Sir Vince Cable will call on Theresa May to display "true leadership" and hold a second Brexit referendum.

In his speech to Lib Dem conference, Cable is set to say May is "delivering a policy she doesn't believe in; failing in negotiations; losing public support" in order to appease Brexit "extremists."

He will accuse hard Brexiteers like Jacob Rees-Mogg of having an "erotic" fixation with leaving the EU.

Cable will address conference amid intense speculation about his leadership.

BRIGHTON — Sir Vince Cable will use his keynote speech to Lib Dem conference to accuse hard Brexiteers like Jacob Rees-Mogg of having an "erotic" fixation with crashing out of the European Union.

Speaking in Brighton on Tuesday morning, Cable will say hard Brexiteers in the Conservative party want to create "years of economic pain justified by the erotic spasm of leaving the European Union."

Cable will also say he is "starting to feel sorry" for Theresa May, who he will claim is "delivering a policy she doesn't believe in; failing in negotiations; losing public support" in order to appease pro-Brexit "extremists."

The Lib Dem leader will call on Prime Minister May to display "true leadership" by giving the British public a People's Vote — a referendum on the final Brexit deal — after Article 50 negotiations come to an end next year.

"She [May] could admit that the Brexit project has gone badly wrong... by conceding that the deal — any deal, or no deal — that she will bring back from Brussels is not going to be better for Britain than remaining in the EU.

"Instead of kowtowing to her enemies in the Conservative Party, she could lead her party and the country by opening her mind to a 'People's Vote' on the final deal," the former minister is set to say.

On Monday, Lib Dem members voted overwhelmingly for a motion calling on the UK government to cancel Brexit by revoking Article 50 if there is no Withdrawal Agreement the beginning of March 2019. A Lib Dem source told BI that this should be the last resort, and used only if the EU refused to extend Article 50 negotiations.

Cable addressed the Lib Dems' annual autumn conference after weeks of speculation about his own future.

This month the former minister confirmed a Business Insider report that he plans to resign as Lib Dem leader prior to the next scheduled general election in 2022, with 2019 being the likely year of his departure.

Gina Miller, the anti-Brexit campaigner who took May's government to court in 2016, ruled herself out of the race to succeed Cable on Monday, telling the conference: "I am not addressing you as your leader-in-waiting."

Miller has been tipped as a potential successor with the party set to pass reforms which will allow non-MPs to stand in future leadership contests, and people who aren't full party members vote in them.