Statement Of Comprehensive Income [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 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||
| Profit (loss) | — | — | — |
119,500,000
GBP
|
119,500,000
GBP
|
77,400,000
GBP
|
77,400,000
GBP
|
— |
| Other comprehensive income [abstract] | ||||||||
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss [abstract] | ||||||||
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss | — | — | — |
1,000,000
GBP
|
— | — |
500,000
GBP
|
— |
| Other comprehensive income | — |
28,300,000
GBP
|
— |
28,300,000
GBP
|
— | — |
21,100,000
GBP
|
21,100,000
GBP
|
| Comprehensive income |
–
GBP
|
— |
–
GBP
|
91,200,000
GBP
|
— | — |
98,500,000
GBP
|
— |