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] | |||
| Other property, plant and equipment |
2,300,000
GBP
|
2,300,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets and goodwill |
1,100,000
GBP
|
1,400,000
GBP
|
— |
| Investment property [abstract] | |||
| Investment property |
4,843,600,000
GBP
|
4,847,300,000
GBP
|
— |
| Investments accounted for using equity method [abstract] | |||
| Investments in joint ventures accounted for using equity method |
24,800,000
GBP
|
27,200,000
GBP
|
— |
| Trade and other non-current receivables [abstract] | |||
| Trade and other non-current receivables |
1,000,000
GBP
|
2,000,000
GBP
|
— |
| Miscellaneous non-current assets [abstract] | |||
| Non-current derivative financial assets |
11,100,000
GBP
|
19,900,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Trade and other current receivables |
22,000,000
GBP
|
24,900,000
GBP
|
— |
| Cash and cash equivalents [abstract] | |||
| Cash [abstract] | |||
| Cash |
36,400,000
GBP
|
47,600,000
GBP
|
— |
| Cash and cash equivalents |
36,200,000
GBP
|
47,400,000
GBP
|
70,900,000
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 |
—
GBP
|
25,100,000
GBP
|
— |
| Borrowings [abstract] | |||
| Non-current portion of non-current borrowings |
474,700,000
GBP
|
474,800,000
GBP
|
— |
| Non-current portion of non-current borrowings, by type [abstract] | |||
| Trade and other non-current payables [abstract] | |||
| Trade and other non-current payables |
1,000,000
GBP
|
2,000,000
GBP
|
— |
| Trade and other current payables [abstract] | |||
| Current accruals and current deferred income including current contract liabilities [abstract] | |||
| Current deferred income including current contract liabilities [abstract] | |||
| Current deferred income including current contract liabilities |
38,600,000
GBP
|
34,700,000
GBP
|
— |
| Trade and other current payables |
106,900,000
GBP
|
111,200,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
19,000,000
GBP
|
18,700,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
1,801,900,000
GBP
|
1,731,900,000
GBP
|
— |
| Miscellaneous equity [abstract] | |||
| Capital redemption reserve |
1,463,900,000
GBP
|
835,100,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
5,102,000,000
GBP
|
5,155,100,000
GBP
|
— |
| Liabilities |
1,768,000,000
GBP
|
1,805,100,000
GBP
|
— |
| Assets (liabilities) |
3,334,000,000
GBP
|
3,350,000,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
58,400,000
GBP
|
97,600,000
GBP
|
— |
| Current liabilities |
147,700,000
GBP
|
147,000,000
GBP
|
— |
| Assets less current liabilities [abstract] |