Nigel Farage has been elected leader of the UK Independence Party (UKIP) to replace Roger Knapman.
Mr Farage will continue to lead the party's MEPs
Mr Farage is an MEP for the South East and already UKIP's leader in the European Parliament.
Mr Farage gained 3,329 votes out of 7,574 cast, Richard Suchorzewski was second, David Campbell-Bannerman third and David Noakes fourth.
Mr Farage pledged to make UKIP a "truly representative party", ending its image as a single issue pressure group.
At a news conference after the count, Mr Farage explained what he hoped to achieve.
"There is now an enormous vacuum in British politics.
Nigel Farage: 3,329
Richard Suchorzewski: 1,782
David Campbell Bannerman: 1,443
David Noakes: 851
Spoiled votes: 169
"David Cameron clearly has decided to abandon Conservatism, and on the big issues of the day you cannot put a cigarette paper between the three major parties.
"There is no real voice of opposition out there today, and the UK Independence Party - I know we're known as being a single issue pressure group - well we're most certainly not going to be a single issue pressure group in the future.
"We're going to be a party fighting on a broad range of domestic policies and together if we're united and disciplined we will become the real voice of opposition in British politics."
He said he intended to make UKIP "a fully-fledged political party that is offering the public a real choice".
'Right of centre'
Mr Farage said UKIP would aim to field 500 candidates at the next general election. He said it was his intention to move away from just the single issue of Europe and campaign on "lower, simpler, flatter taxes", selective education and giving Britain its own independent trade policy.
He said he wanted to give people a voice, particularly those who felt they could no longer vote for the Conservatives. He added: "People may place us as being right of centre, I would place us as being in the centre of public opinion."
Mr Farage's next closest rival Richard Suchorzewski polled 1,782 while David Campbell Bannerman got 1,443 and David Noakes 851. There were 169 spoiled votes.
UKIP's best known policy is a pledge to withdraw the UK from the European Union if it is elected into power.
UKIP has never had anyone elected to the House of Commons, but gained 12 Euro MPs when it finished third in 2004's European Parliament elections, with 16% of all votes.
The party did not do as well as it had hoped at last year's general election, losing its deposit in more than 450 seats, but it has begun to establish itself as a force in Westminster by-elections, coming third in two recent contests.