Ukip members are an "awkward group of strange people", the Conservative MP in charge of piloting David Cameron's EU referendum Bill through parliament has said.
Speaking at the Conservative Party conference in Manchester on Tuesday evening, James Wharton said Tories should not "over-simplistically view Ukip as an EU protest vote" but predicted Nigel Farage's party would not be that effective at the 2015 general election.
"What will be interesting will be when Nigel Farage stands down as leader of Ukip," Wharton said. "Because they are a one man band."
"He has stood down before. He doesn't actually like leading Ukip. It's a very awkward group of strange people. I suspect once he has gone through the European elections he will very quickly get bored of trying to hold the rabble together and may go."
He added: "When you build a party around one individual you are very vulnerable to changes to that individual."
Wharton, who was put in charge of the European Union (Referendum) Bill by chance after winning the private members bill ballot, also warned that Ukip was "undoubtable a very dangerous" and "pernicious force in European elections". He added: "They'll pick up the BNP vote."
And he warned Tory voters not to lend their vote to Ukip at the 2014 EU elections, as Farage had asked. "They need to meet some of these people and find out what the are like."
Wharton's comments are not quite as harsh as when Cameron "fruitcakes, loonies and closet racists" - a statement the prime minister later said he regretted - but it is close.
Farage spent Monday on the fringes of the Conservative conference trying to draw attention away from the main hall at senior Tories including George Osborne and flirting with some Tory backbenchers with talk of a pact.
However Wharton said his colleagues on the Conservative benches should not be too worried about losing votes to Ukip. "They will not be anywhere near as affective in a general election," he said.