Disclosure Of Analysis Of Other Comprehensive Income By Item [Text Block]
| Concept | 2024-01-01 to 2024-12-31 | 2023-01-01 to 2023-12-31 | 
|---|---|---|
| Disclosure of analysis of other comprehensive income by item [text block] | — | — | 
| Disclosure of analysis of other comprehensive income by item [abstract] | ||
| Disclosure of analysis of other comprehensive income by item [line items] | ||
| Other comprehensive income, net of tax, hedges of net investments in foreign operations | — | — | 
| Gains (losses) on hedges of net investments in foreign operations, net of tax | 
                                                2,000,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                –
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
| Other comprehensive income, net of tax, gains (losses) on remeasurements of defined benefit plans | 
                                                0 .3
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                0 .1
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             |