Ukip leader Nigel Farage has insisted the party can win votes from across the political spectrum as he rallied activists.
Speaking at the party's spring conference in Exeter, Mr Farage said there was a "wholesale rejection of the career political class going on".
But he argued that Ukip's recent second place in the Eastleigh by-election - knocking the Tories into third - was about more than protest votes.
In a swipe at David Cameron, Nick Clegg and Ed Miliband, Mr Farage said the public was tired of people who viewed politics as a profession.
"We have really had enough of them," he said. "They really do all look the same... they all go to the same schools, the same Oxbridge colleges. None of them has ever had a job in the real world and not one of them is in politics for principle. That is what we stand for."
Mr Farage said his party was drawing in support from all parties and none - pointing out that many of their backers in Eastleigh had not voted for decades.
"Please don't just think that it is just tired Conservatives that are coming to Ukip," he said. "We are drawing our support from across the spectrum."
He admitted that some of their new voters were eager to "stick two fingers up to the establishment".
But he added: "It is something far more powerful than a protest vote. Actually the vast majority of the people going out and voting Ukip in these by-elections do so because we are the people that are putting forward positive alternative policies that would make this country a better and prouder place."
Mr Farage went on: "We're not hamstrung by political correctness, we are not afraid to take on the issues that others would simply brush under the carpet."