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 |
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 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||||||||||||
| Profit (loss) |
2,300,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
40,200,000
GBP
|
229,500,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
189,300,000
GBP
|
191. 6
GBP
|
4 10.5
GBP
|
–
GBP
|
–
GBP
|
4 19.3
GBP
|
–
GBP
|
1 33.7
GBP
|
2 76.8
GBP
|
–
GBP
|
–
GBP
|
8,800,000
GBP
|
–
GBP
|
–
GBP
|
| Other comprehensive income [abstract] | ||||||||||||||||||||||||
| Components of other comprehensive income that will not be reclassified to profit or loss, before tax [abstract] | ||||||||||||||||||||||||
| Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
3,800,000
GBP
|
3,800,000
GBP
|
5 9.1
GBP
|
–
GBP
|
–
GBP
|
5 9.1
GBP
|
–
GBP
|
— | — |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
| Components of other comprehensive income that will be reclassified to profit or loss, before tax [abstract] | ||||||||||||||||||||||||
| Exchange differences on translation [abstract] | ||||||||||||||||||||||||
| Other comprehensive income, before tax, exchange differences on translation of foreign operations |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
2,300,000
GBP
|
–
GBP
|
–
GBP
|
2,300,000
GBP
|
–
GBP
|
800,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
800,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
| Cash flow hedges [abstract] | ||||||||||||||||||||||||
| Gains (losses) on cash flow hedges, before tax |
–
GBP
|
–
GBP
|
300,000
GBP
|
–
GBP
|
— | — |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
300,000
GBP
|
–
GBP
|
6,600,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
6,600,000
GBP
|
— | — |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
| Reclassification adjustments on cash flow hedges, before tax |
–
GBP
|
–
GBP
|
4,300,000
GBP
|
–
GBP
|
— | — |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
4,300,000
GBP
|
–
GBP
|
9,700,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
9,700,000
GBP
|
— | — |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract] | ||||||||||||||||||||||||
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss | — | — | — | — | — | — | — | — | — | — |
1,000,000
GBP
|
— |
12,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| 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 | — | — | — | — | — | — | — | — | — | — |
1,200,000
GBP
|
— |
3,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Other comprehensive income |
–
GBP
|
–
GBP
|
4,200,000
GBP
|
–
GBP
|
— | — |
–
GBP
|
2,300,000
GBP
|
–
GBP
|
–
GBP
|
7,700,000
GBP
|
9,600,000
GBP
|
3 2.8
GBP
|
–
GBP
|
–
GBP
|
4 6.8
GBP
|
13,200,000
GBP
|
— | — |
–
GBP
|
800,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
| Comprehensive income |
2,300,000
GBP
|
–
GBP
|
4,200,000
GBP
|
–
GBP
|
— | — |
–
GBP
|
2,300,000
GBP
|
–
GBP
|
–
GBP
|
181,600,000
GBP
|
182,000,000
GBP
|
4 43.3
GBP
|
–
GBP
|
–
GBP
|
4 66.1
GBP
|
13,200,000
GBP
|
— | — |
–
GBP
|
800,000
GBP
|
8,800,000
GBP
|
–
GBP
|
–
GBP
|
| Comprehensive income attributable to [abstract] | ||||||||||||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — | — | — | — | — | — | — | — | — |
183,900,000
GBP
|
— |
4 52.1
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Comprehensive income, attributable to non-controlling interests | — | — | — | — | — | — | — | — | — | — |
2,300,000
GBP
|
— |
8,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |