Godfrey Bloom, the colourful former Ukip MEP, has resigned from the party with a warning to its newest recruit, Douglas Carswell, to beware backstabbers among his colleagues.

The politician, whose gaffes have included calling women sluts and complaining of foreign aid going to “bongo-bongo land”, said he was leaving Ukip after party chairman Steve Crowther banned him from speaking at an event in Wearside.

Bloom initially had the Ukip whip withdrawn and subsequently resigned his official role last year, after Nigel Farage said his antics had overshadowed the party’s autumn conference.

He has now decided to leave the party entirely “with a heavy heart”, despite having had a role in founding Ukip and donating large amounts of money to campaigning over the years.

In a message to Carswell, who took up his role as Ukip’s first elected MP on Monday, Bloom told LBC Radio: “I would just say to Douglas: stick to your sort, you believe in libertarianism, you believe in classical liberal economics, don’t be pushed off. But I would say, Douglas, watch your back. If you bear in mind we started in 2009 in Europe with 13 MEPs, we ended up with five, so there are dead bodies of Ukip [politicians] all over the place with a knife quivering in their back, Douglas. Make sure it’s not yours.”

In a trenchant analysis of his former party, the ex-MEP said politics was not about the truth, and that he was “very sorry this disease has been picked up by Ukip”. “It seems to be drifting towards the politically correct mainstream like everyone else,” he said. “Instead of it being the libertarian party of common sense, I’ve been banned from speaking. I don’t know where the party has gone astray, but it has gone astray.”

Despite having formerly shared a flat with Farage in Brussels, Bloom said he had lost contact completely with his former party leader. He said Ukip was now being run by Crowther, who he described as a “svengali-like” figure and a “man of mystery”.

Bloom caused a controversy in summer last year after he criticised recipients of foreign aid in “bongo-bongo” land and proceeded to exacerbate the row by trying to justify the phrase in a series of broadcast interviews. He then became the centre of another row after hitting a journalist round the head with a Ukip brochure and joking that a room debating women in politics was “full of sluts”. He made these remarks after two of his colleagues admitted that they did not clean behind the fridge – a complaint previously made by Bloom – as they spoke at a fringe event at the party conference in London.

Bloom was then caught on camera ranting at Channel 4’s Michael Crick, who asked him why there were no black faces pictured on a Ukip conference brochure, before using the pamphlet to hit him over the head.

After Bloom resigned from the party, he gave an interview to the Guardian claiming Farage was “not interested in the running of the party, or in making policy” but was merely Ukip’s chief salesman.

In April, he argued Farage was not up to the role of “managing director or chairman of the board”, even though he was a “charismatic” and “articulate” advocate for the Ukip brand.

Farage, who described Bloom’s comments as “unhelpful”, has made repeated attempts to ensure Ukip candidates stop making off-colour and eccenrtic remarks by trying to “professionalise” the party. He has appointed a new raft of spokesman to his frontbench over the summer including more women and ethnic minority representatives.