Statement Of Cash Flows [Abstract]
| Concept |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2020-12-31 |
2020-01-01 to 2020-12-31 |
As at 2019-12-31 |
|---|---|---|---|---|---|
| Statement of cash flows [abstract] | |||||
| Cash flows from (used in) operating activities [abstract] | |||||
| Cash flows from (used in) operations | — |
123,000,000
GBP
|
— |
76,600,000
GBP
|
— |
| Income taxes paid (refund), classified as operating activities | — |
9,200,000
GBP
|
— |
10 .7
GBP
|
— |
| Cash flows from (used in) operating activities | — |
113,800,000
GBP
|
— |
65,900,000
GBP
|
— |
| Cash flows from (used in) investing activities [abstract] | |||||
| Proceeds from sales of property, plant and equipment, classified as investing activities | — |
1,600,000
GBP
|
— |
0. 4
GBP
|
— |
| Purchase of property, plant and equipment, classified as investing activities | — |
3,700,000
GBP
|
— |
3,500,000
GBP
|
— |
| Purchase of intangible assets, classified as investing activities | — |
2,900,000
GBP
|
— |
6,300,000
GBP
|
— |
| Dividends received, classified as investing activities | — |
–
GBP
|
— |
200,000
GBP
|
— |
| Interest received, classified as investing activities | — |
200,000
GBP
|
— |
500,000
GBP
|
— |
| Cash flows from (used in) investing activities | — |
14,300,000
GBP
|
— |
28. 1
GBP
|
— |
| Cash flows from (used in) financing activities [abstract] | |||||
| Payments from changes in ownership interests in subsidiaries that do not result in loss of control | — |
–
GBP
|
— |
0 . 1
GBP
|
— |
| Proceeds from issuing shares | — |
1,800,000
GBP
|
— |
0. 6
GBP
|
— |
| Repayments of borrowings, classified as financing activities | — |
0. 1
GBP
|
— |
1,200,000
GBP
|
— |
| Payments of lease liabilities, classified as financing activities | — |
9. 1
GBP
|
— |
8,900,000
GBP
|
— |
| Interest paid, classified as financing activities | — |
2,300,000
GBP
|
— |
2,700,000
GBP
|
— |
| Cash flows from (used in) financing activities | — |
39,900,000
GBP
|
— |
37 .9
GBP
|
— |
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes | — |
88,200,000
GBP
|
— |
0. 1
GBP
|
— |
| Effect of exchange rate changes on cash and cash equivalents [abstract] | |||||
| Effect of exchange rate changes on cash and cash equivalents | — |
–
GBP
|
— |
2,200,000
GBP
|
— |
| Cash and cash equivalents |
261,600,000
GBP
|
— |
17 3.4
GBP
|
— |
175,700,000
GBP
|