Statement Of Cash Flows [Abstract]
| Concept |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of cash flows [abstract] | ||||||||||||||||
| Cash flows from (used in) operating activities [abstract] | ||||||||||||||||
| Profit (loss) |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
93,990,000
GBP
|
93,990,000
GBP
|
25,796,000
GBP
|
–
GBP
|
–
GBP
|
25,796,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
| Adjustments to reconcile profit (loss) [abstract] | ||||||||||||||||
| Adjustments for decrease (increase) in inventories | — | — | — | — | — | — |
4,133,000
GBP
|
— | — | — | — |
19,385,000
GBP
|
— | — | — | — |
| Adjustments for share-based payments | — | — | — | — | — | — |
426,000
GBP
|
— | — | — | — |
618,000
GBP
|
— | — | — | — |
| Cash flows from (used in) operations | — | — | — | — | — | — |
57,038,000
GBP
|
— | — | — | — |
25,777,000
GBP
|
— | — | — | — |
| Interest paid, classified as operating activities | — | — | — | — | — | — |
3,531,000
GBP
|
— | — | — | — |
2,924,000
GBP
|
— | — | — | — |
| Cash flows from (used in) operating activities | — | — | — | — | — | — |
49,861,000
GBP
|
— | — | — | — |
20,726,000
GBP
|
— | — | — | — |
| Cash flows from (used in) investing activities [abstract] | ||||||||||||||||
| Other cash payments to acquire interests in joint ventures, classified as investing activities | — | — | — | — | — | — |
1,624,000
GBP
|
— | — | — | — |
289,000
GBP
|
— | — | — | — |
| Purchase of property, plant and equipment, classified as investing activities | — | — | — | — | — | — |
32,000
GBP
|
— | — | — | — |
115,000
GBP
|
— | — | — | — |
| Interest received, classified as investing activities | — | — | — | — | — | — |
182,000
GBP
|
— | — | — | — |
377,000
GBP
|
— | — | — | — |
| Cash flows from (used in) investing activities | — | — | — | — | — | — |
2,076,000
GBP
|
— | — | — | — |
19,525,000
GBP
|
— | — | — | — |
| Cash flows from (used in) financing activities [abstract] | ||||||||||||||||
| Payments to acquire or redeem entity's shares | — | — | — | — | — | — |
21,000
GBP
|
— | — | — | — |
–
GBP
|
— | — | — | — |
| Payments of lease liabilities, classified as financing activities | — | — | — | — | — | — |
85,000
GBP
|
— | — | — | — |
73,000
GBP
|
— | — | — | — |
| Dividends paid, classified as financing activities | — | — | — | — | — | — |
5,913,000
GBP
|
— | — | — | — |
1,077,000
GBP
|
— | — | — | — |
| Cash flows from (used in) financing activities | — | — | — | — | — | — |
52,610,000
GBP
|
— | — | — | — |
324,000
GBP
|
— | — | — | — |
| Increase (decrease) in cash and cash equivalents after effect of exchange rate changes | — | — | — | — | — | — |
673,000
GBP
|
— | — | — | — |
877,000
GBP
|
— | — | — | — |