Statement Of Cash Flows [Abstract]
| Concept |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
As at 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 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 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
As at 2021-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of cash flows [abstract] | |||||||||||||||||||||
| Cash flows from (used in) operating activities [abstract] | |||||||||||||||||||||
| Profit (loss) |
199,400,000
GBP
|
–
GBP
|
— |
197,600,000
GBP
|
–
GBP
|
1,800,000
GBP
|
197,600,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— |
–
GBP
|
–
GBP
|
184,200,000
GBP
|
182,800,000
GBP
|
1,400,000
GBP
|
–
GBP
|
–
GBP
|
182,800,000
GBP
|
–
GBP
|
— |
| Adjustments to reconcile profit (loss) [abstract] | |||||||||||||||||||||
| Adjustments for decrease (increase) in inventories |
189,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
7,000,000
GBP
|
— | — | — | — | — | — | — |
| Adjustments for provisions |
800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
700,000
GBP
|
— | — | — | — | — | — | — |
| Adjustments for share-based payments |
7,700,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
8,600,000
GBP
|
— | — | — | — | — | — | — |
| Other adjustments to reconcile profit (loss) |
100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
100,000
GBP
|
— | — | — | — | — | — | — |
| Cash flows from (used in) operations |
493,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
294,800,000
GBP
|
— | — | — | — | — | — | — |
| Income taxes paid (refund), classified as operating activities |
82,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
52,700,000
GBP
|
— | — | — | — | — | — | — |
| Cash flows from (used in) operating activities |
410,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
242,100,000
GBP
|
— | — | — | — | — | — | — |
| Cash flows from (used in) investing activities [abstract] | |||||||||||||||||||||
| Proceeds from sales of property, plant and equipment, classified as investing activities |
–
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
1,100,000
GBP
|
— | — | — | — | — | — | — |
| Purchase of property, plant and equipment, classified as investing activities |
21,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
23,700,000
GBP
|
— | — | — | — | — | — | — |
| Purchase of intangible assets, classified as investing activities |
13,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
11,800,000
GBP
|
— | — | — | — | — | — | — |
| Interest received, classified as investing activities |
13,100,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
2,400,000
GBP
|
— | — | — | — | — | — | — |
| Cash flows from (used in) investing activities |
39,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
60,300,000
GBP
|
— | — | — | — | — | — | — |
| Cash flows from (used in) financing activities [abstract] | |||||||||||||||||||||
| Proceeds from issuing shares |
9,200,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
6,200,000
GBP
|
— | — | — | — | — | — | — |
| Payments to acquire or redeem entity's shares |
38,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
34,400,000
GBP
|
— | — | — | — | — | — | — |
| Proceeds from borrowings, classified as financing activities |
62,900,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
4,000,000
GBP
|
— | — | — | — | — | — | — |
| Repayments of borrowings, classified as financing activities |
69,800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
20,600,000
GBP
|
— | — | — | — | — | — | — |
| Payments of lease liabilities, classified as financing activities |
41,400,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
50,300,000
GBP
|
— | — | — | — | — | — | — |
| Interest paid, classified as financing activities |
2,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
2,900,000
GBP
|
— | — | — | — | — | — | — |
| Cash flows from (used in) financing activities |
163,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
183,400,000
GBP
|
— | — | — | — | — | — | — |
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes |
207,600,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
1,600,000
GBP
|
— | — | — | — | — | — | — |
| Effect of exchange rate changes on cash and cash equivalents [abstract] | |||||||||||||||||||||
| Effect of exchange rate changes on cash and cash equivalents |
800,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
7,200,000
GBP
|
— | — | — | — | — | — | — |
| Cash and cash equivalents | — | — |
471,200,000
GBP
|
— | — | — | — | — | — | — |
264,400,000
GBP
|
— | — | — | — | — | — | — | — | — |
273,200,000
GBP
|