The Home Office lost track of 601,222 foreign, non-European Union visitors in two years who should have left the UK.

A report by the chief inspector of the borders and immigration watchdog David Bolt found that the Home Office’s short-lived Exit Check Programme and ensuing exit checking procedures resulted in no record of the exits of half a million non-visa holding visitors including from Argentina and Brazil and 88,000 foreign citizens whose short-term visas had expired.

The report also found that as of August 2017, there were records of 10 million people whose period to remain in the UK had expired in the previous two years, and that by the end of March 2017, the Home Office had made no effort to contact the some 500,000 non-visa visitors to ascertain if they were still in the country.

However, the department wasted resources in chasing 30,000 Chinese citizens – regarded as “low risk” of overstaying – the majority of who had returned to their home country but whose departures had not been logged on the system.

There was also a 201,301-person “unmatched pot” of foreign exits for whom there is no corresponding entry data in the Exit Check Programme, which ran from April 2014 until 31 May 2016 when it was formally closed.

Home Office staff were noted to have spoken of their mistrust in the system, saying it was “rushed” and “flawed”, with one saying that, “We were certainly mis-sold the programme.”

Mr. Bolt said of the findings: “Overall, the sense was that the Home Office had overpromised when setting out its plans for exit checks, and then closed the exit check programme prematurely, declaring exit checks to be ‘business as usual’ when a significant amount of work remained to be done to get full value from them.”

“In the meantime, the Home Office needed to be more careful about presenting exit checks as the answer to managing the illegal migrant population, which for now remained wishful thinking,” the watchdog chief added.

Bolt recommended that the Exit Checks Programme be re-established, with improvements in data collection, accountability of the programme board, and that “all Home Office projects… in support of the Programme are properly prioritised, resourced and co-ordinated”.

The findings will be damning for Prime Minister Theresa May who had promised “100% exit checks” by March 2015 when she was serving as Home Secretary.

The Conservative government abolished exit checks for EU destinations in 1994, under-pro EU Prime Minister John Major, with all other checks on non-EU destinations being dropped by the Labour government in 1997 under anti-Brexit campaigner Prime Minister Tony Blair.

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