Statement Of Cash Flows [Abstract]
| Concept |
2023-01-01 to 2023-12-31 |
As at 2023-12-31 |
2023-01-01 to 2023-12-31 |
As at 2023-12-31 |
As at 2022-12-31 |
2022-01-01 to 2022-12-31 |
As at 2022-12-31 |
2022-01-01 to 2022-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|
| Statement of cash flows [abstract] | ||||||||||
| Cash flows from (used in) operating activities [abstract] | ||||||||||
| Cash flows from (used in) operations |
135,300,000
GBP
|
— |
33,700,000
GBP
|
— | — |
148,700,000
GBP
|
— |
29,800,000
GBP
|
— | — |
| Interest received, classified as operating activities |
800,000
GBP
|
— |
800,000
GBP
|
— | — |
300,000
GBP
|
— |
200,000
GBP
|
— | — |
| Cash flows from (used in) operating activities |
97,000,000
GBP
|
— |
62,100,000
GBP
|
— | — |
111,400,000
GBP
|
— |
58,500,000
GBP
|
— | — |
| Cash flows from (used in) investing activities [abstract] | ||||||||||
| Other cash payments to acquire interests in joint ventures, classified as investing activities |
–
GBP
|
— |
–
GBP
|
— | — |
300,000
GBP
|
— |
–
GBP
|
— | — |
| Purchase of property, plant and equipment, classified as investing activities |
700,000
GBP
|
— |
400,000
GBP
|
— | — |
2,000,000
GBP
|
— |
600,000
GBP
|
— | — |
| Cash flows from (used in) investing activities |
98,000,000
GBP
|
— |
400,000
GBP
|
— | — |
51,700,000
GBP
|
— |
600,000
GBP
|
— | — |
| Cash flows from (used in) financing activities [abstract] | ||||||||||
| Proceeds from issuing shares |
–
GBP
|
— |
–
GBP
|
— | — |
1,200,000
GBP
|
— |
1,200,000
GBP
|
— | — |
| Proceeds from borrowings, classified as financing activities |
300,000
GBP
|
— |
–
GBP
|
— | — |
7,400,000
GBP
|
— |
–
GBP
|
— | — |
| Dividends paid, classified as financing activities |
88,700,000
GBP
|
— |
88,700,000
GBP
|
— | — |
86,800,000
GBP
|
— |
86,800,000
GBP
|
— | — |
| Cash flows from (used in) financing activities |
2,600,000
GBP
|
— |
20,000,000
GBP
|
— | — |
88,600,000
GBP
|
— |
35,800,000
GBP
|
— | — |
| Increase (decrease) in cash and cash equivalents after effect of exchange rate changes |
3,600,000
GBP
|
— |
42,500,000
GBP
|
— | — |
28,900,000
GBP
|
— |
23,300,000
GBP
|
— | — |
| Cash and cash equivalents | — |
73,000,000
GBP
|
— |
24,800,000
GBP
|
76,600,000
GBP
|
— |
67,300,000
GBP
|
— |
105,500,000
GBP
|
90,600,000
GBP
|