Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2024-03-31 |
As at 2023-03-31 |
As at 2022-03-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
5,361,600,000
GBP
|
4,476,900,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets other than goodwill [abstract] | |||
| Intangible assets other than goodwill |
67,700,000
GBP
|
14,900,000
GBP
|
— |
| Goodwill |
179,500,000
GBP
|
163,900,000
GBP
|
— |
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements [abstract] | |||
| Investments in subsidiaries reported in separate financial statements |
–
GBP
|
–
GBP
|
— |
| Investments in associates reported in separate financial statements |
1,000,000
GBP
|
300,000
GBP
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Non-current net defined benefit asset |
26,600,000
GBP
|
29,300,000
GBP
|
— |
| Non-current derivative financial assets |
17,400,000
GBP
|
33,200,000
GBP
|
— |
| Other non-current assets |
8,700,000
GBP
|
23,200,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
353,700,000
GBP
|
238,000,000
GBP
|
— |
| Categories of non-current financial assets [abstract] | |||
| Non-current financial assets at fair value through profit or loss [abstract] | |||
| Non-current financial assets at fair value through profit or loss |
900,000
GBP
|
1,300,000
GBP
|
— |
| Classes of current inventories [abstract] | |||
| Current inventories |
13,200,000
GBP
|
10,000,000
GBP
|
— |
| Classes of current inventories, alternative [abstract] | |||
| Cash and cash equivalents [abstract] | |||
| Cash [abstract] | |||
| Cash |
171,400,000
GBP
|
165,400,000
GBP
|
— |
| Cash and cash equivalents |
145,400,000
GBP
|
143,700,000
GBP
|
351,200,000
GBP
|
| Miscellaneous current assets [abstract] | |||
| Current derivative financial assets |
23,400,000
GBP
|
20,700,000
GBP
|
— |
| Borrowings [abstract] | |||
| Non-current portion of non-current borrowings |
3,742,400,000
GBP
|
3,006,100,000
GBP
|
— |
| Current borrowings and current portion of non-current borrowings [abstract] | |||
| Current borrowings |
238,200,000
GBP
|
124,700,000
GBP
|
— |
| Non-current portion of non-current borrowings, by type [abstract] | |||
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
341,200,000
GBP
|
225,400,000
GBP
|
— |
| Categories of non-current financial liabilities [abstract] | |||
| Non-current financial liabilities at fair value through profit or loss [abstract] | |||
| Non-current financial liabilities at fair value through profit or loss |
31,800,000
GBP
|
34,000,000
GBP
|
— |
| Categories of current financial liabilities [abstract] | |||
| Current financial liabilities at fair value through profit or loss [abstract] | |||
| Current financial liabilities at fair value through profit or loss |
2,600,000
GBP
|
2,600,000
GBP
|
— |
| Miscellaneous non-current liabilities [abstract] | |||
| Non-current derivative financial liabilities |
3,300,000
GBP
|
2,400,000
GBP
|
— |
| Other non-current liabilities |
154,900,000
GBP
|
155,300,000
GBP
|
— |
| Miscellaneous current liabilities [abstract] | |||
| Current derivative financial liabilities |
5,400,000
GBP
|
2,400,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
174,600,000
GBP
|
159,500,000
GBP
|
— |
| Miscellaneous equity [abstract] | |||
| Capital redemption reserve |
157,100,000
GBP
|
157,100,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets (liabilities) |
1,1 62.6
GBP
|
1,125,200,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
567,700,000
GBP
|
442,500,000
GBP
|
— |
| Current liabilities |
587,400,000
GBP
|
355,500,000
GBP
|
— |
| Current assets (liabilities) |
19,700,000
GBP
|
87,000,000
GBP
|
— |
| Assets less current liabilities [abstract] |