Border chiefs are struggling with an enormous backlog of 276,000 immigration cases.
The growing total includes asylum seekers, foreign criminals and illegal migrants and is equivalent to the population of Newcastle.
MPs on the Commons Home Affairs Committee said the UK had become a ‘Bermuda Triangle’ for migrants, a country where it is ‘easy to get in, but impossible to keep track of anyone, let alone get them out’.
Some 21,000 new asylum cases have built up because officials were able to process only 63 per cent of last year’s applications.
In addition, there are 150,000 legal immigrants who came as students and workers but whose visas have since expired. This figure is rising by 100 every day.
The UK Border Agency does not know if these immigrants are still here, despite the fact they have no right to stay.
Forty per cent of this group had never been sent a letter telling them to leave the country, as all those with expired visas should.
Tens of thousands of these lapsed visa cases date back more than five years and are a legacy of Labour’s catastrophic mismanagement of Britain’s immigration system.
There are also 3,900 foreign criminals living in the community and free to commit more crimes, including more than 800 who have been at large for five years or more.
On top of this, another 101,000 asylum and immigration cases remain from the backlog of more than 450,000 found lying around in officials’ cupboards and drawers six years ago.
They were revealed by the then Home Secretary John Reid, who described his own department’s immigration system as ‘not fit for purpose’.
These cases have been placed in a ‘controlled archive’ – effectively put on ice – because they cannot be found. No action will be taken against them unless their whereabouts are discovered as a result of unrelated police or local authority inquiries.
Around 60 per cent of the 450,000 were allowed to stay in the country, many because so much time had passed since their application that they had settled here and had a family.
Mr Reid’s predecessor Charles Clarke was forced to quit after it emerged that more than 1,000 foreign prisoners had been released between 1999 and 2006 without even being considered for deportation.
Astonishingly, despite more than six years passing since that scandal came to light, 60 of those offenders remain untraced and are still at large in the UK.
Keith Vaz, the committee’s chairman, said the backlog, which will take years to clear, was unacceptable, adding that the agency seems to have ‘acquired its own Bermuda Triangle’.
‘It’s easy to get in, but near impossible to keep track of anyone, let alone get them out,’ the Labour MP said. ‘This is the first time the committee has collated all the cases at the UK Border Agency that await resolution.
‘This backlog is now equivalent to the entire population of Newcastle upon Tyne.’
The cross-party group attacked Article 8 of the Human Rights Act which it said ‘weighs too heavily on the side of offenders rather than the safety of the public’.
This, they said, ‘allows criminals facing deportation to live freely in our communities and to endlessly prevent their removal through spurious claims about their right to a private and family life under Article 8’.
But the MPs endorsed Government changes to make it easier to remove foreign criminals, adding: ‘The rights of offenders must be balanced against the rights of law-abiding citizens to live their lives in peace, free from the threat of crime.’
The report also called for deportation proceedings to begin as soon as a prisoner is sentenced, instead of during their prison term, to speed up the process.
The Home Office said: ‘This report highlights improvements we have made to tackle the huge backlog of cases we inherited.
‘Over 2,000 overstayers have recently been removed following targeted enforcement activity, foreign offenders are being removed more quickly and we are performing well against visa processing targets.
‘Talented students are welcome, but we have introduced new powers to toughen up the system, keeping out the fraudulent and unqualified.
‘The report has raised some legitimate concerns about issues that we are already tackling.’