IMMIGRATION minister Des Brown has denied the Government has secretly calculated that as many as 500,000 illegal migrants may be in the country.

The minister, who is in East Kent today said reports the Government had suppressed the publication of the figures were incorrect.

Campaigning for candidates in the two key Labour-held marginal constituencies of Dover and Thanet South, Mr Brown also rubbished Michael Howard’s asylum policies, denouncing them as "unworkable".

Mr Howard, meanwhile, has reaffirmed his party’s stance. "Residents in Kent know more than most that immigration policy is out of control," he said.

Mr Brown also suggested voters were only focusing on the issue because they were less concerned about the state of the economy than they had been in the 2001 general election.

He said: "Asylum and immigration are important issues, there is no doubt about that. Part of the reason for that interest is because issues that were of concern to people last time are no longer of concern. We have been a victim of our success on the economy."

Asked to comment on reports that Home Office officials had calculated there were around 500,000 illegal immigrants in Britain, Mr Brown, who met a group of residents from Dover to talk about local asylum-related issus, said: "Our position is no different to Michael Howard’s when he was asked this question when he was home secretary. He said it was not possible to clarify how many there were. There is no official estimate of illegal immigrants in this country."

He confirmed the Home Office had commissioned academic experts to examine how best to calculate illegal immigrants.

"I was far from satisfied that what was presented to us was going to give us an accurate assessment. We did not come to a figure."

He warned that the Conservative policy would cut the asylum budget by half. "We do need secure border controls. You don’t do that by cutting the budget in half."