Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2022-12-31 |
As at 2021-12-31 |
As at 2020-12-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
1,000,000
GBP
|
800,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets other than goodwill [abstract] | |||
| Intangible assets other than goodwill |
2,900,000
GBP
|
2,400,000
GBP
|
— |
| Goodwill |
24,700,000
GBP
|
24,700,000
GBP
|
— |
| Investments in subsidiaries, joint ventures and associates reported in separate financial statements [abstract] | |||
| Investments in joint ventures reported in separate financial statements |
200,000
GBP
|
300,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Current prepayments and current accrued income other than current contract assets [abstract] | |||
| Current prepayments [abstract] | |||
| Current prepayments |
4,500,000
GBP
|
3,200,000
GBP
|
— |
| Other current receivables |
200,000
GBP
|
1,000,000
GBP
|
— |
| Trade and other current receivables |
8,900,000
GBP
|
6,000,000
GBP
|
— |
| Current prepayments and current accrued income including current contract assets [abstract] | |||
| Current accrued income including current contract assets [abstract] | |||
| Current accrued income including current contract assets |
6,500,000
GBP
|
6,300,000
GBP
|
— |
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
18,700,000
GBP
|
23,100,000
GBP
|
37,000,000
GBP
|
| Trade and other current payables [abstract] | |||
| Current accruals and current deferred income including current contract liabilities [abstract] | |||
| Current deferred income including current contract liabilities [abstract] | |||
| Current contract liabilities [abstract] | |||
| Current contract liabilities |
14,800,000
GBP
|
11,000,000
GBP
|
— |
| Trade and other current payables |
9,500,000
GBP
|
9,300,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
300,000
GBP
|
300,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
48,800,000
GBP
|
46,500,000
GBP
|
— |
| Accumulated other comprehensive income [abstract] | |||
| Reserve of exchange differences on translation |
400,000
GBP
|
–
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
76,500,000
GBP
|
84,000,000
GBP
|
— |
| Liabilities |
34,500,000
GBP
|
40,600,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
39,000,000
GBP
|
39,600,000
GBP
|
— |
| Current liabilities |
25,600,000
GBP
|
24,000,000
GBP
|
— |
| Assets less current liabilities [abstract] |