Ukip leader Nigel Farage insisted the party could win votes from across the political spectrum as he rallied activists on Saturday.
Speaking at the party's spring conference in Exeter, 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, 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."
"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.
He said the Liberal Democrats, Labour and the Conservatives were "all the same" on immigration because they wanted an "open door" to eastern Europeans.
Highlighting fears over inflow from Romania and Bulgaria when movement restrictions are lifted, he insisted the "benefits system in this country should be there to be used by British nationals".
Mr Farage said Ukip represented the good Europeans, who wanted positive relations with other countries without being dictated to.