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 |
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) |
0. 5
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
5 9.5
GBP
|
6 0.0
GBP
|
5 9.5
GBP
|
0 .4
GBP
|
–
GBP
|
0 .8
GBP
|
–
GBP
|
0. 4
GBP
|
–
GBP
|
0. 4
GBP
|
–
GBP
|
–
GBP
|
| Other comprehensive income [abstract] | ||||||||||||||||||
| Components of other comprehensive income that will not be reclassified to profit or loss, net of tax [abstract] | ||||||||||||||||||
| Other comprehensive income, net of tax, gains (losses) on remeasurements of defined benefit plans |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
1,800,000
GBP
|
1. 8
GBP
|
1. 8
GBP
|
0 .4
GBP
|
–
GBP
|
0 .4
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
0. 4
GBP
|
–
GBP
|
–
GBP
|
| Other comprehensive income that will not be reclassified to profit or loss, net of tax | — | — | — | — | — | — | — |
1. 8
GBP
|
— | — | — |
0. 4
GBP
|
— | — | — | — | — | — |
| Components of other comprehensive income that will be reclassified to profit or loss, net of tax [abstract] | ||||||||||||||||||
| Exchange differences on translation [abstract] | ||||||||||||||||||
| Gains (losses) on exchange differences on translation of foreign operations, net of tax | — | — | — | — | — | — | — |
14 . 8
GBP
|
— | — | — |
1. 4
GBP
|
— | — | — | — | — | — |
| Other comprehensive income, net of tax, exchange differences on translation of foreign operations |
0 .7
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
1 4 .1
GBP
|
1 4 .1
GBP
|
14 . 8
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
1. 4
GBP
|
1,100,000
GBP
|
300,000
GBP
|
–
GBP
|
1,100,000
GBP
|
–
GBP
|
–
GBP
|
| Cash flow hedges [abstract] | ||||||||||||||||||
| Gains (losses) on cash flow hedges, net of tax |
–
GBP
|
–
GBP
|
–
GBP
|
0. 5
GBP
|
–
GBP
|
–
GBP
|
0. 5
GBP
|
500,000
GBP
|
–
GBP
|
— | — |
–
GBP
|
— | — | — | — | — | — |
| Hedges of net investment in foreign operations [abstract] | ||||||||||||||||||
| Gains (losses) on hedges of net investments in foreign operations, net of tax |
–
GBP
|
–
GBP
|
–
GBP
|
500,000
GBP
|
–
GBP
|
–
GBP
|
0 .5
GBP
|
500,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
1 .1
GBP
|
1 .1
GBP
|
–
GBP
|
–
GBP
|
1 .1
GBP
|
–
GBP
|
–
GBP
|
| Other comprehensive income that will be reclassified to profit or loss, net of tax | — | — | — | — | — | — | — |
13 . 8
GBP
|
— | — | — |
0. 3
GBP
|
— | — | — | — | — | — |
| Other comprehensive income | — | — | — | — | — | — | — |
12 . 0
GBP
|
— | — | — |
0 .1
GBP
|
— | — | — | — | — | — |
| Comprehensive income |
0. 2
GBP
|
–
GBP
|
–
GBP
|
1. 0
GBP
|
–
GBP
|
1 4 .1
GBP
|
4 8. 2
GBP
|
4 8.0
GBP
|
61. 3
GBP
|
0 .8
GBP
|
–
GBP
|
0. 9
GBP
|
–
GBP
|
0 .1
GBP
|
–
GBP
|
0. 8
GBP
|
–
GBP
|
–
GBP
|
| Comprehensive income attributable to [abstract] | ||||||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — | — | — | — | — | — |
4 8. 2
GBP
|
— | — | — |
0. 8
GBP
|
— | — | — | — | — | — |
| Comprehensive income, attributable to non-controlling interests | — | — | — | — | — | — | — |
0. 2
GBP
|
— | — | — |
0 .1
GBP
|
— | — | — | — | — | — |