Tony Blair has warned asylum seekers they face a jail sentence if they choose to destroy their travel documents.

The tough line is designed to speed up the removals process for failed asylum applicants, 60 per cent of whom claim to have no passport or identification as a means of delaying their deportation.

While ministers are pleased that the number of arrivals seeking refugee status has significantly slowed since in the past two years, the government has faced difficulty in deporting those who are unsuccessful in claiming they are fleeing persecution.

The prime minister promised to introduce a two-year prison term for those failed applicants found to have wilfully destroyed their documents.

He also set home secretary David Blunkett a new target of removing more failed applicants than there are new unfounded applications by the end of next year.

"We were right to concentrate first on reducing unfounded applications. But David Blunkett and I also accept that we have to increase efforts to remove those who remain in this country when their applications have failed," Blair said.

"Thankfully we have been making significant progress. We are removing a far greater number of failed asylum seekers, though not enough.

"We are gradually closing the gap between the number of failed asylum applicants and the number removed. In 1996, the number of removals was equivalent to only 20 per cent of unsuccessful claims. So far this year, that proportion is almost 50 per cent.

"But I accept we need to do a great deal more. It can make a mockery of our asylum system if those properly denied the right to stay simply flout this decision and remain. It is unfair to those who play by the rules and sends the wrong message to those who may try to come to this country without genuine cause. It undermines public faith in the system."