Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2023-12-31 |
As at 2022-12-31 |
As at 2021-12-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
249,700,000
GBP
|
233,700,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets and goodwill |
19,200,000
GBP
|
23,600,000
GBP
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Non-current derivative financial assets |
5,000,000
GBP
|
–
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
31,000,000
GBP
|
44,300,000
GBP
|
— |
| Classes of current inventories [abstract] | |||
| Current inventories |
95,800,000
GBP
|
43,000,000
GBP
|
— |
| Classes of current inventories, alternative [abstract] | |||
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
16,000,000
GBP
|
34,300,000
GBP
|
41,500,000
GBP
|
| Miscellaneous current assets [abstract] | |||
| Current derivative financial assets |
1,600,000
GBP
|
600,000
GBP
|
— |
| Borrowings [abstract] | |||
| Non-current portion of non-current borrowings |
108,800,000
GBP
|
40,000,000
GBP
|
— |
| Current borrowings and current portion of non-current borrowings [abstract] | |||
| Current portion of non-current borrowings |
400,000
GBP
|
200,000
GBP
|
— |
| Non-current portion of non-current borrowings, by type [abstract] | |||
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
66,300,000
GBP
|
89,600,000
GBP
|
— |
| Miscellaneous current liabilities [abstract] | |||
| Current derivative financial liabilities |
5,800,000
GBP
|
–
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
2,100,000
GBP
|
2,100,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
219,800,000
GBP
|
233,400,000
GBP
|
— |
| Accumulated other comprehensive income [abstract] | |||
| Reserve of cash flow hedges |
100,000
GBP
|
600,000
GBP
|
— |
| Miscellaneous equity [abstract] | |||
| Capital redemption reserve |
200,000
GBP
|
200,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
444,700,000
GBP
|
397,600,000
GBP
|
— |
| Liabilities |
236,900,000
GBP
|
177,100,000
GBP
|
— |
| Assets (liabilities) |
207,800,000
GBP
|
220,500,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
146,700,000
GBP
|
122,200,000
GBP
|
— |
| Current liabilities |
93,900,000
GBP
|
108,800,000
GBP
|
— |
| Assets less current liabilities [abstract] |