Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2023-12-31 |
As at 2022-12-31 |
As at 2022-01-01 |
As at 2021-12-31 |
|---|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | ||||
| Property, plant and equipment [abstract] | ||||
| Property, plant and equipment |
2,69 8. 8
GBP
|
2,3 8 8. 0
GBP
|
2 , 310 . 7
GBP
|
— |
| Intangible assets and goodwill [abstract] | ||||
| Intangible assets other than goodwill [abstract] | ||||
| Intangible assets other than goodwill |
81. 5
GBP
|
14 2 . 3
GBP
|
18 8 . 6
GBP
|
— |
| Goodwill |
41 6 . 7
GBP
|
4 24 . 2
GBP
|
416 . 3
GBP
|
— |
| Investments accounted for using equity method [abstract] | ||||
| Investments accounted for using equity method |
8 .9
GBP
|
6,900,000
GBP
|
5,500,000
GBP
|
— |
| Miscellaneous non-current assets [abstract] | ||||
| Non-current net defined benefit asset |
18 .4
GBP
|
3 8.5
GBP
|
4 8 .9
GBP
|
— |
| Non-current derivative financial assets |
293 .6
GBP
|
3 61 . 0
GBP
|
19 0 . 2
GBP
|
— |
| Classes of current inventories [abstract] | ||||
| Current inventories |
328 .4
GBP
|
3 4 8 .1
GBP
|
1 9 9 .1
GBP
|
— |
| Classes of current inventories, alternative [abstract] | ||||
| Cash and cash equivalents [abstract] | ||||
| Cash and cash equivalents |
3 79. 5
GBP
|
23 8.0
GBP
|
3 17. 4
GBP
|
3 1 7. 4
GBP
|
| Miscellaneous current assets [abstract] | ||||
| Current derivative financial assets |
36 8.4
GBP
|
39 6.9
GBP
|
41 0 .1
GBP
|
— |
| Borrowings [abstract] | ||||
| Non-current portion of non-current borrowings |
1, 161. 1
GBP
|
1, 3 9 6 . 6
GBP
|
1,3 20.4
GBP
|
— |
| Current borrowings and current portion of non-current borrowings [abstract] | ||||
| Current borrowings |
2 6 4 . 2
GBP
|
4 4 . 3
GBP
|
4 0 . 6
GBP
|
— |
| Non-current portion of non-current borrowings, by type [abstract] | ||||
| Miscellaneous non-current liabilities [abstract] | ||||
| Non-current derivative financial liabilities |
30 6 .6
GBP
|
6 74 . 7
GBP
|
3 74 . 5
GBP
|
— |
| Miscellaneous current liabilities [abstract] | ||||
| Current derivative financial liabilities |
2 31 . 6
GBP
|
59 0.0
GBP
|
4 8 4 . 2
GBP
|
— |
| Issued capital [abstract] | ||||
| Issued capital |
4 9 .1
GBP
|
4 7. 9
GBP
|
4 7. 7
GBP
|
— |
| Retained earnings [abstract] | ||||
| Retained earnings |
666,400,000
GBP
|
193 . 8
GBP
|
19 8 . 3
GBP
|
— |
| Accumulated other comprehensive income [abstract] | ||||
| Reserve of cash flow hedges |
207 .4
GBP
|
15 2 . 0
GBP
|
1 7 7. 4
GBP
|
— |
| Net assets (liabilities) [abstract] | ||||
| Assets (liabilities) |
1,9 8 3. 0
GBP
|
1, 324 . 2
GBP
|
1, 3 0 6 . 8
GBP
|
— |
| Net current assets (liabilities) [abstract] | ||||
| Current assets |
2, 3 45.4
GBP
|
2 , 3 9 7. 8
GBP
|
1, 8 6 9. 9
GBP
|
— |
| Current liabilities |
2 , 0 8 7. 7
GBP
|
2 , 2 0 8 . 2
GBP
|
1 ,7 5 4 . 4
GBP
|
— |
| Current assets (liabilities) |
2 5 7. 7
GBP
|
18 9. 6
GBP
|
11 5 . 5
GBP
|
— |
| Assets less current liabilities [abstract] |