Statement Of Financial Position [Abstract]
| Concept |
As at 2024-12-28 |
As at 2024-12-28 |
As at 2024-12-28 |
As at 2024-12-28 |
As at 2024-12-28 |
As at 2023-12-30 |
As at 2023-12-30 |
As at 2023-12-30 |
As at 2023-12-30 |
As at 2023-12-30 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | |||||||||||||||
| Assets [abstract] | |||||||||||||||
| Non-current assets [abstract] | |||||||||||||||
| Property, plant and equipment | — | — |
664,700,000
GBP
|
— | — | — | — | — |
510,300,000
GBP
|
— | — | — | — | — | — |
| Right-of-use assets | — | — |
387 .2
GBP
|
— | — | — | — | — |
296,600,000
GBP
|
— | — | — | — | — | — |
| Non-current assets | — | — |
1,076,800,000
GBP
|
— | — | — | — | — |
831,800,000
GBP
|
— | — | — | — | — | — |
| Current assets [abstract] | |||||||||||||||
| Current inventories | — | — |
55,200,000
GBP
|
— | — | — | — | — |
48,800,000
GBP
|
— | — | — | — | — | — |
| Trade and other current receivables | — | — |
62,400,000
GBP
|
— | — | — | — | — |
53,800,000
GBP
|
— | — | — | — | — | — |
| Cash and cash equivalents | — | — |
125,300,000
GBP
|
— | — | — | — | — |
195,300,000
GBP
|
— |
191,600,000
GBP
|
— | — | — | — |
| Current assets | — | — |
242,900,000
GBP
|
— | — | — | — | — |
297 .9
GBP
|
— | — | — | — | — | — |
| Assets | — | — |
1,319,700,000
GBP
|
— | — | — | — | — |
1,129,700,000
GBP
|
— | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||
| Equity [abstract] | |||||||||||||||
| Issued capital | — | — |
2 .0
GBP
|
— | — | — | — | — |
2,000,000
GBP
|
— | — | — | — | — | — |
| Retained earnings | — | — |
543,000,000
GBP
|
— | — | — | — | — |
503,400,000
GBP
|
— | — | — | — | — | — |
| Share premium | — | — |
25,100,000
GBP
|
— | — | — | — | — |
25,100,000
GBP
|
— | — | — | — | — | — |
| Equity attributable to owners of parent | — | — |
570,500,000
GBP
|
— | — | — | — | — |
530,900,000
GBP
|
— | — | — | — | — | — |
| Equity |
400,000
GBP
|
543,000,000
GBP
|
570,500,000
GBP
|
2,000,000
GBP
|
25,100,000
GBP
|
503,400,000
GBP
|
25,100,000
GBP
|
2 .0
GBP
|
530,900,000
GBP
|
400,000
GBP
|
446,000,000
GBP
|
23,100,000
GBP
|
400,000
GBP
|
420,500,000
GBP
|
2 .0
GBP
|
| Liabilities [abstract] | |||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||
| Non-current provisions [abstract] | |||||||||||||||
| Non-current provisions | — | — |
2,900,000
GBP
|
— | — | — | — | — |
2,200,000
GBP
|
— | — | — | — | — | — |
| Deferred tax liabilities | — | — |
72,600,000
GBP
|
— | — | — | — | — |
54,700,000
GBP
|
— | — | — | — | — | — |
| Non-current liabilities | — | — |
439,000,000
GBP
|
— | — | — | — | — |
326,300,000
GBP
|
— | — | — | — | — | — |
| Current liabilities [abstract] | |||||||||||||||
| Current provisions [abstract] | |||||||||||||||
| Current provisions | — | — |
3,400,000
GBP
|
— | — | — | — | — |
4. 0
GBP
|
— | — | — | — | — | — |
| Trade and other current payables | — | — |
243,900,000
GBP
|
— | — | — | — | — |
211,100,000
GBP
|
— | — | — | — | — | — |
| Current liabilities | — | — |
310,200,000
GBP
|
— | — | — | — | — |
272,500,000
GBP
|
— | — | — | — | — | — |
| Liabilities | — | — |
749,200,000
GBP
|
— | — | — | — | — |
598,800,000
GBP
|
— | — | — | — | — | — |