Statement Of Financial Position [Abstract]
| Concept |
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 |
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 financial position [abstract] | ||||||||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||||||||
| Non-current assets [abstract] | ||||||||||||||||||||||||
| Property, plant and equipment |
40,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
44,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Goodwill |
570,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
570,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill |
35,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
52,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current receivables |
400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax assets |
19,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
27,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Non-current assets |
666,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
694,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | ||||||||||||||||||||||||
| Trade and other current receivables |
124,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
145,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents |
280,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
197,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
188,100,000
GBP
|
| Current assets |
575,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
645,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Assets |
1,242,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
1,340,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||||||||
| Issued capital |
10,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
11,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Retained earnings |
578,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
639,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Treasury shares |
500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Other reserves |
250,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
250,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent |
843,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
900,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Non-controlling interests |
600,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
–
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Equity |
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
|
622,500,000
GBP
|
200,000
GBP
|
886,300,000
GBP
|
11,100,000
GBP
|
200,000
GBP
|
2,800,000
GBP
|
250,100,000
GBP
|
886,100,000
GBP
|
| Liabilities [abstract] | ||||||||||||||||||||||||
| Non-current liabilities [abstract] | ||||||||||||||||||||||||
| Trade and other non-current payables |
87,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
102,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities |
6,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
10,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Non-current liabilities |
143,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
161,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | ||||||||||||||||||||||||
| Trade and other current payables |
205,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
222,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Current liabilities |
254,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
278,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Liabilities |
398,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
439,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities |
1,242,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
1,340,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |