Statement Of Financial Position [Abstract]
| Concept |
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 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | |||||||||||||||||||||||||||
| Assets [abstract] | |||||||||||||||||||||||||||
| Non-current assets [abstract] | |||||||||||||||||||||||||||
| Property, plant and equipment | — | — | — |
90,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
107,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Right-of-use assets | — | — | — |
138,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
129,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Deferred tax assets | — | — | — |
30,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
10,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-current assets | — | — | — |
548,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
545,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | |||||||||||||||||||||||||||
| Current inventories | — | — | — |
341,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
211,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — | — |
273,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
309,800,000
GBP
|
— | — | — | — |
217,800,000
GBP
|
— | — | — | — | — |
| Current assets | — | — | — |
2,165,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
1,856,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Assets | — | — | — |
2,713,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
2,401,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||||||||
| Issued capital | — | — | — |
9,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
9,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Retained earnings | — | — | — |
762,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
635,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Share premium | — | — | — |
4,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
4,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Treasury shares | — | — | — |
115,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
111,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent | — | — | — |
740,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
627,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-controlling interests | — | — | — |
4,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
3,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity |
115,500,000
GBP
|
762,300,000
GBP
|
75,000,000
GBP
|
744,800,000
GBP
|
5,400,000
GBP
|
740,500,000
GBP
|
4,000,000
GBP
|
4,300,000
GBP
|
9,300,000
GBP
|
635,500,000
GBP
|
3,100,000
GBP
|
627,800,000
GBP
|
9,300,000
GBP
|
111,700,000
GBP
|
4,000,000
GBP
|
15,700,000
GBP
|
630,900,000
GBP
|
75,000,000
GBP
|
492,600,000
GBP
|
100,000
GBP
|
4,000,000
GBP
|
492,500,000
GBP
|
503,900,000
GBP
|
113,600,000
GBP
|
75,000,000
GBP
|
14,000,000
GBP
|
9,300,000
GBP
|
| Liabilities [abstract] | |||||||||||||||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||||||||||||||
| Non-current provisions [abstract] | |||||||||||||||||||||||||||
| Non-current provisions | — | — | — |
9,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
12,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — | — | — |
25,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
18,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-current liabilities | — | — | — |
185,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
184,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | |||||||||||||||||||||||||||
| Current provisions [abstract] | |||||||||||||||||||||||||||
| Current provisions | — | — | — |
3,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
4,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Trade and other current payables | — | — | — |
1,410,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
1,116,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current liabilities | — | — | — |
1,783,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
1,586,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Liabilities | — | — | — |
1,969,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
1,771,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |