(Bloomberg) -- Can they trust him? That’s the question Britain’s Conservatives face as they consider whether they really want Boris Johnson to become the next prime minister.

Johnson has what looks like an insurmountable lead in the race to succeed Theresa May and a campaign focused on private meetings with potential backers has won him support from Tories on both ends of the Brexit debate. The biggest risk to his chances now could be that one of the factions decides they can’t trust him.

There’s plenty of evidence they shouldn’t.

From the very start of Johnson’s career, when he was fired from the Times newspaper for fabricating a quote, he has left employers and colleagues feeling that he deceived them. As editor of the Spectator, he promised his proprietor, Conrad Black, that he wouldn’t run for Parliament. He ran for Parliament.

As an MP, he assured Tory leader Michael Howard, who had appointed him arts spokesman, that reports of a long-running affair were untrue. They were true. Running to be mayor of London, he promised not to close ticket offices on the London Underground. He closed them.

Even Johnson’s long-term employer, the Telegraph newspaper, has been forced to confront questions about his reliability. Defending itself this year against a complaint that Johnson had made inaccurate claims about polling, the newspaper argued that his article was “clearly comically polemical, and could not be reasonably read as a serious, empirical, in-depth analysis of hard factual matters.’’ The press regulator was unimpressed, and told the newspaper to run a correction.

“He’s lied his way through life, he’s lied his way through politics, he’s a huckster with a degree of charm to which I am immune,” Chris Patten, a veteran europhile Conservative said in an interview with Bloomberg Television last month. “As well as being mendacious he’s incompetent.”

To Johnson’s supporters, the examples people use against him are from too long ago to be relevant. "People should look at what Boris has delivered," a spokesman for the candidate said. "He delivers more than he promises, whether it is election victories, his successes as mayor of London, or his central role in expelling Russian diplomats from Western nations over the Skripal poisoning, his record is continually impressive."

Define Trustworthy

Yet Johnson’s campaign launch on Wednesday was marked by questions about his trustworthiness. One journalist asked: "Can the country trust you?" He replied: "Yes of course."

Johnson invited voters to judge him on a specific definition of trustworthiness. "The key issue here: Do I do what I promise I’m going to do as a politician? That is the issue," he said. "And the answer to that is yes. You look at what we did in City Hall."

But what he’s promising as a politician now -- a wholesale overhaul of the Brexit deal -- is something the European Union says is impossible. EU leaders who already view him with suspicion may be reluctant to help.

Alistair Burt served as a minister in the Foreign Office alongside both Johnson and his nearest rival, Jeremy Hunt, the current Foreign Secretary. He is backing the latter. "Boris has many qualities that could make him a good leader for the United Kingdom,” he said in an interview. "But I think Jeremy Hunt has demonstrated more in terms of the diligence that is required in some pretty difficult ministries and in his ability to master his brief."

Private Promises

If Johnson wins the negotiation with Brussels, he can probably keep all his supporters on board. If he doesn’t, he will have to choose whom to let down. It’s the same dilemma May faced. When she finally made her choice, her downfall was inevitable.

One hardline Brexit-backing Tory MP is determined it won’t be his faction that’s betrayed. Speaking on condition of anonymity, he said Johnson has promised that May’s deal is dead. Whenever he is asked about it, he must say that the withdrawal agreement that May negotiated with the EU has failed and won’t be revived.

If Johnson backslides in his commitments, the staunchest euro-skeptic Tories will withdraw their support for him, even if he’s prime minister by then, the MP said.

That suggests a Johnson government could soon become as fragile and fractious as May’s.

Johnson has been sitting down with MPs one-on-one and discussing their concerns. He’s met some two or three times. His campaign officials say it’s more productive than public campaigning. But it also creates the possibility for different MPs to take away different messages.

Steve Baker, a leading Brexiteer who wants a complete renegotiation or a no-deal exit, said he is backing the former foreign secretary. Priti Patel, a pro-Brexit Conservative who was in the Cabinet with Johnson, is supporting him too.

“At last the British people can feel they have a political leader listening to what they want and who can be trusted to deliver for Britain,” she said in an interview.

Johnson’s team has also convinced three junior ministers who previously backed May’s deal. Oliver Dowden, Rishi Sunak and Robert Jenrick said in a joint article that Johnson has “instant credibility," and signaled they expect him to deliver a quickly renegotiated agreement. Their view might be bolstered by the fact Johnson himself eventually voted for May’s deal -- but only after she’d promised she would stand down once it passed.

In another example of fine-tuning the message to the audience, Johnson told MPs this week he wouldn’t be in favor of suspending Parliament as a way of achieving a no-deal split. The Times then reported he’d told Brexiteers in private that he isn’t ruling it out.

Wrong Impression

It wouldn’t be the first time he’d been caught out by confusion about what he had promised. In the aftermath of the 2016 referendum, fellow Brexiteer Andrea Leadsom was under the impression that he’d said he’d make her Chancellor of the Exchequer if he became prime minister. It was her belief that he had reneged on this deal that spurred her to run herself.

So why are Tories backing him now? Perhaps they are ambitious for their own careers -- it makes sense to back the winner. Another reason is that they think Johnson will keep winning.

The Tories will need a charismatic and pro-Brexit leader to avoid defeat if an election is called soon. The combined threat of Nigel Farage’s new Brexit Party and Jeremy Corbyn’s alternative Labour government is enough to make nervous Conservative MPs overcome any misgivings and flock to the man who won two terms as London mayor and led the victorious Leave campaign in the 2016 referendum.

After all, if Johnson can convince MPs to back him, maybe he can convince the country to do the same.

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To contact the reporters on this story: Robert Hutton in London at rhutton1@bloomberg.net;Tim Ross in London at tross54@bloomberg.net

To contact the editors responsible for this story: Emma Ross-Thomas at erossthomas@bloomberg.net, Stuart Biggs

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