Statement Of Financial Position [Abstract]
| Concept |
As at 2023-04-30 |
As at 2023-04-30 |
As at 2023-04-30 |
As at 2023-04-30 |
As at 2023-04-30 |
As at 2023-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2022-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
As at 2021-04-30 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||
| Non-current assets [abstract] | ||||||||||||||||||
| Property, plant and equipment | — | — | — | — |
34,600,000
GBP
|
— | — | — | — |
40,500,000
GBP
|
— | — | — | — | — | — | — | — |
| Right-of-use assets | — | — | — | — |
5,200,000
GBP
|
— | — | — | — |
5,800,000
GBP
|
— | — | — | — | — | — | — | — |
| Deferred tax assets | — | — | — | — |
114,500,000
GBP
|
— | — | — | — |
1 20.7
GBP
|
— | — | — | — | — | — | — | — |
| Non-current assets | — | — | — | — |
394,900,000
GBP
|
— | — | — | — |
37 4.6
GBP
|
— | — | — | — | — | — | — | — |
| Current assets [abstract] | ||||||||||||||||||
| Current inventories | — | — | — | — |
5,302. 1
GBP
|
— | — | — | — |
5,134. 0
GBP
|
— | — | — | — | — | — | — | — |
| Trade and other current receivables | — | — | — | — |
92,300,000
GBP
|
— | — | — | — |
145,700,000
GBP
|
— | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — | — | — |
1,070. 4
GBP
|
— | — | — | — |
928,900,000
GBP
|
— | — | — | — | — | — | — |
1,428,200,000
GBP
|
| Current assets | — | — | — | — |
6,464,800,000
GBP
|
— | — | — | — |
6,213. 1
GBP
|
— | — | — | — | — | — | — | — |
| Assets | — | — | — | — |
6,859. 7
GBP
|
— | — | — | — |
6,587 . 7
GBP
|
— | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||
| Issued capital | — | — | — | — |
6,300,000
GBP
|
— | — | — | — |
6,500,000
GBP
|
— | — | — | — | — | — | — | — |
| Retained earnings | — | — | — | — |
4,212,300,000
GBP
|
— | — | — | — |
4,016. 1
GBP
|
— | — | — | — | — | — | — | — |
| Share premium | — | — | — | — |
49,800,000
GBP
|
— | — | — | — |
49,800,000
GBP
|
— | — | — | — | — | — | — | — |
| Other reserves | — | — | — | — |
961,300,000
GBP
|
— | — | — | — |
961,300,000
GBP
|
— | — | — | — | — | — | — | — |
| Equity |
961,300,000
GBP
|
4,212,300,000
GBP
|
49,800,000
GBP
|
6,300,000
GBP
|
3,332,300,000
GBP
|
25,200,000
GBP
|
25. 0
GBP
|
6,500,000
GBP
|
4, 016. 1
GBP
|
3, 136. 1
GBP
|
961,300,000
GBP
|
49,800,000
GBP
|
49,800,000
GBP
|
4,055,400,000
GBP
|
961,300,000
GBP
|
6,600,000
GBP
|
24,900,000
GBP
|
3,17 5.4
GBP
|
| Liabilities [abstract] | ||||||||||||||||||
| Non-current liabilities [abstract] | ||||||||||||||||||
| Non-current provisions [abstract] | ||||||||||||||||||
| Non-current provisions | — | — | — | — |
115,100,000
GBP
|
— | — | — | — |
98,500,000
GBP
|
— | — | — | — | — | — | — | — |
| Trade and other non-current payables | — | — | — | — |
863,400,000
GBP
|
— | — | — | — |
719,800,000
GBP
|
— | — | — | — | — | — | — | — |
| Non-current liabilities | — | — | — | — |
1,641,400,000
GBP
|
— | — | — | — |
1,482. 1
GBP
|
— | — | — | — | — | — | — | — |
| Current liabilities [abstract] | ||||||||||||||||||
| Current provisions [abstract] | ||||||||||||||||||
| Current provisions | — | — | — | — |
78,500,000
GBP
|
— | — | — | — |
62,500,000
GBP
|
— | — | — | — | — | — | — | — |
| Trade and other current payables | — | — | — | — |
1,801,600,000
GBP
|
— | — | — | — |
1,904,900,000
GBP
|
— | — | — | — | — | — | — | — |
| Current liabilities | — | — | — | — |
1,886,000,000
GBP
|
— | — | — | — |
1,969,500,000
GBP
|
— | — | — | — | — | — | — | — |
| Liabilities | — | — | — | — |
3,527 .4
GBP
|
— | — | — | — |
3,451,600,000
GBP
|
— | — | — | — | — | — | — | — |