Disclosure Of Interests In Other Entities [Text Block]
| Concept | 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 | 2022-01-01 to 2022-12-31 | 2022-01-01 to 2022-12-31 | 2021-01-01 to 2021-12-31 | As at 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 | 2021-01-01 to 2021-12-31 | 2021-01-01 to 2021-12-31 | 2021-01-01 to 2021-12-31 | As at 2020-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Disclosure of interests in other entities [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of interests in subsidiaries [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of subsidiaries [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of subsidiaries [abstract] | |||||||||||||||||||||||||
| Disclosure of subsidiaries [line items] | |||||||||||||||||||||||||
| Current assets | 
                                                15,099,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                8,591,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current assets | 
                                                71,160,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                87 ,565
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Current liabilities | 
                                                2,883,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                10,339,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Non-current liabilities | 
                                                27 ,200
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                19, 700
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
| Profit (loss) | — | — | 
                                                7 ,116
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | 
                                                10,381,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                3,265,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                2,939,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                9,005,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | 
                                                11,944,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
| Comprehensive income | — | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                7 ,116
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                7, 116
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                11,944,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                11,944,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | 
| Disclosure of interests in associates [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of associates [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of associates [abstract] | |||||||||||||||||||||||||
| Disclosure of associates [line items] | |||||||||||||||||||||||||
| Disclosure of interests in joint arrangements [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of joint ventures [text block] | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of joint ventures [abstract] | |||||||||||||||||||||||||
| Disclosure of joint ventures [line items] | |||||||||||||||||||||||||
| Cash and cash equivalents | 
                                                7, 2 0 6
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                5,715,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                3, 295
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
| Tax expense (income) | — | — | 
                                                18,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                18,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                304,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — | — | 
                                                304,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | — | — |