We are putting a lot of effort into improving the removal of asylum seekers

Home Secretary Jack Straw

However, he said that because asylum seekers could not be detained some were bound to disappear.

"Given the fact that we don't detain all asylum seekers, people are free to come and go.

"Some move so the result of that is we don't know the whereabouts today of every one of those asylum seekers."

Mr Straw denied suggestions that the number of asylum seekers with whom officials had lost contact "had shot up" in recent years.

"We are putting a lot of effort into maintaining contact with them, for example, by reporting centres which are being established around the country."

Mr Straw added: "We are putting a lot of effort into improving the removal of asylum seekers.

"In some cases we are being successful in that. In other cases, there are significant problems in removing asylum seekers from this country."

Border controls

He said improving and tightening border controls would prevent many people who are unlikely to be granted asylum from entering the country.

But one of the committee members Conservative MP Humfrey Malins suggested that failure to identify and remove failed asylum seekers was making a mockery of the immigration process.

"With tens of thousands of failed asylum seekers at large in the country and a similar backlog of people with whom the Home office has lost touch completely, the chance of actually being removed is so low as to bring the whole system to rather a mockery," he said.

Mr Straw rejected the claim and suggested that many of the current problems had been caused by underfunding by the previous Conservative government.

Latest figures show that immigration officials have heard 763 appeals for asylum this year. Of those 28 were allowed to stay.

However, just 231 of 735 individuals who were refused asylum have left the UK, either by their own accord or they were removed.

Extra investment

Mr Straw said extra investment in the immigration service would make a difference.

"We have put �600,000 into the system, hundreds more staff into the system including into removals.

"That additional staff will start to make a very significant difference on the number of people being removed from this country."

The Home Office has set a target of removing 30,000 failed asylum seekers from the UK by 2002.

MPs expressed doubts that such a figure could be achieved. Mr Straw accepted it was "a major increase".