Statement Of Financial Position [Abstract]
| Concept |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | |||||||||||||||
| Assets [abstract] | |||||||||||||||
| Non-current assets [abstract] | |||||||||||||||
| Property, plant and equipment |
39,600,000
GBP
|
— | — | — | — |
41,300,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Investment property |
2,295,000,000
GBP
|
— | — | — | — |
2,247,100,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Investments accounted for using equity method |
2,700,000
GBP
|
— | — | — | — |
6,600,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Deferred tax assets |
2,800,000
GBP
|
— | — | — | — |
2,600,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Non-current assets |
2,351,400,000
GBP
|
— | — | — | — |
2,308,800,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Current assets [abstract] | |||||||||||||||
| Trade and other current receivables |
15,800,000
GBP
|
— | — | — | — |
18,100,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Cash and cash equivalents |
113,900,000
GBP
|
— | — | — | — |
167,400,000
GBP
|
— | — | — | — |
235,700,000
GBP
|
— | — | — | — |
| Non-current assets or disposal groups classified as held for sale or as held for distribution to owners |
20,300,000
GBP
|
— | — | — | — |
44,200,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Current assets |
129,700,000
GBP
|
— | — | — | — |
185,500,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Assets |
2,501,400,000
GBP
|
— | — | — | — |
2,538,500,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | |||||||||||||||
| Equity [abstract] | |||||||||||||||
| Issued capital |
11,000,000
GBP
|
— | — | — | — |
11,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Retained earnings |
1,011,300,000
GBP
|
— | — | — | — |
1,147,900,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Share premium |
83,100,000
GBP
|
— | — | — | — |
83,100,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Other reserves |
115,400,000
GBP
|
— | — | — | — |
88,700,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Equity |
1,220,800,000
GBP
|
83,100,000
GBP
|
1,011,300,000
GBP
|
11,000,000
GBP
|
115,400,000
GBP
|
1,330,700,000
GBP
|
1,147,900,000
GBP
|
88,700,000
GBP
|
83,100,000
GBP
|
11,000,000
GBP
|
1,270,600,000
GBP
|
11,000,000
GBP
|
1,059,200,000
GBP
|
117,300,000
GBP
|
83,100,000
GBP
|
| Liabilities [abstract] | |||||||||||||||
| Non-current liabilities [abstract] | |||||||||||||||
| Deferred tax liabilities |
110,500,000
GBP
|
— | — | — | — |
109,900,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Non-current liabilities |
1,046,600,000
GBP
|
— | — | — | — |
975,900,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Current liabilities [abstract] | |||||||||||||||
| Trade and other current payables |
58,600,000
GBP
|
— | — | — | — |
57,600,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Current tax liabilities, current |
2,000,000
GBP
|
— | — | — | — |
4,500,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Current liabilities |
234,000,000
GBP
|
— | — | — | — |
231,900,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Liabilities |
1,280,600,000
GBP
|
— | — | — | — |
1,207,800,000
GBP
|
— | — | — | — | — | — | — | — | — |