Statement Of Financial Position [Abstract]
| Concept |
As at 2024-12-31 |
As at 2024-12-31 |
As at 2024-12-31 |
As at 2024-12-31 |
As at 2024-12-31 |
As at 2024-12-31 |
As at 2024-12-31 |
As at 2024-12-31 |
As at 2024-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
As at 2023-12-31 |
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 |
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 | — | — | — | — | — | — | — | — |
6,800,000
GBP
|
8,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Right-of-use assets | — | — | — | — | — | — | — | — |
16,200,000
GBP
|
17,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements | — | — | — | — | — | — | — | — |
2,300,000
GBP
|
4,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current receivables | — | — | — | — | — | — | — | — |
500,000
GBP
|
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax assets | — | — | — | — | — | — | — | — |
19,500,000
GBP
|
19,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-current assets | — | — | — | — | — | — | — | — |
81,800,000
GBP
|
76,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | |||||||||||||||||||||||||||
| Current inventories | — | — | — | — | — | — | — | — |
28,800,000
GBP
|
24,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other current receivables | — | — | — | — | — | — | — | — |
48,000,000
GBP
|
38,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — | — | — | — | — | — | — |
11,100,000
GBP
|
13,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Current assets | — | — | — | — | — | — | — | — |
87,900,000
GBP
|
77,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Assets | — | — | — | — | — | — | — | — |
169,700,000
GBP
|
153,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||||||||
| Issued capital | — | — | — | — | — | — | — | — |
23,300,000
GBP
|
23,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Retained earnings | — | — | — | — | — | — | — | — |
316,000,000
GBP
|
321,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Share premium | — | — | — | — | — | — | — | — |
115,100,000
GBP
|
115,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Other reserves | — | — | — | — | — | — | — | — |
2,100,000
GBP
|
2,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent | — | — | — | — | — | — | — | — |
1,900,000
GBP
|
7,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-controlling interests | — | — | — | — | — | — | — | — |
11,000,000
GBP
|
5,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity |
200,000
GBP
|
316,000,000
GBP
|
115,100,000
GBP
|
23,300,000
GBP
|
11,000,000
GBP
|
1,900,000
GBP
|
2,100,000
GBP
|
173,400,000
GBP
|
12,900,000
GBP
|
12,600,000
GBP
|
321,900,000
GBP
|
200,000
GBP
|
2,400,000
GBP
|
5,100,000
GBP
|
115,100,000
GBP
|
23,300,000
GBP
|
173,400,000
GBP
|
7,500,000
GBP
|
9,200,000
GBP
|
1,800,000
GBP
|
300,000
GBP
|
115,100,000
GBP
|
200,000
GBP
|
322,700,000
GBP
|
23,300,000
GBP
|
173,400,000
GBP
|
8,900,000
GBP
|
| Liabilities [abstract] | |||||||||||||||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||||||||||||||
| Non-current provisions [abstract] | |||||||||||||||||||||||||||
| Non-current provisions for employee benefits | — | — | — | — | — | — | — | — |
48,300,000
GBP
|
54,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current payables | — | — | — | — | — | — | — | — |
15,200,000
GBP
|
5,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — | — | — | — | — | — | — | — |
3,800,000
GBP
|
2,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-current liabilities | — | — | — | — | — | — | — | — |
123,500,000
GBP
|
122,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | |||||||||||||||||||||||||||
| Trade and other current payables | — | — | — | — | — | — | — | — |
48,100,000
GBP
|
37,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Current liabilities | — | — | — | — | — | — | — | — |
59,100,000
GBP
|
43,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Liabilities | — | — | — | — | — | — | — | — |
182,600,000
GBP
|
166,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities | — | — | — | — | — | — | — | — |
169,700,000
GBP
|
153,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |