Statement Of Comprehensive Income [Abstract]
| Concept |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
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 |
2022-01-01 to 2022-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||||
| Profit (loss) |
–
GBP
|
–
GBP
|
145 .4
GBP
|
–
GBP
|
14 5. 4
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
401 . 5
GBP
|
–
GBP
|
–
GBP
|
4 01. 5
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) from investments in equity instruments | — | — |
5,000,000
GBP
|
— | — | — | — | — | — | — |
5,000,000
GBP
|
— | — | — | — | — |
| Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans | — | — |
0. 6
GBP
|
— | — | — | — | — | — | — |
13 .1
GBP
|
— | — | — | — | — |
| Components of other comprehensive income that will be reclassified to profit or loss, before tax [abstract] | ||||||||||||||||
| Cash flow hedges [abstract] | ||||||||||||||||
| Other comprehensive income, before tax, cash flow hedges | — | — |
6 .1
GBP
|
— | — | — | — | — | — | — |
400,000
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 | — | — |
0. 2
GBP
|
— | — | — | — | — | — | — |
4 . 0
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 | — | — |
1,100,000
GBP
|
— | — | — | — | — | — | — |
–
GBP
|
— | — | — | — | — |
| Other comprehensive income |
–
GBP
|
–
GBP
|
42 . 9
GBP
|
5 .0
GBP
|
4 . 9
GBP
|
–
GBP
|
–
GBP
|
4 3 . 0
GBP
|
400,000
GBP
|
–
GBP
|
32,900,000
GBP
|
–
GBP
|
–
GBP
|
1 2 .7
GBP
|
19. 8
GBP
|
–
GBP
|
| Comprehensive income |
–
GBP
|
–
GBP
|
10 2.5
GBP
|
5,000,000
GBP
|
140 . 5
GBP
|
–
GBP
|
–
GBP
|
4 3 . 0
GBP
|
400,000
GBP
|
–
GBP
|
434,400,000
GBP
|
–
GBP
|
–
GBP
|
41 4. 2
GBP
|
19,800,000
GBP
|
–
GBP
|