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) operating activities | — |
439,000,000
GBP
|
— |
584,700,000
GBP
|
| Cash flows from (used in) investing activities [abstract] | ||||
| Cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities | — |
—
GBP
|
— |
200,000
GBP
|
| Purchase of property, plant and equipment, classified as investing activities | — |
29,300,000
GBP
|
— |
20,100,000
GBP
|
| Purchase of intangible assets, classified as investing activities | — |
109,400,000
GBP
|
— |
140,700,000
GBP
|
| Cash flows from (used in) investing activities | — |
138,700,000
GBP
|
— |
161,000,000
GBP
|
| Cash flows from (used in) financing activities [abstract] | ||||
| Payments to acquire or redeem entity's shares | — |
101,000,000
GBP
|
— |
30,000,000
GBP
|
| Payments of lease liabilities, classified as financing activities | — |
101,900,000
GBP
|
— |
12,500,000
GBP
|
| Dividends paid, classified as financing activities | — |
300,800,000
GBP
|
— |
295,900,000
GBP
|
| Cash flows from (used in) financing activities | — |
572,000,000
GBP
|
— |
151,800,000
GBP
|
| Increase (decrease) in cash and cash equivalents after effect of exchange rate changes | — |
271,700,000
GBP
|
— |
271,900,000
GBP
|
| Cash and cash equivalents |
955,700,000
GBP
|
— |
1,220,100,000
GBP
|
— |