Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2024-12-28 |
As at 2023-12-30 |
As at 2022-12-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
664,700,000
GBP
|
510,300,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets and goodwill |
24,900,000
GBP
|
18,300,000
GBP
|
— |
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements [abstract] | |||
| Investments in subsidiaries reported in separate financial statements |
–
GBP
|
–
GBP
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Non-current net defined benefit asset |
–
GBP
|
6,600,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
62,400,000
GBP
|
53,800,000
GBP
|
— |
| Classes of current inventories [abstract] | |||
| Current inventories |
55,200,000
GBP
|
48,800,000
GBP
|
— |
| Classes of current inventories, alternative [abstract] | |||
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
125,300,000
GBP
|
195,300,000
GBP
|
191,600,000
GBP
|
| Trade and other non-current payables [abstract] | |||
| Other non-current payables |
1,800,000
GBP
|
2,300,000
GBP
|
— |
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
243,900,000
GBP
|
211,100,000
GBP
|
— |
| Miscellaneous current liabilities [abstract] | |||
| Current net defined benefit liability |
400,000
GBP
|
–
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
2 .0
GBP
|
2,000,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
543,000,000
GBP
|
503,400,000
GBP
|
— |
| Miscellaneous equity [abstract] | |||
| Capital redemption reserve |
400,000
GBP
|
400,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
1,319,700,000
GBP
|
1,129,700,000
GBP
|
— |
| Liabilities |
749,200,000
GBP
|
598,800,000
GBP
|
— |
| Assets (liabilities) |
570,500,000
GBP
|
530,900,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
242,900,000
GBP
|
297 .9
GBP
|
— |
| Current liabilities |
310,200,000
GBP
|
272,500,000
GBP
|
— |
| Assets less current liabilities [abstract] |