Statement Of Cash Flows [Abstract]
| Concept |
2023-01-01 to 2023-12-31 |
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 |
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 |
As at 2021-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of cash flows [abstract] | |||||||||||||
| Cash flows from (used in) operating activities [abstract] | |||||||||||||
| Profit (loss) |
–
GBP
|
–
GBP
|
23,500,000
GBP
|
— |
23,500,000
GBP
|
–
GBP
|
— |
–
GBP
|
–
GBP
|
24,500,000
GBP
|
24,500,000
GBP
|
–
GBP
|
— |
| Adjustments to reconcile profit (loss) [abstract] | |||||||||||||
| Adjustments for provisions | — | — |
0. 2
GBP
|
— | — | — | — | — | — |
0. 5
GBP
|
— | — | — |
| Adjustments for share-based payments | — | — |
1,600,000
GBP
|
— | — | — | — | — | — |
1,800,000
GBP
|
— | — | — |
| Cash flows from (used in) operations | — | — |
39,200,000
GBP
|
— | — | — | — | — | — |
34,000,000
GBP
|
— | — | — |
| Interest paid, classified as operating activities | — | — |
0. 4
GBP
|
— | — | — | — | — | — |
600,000
GBP
|
— | — | — |
| Income taxes paid (refund), classified as operating activities | — | — |
6. 5
GBP
|
— | — | — | — | — | — |
6 . 2
GBP
|
— | — | — |
| Cash flows from (used in) operating activities | — | — |
32,200,000
GBP
|
— | — | — | — | — | — |
27,200,000
GBP
|
— | — | — |
| Cash flows from (used in) investing activities [abstract] | |||||||||||||
| Purchase of property, plant and equipment, classified as investing activities | — | — |
600,000
GBP
|
— | — | — | — | — | — |
0 .7
GBP
|
— | — | — |
| Interest received, classified as investing activities | — | — |
300,000
GBP
|
— | — | — | — | — | — |
–
GBP
|
— | — | — |
| Cash flows from (used in) investing activities | — | — |
3 .1
GBP
|
— | — | — | — | — | — |
2. 3
GBP
|
— | — | — |
| Cash flows from (used in) financing activities [abstract] | |||||||||||||
| Payments to acquire or redeem entity's shares | — | — |
4,800,000
GBP
|
— | — | — | — | — | — |
5 .6
GBP
|
— | — | — |
| Payments of lease liabilities, classified as financing activities | — | — |
1. 3
GBP
|
— | — | — | — | — | — |
1. 6
GBP
|
— | — | — |
| Dividends paid, classified as financing activities | — | — |
19 . 7
GBP
|
— | — | — | — | — | — |
22 .5
GBP
|
— | — | — |
| Cash flows from (used in) financing activities | — | — |
2 5. 8
GBP
|
— | — | — | — | — | — |
2 9.7
GBP
|
— | — | — |
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes | — | — |
3,300,000
GBP
|
— | — | — | — | — | — |
4,800,000
GBP
|
— | — | — |
| Effect of exchange rate changes on cash and cash equivalents [abstract] | |||||||||||||
| Effect of exchange rate changes on cash and cash equivalents | — | — |
0. 2
GBP
|
— | — | — | — | — | — |
400,000
GBP
|
— | — | — |
| Cash and cash equivalents | — | — | — |
21,800,000
GBP
|
— | — |
18,700,000
GBP
|
— | — | — | — | — |
23,100,000
GBP
|