Boris Johnson has vowed to withhold Britain’s £39bn Brexit “divorce” payment until the EU agrees better terms for the UK to leave.

Withholding the cash, scrapping the Northern Ireland backstop, guaranteeing the rights of all EU citizens in Britain while stepping up preparations for a No Deal “disruption” in the wake of no deal are among measures the government would carry out if he was elected leader of the Conservative party, he said.

Failure to deliver Brexit, with or without a deal, by the October 31 deadline threatened the Tory party’s very survival, he warned. He said he thought it “extraordinary” the UK agreed to write the so-called divorce cheque before having the final deal signed.

“I think our friends and partners need to understand that the money is going to be retained until such time as we have greater clarity about the way forward,” he said in an interview with the Sunday Times newspaper. The money, he said, was a “great solvent and a great lubricant” in getting a good deal.

Johnson is an early favourite to win the Conservative Party leadership race. An opinion poll of grass roots party members by the ConservativeHome website on Saturday put Johnson in the clear lead at 43 per cent with Michael Gove second on 12 per cent.

In the interview Johnson claims he has “forgiven” Michael Gove for his betrayal during the 2016 leadership contest, suggesting he could give Gove a cabinet role if he was elected party leader.

He maintained that he was the only candidate who could beat both Labour and the Brexit party. “I truly believe that only I can steer the country between the Scylla and Charybdis of Corbyn and Farage and onto calmer waters,” he said.

This can only be achieved by delivering Brexit by the end of October and returning to One Nation Tory policies in the UK he added.

Johnson refused to commit to television leadership debates being organised by the BBC , ITV and Sky.

Communities secretary James Brokenshire gave his backing to Johnson on Saturday, saying he has the “character, the ingenuity, the resilience and an ability to convey a compelling message”.

Scottish Tory leader Ruth Davidson endorsed home secretary Sajid Javid.