The Home Office does not have an up-to-date estimate of how many people are in the UK illegally, according to a report by the country's independent public spending watchdog.
The National Audit Office (NAO), said the size of Britain’s illegal population was last gauged in 2005, when it was suggested that around 430,000 people were in the country with no right to remain.
But the report added that independent research over the 15 years since has put the figure at more than one million.
The government’s immigration enforcement directorate has instead been estimating demand for immigration enforcement activity, which it put at between 240,000 and 320,000 cases per year.
However, the NAO also found that the department had no baseline against which to measure progress or to show whether demand for enforcement activity is going up or down.
Meg Hillier, chairwoman of the Public Accounts Committee, said: “The Home Office has no idea how many people are in the country illegally and doesn’t seem interested in finding out.”
The Labour MP added: “It can’t demonstrate that its actions to control illegal immigration are working as intended, and doesn’t understand how different aspects of its work fit together.”
But the report also concluded that despite collecting information around its missions and objectives, the department often cannot show whether its measures are working.
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