The British National Party will field a record number of candidates in next month's council elections in an effort to spread its far-right message beyond its traditional heartlands.
Anti-racist campaigners are warning the party could make a breakthrough in at least three councils - Bradford, Stoke-on-Trent and Epping in Essex.
They also believe the party is targeting areas where it has previously been weak to lay the foundations for winning a seat in the next European Parliament elections.
More than 350 BNP candidates will fight the elections in an attempt toincrease the party's total of 23 councillors. They are attempting to exploit anger over the suicide bombings in London on 7 July to turn the contests on 4 May into a "referendum on Islam".
The party is looking beyond its strongest areas in east Lancashire, West Yorkshire, the Black Country and the east London/Essex border to Birmingham, where it will contest all 40 wards, and Leeds, where it is standing in 22 wards.
It is pouring resources into two West Yorkshire councils; Kirklees, where it won more than 5,000 votes in Dewsbury in last year's general election, and Bradford, where it already has three councillors.
Eight BNP candidates are standing in the Lancashire town of Burnley, where it already has six councillors.
It hopes to boost support in Stoke, where the party has taken advantage of disillusionment with Labour's dominance of the council, and to build on a history of support for the far-right in the Black Country, notably the borough of Sandwell.
It could win several seats in the east London borough of Dagenham and Barking, where it has pockets of strong backing and could be a base for a drive for votes across the capital, with an eye on elections for the London assembly in 2008.
Parts of south Essex are also being targeted, including Epping, where there are already three BNP councillors, Thurrock and Basildon.
Last night, Labour members around the country were circulated details of where the BNP threat was most potent. According to an assessment by Searchlight, the anti-fascist group, the party stand a chance of victory in as many as 80 wards. It is more likely that they will end up with about 30 councillors.
Jon Cruddas, the Labour MP for Dagenham, said: "Wherever the BNP are elected, there's a correlation with racist attacks. It also scares off investors where they are sitting on councils."
Backed by major trade unions, Billy Bragg, the left-wing singer songwriter, begins a 14-date "stop the BNP tour" later this month.
He said BNP support in his home town of Barking was an "angry vote" that wanted to "stick two fingers up to the Labour Party because they are angry with the Government. But he added: "It's a retrievable vote."
Phil Edwards, spokesman for the BNP, said: "We've got everybody against us apart from the great British public. We're continuing to grow - we're lapping it up and having a great time."
He said the party made no apologies for focusing on Islam. He said: "If there's a problem in a democracy and people are worried about it ... whether Muslims are going around killing people and taking over the country ... surely a party has a duty to address those worries."
At the last general election, the BNP picked up nearly 200,000 votes in the 120 constituencies it contested and retained its deposit in 40 of the seats.Reuse content