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 |
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 |
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 |
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 |
42,000,000
GBP
|
— | — | — | — |
48,800,000
GBP
|
7. 5
GBP
|
300,000
GBP
|
400,000
GBP
|
— |
3. 4
GBP
|
46,500,000
GBP
|
— |
43,400,000
GBP
|
— | — |
–
GBP
|
300,000
GBP
|
— | — |
59,800,000
GBP
|
300,000
GBP
|
–
GBP
|
100,000
GBP
|
60,200,000
GBP
|
| Changes in equity [abstract] | |||||||||||||||||||||||||
| Comprehensive income [abstract] | |||||||||||||||||||||||||
| Profit (loss) | — |
–
GBP
|
–
GBP
|
24,500,000
GBP
|
24,500,000
GBP
|
— | — | — | — |
–
GBP
|
— | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
— | — |
19,200,000
GBP
|
19,200,000
GBP
|
— | — | — | — | — |
| Other comprehensive income | — |
–
GBP
|
–
GBP
|
400,000
GBP
|
–
GBP
|
— | — | — | — |
400,000
GBP
|
— | — |
–
GBP
|
— |
0 .1
GBP
|
–
GBP
|
— | — |
0 .1
GBP
|
–
GBP
|
— | — | — | — | — |
| Comprehensive income | — |
–
GBP
|
–
GBP
|
24,900,000
GBP
|
24,500,000
GBP
|
— | — | — | — |
400,000
GBP
|
— | — |
–
GBP
|
— |
0 .1
GBP
|
–
GBP
|
— | — |
19,100,000
GBP
|
19,200,000
GBP
|
— | — | — | — | — |
| Dividends recognised as distributions to owners | — |
–
GBP
|
–
GBP
|
22,500,000
GBP
|
22,500,000
GBP
|
— | — | — | — |
–
GBP
|
— | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
— | — |
3 2 .7
GBP
|
32 .7
GBP
|
— | — | — | — | — |
| Increase (decrease) through share-based payment transactions, equity | — |
–
GBP
|
–
GBP
|
1,500,000
GBP
|
1,500,000
GBP
|
— | — | — | — |
–
GBP
|
— | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
— | — |
1,100,000
GBP
|
1,100,000
GBP
|
— | — | — | — | — |