Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2022-12-31 |
As at 2021-12-31 |
As at 2020-12-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
25,500,000
GBP
|
22,500,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets and goodwill |
188,900,000
GBP
|
183,200,000
GBP
|
— |
| Investment property [abstract] | |||
| Investment property |
1,000,000
GBP
|
1,200,000
GBP
|
— |
| Trade and other non-current receivables [abstract] | |||
| Trade and other non-current receivables |
2,600,000
GBP
|
1,000,000
GBP
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Non-current net defined benefit asset |
15,800,000
GBP
|
25,800,000
GBP
|
— |
| Non-current investments other than investments accounted for using equity method |
1,200,000
GBP
|
1,000,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
150. 1
GBP
|
117 .4
GBP
|
— |
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
384,400,000
GBP
|
261,600,000
GBP
|
173,400,000
GBP
|
| Miscellaneous current assets [abstract] | |||
| Current investments |
3,500,000
GBP
|
10,300,000
GBP
|
— |
| Trade and other non-current payables [abstract] | |||
| Trade and other non-current payables |
5,800,000
GBP
|
2,700,000
GBP
|
— |
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
335,900,000
GBP
|
235,400,000
GBP
|
— |
| Miscellaneous non-current liabilities [abstract] | |||
| Non-current net defined benefit liability |
400,000
GBP
|
3,800,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
7. 7
GBP
|
7. 6
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
287 .2
GBP
|
245,300,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets (liabilities) |
4 13.2
GBP
|
36 1.6
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
543,400,000
GBP
|
391,800,000
GBP
|
— |
| Current liabilities |
366,200,000
GBP
|
257 .3
GBP
|
— |
| Current assets (liabilities) |
177 .2
GBP
|
134,500,000
GBP
|
— |
| Assets less current liabilities [abstract] |