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 | — |
972 .8
GBP
|
— |
993. 3
GBP
|
— |
| Interest paid, classified as operating activities | — |
3. 7
GBP
|
— |
4 .1
GBP
|
— |
| Interest received, classified as operating activities | — |
1,900,000
GBP
|
— |
4,700,000
GBP
|
— |
| Income taxes paid (refund), classified as operating activities | — |
1 86. 2
GBP
|
— |
228 .4
GBP
|
— |
| Cash flows from (used in) operating activities | — |
784,800,000
GBP
|
— |
765. 5
GBP
|
— |
| Cash flows from (used in) investing activities [abstract] | |||||
| Proceeds from sales of property, plant and equipment, classified as investing activities | — |
900,000
GBP
|
— |
800,000
GBP
|
— |
| Purchase of property, plant and equipment, classified as investing activities | — |
20. 9
GBP
|
— |
18,900,000
GBP
|
— |
| Cash flows from (used in) investing activities | — |
18 .2
GBP
|
— |
1 8 .1
GBP
|
— |
| Cash flows from (used in) financing activities [abstract] | |||||
| Payments of lease liabilities, classified as financing activities | — |
3,300,000
GBP
|
— |
3,600,000
GBP
|
— |
| Dividends paid, classified as financing activities | — |
74 9 .6
GBP
|
— |
3 50.7
GBP
|
— |
| Cash flows from (used in) financing activities | — |
7 5 4 .1
GBP
|
— |
3 5 7. 2
GBP
|
— |
| Increase (decrease) in cash and cash equivalents after effect of exchange rate changes | — |
12,500,000
GBP
|
— |
390. 2
GBP
|
— |
| Cash and cash equivalents |
1 , 24 6 .6
GBP
|
— |
1 , 23 4 .1
GBP
|
— |
8 43.9
GBP
|