As campaigning for the local elections intensifies, Iain Duncan Smith has warned the political mainstream that a failure to tackle tough issues such as race creates a "vacuum" for the BNP.

With party leaders taking to the campaign trail in an attempt to turn around public indifference to local elections, the Conservative leader pledged to take right-wing extremists "head on".

"The best way for politicians to deal with [asylum] is not abandoning issues to the BNP, who will enter that vacuum very gladly," he told a Manchester audience. "That is what happened in France."

His argument and the row over David Blunkett's tough talking on asylum will revive fears among some commentators that mainstream, centrist politicians may play into the hands of the BNP by giving credence to anti-immigration prejudices.

Conservatives, Duncan Smith said, are going all out to fight the BNP.

"We have already been making sure we take them head-on. Wherever we can we are putting up candidates in seats against the BNP, even in seats where normally it would be more difficult for us to take them on," he said.

National party leaders are backing local campaigners as anxiety grows over predictions of a dire turnout at the May 2 local government poll.

Efforts have been stepped up following the surprising success of French national front leader Jean-Marie Le Pen in the first round of the country's presidential elections, prompting fears that the far right could do well in the poll in Britain.

Tony Blair visited a community centre in Birmingham on Thursday, in a contest that his party has admitted is an "uphill struggle".

"These are less and less a verdict on government in power and more and more focused on local issues and we believe that this will continue to be the case," said Labour chairman Charles Clarke.

Liberal Democrat leader Charles Kennedy was visiting Milton Keynes and Oxford as Labour publishes a leaked memo from the Association of Liberal Democrat Councillors telling their members to "act shamelessly" in their campaign methods.

"Oppose all service cuts. No cut is going to be that popular and why court the unpopularity that goes with the responsibility of power. You are NOT running the council. It's not your problem, it's theirs," it reads.

Labour slammed the document saying it was "not a programme for serious local government".

Lib Dem chairman Mark Oaten said the government was fearful of big losses.

"This shows Labour are running scared of the Lib Dems on May 2. We campaign hard and we work hard. That is why we win so many local seats," he said.

Public disaffection with Labour, Conservatives and the Liberal Democrats is being cited as a possible cause of a record number of minority party and independent candidates.

Of the 5900 local wards being contested in next week's poll, 311 are being defended by independent and minority party incumbents.

The Green Party is fielding 1074 candidates, the largest number for a decade and double the number who stood in 1995.

The BNP has 68 candidates standing, most notably in Oldham and Burnley where race riots occurred last year.

Although the anti-EU UK Independence party has stood in a limited number of previous elections, this year 160 candidates will contest seats.

The Socialist Alliance is fielding 220 candidates, while for the first time the voters in 69 wards will be able to vote for the Christian Peoples Alliance.