Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
|---|---|---|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | ||||||
| Property, plant and equipment [abstract] | ||||||
| Property, plant and equipment |
54,300,000
GBP
|
21,000,000
GBP
|
54,000,000
GBP
|
22,600,000
GBP
|
— | — |
| Investment property [abstract] | ||||||
| Investment property |
5,002,000,000
GBP
|
–
GBP
|
5,361,200,000
GBP
|
–
GBP
|
— | — |
| Investments accounted for using equity method [abstract] | ||||||
| Investments accounted for using equity method |
43,900,000
GBP
|
2,224,700,000
GBP
|
51,100,000
GBP
|
1,749,800,000
GBP
|
— | — |
| Trade and other non-current receivables [abstract] | ||||||
| Other non-current receivables |
188,100,000
GBP
|
–
GBP
|
159,300,000
GBP
|
–
GBP
|
— | — |
| Miscellaneous non-current assets [abstract] | ||||||
| Non-current net defined benefit asset |
1,200,000
GBP
|
1,200,000
GBP
|
1,800,000
GBP
|
1,800,000
GBP
|
— | — |
| Non-current derivative financial assets |
5,000,000
GBP
|
5,000,000
GBP
|
–
GBP
|
–
GBP
|
— | — |
| Trade and other current receivables [abstract] | ||||||
| Trade and other current receivables |
42,400,000
GBP
|
1,788,000,000
GBP
|
41,000,000
GBP
|
1,898,900,000
GBP
|
— | — |
| Cash and cash equivalents [abstract] | ||||||
| Cash and cash equivalents |
76,600,000
GBP
|
67,300,000
GBP
|
105,500,000
GBP
|
90,600,000
GBP
|
72,700,000
GBP
|
88,500,000
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 |
54,200,000
GBP
|
–
GBP
|
102,800,000
GBP
|
–
GBP
|
— | — |
| Borrowings [abstract] | ||||||
| Non-current portion of non-current borrowings |
1,229,400,000
GBP
|
1,048,400,000
GBP
|
1,237,100,000
GBP
|
1,054,700,000
GBP
|
— | — |
| Current borrowings and current portion of non-current borrowings [abstract] | ||||||
| Current borrowings |
19,700,000
GBP
|
–
GBP
|
12,300,000
GBP
|
–
GBP
|
— | — |
| Non-current portion of non-current borrowings, by type [abstract] | ||||||
| Trade and other current payables [abstract] | ||||||
| Trade and other current payables |
148,100,000
GBP
|
1,707,500,000
GBP
|
145,900,000
GBP
|
1,304,100,000
GBP
|
— | — |
| Miscellaneous non-current liabilities [abstract] | ||||||
| Non-current derivative financial liabilities |
–
GBP
|
–
GBP
|
400,000
GBP
|
400,000
GBP
|
— | — |
| Miscellaneous current liabilities [abstract] | ||||||
| Current derivative financial liabilities |
–
GBP
|
–
GBP
|
400,000
GBP
|
400,000
GBP
|
— | — |
| Issued capital [abstract] | ||||||
| Issued capital |
5,600,000
GBP
|
5,600,000
GBP
|
5,600,000
GBP
|
5,600,000
GBP
|
— | — |
| Retained earnings [abstract] | ||||||
| Retained earnings |
2,931,400,000
GBP
|
202,200,000
GBP
|
3,299,700,000
GBP
|
255,700,000
GBP
|
— | — |
| Net assets (liabilities) [abstract] | ||||||
| Assets |
5,509,400,000
GBP
|
4,110,200,000
GBP
|
5,909,600,000
GBP
|
3,767,300,000
GBP
|
— | — |
| Liabilities |
1,433,900,000
GBP
|
2,779,900,000
GBP
|
1,467,800,000
GBP
|
2,385,000,000
GBP
|
— | — |
| Assets (liabilities) |
4,075,500,000
GBP
|
1,330,300,000
GBP
|
4,441,800,000
GBP
|
1,382,300,000
GBP
|
— | — |
| Net current assets (liabilities) [abstract] | ||||||
| Current assets |
160,700,000
GBP
|
1,855,300,000
GBP
|
179,100,000
GBP
|
1,989,500,000
GBP
|
— | — |
| Current liabilities |
169,200,000
GBP
|
1,709,700,000
GBP
|
210,600,000
GBP
|
1,306,700,000
GBP
|
— | — |
| Assets less current liabilities [abstract] |