Disclosure Of Revenue From Contracts With Customers [Text Block]
| Concept | As at 2023-12-31 | As at 2022-12-31 | 
|---|---|---|
| Disclosure of revenue from contracts with customers [text block] | — | — | 
| Contract assets [abstract] | ||
| Current contract assets | 
                                                84,200,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                54,300,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
| Contract liabilities [abstract] | ||
| Current contract liabilities | 
                                                7,200,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                7,700,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             |