Statement Of Financial Position [Abstract]
| Concept |
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 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 2021-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | |||||||||||||||||||||
| Assets [abstract] | |||||||||||||||||||||
| Non-current assets [abstract] | |||||||||||||||||||||
| Property, plant and equipment |
249,700,000
GBP
|
— | — | — | — | — | — |
233,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Right-of-use assets |
24,100,000
GBP
|
— | — | — | — | — | — |
18,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-current assets |
298,000,000
GBP
|
— | — | — | — | — | — |
275,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | |||||||||||||||||||||
| Current inventories |
95,800,000
GBP
|
— | — | — | — | — | — |
43,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other current receivables |
31,000,000
GBP
|
— | — | — | — | — | — |
44,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents |
16,000,000
GBP
|
— | — | — | — | — | — |
34,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
41,500,000
GBP
|
— | — |
| Current assets |
146,700,000
GBP
|
— | — | — | — | — | — |
122,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Assets |
444,700,000
GBP
|
— | — | — | — | — | — |
397,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||
| Issued capital |
2,100,000
GBP
|
— | — | — | — | — | — |
2,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Retained earnings |
219,800,000
GBP
|
— | — | — | — | — | — |
233,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Treasury shares |
14,200,000
GBP
|
— | — | — | — | — | — |
15,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity |
207,800,000
GBP
|
219,800,000
GBP
|
200,000
GBP
|
–
GBP
|
2,100,000
GBP
|
14,200,000
GBP
|
100,000
GBP
|
220,500,000
GBP
|
–
GBP
|
200,000
GBP
|
233,400,000
GBP
|
15,800,000
GBP
|
2,100,000
GBP
|
600,000
GBP
|
4,600,000
GBP
|
213,400,000
GBP
|
–
GBP
|
23,900,000
GBP
|
234,800,000
GBP
|
200,000
GBP
|
2,300,000
GBP
|
| Liabilities [abstract] | |||||||||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||||||||
| Non-current provisions [abstract] | |||||||||||||||||||||
| Non-current provisions |
9,400,000
GBP
|
— | — | — | — | — | — |
10,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities |
6,300,000
GBP
|
— | — | — | — | — | — |
5,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-current liabilities |
143,000,000
GBP
|
— | — | — | — | — | — |
68,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | |||||||||||||||||||||
| Current provisions [abstract] | |||||||||||||||||||||
| Current provisions |
15,700,000
GBP
|
— | — | — | — | — | — |
14,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other current payables |
66,300,000
GBP
|
— | — | — | — | — | — |
89,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Current liabilities |
93,900,000
GBP
|
— | — | — | — | — | — |
108,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Liabilities |
236,900,000
GBP
|
— | — | — | — | — | — |
177,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |