Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2023-03-31 |
As at 2022-03-31 |
As at 2021-03-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
400,000
GBP
|
900,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets and goodwill |
10,500,000
GBP
|
10,700,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
5,000,000
GBP
|
2,800,000
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 |
1,277,000,000
GBP
|
1,410,800,000
GBP
|
— |
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
22,900,000
GBP
|
78,100,000
GBP
|
160,700,000
GBP
|
| Miscellaneous current assets [abstract] | |||
| Current restricted cash and cash equivalents |
–
GBP
|
2,300,000
GBP
|
— |
| Miscellaneous assets [abstract] | |||
| Restricted cash and cash equivalents |
–
GBP
|
2,300,000
GBP
|
— |
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
9,600,000
GBP
|
14,300,000
GBP
|
— |
| Categories of non-current financial liabilities [abstract] | |||
| Non-current financial liabilities |
89,000,000
GBP
|
30,000,000
GBP
|
— |
| Categories of current financial liabilities [abstract] | |||
| Current financial liabilities |
300,000
GBP
|
400,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
1,500,000
GBP
|
1,500,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
552,300,000
GBP
|
795,700,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets (liabilities) |
1,194,100,000
GBP
|
1,433,800,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
27,900,000
GBP
|
80,900,000
GBP
|
— |
| Current liabilities |
9,900,000
GBP
|
14,700,000
GBP
|
— |
| Assets less current liabilities [abstract] |