Disclosure Of Cash Flow Statement [Text Block]
| Concept | 2023-12-31 to 2024-12-28 | As at 2024-12-28 | As at 2023-12-30 | As at 2022-12-31 | 
|---|---|---|---|---|
| Disclosure of cash flow statement [text block] |  | — | — | — | 
| Description of accounting policy for determining components of cash and cash equivalents [text block] | 
                                                Cash and cash equivalents
                                                
                                             | — | — | — | 
| Cash and cash equivalents if different from statement of financial position [abstract] | ||||
| Cash and cash equivalents | — | 
                                                10,900,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                10,700,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             | 
                                                27,000,000
                                                
                                                    
                                                        GBP
                                                    
                                                
                                             |