Statement Of Financial Position [Abstract]
| Concept |
As at 2022-12-30 |
As at 2022-12-30 |
As at 2022-12-30 |
As at 2022-12-30 |
As at 2022-12-30 |
As at 2022-12-30 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2020-12-25 |
As at 2020-12-25 |
As at 2020-12-25 |
As at 2020-12-25 |
As at 2020-12-25 |
As at 2020-12-25 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||
| Non-current assets [abstract] | ||||||||||||||||||
| Property, plant and equipment | — | — |
231,600,000
GBP
|
— | — | — |
242,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Right-of-use assets | — | — |
68,400,000
GBP
|
— | — | — |
89,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Goodwill | — | — |
55,800,000
GBP
|
— | — | — |
167,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill | — | — |
53,400,000
GBP
|
— | — | — |
110,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Deferred tax assets | — | — |
56,800,000
GBP
|
— | — | — |
5,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Non-current assets | — | — |
1,525,000,000
GBP
|
— | — | — |
1,767,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | ||||||||||||||||||
| Current inventories | — | — |
7,900,000
GBP
|
— | — | — |
8,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other current receivables | — | — |
30,000,000
GBP
|
— | — | — |
30,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — |
17,100,000
GBP
|
— | — | — |
75,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current assets | — | — |
67,300,000
GBP
|
— | — | — |
124,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Assets | — | — |
1,592,300,000
GBP
|
— | — | — |
1,892,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||
| Issued capital | — | — |
6,200,000
GBP
|
— | — | — |
6,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Retained earnings | — | — |
581,100,000
GBP
|
— | — | — |
309,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Share premium | — | — |
13,000,000
GBP
|
— | — | — |
12,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Other reserves | — | — |
2,000,000
GBP
|
— | — | — |
2,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity |
2,000,000
GBP
|
141,700,000
GBP
|
422,200,000
GBP
|
581,100,000
GBP
|
13,000,000
GBP
|
6,200,000
GBP
|
151,100,000
GBP
|
6,200,000
GBP
|
141,700,000
GBP
|
309,600,000
GBP
|
2,300,000
GBP
|
12,900,000
GBP
|
335,100,000
GBP
|
3,000,000
GBP
|
177,500,000
GBP
|
6,200,000
GBP
|
141,700,000
GBP
|
12,700,000
GBP
|
| Liabilities [abstract] | ||||||||||||||||||
| Non-current liabilities [abstract] | ||||||||||||||||||
| Non-current provisions [abstract] | ||||||||||||||||||
| Non-current provisions | — | — |
21,800,000
GBP
|
— | — | — |
9,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Other non-current financial liabilities | — | — |
506,900,000
GBP
|
— | — | — |
518,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Non-current liabilities | — | — |
1,832,200,000
GBP
|
— | — | — |
1,863,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | ||||||||||||||||||
| Current provisions [abstract] | ||||||||||||||||||
| Current provisions | — | — |
3,400,000
GBP
|
— | — | — |
2,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other current payables | — | — |
60,900,000
GBP
|
— | — | — |
59,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Other current financial liabilities | — | — |
12,200,000
GBP
|
— | — | — |
11,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current liabilities | — | — |
182,300,000
GBP
|
— | — | — |
179,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Liabilities | — | — |
2,014,500,000
GBP
|
— | — | — |
2,043,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities | — | — |
1,592,300,000
GBP
|
— | — | — |
1,892,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |