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 | — | — |
120,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
122,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Right-of-use assets | — | — |
448,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
453,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Deferred tax assets | — | — |
2,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
2,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-current assets | — | — |
3,409,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
3,037,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | |||||||||||||||||||||||||||
| Current inventories | — | — |
1,474,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
1,432,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Trade and other current receivables | — | — |
1,431,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
1,395,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — |
776,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
944,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current assets | — | — |
3,704,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
3,791,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Assets | — | — |
7,114,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
6,829,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||||||||
| Issued capital | — | — |
108,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
108,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Retained earnings | — | — |
2,151,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
1,799,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Share premium | — | — |
194,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
187,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Other reserves | — | — |
19,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
14,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent | — | — |
2,203,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
1,919,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity |
2,204,400,000
GBP
|
16,100,000
GBP
|
2,203,900,000
GBP
|
400,000
GBP
|
52,900,000
GBP
|
2,500,000
GBP
|
194,200,000
GBP
|
269,200,000
GBP
|
108,400,000
GBP
|
1,873,100,000
GBP
|
4,300,000
GBP
|
108,300,000
GBP
|
2,500,000
GBP
|
190,900,000
GBP
|
73,400,000
GBP
|
187,700,000
GBP
|
1,919,100,000
GBP
|
16,100,000
GBP
|
111,800,000
GBP
|
69,900,000
GBP
|
184,000,000
GBP
|
1,744,300,000
GBP
|
2,500,000
GBP
|
1,617,500,000
GBP
|
16,100,000
GBP
|
2,400,000
GBP
|
108,300,000
GBP
|
| Liabilities [abstract] | |||||||||||||||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||||||||||||||
| Non-current provisions [abstract] | |||||||||||||||||||||||||||
| Non-current provisions | — | — |
56,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
55,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — | — |
151,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
105,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current tax liabilities, non-current | — | — |
1,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
2,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-current liabilities | — | — |
2,135,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
2,242,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | |||||||||||||||||||||||||||
| Current provisions [abstract] | |||||||||||||||||||||||||||
| Current provisions | — | — |
8,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
8,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Trade and other current payables | — | — |
1,921,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
1,836,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current tax liabilities, current | — | — |
42,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
75,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current liabilities | — | — |
2,774,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
2,667,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Liabilities | — | — |
4,910,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
4,910,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity and liabilities | — | — |
7,114,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
6,829,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |