Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2023-12-31 |
As at 2022-12-31 |
As at 2021-12-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
41,800,000
GBP
|
39,600,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets and goodwill |
2,900,000
GBP
|
2,800,000
GBP
|
— |
| Investment property [abstract] | |||
| Investment property |
1,850,500,000
GBP
|
2,295,000,000
GBP
|
— |
| Investments accounted for using equity method [abstract] | |||
| Investments accounted for using equity method |
1,400,000
GBP
|
2,700,000
GBP
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Non-current derivative financial assets |
3,600,000
GBP
|
8,500,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
16,700,000
GBP
|
15,800,000
GBP
|
— |
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
70,600,000
GBP
|
113,900,000
GBP
|
167,400,000
GBP
|
| Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract] | |||
| Non-current assets or disposal groups classified as held for sale or as held for distribution to owners |
172,700,000
GBP
|
20,300,000
GBP
|
— |
| Miscellaneous current assets [abstract] | |||
| Current derivative financial assets |
700,000
GBP
|
–
GBP
|
— |
| Borrowings [abstract] | |||
| Non-current portion of non-current borrowings |
876,700,000
GBP
|
932,500,000
GBP
|
— |
| Current borrowings and current portion of non-current borrowings [abstract] | |||
| Current borrowings |
193,900,000
GBP
|
173,400,000
GBP
|
— |
| Non-current portion of non-current borrowings, by type [abstract] | |||
| Trade and other current payables [abstract] | |||
| Trade and other current payables |
68,600,000
GBP
|
58,600,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
11,000,000
GBP
|
11,000,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
728,400,000
GBP
|
1,011,300,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
2,160,900,000
GBP
|
2,501,400,000
GBP
|
— |
| Liabilities |
1,231,700,000
GBP
|
1,280,600,000
GBP
|
— |
| Assets (liabilities) |
929,200,000
GBP
|
1,220,800,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
88,000,000
GBP
|
129,700,000
GBP
|
— |
| Current liabilities |
262,800,000
GBP
|
234,000,000
GBP
|
— |
| Assets less current liabilities [abstract] |