Nigel Farage has quit from UKIP after its leader Gerard Batten appointed Tommy Robinson as a personal advisor.
Farage described Batten as being “obsessed” with Robinson and the issue of Islam.
He added that UKIP had changed since he joined the party and he warned it would be “catastrophic”.
Hosting his show, the former UKIP leader said: “The aim [of the party] was very simple, it was to take votes away from the establishment parties to force a vote in this country that would get us back our independence.”
“I made sure that UKIP talked about tough issues but we excluded anybody who had ever been part of the British National Party or the English Defence League.
“We wanted to make sure that when the abuse was thrown at us, it could not possibly be proved to be true.
“Over the course of the last few months, under this leader Gerard Batten a lot has changed and he seems to be pretty obsessed with the issue of Islam – not just Islamic extremism, but Islam.
“UKIP was not founded to be a party based on fighting a religious crusade.”
'Scuffles and violence'
Farage added that UKIP had become a party “of street activism”, not an electoral party.
“Batten has also become obsessed with this figure Tommy Robinson, whose real name is Stephen Yaxley Lennon, who is seen by some as a great hero standing up and fighting for working class people but who has a pretty suspect record,” he said.
“He brings with him a group of people, I am afraid amongst which we see the scuffles, violence and many have criminal records.
“All of this has been dragging UKIP away from being an electoral party, into a party of street activism.
“I have warned this direction is catastrophic, particularly at a time where the great Brexit betrayal is upon us.”
'Tommy Robinson is not far right'
Watch: Gerard Batten defend his decision to appoint Tommy Robinson as an advisor
Batten has defended his decision to make Robinson his personal advisor on prison reform and rape gangs.
Talking to talkRADIO's Matthew Wright, he said: “We’re not far right. I’ve never been far right, UKIP’s not far right, and Tommy Robinson’s not far right,” Batten responded.
“You may not like some of our policies or ideas - some people don’t like the idea that we want to leave the European Union but it’s not far right.
“I’ve never been far right. And Nigel’s known me for 26 years, whatever our disagreements over the years, neither of us would level that charge at each other.
“The reason I’ve asked Tommy to come on in this more high profile manner, is because he can help us connect with a lot more people out there.”