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 |
|---|---|---|---|---|
| Statement of cash flows [abstract] | ||||
| Cash flows from (used in) operating activities [abstract] | ||||
| Cash flows from (used in) operations | — |
371,300,000
GBP
|
— |
783. 8
GBP
|
| Interest received, classified as operating activities | — |
4 6.6
GBP
|
— |
52 .6
GBP
|
| Income taxes paid (refund), classified as operating activities | — |
1 26 .7
GBP
|
— |
17 5 . 0
GBP
|
| Cash flows from (used in) operating activities | — |
24 4 .6
GBP
|
— |
608,800,000
GBP
|
| Cash flows from (used in) investing activities [abstract] | ||||
| Purchase of property, plant and equipment, classified as investing activities | — |
6 9 . 2
GBP
|
— |
4 3 . 1
GBP
|
| Cash flows from (used in) investing activities | — |
38 7. 8
GBP
|
— |
4 3 . 1
GBP
|
| Cash flows from (used in) financing activities [abstract] | ||||
| Payments of lease liabilities, classified as financing activities | — |
9 . 6
GBP
|
— |
9 . 4
GBP
|
| Dividends paid, classified as financing activities | — |
720,900,000
GBP
|
— |
4 2 5 .7
GBP
|
| Interest paid, classified as financing activities | — |
2 0 . 2
GBP
|
— |
1 9 . 2
GBP
|
| Cash flows from (used in) financing activities | — |
5 6 4 . 8
GBP
|
— |
4 9 8 . 1
GBP
|
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes | — |
6 7. 6
GBP
|
— |
6 7. 6
GBP
|
| Effect of exchange rate changes on cash and cash equivalents [abstract] | ||||
| Effect of exchange rate changes on cash and cash equivalents | — |
5 . 3
GBP
|
— |
2,400,000
GBP
|
| Cash and cash equivalents |
372. 7
GBP
|
— |
298,200,000
GBP
|
— |