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 |
44,300,000
GBP
|
— | — | — | — | — | — |
48,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Right-of-use assets |
440,900,000
GBP
|
— | — | — | — | — | — |
434,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Goodwill |
906,700,000
GBP
|
— | — | — | — | — | — |
945,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill |
115,600,000
GBP
|
— | — | — | — | — | — |
158,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements |
32,100,000
GBP
|
— | — | — | — | — | — |
23,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current receivables |
14,800,000
GBP
|
— | — | — | — | — | — |
16,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax assets |
235,700,000
GBP
|
— | — | — | — | — | — |
244,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-current assets |
1,827,500,000
GBP
|
— | — | — | — | — | — |
1,936,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | |||||||||||||||||||||
| Current inventories |
24,100,000
GBP
|
— | — | — | — | — | — |
22,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other current receivables |
329,000,000
GBP
|
— | — | — | — | — | — |
374,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents |
94,400,000
GBP
|
— | — | — | — | — | — |
57,200,000
GBP
|
— | — | — | — | — | — | — | — |
198,400,000
GBP
|
— | — | — | — |
| Current assets |
782,800,000
GBP
|
— | — | — | — | — | — |
814,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Assets |
2,610,300,000
GBP
|
— | — | — | — | — | — |
2,750,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||
| Issued capital |
22,100,000
GBP
|
— | — | — | — | — | — |
24,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Retained earnings |
659,100,000
GBP
|
— | — | — | — | — | — |
670,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Share premium |
463,100,000
GBP
|
— | — | — | — | — | — |
463,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Other reserves |
110,300,000
GBP
|
— | — | — | — | — | — |
129,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent |
1,034,000,000
GBP
|
— | — | — | — | — | — |
1,028,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-controlling interests |
300,000
GBP
|
— | — | — | — | — | — |
1,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity |
1,033,700,000
GBP
|
659,100,000
GBP
|
110,300,000
GBP
|
300,000
GBP
|
463,100,000
GBP
|
22,100,000
GBP
|
1,034,000,000
GBP
|
1,029,700,000
GBP
|
129,900,000
GBP
|
1,500,000
GBP
|
463,100,000
GBP
|
670,600,000
GBP
|
24,400,000
GBP
|
1,028,200,000
GBP
|
542,800,000
GBP
|
23,600,000
GBP
|
— |
1,006,700,000
GBP
|
1,700,000
GBP
|
463,100,000
GBP
|
24,400,000
GBP
|
| Liabilities [abstract] | |||||||||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||||||||
| Non-current provisions [abstract] | |||||||||||||||||||||
| Non-current provisions |
77,400,000
GBP
|
— | — | — | — | — | — |
73,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current payables |
9,200,000
GBP
|
— | — | — | — | — | — |
6,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities |
50,900,000
GBP
|
— | — | — | — | — | — |
53,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-current liabilities |
678,800,000
GBP
|
— | — | — | — | — | — |
696,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | |||||||||||||||||||||
| Current provisions [abstract] | |||||||||||||||||||||
| Current provisions |
92,900,000
GBP
|
— | — | — | — | — | — |
134,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Trade and other current payables |
558,000,000
GBP
|
— | — | — | — | — | — |
622,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Current liabilities |
897,800,000
GBP
|
— | — | — | — | — | — |
1,024,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |
| Liabilities |
1,576,600,000
GBP
|
— | — | — | — | — | — |
1,720,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — |