Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2023-06-30 |
As at 2022-06-30 |
As at 2021-06-30 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
2,800,000
GBP
|
2,700,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets other than goodwill [abstract] | |||
| Intangible assets other than goodwill |
19,900,000
GBP
|
13,400,000
GBP
|
— |
| Trade and other receivables [abstract] | |||
| Other receivables |
4,900,000
GBP
|
4,300,000
GBP
|
— |
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
52,200,000
GBP
|
58,900,000
GBP
|
56,700,000
GBP
|
| Trade and other payables [abstract] | |||
| Accruals and deferred income including contract liabilities [abstract] | |||
| Deferred income including contract liabilities [abstract] | |||
| Deferred income including contract liabilities |
144,800,000
GBP
|
145,100,000
GBP
|
— |
| Other payables |
13,800,000
GBP
|
14,100,000
GBP
|
— |
| Miscellaneous liabilities [abstract] | |||
| Investment contracts liabilities |
1,101,500,000
GBP
|
1,092,300,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
68,800,000
GBP
|
68,800,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
1,500,000
GBP
|
1,700,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
1,318,600,000
GBP
|
1,311,200,000
GBP
|
— |
| Liabilities |
1,296,800,000
GBP
|
1,289,000,000
GBP
|
— |
| Assets (liabilities) |
21,800,000
GBP
|
22,200,000
GBP
|
— |
| Assets less current liabilities [abstract] |