Anthony Scaramucci, Donald Trump’s former communications director, believes the US president is a "political genius" who used Twitter to win the election.

Addressing the Oxford Union on Monday night, Mr Scaramucci discussed how Mr Trump defeated Hillary Clinton in November, despite the Democratic nominee's greater financial clout.

"I firmly believe that President Trump, without the tool of Twitter, likely would have not won," Mr Scaramucci said.

"Trump was outspent by Clinton by 1.7 times, she had 2.4 more personnel than us. It’s not clear to me that the money is as important as the ideas.

"You have to accept he’s a political genius. In 19 months, he went from 0 to POTUS (President of the United States). You can’t say there wasn’t some level of genius in terms of his judgment."