Sir Vince Cable will compare Boris Johnson to a dictator in his first conference speech

Sir Vince Cable will use his first conference speech as Lib Dem chief to compare Boris Johnson to a dictator and Jeremy Corbyn to the brutal Venezuelan socialist tyrant Nicolas Maduro.

He will attempt to paint the Tory and Labour parties as extremist to appeal to centrist voters.

And the 74-year-old veteran will say it is time for “political adults” in the Tory and Labour parties to join him to reverse Brexit.

Sir Vince will challenge Mr Johnson and fellow Brexiteers to defend any deal struck with Brussels in a new referendum.

He claims their opposition to a second vote is the “slogan of dictators – one person, one vote, once.”

The new Lib Dem boss will say: "We believe the public have a right to change their mind.

"At the end of these tortuous divorce negotiations, the British public must be given a vote on the outcome."

Sir Vince will also take aim at Mr Corbyn – highlighting criticism of his failure to condemn President Maduro’s bloody suppression of opponents over the summer.

He will say: “Jeremy Corbyn’s acolytes are focused on how to maximise the contradictions of capitalism.

"You don’t qualify for the Shadow Cabinet these days unless you have studied the Venezuelan guide on how to bankrupt a rich economy.”

"No wonder they back Brexit. No wonder they lined up behind Theresa May, maximising the chance of chaos and disruption.”

Sir Vince, who will be 79 by the time of the 2022 General Election, will risk drawing attention to his age by saying the country “what the country desperately needs is some political adults”.

He will say: "There are sensible grown-ups in the Conservative Party, and the Labour Party and the Greens.

"We have to put aside tribal differences and work alongside like-minded people to keep the single market and customs union, essential for trade and jobs."