The Conservatives on Friday came under intense fire over their plans to detain asylum seekers in secure detention centres.

William Hague, in a speech to party supporters in Dover, claimed that the government's asylum policy was in chaos.

"It is little wonder that as a result of Labour policies, Britain is not a safe haven, Britain has become a soft touch," he said.

He claimed there was now "sustained and systematic abuse" of the immigration system.

Hague denied that he was against asylum, saying that Britain had benefited from migration by Huguenots, Jews fleeing Nazi oppression and Ugandan Asians.

"Britain has provided a safe haven for these people and others like them. I value the great contribution these people have made to our national life. Each new group of settlers has enriched our island," Hague told the audience. "Everyone knows this country cannot take infinite people who want to come to this country for economic reasons."

He also hit out at the racketeers behind a "miserable, violent, utterly tragic multi-billion pound trade in asylum seekers" and promised that the Conservatives would "clear up Labour's mess".

Both Labour and the Liberal Democrats have criticised the plans to "lock-up" asylum seekers until their case has been verified.

The Lib Dems said Hague was "failed comprehensively" to make an impact on issues like schools and hospitals saying the party was now resorting to "Alf Garnett" style tactics.

The Tories believe the plan to detain those seeking to enter the country would stop "bogus" asylum seekers going missing and make it easier to return them to their country of origin when their case for asylum is unfounded.

Francis Maude, the shadow foreign secretary, said that Britain is seen as a soft touch on asylum. "There is no country in the world that accepts that people should pitch up and have the right to be admitted," he said.

Labour and the Lib Dems used their morning press conferences to attack the Conservative plans.

Charles Kennedy, the Lib Dem leader, said the party's plans were "mad, bad and dangerous".

Describing the Conservatives' plans as "distasteful", Kennedy said: "The Conservative leadership has the political instincts of Alf Garnett and the electoral appeal of Michael Foot."

The Lib Dem leader said the party "ought to be ashamed of themselves".

Labour argued that the Tories would not be able to afford to be tough on asylum seekers whilst pursuing £20 billion of cuts in public spending.

Speaking on Friday, the prime minister said: "Asylum is a big issue for people and it's absolutely essential and important that we deal with it, as we have been doing for the past couple of years.

"The numbers of asylum claims in Britain are falling compared with last year whereas they are rising in most other European countries. We have put in place measures both to make sure that we criminalise those that take in illegal immigrants."

Blair warned that William Hague would not be able to deliver. "We understand it's a problem but the Conservatives oppose each and every one of the measures that we have taken to deal with it. And because they are committed to these £20 billion of cuts, some of those cuts would fall on the immigration service when we need additional immigration officers in order to deal with the problem," he said.

The Refugee Council also attacked the Conservatives' plans for detention centres. Nick Hardwick said: On principle, this proposal is inhumane. It means detaining people who have not committed any crime, including women and children, many of whom would have been persecuted."