A former Breitbart editor referred to Donald Trump as 'a turd tornado' days after the GOP candidate hired a boss from the conservative news website to his campaign team.

Ben Shapiro, who left Breitbart after it declared its support for Trump, made his feelings for the Republican nominee perfectly clear when asked about the website's executive Steve Bannon joining Trump's campaign team.

"As you probably know, I think Donald Tramp is a turd tornado, but I also understand that he has no capacity whatsoever to control himself and be the sort of staid politician that so many people want him to be," Shapiro told CNN.

"So telling him to double down is not necessarily a terrible strategy. If he is going to go down, he is going to go down being Trump and that's probably what Steve Bannon is telling him to do."

Asked to clarify what he meant by 'turd tornado' by CNN presenter Brianna Keilar, Shapiro replied: "A turd tornado. It's like a 'Sharknado' except with poop."

Shapiro has been outspoken in his dislike of the GOP candidate since leaving Breitbart, referring to him as a 'bully' and stating when he left the website that Bannon had 'sold out' by supporting Trump.

His departure from the website came after an incident in which then-Trump campaign manager Corey Lewandowski was accused of grabbing Breitbart reporter Michelle Fields. Shapiro and Fields resigned after the incident stating the website had not given Fields any support over the matter.

In an op ed for Daily Wire, Shapiro responded to Trump's appointment of Bannon by stating: "The new team at Trump headquarters will undoubtedly include all the Breitbart staffers who openly lusted after power within the Trump campaign."

He added: "Bannon is a smarter version of Trump: he's an aggressive self-promoter who name-drops to heighten his profile and woo bigger names, and then uses those bigger names as stepping stools to his next destination. Trump may be his final destination. Or it may not."

Shapiro also accused Bannon of leading Sarah Palin on the path from 'legitimate political figure to parody artist to Trump endorser' and suggested the Breitbart boss would do anything for power.