The home secretary, Charles Clarke, yesterday vowed to use his controversial new anti-terrorism legislation to tackle head on "an extremism that knows no bounds" and strenuously denied that a change of government policy on Iraq would remove Britain "from the firing line".

Mr Clarke also used his conference speech to accuse the Conservatives of using the issues of immigration and crime to run the "most unpleasant and pernicious" general election campaign in his memory. He told delegates that by the next general election he would "eliminate antisocial behaviour", ensure Britain has a fairer immigration system, and cut the levels of violent crime.