Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2025-03-31 |
As at 2024-03-31 |
As at 2023-03-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
18,824,100,000
GBP
|
16 ,61 1 . 5
GBP
|
— |
| Investments accounted for using equity method [abstract] | |||
| Investments accounted for using equity method |
1,9 87 .3
GBP
|
1, 963.2
GBP
|
— |
| Trade and other non-current receivables [abstract] | |||
| Other non-current receivables |
199,900,000
GBP
|
170,100,000
GBP
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Non-current net defined benefit asset |
501 .8
GBP
|
42 1 .6
GBP
|
— |
| Non-current derivative financial assets |
63 .5
GBP
|
64,200,000
GBP
|
— |
| Non-current investments other than investments accounted for using equity method |
8,800,000
GBP
|
3,200,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
2,9 43 .2
GBP
|
2,654,100,000
GBP
|
— |
| Classes of current inventories [abstract] | |||
| Current inventories |
462,900,000
GBP
|
343 .0
GBP
|
— |
| Classes of current inventories, alternative [abstract] | |||
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
1,0 90 .5
GBP
|
1,0 35 .9
GBP
|
891. 8
GBP
|
| Miscellaneous current assets [abstract] | |||
| Current derivative financial assets |
178,400,000
GBP
|
536 .1
GBP
|
— |
| Borrowings [abstract] | |||
| Non-current portion of non-current borrowings |
8,640,400,000
GBP
|
8,00 5.7
GBP
|
— |
| Current borrowings and current portion of non-current borrowings [abstract] | |||
| Current borrowings and current portion of non-current borrowings |
1 ,964.0
GBP
|
1,12 8.0
GBP
|
— |
| Non-current portion of non-current borrowings, by type [abstract] | |||
| Current borrowings and current portion of non-current borrowings, by type [abstract] | |||
| Trade and other non-current payables [abstract] | |||
| Trade and other non-current payables |
1,2 4 7 .9
GBP
|
1,0 92 .8
GBP
|
— |
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
2,8 9 7 .9
GBP
|
3, 32 2. 5
GBP
|
— |
| Miscellaneous non-current liabilities [abstract] | |||
| Non-current derivative financial liabilities |
167 .7
GBP
|
222. 2
GBP
|
— |
| Miscellaneous current liabilities [abstract] | |||
| Current derivative financial liabilities |
126,300,000
GBP
|
345,200,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
555,600,000
GBP
|
548,100,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
8,336,700,000
GBP
|
7, 5 4 0 . 0
GBP
|
— |
| Accumulated other comprehensive income [abstract] | |||
| Reserve of exchange differences on translation |
8,600,000
GBP
|
2,600,000
GBP
|
— |
| Miscellaneous equity [abstract] | |||
| Capital redemption reserve |
52 .6
GBP
|
52,600,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
30,363 .6
GBP
|
28, 270 . 2
GBP
|
— |
| Liabilities |
17 ,670.8
GBP
|
16 ,4 67 . 1
GBP
|
— |
| Assets (liabilities) |
12,69 2.8
GBP
|
11,80 3.1
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
5,09 7 .4
GBP
|
5,358,900,000
GBP
|
— |
| Current liabilities |
5,071,100,000
GBP
|
4,860. 8
GBP
|
— |
| Assets less current liabilities [abstract] |