Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2024-12-31 |
As at 2023-12-31 |
As at 2022-12-25 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
104,200,000
GBP
|
113,600,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets other than goodwill [abstract] | |||
| Other intangible assets |
843,300,000
GBP
|
840,800,000
GBP
|
— |
| Goodwill |
35,900,000
GBP
|
35,900,000
GBP
|
— |
| Investments accounted for using equity method [abstract] | |||
| Investments in associates accounted for using equity method |
14,100,000
GBP
|
14,500,000
GBP
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Non-current net defined benefit asset |
72,400,000
GBP
|
66,000,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
87,600,000
GBP
|
85,100,000
GBP
|
— |
| Classes of current inventories [abstract] | |||
| Current inventories |
10,200,000
GBP
|
11,400,000
GBP
|
— |
| Classes of current inventories, alternative [abstract] | |||
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
20,800,000
GBP
|
19,900,000
GBP
|
40,400,000
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 |
2,600,000
GBP
|
11,000,000
GBP
|
— |
| Borrowings [abstract] | |||
| Current borrowings and current portion of non-current borrowings [abstract] | |||
| Current borrowings |
35,000,000
GBP
|
30,000,000
GBP
|
— |
| Trade and other non-current payables [abstract] | |||
| Trade and other non-current payables |
–
GBP
|
1,100,000
GBP
|
— |
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
105,300,000
GBP
|
96,200,000
GBP
|
— |
| Miscellaneous non-current liabilities [abstract] | |||
| Non-current net defined benefit liability |
117,700,000
GBP
|
168,800,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
32,200,000
GBP
|
32,200,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
624,600,000
GBP
|
583,200,000
GBP
|
— |
| Miscellaneous equity [abstract] | |||
| Capital redemption reserve |
4,400,000
GBP
|
4,400,000
GBP
|
— |
| Merger reserve |
17,400,000
GBP
|
17,400,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
1,209,500,000
GBP
|
1,219,300,000
GBP
|
— |
| Liabilities |
530,900,000
GBP
|
582,100,000
GBP
|
— |
| Assets (liabilities) |
678,600,000
GBP
|
637,200,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
129,700,000
GBP
|
135,500,000
GBP
|
— |
| Current liabilities |
158,400,000
GBP
|
157,000,000
GBP
|
— |
| Assets less current liabilities [abstract] |