Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2023-12-31 |
As at 2022-12-31 |
|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | ||
| Property, plant and equipment [abstract] | ||
| Property, plant and equipment |
500,000
GBP
|
400,000
GBP
|
| Intangible assets and goodwill [abstract] | ||
| Intangible assets and goodwill |
6,200,000
GBP
|
—
GBP
|
| Investment property [abstract] | ||
| Investment property |
2,779 .3
GBP
|
2,796,300,000
GBP
|
| Miscellaneous non-current assets [abstract] | ||
| Non-current derivative financial assets |
900,000
GBP
|
19 .6
GBP
|
| Trade and other current receivables [abstract] | ||
| Trade and other current receivables |
24,900,000
GBP
|
17 .8
GBP
|
| Classes of current inventories [abstract] | ||
| Current work in progress |
1,400,000
GBP
|
1,300,000
GBP
|
| Classes of current inventories, alternative [abstract] | ||
| Cash and cash equivalents [abstract] | ||
| Cash and cash equivalents |
3,200,000
GBP
|
29 .1
GBP
|
| Miscellaneous current assets [abstract] | ||
| Current derivative financial assets |
10,500,000
GBP
|
—
GBP
|
| Non-current portion of non-current borrowings, by type [abstract] | ||
| Non-current portion of non-current loans received |
664,500,000
GBP
|
682,500,000
GBP
|
| Non-current portion of non-current bonds issued |
656,400,000
GBP
|
614,600,000
GBP
|
| Current borrowings and current portion of non-current borrowings, by type [abstract] | ||
| Current loans received and current portion of non-current loans received |
2,400,000
GBP
|
2,300,000
GBP
|
| Trade and other non-current payables [abstract] | ||
| Trade and other non-current payables |
4,100,000
GBP
|
—
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 other than current contract liabilities | — | — |
| Rent deferred income classified as current |
30,400,000
GBP
|
29 .2
GBP
|
| Trade and other current payables |
31,700,000
GBP
|
32,600,000
GBP
|
| Miscellaneous non-current liabilities [abstract] | ||
| Non-current derivative financial liabilities |
—
GBP
|
12,500,000
GBP
|
| Miscellaneous current liabilities [abstract] | ||
| Current derivative financial liabilities |
6,700,000
GBP
|
—
GBP
|
| Issued capital [abstract] | ||
| Issued capital |
167 .1
GBP
|
167 .1
GBP
|
| Retained earnings [abstract] | ||
| Retained earnings |
369 .1
GBP
|
430,100,000
GBP
|
| Accumulated other comprehensive income [abstract] | ||
| Reserve of cash flow hedges |
7 .0
GBP
|
11,100,000
GBP
|
| Net assets (liabilities) [abstract] | ||
| Assets |
2,826,900,000
GBP
|
2,864,500,000
GBP
|
| Liabilities |
1,403,000,000
GBP
|
1,382,300,000
GBP
|
| Assets (liabilities) |
1,423,900,000
GBP
|
1,482,200,000
GBP
|
| Net current assets (liabilities) [abstract] | ||
| Current assets |
40,000,000
GBP
|
48,200,000
GBP
|
| Current liabilities |
71,200,000
GBP
|
64,100,000
GBP
|
| Assets less current liabilities [abstract] |