Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2021-12-31 |
As at 2020-12-31 |
As at 2019-12-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
44,100,000
GBP
|
47,400,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets other than goodwill [abstract] | |||
| Intangible assets other than goodwill |
52,100,000
GBP
|
70,800,000
GBP
|
— |
| Goodwill |
570,600,000
GBP
|
570,600,000
GBP
|
— |
| Trade and other non-current receivables [abstract] | |||
| Trade and other non-current receivables |
500,000
GBP
|
500,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
145,000,000
GBP
|
187,300,000
GBP
|
— |
| Categories of current financial assets [abstract] | |||
| Current financial assets at fair value through profit or loss [abstract] | |||
| Current financial assets at fair value through profit or loss |
303,500,000
GBP
|
261,100,000
GBP
|
— |
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
197,300,000
GBP
|
188,100,000
GBP
|
179,400,000
GBP
|
| Borrowings [abstract] | |||
| Non-current portion of non-current borrowings |
49,300,000
GBP
|
49,200,000
GBP
|
— |
| Non-current portion of non-current borrowings, by type [abstract] | |||
| Trade and other non-current payables [abstract] | |||
| Trade and other non-current payables |
102,300,000
GBP
|
87,400,000
GBP
|
— |
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
222,200,000
GBP
|
212,800,000
GBP
|
— |
| Categories of current financial liabilities [abstract] | |||
| Current financial liabilities at fair value through profit or loss [abstract] | |||
| Current financial liabilities at fair value through profit or loss |
52,300,000
GBP
|
89,400,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
11,100,000
GBP
|
11,100,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
639,700,000
GBP
|
622,500,000
GBP
|
— |
| Accumulated other comprehensive income [abstract] | |||
| Reserve of exchange differences on translation |
300,000
GBP
|
2,800,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
1,340,700,000
GBP
|
1,345,800,000
GBP
|
— |
| Liabilities |
439,900,000
GBP
|
459,700,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
645,800,000
GBP
|
636,500,000
GBP
|
— |
| Current liabilities |
278,000,000
GBP
|
310,600,000
GBP
|
— |
| Assets less current liabilities [abstract] |