Statement Of Financial Position [Abstract]
| Concept |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2023-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||||||||||||||
| Non-current assets [abstract] | ||||||||||||||||||||||||||||||
| Property, plant and equipment | — | — | — |
478,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
710,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Right-of-use assets | — | — | — |
159,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
334,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Goodwill | — | — | — |
781,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
783,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill | — | — | — |
140,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
176,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Investments accounted for using equity method | — | — | — |
57,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
54,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current receivables | — | — | — |
6,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
9,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Deferred tax assets | — | — | — |
112,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
47,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Non-current assets | — | — | — |
1,872,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
2,463,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | ||||||||||||||||||||||||||||||
| Current inventories | — | — | — |
126,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
142,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other current receivables | — | — | — |
506,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
488,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Other current financial assets | — | — | — |
1,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
–
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — | — |
451,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,146,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current assets | — | — | — |
1,437,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
2,137,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Assets | — | — | — |
3,309,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
4,600,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||||||||||||||
| Issued capital | — | — | — |
303,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
303,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Retained earnings | — | — | — |
1,568,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,241,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Share premium | — | — | — |
873,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
873,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Other reserves | — | — | — |
746,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
747,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent | — | — | — |
353,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
682,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Non-controlling interests | — | — | — |
17,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
19,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity |
353,900,000
GBP
|
3,000,000
GBP
|
768,800,000
GBP
|
370,900,000
GBP
|
873,000,000
GBP
|
303,400,000
GBP
|
30,600,000
GBP
|
17,000,000
GBP
|
1,568,800,000
GBP
|
56,100,000
GBP
|
30,600,000
GBP
|
682,000,000
GBP
|
768,800,000
GBP
|
4,000,000
GBP
|
303,400,000
GBP
|
56,400,000
GBP
|
873,000,000
GBP
|
1,241,400,000
GBP
|
701,500,000
GBP
|
19,500,000
GBP
|
30,600,000
GBP
|
1,671,700,000
GBP
|
229,000,000
GBP
|
303,400,000
GBP
|
873,000,000
GBP
|
16,000,000
GBP
|
213,000,000
GBP
|
48,400,000
GBP
|
768,800,000
GBP
|
42,700,000
GBP
|
| Liabilities [abstract] | ||||||||||||||||||||||||||||||
| Non-current liabilities [abstract] | ||||||||||||||||||||||||||||||
| Non-current provisions [abstract] | ||||||||||||||||||||||||||||||
| Non-current provisions | — | — | — |
80,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
60,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current payables | — | — | — |
900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — | — | — |
7,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
9,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Non-current liabilities | — | — | — |
1,245,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,416,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | ||||||||||||||||||||||||||||||
| Current provisions [abstract] | ||||||||||||||||||||||||||||||
| Current provisions | — | — | — |
67,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
55,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other current payables | — | — | — |
911,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
888,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current liabilities | — | — | — |
1,693,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
2,482,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Liabilities | — | — | — |
2,939,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
3,899,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities | — | — | — |
3,309,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — |
4,600,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |