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 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | |||||||||||||||||||||
| Assets [abstract] | |||||||||||||||||||||
| Property, plant and equipment |
473,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
531,800,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Goodwill |
249,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
401,400,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Intangible assets other than goodwill |
293,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
321,800,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Investments accounted for using equity method |
2,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
2,200,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Current tax assets |
1,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
5,800,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Deferred tax assets |
10,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
36,700,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Cash and cash equivalents |
290,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
231,000,000
GBP
|
— | — |
151,200,000
GBP
|
— | — | — | — | — | — |
| Assets |
1,828,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
2,106,200,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||||||||
| Equity [abstract] | |||||||||||||||||||||
| Issued capital |
5,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
5,700,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Retained earnings |
456,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
742,300,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Share premium |
147,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
147,600,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Equity |
626,500,000
GBP
|
41,000,000
GBP
|
147,600,000
GBP
|
5,500,000
GBP
|
456,800,000
GBP
|
3,200,000
GBP
|
27,600,000
GBP
|
742,300,000
GBP
|
147,600,000
GBP
|
5,700,000
GBP
|
40,800,000
GBP
|
926,100,000
GBP
|
6,400,000
GBP
|
16,700,000
GBP
|
968,300,000
GBP
|
147,600,000
GBP
|
5,800,000
GBP
|
40,800,000
GBP
|
6,300,000
GBP
|
772,000,000
GBP
|
4,200,000
GBP
|
| Liabilities [abstract] | |||||||||||||||||||||
| Current tax liabilities |
3,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
6,600,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Deferred tax liabilities |
101,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
94,400,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Liabilities |
1,201,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
1,180,100,000
GBP
|
— | — | — | — | — | — | — | — | — |