Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2022-12-30 |
As at 2021-12-31 |
|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | ||
| Property, plant and equipment [abstract] | ||
| Property, plant and equipment |
231,600,000
GBP
|
242,100,000
GBP
|
| Intangible assets and goodwill [abstract] | ||
| Intangible assets other than goodwill [abstract] | ||
| Intangible assets other than goodwill |
53,400,000
GBP
|
110,700,000
GBP
|
| Goodwill |
55,800,000
GBP
|
167,900,000
GBP
|
| Trade and other current receivables [abstract] | ||
| Trade and other current receivables |
30,000,000
GBP
|
30,000,000
GBP
|
| Classes of current inventories [abstract] | ||
| Current inventories |
7,900,000
GBP
|
8,600,000
GBP
|
| Classes of current inventories, alternative [abstract] | ||
| Cash and cash equivalents [abstract] | ||
| Cash and cash equivalents |
17,100,000
GBP
|
75,700,000
GBP
|
| Miscellaneous assets [abstract] | ||
| Restricted cash and cash equivalents |
–
GBP
|
–
GBP
|
| Trade and other non-current payables [abstract] | ||
| Non-current accruals and non-current deferred income including non-current contract liabilities [abstract] | ||
| Non-current deferred income including non-current contract liabilities [abstract] | ||
| Non-current contract liabilities [abstract] | ||
| Non-current contract liabilities |
1,217,600,000
GBP
|
1,237,900,000
GBP
|
| Trade and other current payables [abstract] | ||
| Current accruals and current deferred income including current contract liabilities [abstract] | ||
| Current deferred income including current contract liabilities [abstract] | ||
| Current contract liabilities [abstract] | ||
| Current contract liabilities |
98,800,000
GBP
|
99,600,000
GBP
|
| Trade and other current payables |
60,900,000
GBP
|
59,500,000
GBP
|
| Miscellaneous non-current liabilities [abstract] | ||
| Non-current net defined benefit liability |
10,800,000
GBP
|
19,700,000
GBP
|
| Other non-current liabilities |
1,800,000
GBP
|
2,200,000
GBP
|
| Issued capital [abstract] | ||
| Issued capital |
6,200,000
GBP
|
6,200,000
GBP
|
| Retained earnings [abstract] | ||
| Retained earnings |
581,100,000
GBP
|
309,600,000
GBP
|
| Miscellaneous equity [abstract] | ||
| Capital redemption reserve |
141,700,000
GBP
|
141,700,000
GBP
|
| Net assets (liabilities) [abstract] | ||
| Assets |
1,592,300,000
GBP
|
1,892,000,000
GBP
|
| Liabilities |
2,014,500,000
GBP
|
2,043,100,000
GBP
|
| Net current assets (liabilities) [abstract] | ||
| Current assets |
67,300,000
GBP
|
124,300,000
GBP
|
| Current liabilities |
182,300,000
GBP
|
179,800,000
GBP
|
| Assets less current liabilities [abstract] |