Statement Of Financial Position [Abstract]
| Concept |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||||
| Non-current assets [abstract] | ||||||||||||||||||||
| Property, plant and equipment | — | — | — | — |
900,000
GBP
|
— | — | — | — |
1,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Deferred tax assets | — | — | — | — |
1,600,000
GBP
|
— | — | — | — |
–
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-current assets | — | — | — | — |
1,424,000,000
GBP
|
— | — | — | — |
879,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current assets [abstract] | ||||||||||||||||||||
| Trade and other current receivables | — | — | — | — |
2,800,000
GBP
|
— | — | — | — |
3,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — | — | — |
78,100,000
GBP
|
— | — | — | — |
160,700,000
GBP
|
— | — | — | — | — |
34,100,000
GBP
|
— | — | — | — |
| Current assets | — | — | — | — |
80,900,000
GBP
|
— | — | — | — |
164,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||||
| Issued capital | — | — | — | — |
1,500,000
GBP
|
— | — | — | — |
1,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Retained earnings | — | — | — | — |
795,700,000
GBP
|
— | — | — | — |
497,500,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Share premium | — | — | — | — |
615,900,000
GBP
|
— | — | — | — |
508,300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Treasury shares | — | — | — | — |
8,200,000
GBP
|
— | — | — | — |
300,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Other reserves | — | — | — | — |
28,900,000
GBP
|
— | — | — | — |
26,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Equity |
8,200,000
GBP
|
1,500,000
GBP
|
615,900,000
GBP
|
795,700,000
GBP
|
1,433,800,000
GBP
|
28,900,000
GBP
|
300,000
GBP
|
497,500,000
GBP
|
26,200,000
GBP
|
1,033,100,000
GBP
|
1,400,000
GBP
|
508,300,000
GBP
|
1,033,100,000
GBP
|
659,500,000
GBP
|
26,200,000
GBP
|
— |
–
GBP
|
400,700,000
GBP
|
1,200,000
GBP
|
231,400,000
GBP
|
| Liabilities [abstract] | ||||||||||||||||||||
| Non-current liabilities [abstract] | ||||||||||||||||||||
| Non-current provisions [abstract] | ||||||||||||||||||||
| Non-current provisions | — | — | — | — |
300,000
GBP
|
— | — | — | — |
-
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — | — | — | — |
26,100,000
GBP
|
— | — | — | — |
400,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Non-current liabilities | — | — | — | — |
56,400,000
GBP
|
— | — | — | — |
700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | ||||||||||||||||||||
| Trade and other current payables | — | — | — | — |
14,300,000
GBP
|
— | — | — | — |
9,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
| Current liabilities | — | — | — | — |
14,700,000
GBP
|
— | — | — | — |
10,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |