Rishi Sunak has repeatedly refused to rule out a leadership bid if Boris Johnson is toppled by Tory MPs over the partygate scandal.

While the Chancellor on Thursday insisted that a contest remained a “hypothetical situation”, he refused to be drawn three times on whether he would run should the opportunity arise.

Told that a number of Conservative MPs would like to see him replace Mr Johnson, he replied: “I know a few of my colleagues have said that and they’ll have their reasons for doing that, but I don’t think that’s the situation we’re in.

“Well, that’s very kind of them to suggest that, but what I think people want from me is to focus on my job,” he said in an interview with the BBC. “The Prime Minister has my full support.”

It came as government sources last night told The Telegraph that links between the Prime Minister’s advisers and the Chancellor’s aides had noticeably deteriorated in recent weeks.

While both Number 10 and Number 11 have publicly attempted to display a united front, it is claimed that the numerous revelations about parties in the former have infuriated allies of Mr Sunak.

‘Relationship is still cordial’ 

“The relationship between the principals is still cordial, but things have soured between the teams,” said one observer.

Meanwhile David Davis, the former Brexit Secretary, signalled on Thursday that he could submit a letter of no confidence in Mr Johnson within days.

Arguing that the Prime Minister had now lost the trust of “large parts of the population”, Mr Davis added that he would consult his local Conservative association on whether he should write to Sir Graham Brady, the chairman of the 1922 committee.

“I will recommend that we send in a letter, but I will take their views first,” he told Times Radio.

Should he press ahead, Mr Davis would become the 18th MP thought to have submitted a letter of no confidence, although only nine have declared publicly.

At least 54 MPs need to write to Sir Graham to trigger a vote on the PM’s leadership of the party.

However, after five called for Johnson’s resignation between Wednesday and Thursday, a source told this newspaper they feared the mood among moderate backbenchers had shifted mid-week.

Referring to the One Nation group, which loosely compromises up to 100 MPs, they added: “At the beginning of the week things were starting to calm down. But now, on the One Nation side of things, there feels like there is some movement.”

A senior MP in the group added: “There is not a plot going on, but this is a lot of people coming to their own individual decisions which in a way ought to be a much bigger worry for the Prime Minister.”

Despite growing speculation over his future, Mr Johnson on Thursday insisted he wanted to stay on until 2029.

Asked whether he would defy calls to step down, he told The Sun: “I’ve got a lot more work to do. I am getting on with the job and I will do so for as long as I have the privilege and honour to serve in this position.”

However, in a sign that tensions on Mr Johnson’s frontbench are growing, Mr Sunak said he shared the public’s “frustration and anger about the situation”.

‘He’s making the changes’

“I think it’s now the job of all of us in Government, all politicians, to restore people’s trust,” he continued.

“I think it’s right that the Prime Minister apologised as he’s done in Parliament and has committed to taking on board all the suggestions in Sue Gray’s report and making those changes.

“I share people’s frustration and anger about the situation. Of course I do. But I’m glad that he’s apologised. I’m glad that he’s making the changes that he is.”

He also confirmed that he was at one of the events subject to police inquiries – a birthday do held by No 10 staff for Mr Johnson in the Cabinet Room in June 2020.

However, he insisted that he had been there for a routine meeting to discuss the Covid situation and would not be drawn further on what took place.

“I am in the Cabinet Room for a Covid meeting much like the other 100, 200, God knows how many other Covid meetings,” he said.

“You’re asking me about something that happened almost two years ago. I went to that Cabinet Room, as I did many other times for Covid meetings. And it’s right that we allow this police investigation.”