Subclassifications Of Assets, Liabilities And Equities [Abstract]
| Concept |
As at 2021-12-31 |
As at 2020-12-31 |
As at 2019-12-31 |
|---|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | |||
| Property, plant and equipment [abstract] | |||
| Property, plant and equipment |
800,000
GBP
|
900,000
GBP
|
— |
| Intangible assets and goodwill [abstract] | |||
| Intangible assets other than goodwill [abstract] | |||
| Other intangible assets |
2,400,000
GBP
|
2,200,000
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 |
300,000
GBP
|
400,000
GBP
|
— |
| Trade and other current receivables [abstract] | |||
| Current trade receivables |
6,000,000
GBP
|
5,800,000
GBP
|
— |
| Current prepayments and current accrued income other than current contract assets [abstract] | |||
| Current prepayments [abstract] | |||
| Current prepayments |
3,200,000
GBP
|
2,100,000
GBP
|
— |
| Other current receivables |
1,000,000
GBP
|
800,000
GBP
|
— |
| Current prepayments and current accrued income including current contract assets [abstract] | |||
| Cash and cash equivalents [abstract] | |||
| Cash and cash equivalents |
23,100,000
GBP
|
37,000,000
GBP
|
58,800,000
GBP
|
| Classes of other provisions [abstract] | |||
| Other provisions [abstract] | |||
| Other non-current provisions |
1,400,000
GBP
|
1,400,000
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 |
11,000,000
GBP
|
7,000,000
GBP
|
— |
| Trade and other current payables |
9,300,000
GBP
|
8,100,000
GBP
|
— |
| Issued capital [abstract] | |||
| Issued capital |
300,000
GBP
|
300,000
GBP
|
— |
| Retained earnings [abstract] | |||
| Retained earnings |
46,500,000
GBP
|
59,800,000
GBP
|
— |
| Accumulated other comprehensive income [abstract] | |||
| Reserve of exchange differences on translation |
–
GBP
|
100,000
GBP
|
— |
| Net assets (liabilities) [abstract] | |||
| Assets |
84,000,000
GBP
|
95,500,000
GBP
|
— |
| Liabilities |
40,600,000
GBP
|
35,300,000
GBP
|
— |
| Net current assets (liabilities) [abstract] | |||
| Current assets |
39,600,000
GBP
|
50,700,000
GBP
|
— |
| Current liabilities |
24,000,000
GBP
|
18,100,000
GBP
|
— |
| Assets less current liabilities [abstract] |