Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2024-12-31 |
As at 2023-12-31 |
As at 2022-12-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
234,800,000
GBP
|
249,400,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets other than goodwill [abstract] | |||
| Intangible assets other than goodwill |
217,800,000
GBP
|
227,500,000
GBP
|
— |
| Goodwill |
324,400,000
GBP
|
324,400,000
GBP
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Non-current net defined benefit asset |
24,100,000
GBP
|
11,000,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
80,800,000
GBP
|
93,400,000
GBP
|
— |
| Classes of current inventories [abstract] | |||
| Current inventories |
138,200,000
GBP
|
125,100,000
GBP
|
— |
| Classes of current inventories, alternative [abstract] | |||
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
18,900,000
GBP
|
34,500,000
GBP
|
56,300,000
GBP
|
| Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract] | |||
| Non-current assets or disposal groups classified as held for sale or as held for distribution to owners |
1,500,000
GBP
|
2,400,000
GBP
|
— |
| Miscellaneous current assets [abstract] | |||
| Current derivative financial assets |
1,100,000
GBP
|
1,900,000
GBP
|
— |
| Borrowings [abstract] | |||
| Non-current portion of non-current borrowings |
152,800,000
GBP
|
207,400,000
GBP
|
— |
| Non-current portion of non-current borrowings, by type [abstract] | |||
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
132,100,000
GBP
|
127,500,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
63,200,000
GBP
|
63,200,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
393,700,000
GBP
|
373,100,000
GBP
|
— |
| Accumulated other comprehensive income [abstract] | |||
| Reserve of exchange differences on translation |
700,000
GBP
|
500,000
GBP
|
— |
| Reserve of cash flow hedges |
1,500,000
GBP
|
2,100,000
GBP
|
— |
| Miscellaneous equity [abstract] | |||
| Capital redemption reserve |
75,400,000
GBP
|
75,400,000
GBP
|
— |
| Merger reserve |
141,600,000
GBP
|
141,600,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
1,076,100,000
GBP
|
1,114,100,000
GBP
|
— |
| Liabilities |
414,800,000
GBP
|
472,800,000
GBP
|
— |
| Assets (liabilities) |
661,300,000
GBP
|
641,300,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
240,500,000
GBP
|
259,000,000
GBP
|
— |
| Current liabilities |
148,600,000
GBP
|
138,500,000
GBP
|
— |
| Assets less current liabilities [abstract] |