Nigel Farage on Todaypublished at 08:14
BBC Radio 4 Today
Is UKIP still capable of making life difficult for the main parties? How will they exercise influence? the Today programme asks.
The purpose of UKIP is to get out of Europe; but to get a referendum, don't people have to vote Conservative? John Humphrys asks the UKIP leader.
"We started as a protest movement against Britain's membership of the EU. We've moved on from that," Mr Farage says, pointing to his other manifesto commitments.
But the question is, how do we get a referendum, he says. He explains that Mr Cameron said in 2011 and 2012 it wasn't in the national interest, but now he says he is going to have a referendum.
"OK, there's only one way he can be kept to that promise - and certainly only one way we will get a full free and fair referendum - that is if there are enough UKIP MPs in the House of Commons to hold his feet to the fire."