Statement Of Financial Position [Abstract]
| Concept |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-01-01 |
As at 2023-01-01 |
As at 2023-01-01 |
As at 2023-01-01 |
As at 2023-01-01 |
As at 2023-01-01 |
As at 2023-01-01 |
As at 2023-01-01 |
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 |
As at 2022-12-31 |
As at 2022-01-01 |
As at 2022-01-01 |
As at 2022-01-01 |
As at 2022-01-01 |
As at 2022-01-01 |
As at 2022-01-01 |
As at 2022-01-01 |
As at 2022-01-01 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||||||||||||||||
| Property, plant and equipment |
20,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
20,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Goodwill |
827,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
804,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill |
409,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
456,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements |
562,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
552,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax assets |
-
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents |
4 18.3
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
67 6.8
GBP
|
67 6.8
GBP
|
— | — | — | — | — | — | — | — | — | — |
398,700,000
GBP
|
— | — | — | — |
| Assets |
6,085,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
6,015,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||||||||||||||||
| Issued capital |
17 3.4
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
17 3.6
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Retained earnings |
1,184,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,116,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Share premium |
361,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
360,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity |
3,318,500,000
GBP
|
1,18 4.8
GBP
|
1,500,000
GBP
|
1,199,500,000
GBP
|
361,000,000
GBP
|
173,400,000
GBP
|
14,700,000
GBP
|
1,597,800,000
GBP
|
1,300,000
GBP
|
1,116,200,000
GBP
|
17,400,000
GBP
|
1,133,600,000
GBP
|
1,597,800,000
GBP
|
17 3.6
GBP
|
360,800,000
GBP
|
3,249,700,000
GBP
|
3,24 9.7
GBP
|
1,133,600,000
GBP
|
360,800,000
GBP
|
1,300,000
GBP
|
1,116,200,000
GBP
|
17,400,000
GBP
|
173,600,000
GBP
|
1,597,800,000
GBP
|
1,094,800,000
GBP
|
361,100,000
GBP
|
111,200,000
GBP
|
2,390,600,000
GBP
|
1,098,200,000
GBP
|
3,400,000
GBP
|
823,500,000
GBP
|
-
GBP
|
| Liabilities [abstract] | ||||||||||||||||||||||||||||||||
| Deferred tax liabilities |
21,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
-
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Liabilities |
2,7 66.9
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
2,7 66.0
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |