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 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 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||||||||
| Non-current assets [abstract] | ||||||||||||||||||||||||
| Property, plant and equipment |
37,500,000
GBP
|
— | — | — | — | — | — | — |
40,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Goodwill |
494,400,000
GBP
|
— | — | — | — | — | — | — |
570,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill |
17,500,000
GBP
|
— | — | — | — | — | — | — |
35,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current receivables |
400,000
GBP
|
— | — | — | — | — | — | — |
400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax assets |
16,100,000
GBP
|
— | — | — | — | — | — | — |
19,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-current assets |
567,700,000
GBP
|
— | — | — | — | — | — | — |
666,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | ||||||||||||||||||||||||
| Trade and other current receivables |
137,600,000
GBP
|
— | — | — | — | — | — | — |
124,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents |
268,200,000
GBP
|
— | — | — | — | — | — | — |
280,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
197,300,000
GBP
|
— | — | — | — |
| Current assets |
639,900,000
GBP
|
— | — | — | — | — | — | — |
575,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Assets |
1,207,600,000
GBP
|
— | — | — | — | — | — | — |
1,242,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||||||||
| Issued capital |
10,900,000
GBP
|
— | — | — | — | — | — | — |
10,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Retained earnings |
527,000,000
GBP
|
— | — | — | — | — | — | — |
578,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Treasury shares |
700,000
GBP
|
— | — | — | — | — | — | — |
500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Other reserves |
250,300,000
GBP
|
— | — | — | — | — | — | — |
250,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent |
789,500,000
GBP
|
— | — | — | — | — | — | — |
843,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-controlling interests |
-
GBP
|
— | — | — | — | — | — | — |
600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity |
789,500,000
GBP
|
527,000,000
GBP
|
250,300,000
GBP
|
–
GBP
|
10,900,000
GBP
|
2,000,000
GBP
|
700,000
GBP
|
789,500,000
GBP
|
843,900,000
GBP
|
250,300,000
GBP
|
600,000
GBP
|
578,900,000
GBP
|
500,000
GBP
|
10,900,000
GBP
|
3,700,000
GBP
|
843,300,000
GBP
|
400,000
GBP
|
639,700,000
GBP
|
250,100,000
GBP
|
900,800,000
GBP
|
900,800,000
GBP
|
–
GBP
|
300,000
GBP
|
11,100,000
GBP
|
| Liabilities [abstract] | ||||||||||||||||||||||||
| Non-current liabilities [abstract] | ||||||||||||||||||||||||
| Trade and other non-current payables |
59,700,000
GBP
|
— | — | — | — | — | — | — |
87,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities |
2,300,000
GBP
|
— | — | — | — | — | — | — |
6,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-current liabilities |
111,700,000
GBP
|
— | — | — | — | — | — | — |
143,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | ||||||||||||||||||||||||
| Current provisions [abstract] | ||||||||||||||||||||||||
| Current provisions |
4,700,000
GBP
|
— | — | — | — | — | — | — |
2,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other current payables |
221,400,000
GBP
|
— | — | — | — | — | — | — |
202,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Current liabilities |
306,400,000
GBP
|
— | — | — | — | — | — | — |
254,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Liabilities |
418,100,000
GBP
|
— | — | — | — | — | — | — |
398,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities |
1,207,600,000
GBP
|
— | — | — | — | — | — | — |
1,242,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |