Disclosure Of Employee Benefits [Text Block]
| 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 | 
|---|---|---|---|---|---|---|---|---|---|---|
| Disclosure of employee benefits [text block] | — | 
                                                8
                                                
                                             | — | — | — | — | — | — | — | — | 
| Disclosure of information about defined benefit plans [abstract] | ||||||||||
| Disclosure of defined benefit plans [text block] | — | — | — | — | — | — | — | — | — | — | 
| Disclosure of defined benefit plans [abstract] | ||||||||||
| Disclosure of defined benefit plans [line items] | ||||||||||
| Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans [abstract] | ||||||||||
| Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                200,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                200,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                9,200,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                9,200,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             |