Statement Of Cash Flows [Abstract]
| Concept |
2023-01-01 to 2023-12-31 |
As at 2023-12-31 |
2023-01-01 to 2023-12-31 |
As at 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
|---|---|---|---|---|---|---|
| Statement of cash flows [abstract] | ||||||
| Cash flows from (used in) operating activities [abstract] | ||||||
| Profit (loss) |
526,200,000
GBP
|
— |
526,200,000
GBP
|
— |
474,400,000
GBP
|
474,400,000
GBP
|
| Adjustments to reconcile profit (loss) [abstract] | ||||||
| Other adjustments for non-cash items |
6,500,000
GBP
|
— | — | — |
15,900,000
GBP
|
— |
| Income taxes paid (refund), classified as operating activities |
188,600,000
GBP
|
— | — | — |
173,600,000
GBP
|
— |
| Cash flows from (used in) operating activities |
904,000,000
GBP
|
— | — | — |
951,600,000
GBP
|
— |
| Cash flows from (used in) investing activities [abstract] | ||||||
| Cash flows from losing control of subsidiaries or other businesses, classified as investing activities |
–
GBP
|
— | — | — |
49,900,000
GBP
|
— |
| Cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities |
337,700,000
GBP
|
— | — | — |
243,600,000
GBP
|
— |
| Proceeds from sales of property, plant and equipment, classified as investing activities |
2,100,000
GBP
|
— | — | — |
1,000,000
GBP
|
— |
| Purchase of property, plant and equipment, classified as investing activities |
58,300,000
GBP
|
— | — | — |
46,700,000
GBP
|
— |
| Interest received, classified as investing activities |
54,400,000
GBP
|
— | — | — |
16,200,000
GBP
|
— |
| Cash flows from (used in) investing activities |
339,500,000
GBP
|
— | — | — |
223,200,000
GBP
|
— |
| Cash flows from (used in) financing activities [abstract] | ||||||
| Payments to acquire or redeem entity's shares |
76,400,000
GBP
|
— | — | — |
74,000,000
GBP
|
— |
| Proceeds from borrowings, classified as financing activities |
–
GBP
|
— | — | — |
346,400,000
GBP
|
— |
| Repayments of borrowings, classified as financing activities |
159,500,000
GBP
|
— | — | — |
131,800,000
GBP
|
— |
| Payments of lease liabilities, classified as financing activities |
188,000,000
GBP
|
— | — | — |
175,100,000
GBP
|
— |
| Dividends paid, classified as financing activities |
209,700,000
GBP
|
— | — | — |
190,500,000
GBP
|
— |
| Interest paid, classified as financing activities |
107,600,000
GBP
|
— | — | — |
61,900,000
GBP
|
— |
| Cash flows from (used in) financing activities |
666,900,000
GBP
|
— | — | — |
331,000,000
GBP
|
— |
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes |
102,400,000
GBP
|
— | — | — |
397,400,000
GBP
|
— |
| Effect of exchange rate changes on cash and cash equivalents [abstract] | ||||||
| Effect of exchange rate changes on cash and cash equivalents |
23,800,000
GBP
|
— | — | — |
55,400,000
GBP
|
— |
| Cash and cash equivalents | — |
1,426,100,000
GBP
|
— |
1,504,000,000
GBP
|
— | — |