RUTH Davidson has confirmed she would canvas on the doorstep for Boris Johnson if he becomes Prime Minister, despite previously being one of his sharpest critics.

The Scottish Tory leader told Radio 4’s Today programme she still wanted her preferred candidate, the Home Secretary Sajid Javid, to win the Tory leadership contest.

However she was ready to back Mr Johnson against Labour leader Jeremy Corbyn.

She also said Tory members who thought Scottish independence was a price worth paying for Brexit should “take a long hard look at themselves” and “be careful” what they said.

Ms Davidson, who campaigned in 2016 for Remain against Ms Johnson, the leader of the Leave campaign, has previosuly said he is not truthful or serious enough about Brexit.

She even banned the frontrunner to replace Theresa May from her party’s recent spring conference in Aberdeen.

READ MORE: Ruth Davidson bans Boris Johnson from Scottish Conservative conference

Asked if she thought Mr Johnson would make a good Prime Minister, Ms Davidson said: “Em, obviously I believe that Saj would make a better one, that’s why I’m backing him over any of the other candidates, Boris included.

“But I think that you can never tell how someone’s going to perform in the office of Prime Minister until they assume that office.

“It is so unique, it is so unlike anything else out there, that it’s very hard to say that past performance will give you an indication of what happens next.”

Asked whether she had changed her previous low opinion on the former Foreign Secretary, she said haltingly: “Well I think that, um, er, I have challenged Boris Johnson, I’ve challenged lots of colleagues when I think they’ve merited challenging.

“I think in terms of the debates on Brexit, what I said, I didn’t call him a liar, I said that the people out there deserved the truth, and they did, and I stand by that.

“And if there’s something which I think deserves challenging, if he does end up in public office again, then I won’t resile from that, and I don’t think he would expect me too either.”

READ MORE: Kevin McKenna: Prime Minister Boris Johnson spells disaster for Ruth Davidson

Interviewer Sarah Smith then asked the Edinburgh Central MSP if she could go into an election campaign, knocking on doors and telling voters she believed Mr Johnson would be the best Prime Minister for the country, and whether she would expect voters to believe her.

Ms Davidson replied: “Up against Jeremy Corbyn? Yes.”

A YouGov poll published on Tuesday found 63 per cent of Tory members UK-wide said they would be willing to accept Scottish independence in return for Brexit being delivered.

Ms Davidson said: “I think that there are members of our party that responded to this poll that need to take a long hard look at themselves, quite frankly.

“Because yes I understand that referendas [sic] need to be respected. I’ve always said that, whether it’s been the Scotrtish independence referendum result, whether that’s been the Brexit referendum result even though I was on the winning side of one and the losing side of the other. Yes we need therefore to get Brexit over the line.

“But , you know, at the expense of breaking up the United Kingdom? I think probably what’s most likely is that Conservative members don’t believe it’s an either/or, and therefore it’s an easy question for them to answer. But I think they really need to be careful, because there are people across this country who read that.”

None of Ms Davidson’s 13 MPs have publicly backed her choice for Prime Minister.

In Tuesday’s second round of voting, six went for Michael Gove, four for Mr Johnson, one for Jeremy Hunt, one for Rory Stewart, and one was keeping his counsel.