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 |
2019-01-01 to 2019-12-31 |
As at 2019-12-31 |
|---|---|---|---|---|---|---|
| Statement of cash flows [abstract] | ||||||
| Cash flows from (used in) operating activities [abstract] | ||||||
| Cash flows from (used in) operating activities | — |
2 ,032 . 8
GBP
|
— |
2,05 4 .8
GBP
|
1,8 50. 5
GBP
|
— |
| Cash flows from (used in) investing activities [abstract] | ||||||
| Proceeds from sales of property, plant and equipment, classified as investing activities | — |
8,700,000
GBP
|
— |
11 .2
GBP
|
174,000,000
GBP
|
— |
| Purchase of property, plant and equipment, classified as investing activities | — |
263 .2
GBP
|
— |
218 .3
GBP
|
339,300,000
GBP
|
— |
| Purchase of intangible assets, classified as investing activities | — |
2 9.9
GBP
|
— |
54,400,000
GBP
|
5 4 . 8
GBP
|
— |
| Cash flows from (used in) investing activities | — |
64 2 . 2
GBP
|
— |
1 6 7. 6
GBP
|
1,759 .6
GBP
|
— |
| Cash flows from (used in) financing activities [abstract] | ||||||
| Proceeds from changes in ownership interests in subsidiaries that do not result in loss of control | — |
3 9. 5
GBP
|
— |
–
GBP
|
−
GBP
|
— |
| Payments from changes in ownership interests in subsidiaries that do not result in loss of control | — |
13 5 . 0
GBP
|
— |
80,600,000
GBP
|
62 . 7
GBP
|
— |
| Payments to acquire or redeem entity's shares | — |
81 8 . 5
GBP
|
— |
29 0. 2
GBP
|
4 3 . 8
GBP
|
— |
| Repayments of borrowings, classified as financing activities | — |
397 .1
GBP
|
— |
282 .7
GBP
|
1, 7 13. 2
GBP
|
— |
| Payments of lease liabilities, classified as financing activities | — |
320. 7
GBP
|
— |
3 0 0.1
GBP
|
2 4 9. 8
GBP
|
— |
| Cash flows from (used in) financing activities | — |
2 , 0 5 7. 0
GBP
|
— |
250. 5
GBP
|
2, 922.0
GBP
|
— |
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes | — |
666 .4
GBP
|
— |
1,636,700,000
GBP
|
6 8 8 .1
GBP
|
— |
| Effect of exchange rate changes on cash and cash equivalents [abstract] | ||||||
| Effect of exchange rate changes on cash and cash equivalents | — |
130,100,000
GBP
|
— |
9 9. 2
GBP
|
8 9. 7
GBP
|
— |
| Cash and cash equivalents |
3, 8 82 .9
GBP
|
— |
1 2 , 8 9 9.1
GBP
|
— | — |
11, 30 5.7
GBP
|