Statement Of Financial Position [Abstract]
| Concept |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2025-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
As at 2024-03-31 |
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 2023-03-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||||||||||||||
| Non-current assets [abstract] | ||||||||||||||||||||||||||||||
| Property, plant and equipment | — | — |
558,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
517,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Right-of-use assets | — | — |
228,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
175,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Goodwill | — | — |
778. 2
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
780. 1
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill | — | — |
142,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
148,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Investments accounted for using equity method | — | — |
43,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
59,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current receivables | — | — |
18,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
13,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Deferred tax assets | — | — |
102,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
132,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Non-current assets | — | — |
2,010,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,968,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | ||||||||||||||||||||||||||||||
| Current inventories | — | — |
162,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
187,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other current receivables | — | — |
507,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
487,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Other current financial assets | — | — |
1,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — |
646,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
570,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current assets | — | — |
1,679,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,535,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Assets | — | — |
3,690,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
3,503,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||||||||||||||
| Issued capital | — | — |
303,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
303,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Retained earnings | — | — |
1,292,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,523,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Share premium | — | — |
873,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
873,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Other reserves | — | — |
720,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
736,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent | — | — |
604,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
388,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Non-controlling interests | — | — |
17,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
17,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity |
6,300,000
GBP
|
768,800,000
GBP
|
621,800,000
GBP
|
17,400,000
GBP
|
30,600,000
GBP
|
873,000,000
GBP
|
303,400,000
GBP
|
1,2 92.3
GBP
|
604,400,000
GBP
|
85,400,000
GBP
|
388,900,000
GBP
|
768,800,000
GBP
|
5,300,000
GBP
|
1,523,900,000
GBP
|
17,200,000
GBP
|
873,000,000
GBP
|
303,400,000
GBP
|
30,600,000
GBP
|
406,100,000
GBP
|
68,300,000
GBP
|
353,900,000
GBP
|
768,800,000
GBP
|
3,000,000
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
|
| Liabilities [abstract] | ||||||||||||||||||||||||||||||
| Non-current liabilities [abstract] | ||||||||||||||||||||||||||||||
| Non-current provisions [abstract] | ||||||||||||||||||||||||||||||
| Non-current provisions | — | — |
58,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
79,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other non-current payables | — | — |
4,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
5,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — | — |
5,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
6,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Non-current liabilities | — | — |
1,1 98.3
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,292,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | ||||||||||||||||||||||||||||||
| Current provisions [abstract] | ||||||||||||||||||||||||||||||
| Current provisions | — | — |
80,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
79,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Trade and other current payables | — | — |
948,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
949,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Current liabilities | — | — |
1,870,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
1,804,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Liabilities | — | — |
3,068,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
3,097,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities | — | — |
3,690,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
3,503,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |