Statement Of Cash Flows [Abstract]
| Concept |
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 2021-12-31 |
|---|---|---|---|---|---|
| Statement of cash flows [abstract] | |||||
| Cash flows from (used in) operating activities [abstract] | |||||
| Cash flows from (used in) operations |
184,900,000
GBP
|
— | — |
179,000,000
GBP
|
— |
| Income taxes paid (refund), classified as operating activities |
400,000
GBP
|
— | — |
1,600,000
GBP
|
— |
| Cash flows from (used in) operating activities |
185,300,000
GBP
|
— | — |
177,400,000
GBP
|
— |
| Cash flows from (used in) investing activities [abstract] | |||||
| Other cash payments to acquire interests in joint ventures, classified as investing activities |
300,000
GBP
|
— | — |
2,800,000
GBP
|
— |
| Purchase of other long-term assets, classified as investing activities |
2,400,000
GBP
|
— | — |
—
GBP
|
— |
| Interest received, classified as investing activities |
200,000
GBP
|
— | — |
100,000
GBP
|
— |
| Cash flows from (used in) investing activities |
67,200,000
GBP
|
— | — |
302,100,000
GBP
|
— |
| Cash flows from (used in) financing activities [abstract] | |||||
| Proceeds from borrowings, classified as financing activities |
409,000,000
GBP
|
— | — |
319,000,000
GBP
|
— |
| Repayments of borrowings, classified as financing activities |
407,000,000
GBP
|
— | — |
52,000,000
GBP
|
— |
| Dividends paid, classified as financing activities |
135,300,000
GBP
|
— | — |
129,200,000
GBP
|
— |
| Interest paid, classified as financing activities |
47,900,000
GBP
|
— | — |
35,800,000
GBP
|
— |
| Cash flows from (used in) financing activities |
129,200,000
GBP
|
— | — |
101,200,000
GBP
|
— |
| Increase (decrease) in cash and cash equivalents after effect of exchange rate changes |
11,200,000
GBP
|
— | — |
23,500,000
GBP
|
— |
| Cash and cash equivalents | — |
36,200,000
GBP
|
47,400,000
GBP
|
— |
70,900,000
GBP
|