LONDON - The leader of Britain's rising right-wing anti-EU party on Friday promised a political "earthquake" with victory in next year's European elections, a challenge that could threaten David Cameron's hopes of a second term as prime minister.
Nigel Farage, head of the anti-mass immigration UK Independence Party (UKIP), told the party's annual conference he planned to overturn decades of dominance by Britain's main three parties, the Conservatives, Labour and the LibDems.
But coverage of his speech was overshadowed by a senior party member's outburst and an altercation with a journalist.
Godfrey Bloom, a UKIP member of the European Parliament, described women at a political meeting as "sluts" and later hit a journalist over the head with a copy of a party brochure.
The incidents, which threatened to distract from Farage's political message, were unlikely to be welcomed by a party once derided by Cameron as full of "fruitcakes, loonies and closet racists" and now trying to portray itself as more mainstream.
UKIP has increased its support to around 10 per cent, according to pollsters YouGov, after taking just three per cent of the vote in the last national election in 2010 and failing to secure a single parliamentary seat.
Farage said if UKIP wins a majority of the UK seats in the 2014 election for European Parliament it would effectively be a condemnation of "open-door immigration" and Britain's membership in the 28-nation bloc, which the main parties generally support.
UKIP had a 16.5 per cent share of the vote at the last European elections in 2009, securing 13 of Britain's 72 seats.
"We can come first and cause an earthquake," Farage said at the conference on the party's 20th anniversary. "We're changing the face of British politics."
Bloom said on Twitter he had been joking and had used the word "slut" in the sense of "untidy" to describe women who don't clean their kitchens thoroughly, rather than to mean they were promiscuous.
UKIP said it would exclude Bloom from the party, pending an investigation. In the meantime, Farage said his behaviour was "beyond the pale", but also offered some defence.
"He's not a racist, he's not an extremist ... he's not anti-women," he told the BBC. "But time and time again he says things that overshadow the whole agenda."