Roger Lord, who had been the Ukip general election candidate for Clacton until Douglas Carswell jumped ship yesterday, has called the Tory defector an "idiot".
"If somebody pushes me, I'm going to push back," he said. "Has he [Carswell] got a membership card? I'm not sure he's officially a member yet."
Mr Lord told ITV News Political Correspondent Libby Wiener that Mr Carswell "could have said sorry, but he hasn't got the guts to do it".
More top news
Michel Platini has formally announced that he intends to stand for the Fifa presidency when Sepp Blatter vacates the position
Microsoft's new system Windows 10 has been met with approval after its disastrous predecessor but users have yet to be entirely convinced.
Alton Towers crash victim Leah Washington, who lost a leg as a result of the horrific incident, celebrated her 18th birthday last night.