Boris Johnson will not push for the prime minister to leave office before she has ratified a Brexit deal, according to friends of the former Foreign Secretary

The ardent Brexiteer is the bookies' favourite to replace Theresa May, but allies are said to believe Theresa May should stay in to negotiate the difficult attempts to pass the withdrawal deal.

"They're not going to push for her to go. They can't see any advantage of her standing down now," said one Tory MP familiar with his team's thinking.

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LONDON — Boris Johnson will not push for Theresa May to quit as Conservative party leader before Brexit, friends of the current frontrunner to become Britain's next prime minister have told Business Insider.

The former foreign secretary and ardent Brexiteer is the bookies' favourite to replace Theresa May, who has promised to stand down once she has ratified a withdrawal deal with the EU.

Pro-Brexit Conservative MPs are desperate for May to be ousted within weeks, following her decision to allow Britain's exit to be delayed by another six months.

However, Johnson's allies say he will not put public or private pressure on the prime minister to stand down before Britain's departure, preferring to let May lead the difficult attempts to pass a Brexit deal in parliament.

"They're not going to push for her to go," said one Conservative MP familiar with Johnson's campaign's thinking. "They can't see any advantage of her standing down now."

Johnson today used his regular column in the Daily Telegraph to point towards the Conservative party's future after Brexit.

He wrote that there would be a "pent-up tide of Tory ideas," that would "flood the country" after Britain has left the EU, followed by an "outbreak of unity" in the party.

Cabinet rivals to succeed Theresa May are also backing the prime minister to stay in Downing Street until autumn, and have made clear privately that they do not want a leadership contest before the first stage of Brexit is resolved, according to a Times report.

It forms part of a growing consensus among her colleagues that the prime minister has no intention of leaving Downing Street before she passes her deal.

Conservative party rules mean MPs cannot vote to remove Theresa May from office until December due to a failed coup before Christmas.

One minister told Business Insider last week : "She is a limpet and I don't think she will stand down until her deal goes through."

Chancellor Philip Hammond also hinted over the weekend that the prime minister would stay on until she had passed her deal, which could come as late as October, when the UK's new Brexit deadline expires.

Theresa May told colleagues in March that she would stand down in the second phase of Brexit negotiations and make way for a new leader, but many MPs believe her failure to pass a deal means she should go sooner to make way for a summer leadership contest.

Former Conservative leader Iain Duncan Smith this weekend called publicly for the prime minister resign next month.

"I know that the prime minister has already said she’s going. She said she would go as and when the agreement was ratified, which was looking at around about May, June. I think those dates still stand," he told Sky’s Sophy Ridge on Sunday.

One Conservative MP said that vocal Brexiteers such as Johnson and Dominic Raab, another frontrunner, appeared to see little appeal in taking over from the prime minister before she had passed a Brexit deal held because they have made undeliverable pledges to re-open the Brexit withdrawal agreement, something the EU has repeatedly rejected.

"Both Raab and Boris would immediately disappoint on day one because they can't change the withdrawal agreement," said one Conservative MP.

Johnson's nascent leadership campaign has also received a boost in the shape of James Wharton, a former Tory MP who has joined his campaign team.