Statement Of Cash Flows [Abstract]
| Concept |
As at 2022-12-31 |
2022-01-01 to 2022-12-31 |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2020-12-31 |
|---|---|---|---|---|---|
| Statement of cash flows [abstract] | |||||
| Cash flows from (used in) operating activities [abstract] | |||||
| Cash flows from (used in) operations | — |
179,000,000
GBP
|
— |
192,100,000
GBP
|
— |
| Income taxes paid (refund), classified as operating activities | — |
1,600,000
GBP
|
— |
4,000,000
GBP
|
— |
| Cash flows from (used in) operating activities | — |
177,400,000
GBP
|
— |
196,100,000
GBP
|
— |
| Cash flows from (used in) investing activities [abstract] | |||||
| Other cash payments to acquire interests in joint ventures, classified as investing activities | — |
2,800,000
GBP
|
— |
500,000
GBP
|
— |
| Interest received, classified as investing activities | — |
100,000
GBP
|
— |
—
GBP
|
— |
| Cash flows from (used in) investing activities | — |
302,100,000
GBP
|
— |
327,300,000
GBP
|
— |
| Cash flows from (used in) financing activities [abstract] | |||||
| Proceeds from borrowings, classified as financing activities | — |
319,000,000
GBP
|
— |
245,500,000
GBP
|
— |
| Repayments of borrowings, classified as financing activities | — |
52,000,000
GBP
|
— |
245,500,000
GBP
|
— |
| Dividends paid, classified as financing activities | — |
129,200,000
GBP
|
— |
114,300,000
GBP
|
— |
| Interest paid, classified as financing activities | — |
35,800,000
GBP
|
— |
37,500,000
GBP
|
— |
| Cash flows from (used in) financing activities | — |
101,200,000
GBP
|
— |
144,500,000
GBP
|
— |
| Increase (decrease) in cash and cash equivalents after effect of exchange rate changes | — |
23,500,000
GBP
|
— |
13,300,000
GBP
|
— |
| Cash and cash equivalents |
47,400,000
GBP
|
— |
70,900,000
GBP
|
— |
57,600,000
GBP
|