T he Government is to reintroduce "counting out" at UK borders after it emerged there may be many more failed asylum seekers in the country than previously thought.
Officials are believed to have found up to 450,000 failed applicants in the country.
The figure is far higher than the 283,000 produced by the National Audit Office last year, which Ministers insisted was 50,000 too high.
Thousands of "lost" case files have apparently been found in a recent trawl of the Home Office. It has not yet been established how many relate to asylum seekers whose applications failed.
Immigration Minister Liam Byrne (Lab Hodge Hill) said problems with producing figures on those illegally in the UK were "not new".
He said difficulties had been around since the Conservative Government stopped monitoring how many people were leaving, in 1994.
"That's exactly why you must be determined to count people out. We'll have a lot more to say about that over the next few days," he said. "That is the direction I think we need to go in. We need to toughen borders, and counting people in and out is a basic discipline we need to reintroduce."
Mr Byrne said it was not "helpful" to give a "ball-park" figure for the number of asylum seekers remaining.
He also insisted the Government was determined to pursue individuals illegally in Britain as well as companies employing them.
Shadow Home Secretary David Davis said the upward revision of figures was "extraordinary".
"What John Reid must now do is come forward and explain exactly how he intends to deal with this huge backlog.
Dr Reid said later: "No Government has been able to say how many failed asylum seekers there are. What I can do is say we are now getting to the stage where we are treating these things very quickly -it used to take 22 months to do an asylum case - it now takes two months.
"Secondly, there are now more failed asylum seekers being deported than are being brought into the country."