Nigel Farage: Britain would prosper outside EU
Britain would flourish outside the EU, Nigel Farage has said, predicting UKIP will cause a "political earthquake" in European elections next year.
Addressing the party's annual conference, he said leaving the union would "open a door to the world".
He described his party as the "true Europeans" as he claimed credit for shifting the terms of the debate on immigration and holding a referendum.
But the speech was overshadowed by a row over remarks by MEP Godfrey Bloom.
Mr Bloom has had the whip removed after he referred to a group of female activists as "sluts" - although he maintained that it was meant and taken as a joke.
UKIP has reached unprecedented heights in the opinion polls under Mr Farage, coming second in the European elections in 2009 and winning hundreds of seats in the May local elections.
Mr Farage has refused to predict how the party's Westminster candidates would fare in an election in 2015 but said he wants to turn the next European elections "into a referendum on EU membership".
"My ambition and my conviction is that we can come first across the United Kingdom," he told activists.
"Let us send an earthquake through Westminster politics and let's say we want our country back."
The party has sought to broaden its appeal beyond its core message of EU withdrawal, announcing policies in recent days on energy and welfare.
But, in a speech dominated by Europe, Mr Farage said the European Commission had "hijacked" the EU's original ideals and the UK would begin a process of "national renewal" by going its own way.
Those who warn that British trade would be harmed by a UK exit were the "true voices of Little England", he told party members.
"Those 10,000 trucks a day coming in from the Continent bringing goods into this country. They won't stop coming," he said.
"The idea that the EU will start a trade war with Britain is simply not credible. The real reason the EU won't be able or willing to stop trading with us is that the German car industry won't allow it."
UKIP was growing in strength and, by the time of the next election, Mr Farage said it would be the third largest party in the country in terms of membership, overtaking the Liberal Democrats.
The party is meeting just days after one of its former deputy leaders quit the organisation, frustrated by what he had described as its "totalitarian" leadership.
Mike Nattrass, West Midlands MEP and a member for 15 years, accused Mr Farage of silencing dissent and surrounding himself with "cronies".
But Mr Farage, by far the party's best-known figure, outlined his popularity with voters, saying in his speech: "They are fed up to the back teeth with the cardboard cut-out careerists in Westminster, the spot-the-difference politicians... the politicians who daren't say what they really mean."
While there was no mention of the members who quit in protest at his leadership, he acknowledged internal clashes.
Mr Farage told party members he had a "blistering row" with Godfrey Bloom, the UKIP MEP who courted controversy recently by claiming British foreign aid goes to "bongo-bongo land".
Alluding to the comments, he referred to "public pronouncements that I would not always choose myself" and urged those with passionate views to focus on the "big messages".
Immigration was the "biggest single issue facing" the UK, he said, as he warned of an "even darker side to the opening of the door".
He claimed London had been gripped by a "Romanian crime wave".
"This gets to the heart of immigration," he said. "We should not be opening our doors on 1 January to Romanian criminal gangs."
The "Establishment" had dismissed anyone wanting to debate immigration as "bad and racist", he claimed.
UKIP gained 16.5% of the popular vote, second only to the Conservatives, in the 2009 European elections and returned 13 Members of the European Parliament (MEPs).
But, at the 2010 general election, support dwindled to 3.1% and UKIP did not win a Westminster seat.
Earlier on Friday, the party's energy spokesman Roger Helmer announced it would invest profits from shale gas extraction in a sovereign wealth fund.
The two-day conference is also set to discuss plans to ensure migrants have private health insurance and for social housing to be prioritised for people whose parents or grandparents were born locally.