Estimates are far higher - a true figure cannot be known because many are never detected and many who enter legally later become visa overstayers. According to https://migrationobservatory.ox.ac.uk/resources/briefings/unauthorised-migration-in-the-uk/ The Estimated total unauthorised (illegal) population currently in the UK: around 700,000 to 900,000, according to the latest revised academic estimates. This includes illegal entrants, overstayers, and others without legal status. Of those - to truly know 'how many are truly on the loose' (whereabouts unknown) is impossible to tell, neither the Home Office nor independent researchers have published a credible estimate. The article mentioned 50,000+, which is only the reported number of people known to the Home Office who have absconded or whose whereabouts are unknown. There is a significantly larger unknown number of unknowns. The article fails to highlight that, thus presenting a significant underestimation.