A new report has claimed that the UK Border Agency (UKBA) made no effort to trace more than 120,000 asylum seekers and migrants.
John Vine, the independent chief inspector of borders and immigration, said the agency incorrectly reassured MPs that "extensive checks" were regularly being carried out.
The inquiry report said that because the agency could not find the individuals, it was able to move the cases into an archive and therefore clear its backlog before a deadline last year, while the failures have led to asylum seekers and migrants, who would otherwise have faced removal from the country, gaining rights to remain in the UK.
Some 37,500 applicants whose cases were effectively written off as there was no apparent trace of them are now expected to be located after a review, The Telegraph reports.
According to the paper, the agency was so overwhelmed with work that at one point more than 150 boxes of post, including letters from applicants, MPs and their legal representatives, simply lay unopened in a room in Liverpool, the report said.
Keith Vaz, chairman of the home affairs select committee, which was given misleading information by the agency's then-acting chief executive, Jonathan Sedgwick, said it was a "devastating" report which showed the agency was "in danger of overseeing an effective amnesty" for asylum seekers, the paper said.
Vaz added that the agency's current chief executive, Rob Whiteman, will also be asked to "check every fact and figure that he has given the committee over the last two years", the paper added.