
–
GBP
|
–
GBP
|
168,400,000
GBP
|
242,100,000
GBP
|
| Purchase of treasury shares |
–
GBP
|
300,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
48,500,000
GBP
|
48,500,000
GBP
|
48,200,000
GBP
|
10,600,000
GBP
|
100,000
GBP
|
–
GBP
|
10,700,000
GBP
|
–
GBP
|
–
GBP
|
10,700,000
GBP
|
–
GBP
|