Analysis Of Income And Expense [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 |
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 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Analysis of income and expense [abstract] | ||||||||||||||||||||
| Revenue [abstract] | ||||||||||||||||||||
| Revenue | — |
667,200,000
GBP
|
–
GBP
|
— | — | — | — | — |
667,200,000
GBP
|
— |
578,100,000
GBP
|
— | — |
578,100,000
GBP
|
–
GBP
|
— | — | — | — | — |
| Material income and expense [abstract] | ||||||||||||||||||||
| Finance income (cost) | — |
1,500,000
GBP
|
–
GBP
|
— | — | — | — | — |
1,500,000
GBP
|
— |
2,100,000
GBP
|
— | — |
2,000,000
GBP
|
100,000
GBP
|
— | — | — | — | — |
| Miscellaneous other comprehensive income [abstract] | ||||||||||||||||||||
| Other comprehensive income, net of tax, exchange differences on translation of foreign operations and hedges of net investments in foreign operations [abstract] | ||||||||||||||||||||
| Other comprehensive income, net of tax, exchange differences on translation of foreign operations | — | — | — | — | — | — | — | — |
1,200,000
GBP
|
— |
900,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Income tax relating to components of other comprehensive income [abstract] | ||||||||||||||||||||
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss | — | — | — | — | — | — | — | — |
800,000
GBP
|
— |
100,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Comprehensive income, continuing and discontinued operations [abstract] | ||||||||||||||||||||
| Comprehensive income |
–
GBP
|
— | — |
–
GBP
|
–
GBP
|
–
GBP
|
6,000,000
GBP
|
–
GBP
|
16,600,000
GBP
|
22,600,000
GBP
|
19,600,000
GBP
|
–
GBP
|
–
GBP
|
— | — |
20,500,000
GBP
|
–
GBP
|
900,000
GBP
|
–
GBP
|
–
GBP
|
| Comprehensive income attributable to owners of parent, continuing and discontinued operations [abstract] | ||||||||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — | — | — | — | — | — | — |
16,600,000
GBP
|
— |
19,600,000
GBP
|
— | — | — | — | — | — | — | — | — |