Every asylum-seeker would be kept in secure centres after arriving in Britain until they had been investigated and cleared by the security services, under Conservative plans announced today.

Iain Duncan Smith and Oliver Letwin insist the checks are a necessary part of the war against terrorism.

Letwin said: "Terrorists know that they can gain access to Britain by taking advantage of our chaotic asylum system.

"This cannot be allowed to go on, especially at this dangerous period in our history."

Iain Duncan Smith added that "no one should be allowed on our streets unless we are satisfied they pose no threat to other occupants of our streets".

The home secretary, David Blunkett, last night called for more tolerant attitudes towards asylum-seekers and said that some media coverage of the issue was racist.

The Sun has responded with a front page attack on the home secretary saying they "fear for his sanity".

In a further retreat from Tony Blair's stern words at the weekend the FT reports Downing Street playing down threats to opt out of European Convention on Human Rights after warnings such a move would be contested in the courts.

Today's Guardian reveals that Conservatives in Oliver Letwin's Dorset constituency are secretly organising opposition to a new asylum centre in their area.