Statement Of Changes In Equity [Abstract]
| Concept | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | 2023-01-01 to 2023-12-31 | 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 | 
|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | ||||||||||
| Statement of changes in equity [line items] | ||||||||||
| Increase (decrease) through exercise of options, equity | — | — | — | — | — | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                1,600,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                1,600,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
| Increase (decrease) through transactions with owners, equity | 
                                                900,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                8,600,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                1,500,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                9,200,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                100,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                2,800,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                200,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                2,900,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             |