Boris Johnson has said he would be "crazy" to quit if the Conservatives are dealt a double blow by losing two crunch by-elections this week.
Voters in the Yorkshire red wall seat of Wakefield and the Devon constituency of Tiverton and Honiton are going to the polls on Thursday in another crucial test for the Prime Minister’s popularity.
But, as he headed to Rwanda for the start of a summit of Commonwealth leaders, Mr Johnson tried to manage expectations ahead of the votes.
“Are you crazy?” he told reporters travelling with him on his flight to Kigali when prospects of his departure was raised.
Mr Johnson added: “Come on, it was only a year ago that we won the Hartlepool by-election, that everybody thought was... You know, we hadn’t won Hartlepool for, I can’t remember when the Tory party last won Hartlepool - a long time. I don’t think it ever had.
“Governing parties generally do not win by-elections particularly not in mid-term. You know, I’m very hopeful, but you know, there you go. That’s just the reality.”
Although Mr Johnson won a confidence vote of Tory MPs earlier this month, 41 per cent did not back him and many of his critics in the party are watching the results of the two by-elections on Friday for signs he may have lost his election-winning touch.
The last time a Government lost two by-elections on the same day was more than 30 years ago when Tory prime minister John Major was dealt a double defeat.
Under current Conservative rules, Mr Johnson is safe from a new vote on his leadership for a year but the Tory 1922 Committee could change the rules to allow a challenge sooner.
"I'm focused entirely on delivering on the agenda of this government,” he said. “My golden rule is the less you talk about Westminster issues, the more you talk about the things you want to talk to the country about.”
Arriving in Kigali on Thursday morning for the Commonwealth Heads of Government meeting, Mr Johnson was also forced to defend his Government’s contentious plans to send illegal asylum seekers to Rwanda.
Speaking from a school in the capital Kigali, the Prime Minister said: "This is a plan that I think is absolutely necessary and right to fix the problem of illegal cross-Channel trafficking of people whose lives are being put at risk by the gangs.
"You have to break the business model of the gangs, it is totally the right thing to do.
"I think what people need to understand, what the critics of the policy need to understand, and I have seen loads and loads of criticism, is that Rwanda has undergone an absolute transformation in the last couple of decades."
He said that the country has come on "leaps and bounds" in education and in "taking the society forward".
He said that the UK and Rwanda have done an "immense amount of due diligence on the way things work, both in the UK and in Rwanda so that everything we do is in conformity with human rights, with everything you would expect".
He also said he will stress the "obvious merits" of his Rwanda asylum policy to Prince Charles when they meet in Kigali on Friday.
The Prince of Wales, who is also in Rwanda for the CHOGM summit, is said to have privately described the scheme as “appalling”.
Mr Johnson said: "I am delighted that Prince Charles and everybody is here today to see a country that has undergone a complete, or a very substantial transformation."
Asked if he will defend the deportation strategy in his meeting with Charles, Mr Johnson said: "People need to keep an open mind about the policy, the critics need to keep an open mind about the policy. A lot of people can see its obvious merits. So yeah, of course, if I am seeing the prince tomorrow, I am going to be making that point."