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 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | |||||||||||||||||||||
| Assets [abstract] | |||||||||||||||||||||
| Non-current assets [abstract] | |||||||||||||||||||||
| Property, plant and equipment | — |
33,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
22,900,000
GBP
|
— | — | — | — | — | — | — |
| Right-of-use assets | — |
39,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
30,200,000
GBP
|
— | — | — | — | — | — | — |
| Investments accounted for using equity method | — |
2,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
—
GBP
|
— | — | — | — | — | — | — |
| Trade and other non-current receivables | — |
17,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
14,400,000
GBP
|
— | — | — | — | — | — | — |
| Deferred tax assets | — |
10,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
19,500,000
GBP
|
— | — | — | — | — | — | — |
| Non-current assets | — |
157,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
128,900,000
GBP
|
— | — | — | — | — | — | — |
| Current assets [abstract] | |||||||||||||||||||||
| Current inventories | — |
18,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
8,200,000
GBP
|
— | — | — | — | — | — | — |
| Trade and other current receivables | — |
103,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
92,500,000
GBP
|
— | — | — | — | — | — | — |
| Cash and cash equivalents | — |
1,290,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
379,100,000
GBP
|
— | — |
229,800,000
GBP
|
— | — | — | — |
| Current assets | — |
1,412,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
479,800,000
GBP
|
— | — | — | — | — | — | — |
| Assets | — |
1,570,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
608,700,000
GBP
|
— | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||
| Issued capital | — |
9,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
7,100,000
GBP
|
— | — | — | — | — | — | — |
| Retained earnings | — |
1,386,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
1,135,700,000
GBP
|
— | — | — | — | — | — | — |
| Share premium | — |
1,013,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
—
GBP
|
— | — | — | — | — | — | — |
| Equity |
1,386,700,000
GBP
|
1,073,700,000
GBP
|
1,288,500,000
GBP
|
1,013,000,000
GBP
|
161,200,000
GBP
|
11,600,000
GBP
|
9,300,000
GBP
|
1,135,700,000
GBP
|
7,100,000
GBP
|
1,153,500,000
GBP
|
3,100,000
GBP
|
—
GBP
|
153,300,000
GBP
|
175,100,000
GBP
|
6,400,000
GBP
|
—
GBP
|
30,400,000
GBP
|
778,600,000
GBP
|
909,300,000
GBP
|
100,800,000
GBP
|
5,900,000
GBP
|
| Liabilities [abstract] | |||||||||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||||||||
| Non-current provisions [abstract] | |||||||||||||||||||||
| Non-current provisions | — |
81,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
112,300,000
GBP
|
— | — | — | — | — | — | — |
| Non-current liabilities | — |
118,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
141,000,000
GBP
|
— | — | — | — | — | — | — |
| Current liabilities [abstract] | |||||||||||||||||||||
| Trade and other current payables | — |
368,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
285,300,000
GBP
|
— | — | — | — | — | — | — |
| Current liabilities | — |
378,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
292,600,000
GBP
|
— | — | — | — | — | — | — |
| Liabilities | — |
496,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
433,600,000
GBP
|
— | — | — | — | — | — | — |