Statement Of Cash Flows [Abstract]
| Concept |
As at 2024-12-31 |
2024-01-01 to 2024-12-31 |
As at 2023-12-31 |
2023-01-01 to 2023-12-31 |
|---|---|---|---|---|
| Statement of cash flows [abstract] | ||||
| Cash flows from (used in) operating activities [abstract] | ||||
| Cash flows from (used in) operations | — |
172,700,000
GBP
|
— |
221,200,000
GBP
|
| Income taxes paid (refund), classified as operating activities | — |
43,900,000
GBP
|
— |
25,200,000
GBP
|
| Cash flows from (used in) operating activities | — |
128,800,000
GBP
|
— |
196,000,000
GBP
|
| Cash flows from (used in) investing activities [abstract] | ||||
| Proceeds from sales of property, plant and equipment, classified as investing activities | — |
1,900,000
GBP
|
— |
2,000,000
GBP
|
| Purchase of property, plant and equipment, classified as investing activities | — |
18,200,000
GBP
|
— |
14,300,000
GBP
|
| Purchase of intangible assets, classified as investing activities | — |
–
GBP
|
— |
300,000
GBP
|
| Interest received, classified as investing activities | — |
18,000,000
GBP
|
— |
10,000,000
GBP
|
| Cash flows from (used in) investing activities | — |
4,700,000
GBP
|
— |
11,000,000
GBP
|
| Cash flows from (used in) financing activities [abstract] | ||||
| Payments to acquire or redeem entity's shares | — |
47,200,000
GBP
|
— |
11,300,000
GBP
|
| Payments of lease liabilities, classified as financing activities | — |
25,800,000
GBP
|
— |
21,200,000
GBP
|
| Dividends paid, classified as financing activities | — |
56,100,000
GBP
|
— |
48,100,000
GBP
|
| Interest paid, classified as financing activities | — |
1,900,000
GBP
|
— |
2,400,000
GBP
|
| Cash flows from (used in) financing activities | — |
101,800,000
GBP
|
— |
78,900,000
GBP
|
| Increase (decrease) in cash and cash equivalents after effect of exchange rate changes | — |
31,700,000
GBP
|
— |
106,100,000
GBP
|
| Cash and cash equivalents |
544,200,000
GBP
|
— |
541,300,000
GBP
|
— |