Statement Of Changes In Equity [Abstract]
| Concept |
As at 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
2022-01-01 to 2022-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | ||||||||||||||||||||||||||||||||||||||||
| Statement of changes in equity [line items] | ||||||||||||||||||||||||||||||||||||||||
| Equity |
445,200,000
GBP
|
— | — | — | — | — | — | — |
22 .5
GBP
|
2. 3
GBP
|
476,000,000
GBP
|
43,300,000
GBP
|
23,400,000
GBP
|
9,200,000
GBP
|
100,000
GBP
|
— |
46,600,000
GBP
|
441,500,000
GBP
|
2,300,000
GBP
|
— |
22,500,000
GBP
|
— | — |
367,100,000
GBP
|
1,600,000
GBP
|
— | — | — |
32,600,000
GBP
|
23,400,000
GBP
|
— | — |
406,600,000
GBP
|
900,000
GBP
|
23,400,000
GBP
|
45,200,000
GBP
|
5,000,000
GBP
|
22,500,000
GBP
|
370,500,000
GBP
|
2,300,000
GBP
|
| Changes in equity [abstract] | ||||||||||||||||||||||||||||||||||||||||
| Comprehensive income [abstract] | ||||||||||||||||||||||||||||||||||||||||
| Profit (loss) | — |
–
GBP
|
–
GBP
|
–
GBP
|
56,800,000
GBP
|
56,800,000
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
–
GBP
|
— | — | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
41,900,000
GBP
|
41,900,000
GBP
|
— | — | — | — | — | — | — | — |
| Other comprehensive income | — |
–
GBP
|
–
GBP
|
–
GBP
|
37,400,000
GBP
|
2,900,000
GBP
|
1,500,000
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
41,800,000
GBP
|
— | — | — |
700,000
GBP
|
— |
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
37,600,000
GBP
|
–
GBP
|
— | — |
36,300,000
GBP
|
600,000
GBP
|
— | — | — | — | — | — | — | — |
| Comprehensive income | — |
–
GBP
|
–
GBP
|
–
GBP
|
94,200,000
GBP
|
53,900,000
GBP
|
1,500,000
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
41,800,000
GBP
|
— | — | — |
700,000
GBP
|
— |
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
37,600,000
GBP
|
–
GBP
|
— | — |
5,600,000
GBP
|
42,500,000
GBP
|
— | — | — | — | — | — | — | — |
| Dividends recognised as distributions to owners | — |
–
GBP
|
–
GBP
|
–
GBP
|
18,900,000
GBP
|
18,900,000
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
–
GBP
|
— | — | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
4,900,000
GBP
|
4. 9
GBP
|
— | — | — | — | — | — | — | — |
| Increase (decrease) through share-based payment transactions, equity | — |
–
GBP
|
–
GBP
|
–
GBP
|
3,200,000
GBP
|
3,200,000
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
–
GBP
|
— | — | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
200,000
GBP
|
0. 2
GBP
|
— | — | — | — | — | — | — | — |