Statement Of Cash Flows [Abstract]
| Concept |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
As at 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of cash flows [abstract] | ||||||||||||||||||||
| Cash flows from (used in) operating activities [abstract] | ||||||||||||||||||||
| Profit (loss) |
1 . 2
GBP
|
–
GBP
|
9 97. 9
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
9 9 6 .7
GBP
|
9 97. 9
GBP
|
5 27. 8
GBP
|
528. 8
GBP
|
–
GBP
|
–
GBP
|
— |
–
GBP
|
–
GBP
|
1 .0
GBP
|
–
GBP
|
528. 8
GBP
|
| Adjustments to reconcile profit (loss) [abstract] | ||||||||||||||||||||
| Adjustments for income tax expense | — | — | — | — | — | — | — | — |
132,500,000
GBP
|
— |
10 9. 8
GBP
|
— | — | — | — | — | — | — | — | — |
| Adjustments for finance costs | — | — | — | — | — | — | — | — |
12,000,000
GBP
|
— |
12,400,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Adjustments for share-based payments | — | — | — | — | — | — | — | — |
65. 2
GBP
|
— |
54,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| 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
|
— | — | — | — | — |