Rishi Sunak has hinted that he wouldn't take a Cabinet post if his rival Liz Truss wins the Tory leadership race.
The former Chancellor insisted he was "not thinking about jobs for me or anyone else" as the bitter contest to be the next Prime Minister enters its final weeks.
But he gave his strongest signal yet that he wouldn't accept a job from Ms Truss if she wins, saying he had learned that "you really need to agree on the big things" in Government in a nod to his time in the Treasury.
Mr Sunak's resignation as Chancellor last month after clashes with Boris Johnson was widely credited with opening the floodgates on the rebellion that torpedoed Mr Johnson's premiership.
But Mr Sunak's hopes of succeeding him are fading as Foreign Secretary Liz Truss' popularity with Tory activists surges.
Some members have expressed anger at Mr Sunak over his role in Mr Johnson's downfall.
Mr Truss is reportedly considering offering her rival the role of Health Secretary if she wins power in September.
Asked if he would take the job, Mr Sunak told BBC Radio 2: "I'm not focused on all of that and I doubt Liz is to be honest.
"I'm focused on just getting out and about and trying to win this race at the moment.
"I'm not thinking about jobs for me or anyone else.
"One thing I have reflected on as well a bit is, you know being in the Government and the Cabinet over the last couple of years, that you really need to agree with the big things because it's tough as I found if you don't.
"I wouldn't want to end up in a situation like that again."
The winning candidate usually offers a top job to their rival - partly to keep them inside the tent rather than allowing them to make trouble.
Boris Johnson offered his defeated rival Jeremy Hunt a Cabinet post in 2019 but Mr Hunt declined the role.
He returned to the back benches and later became a vocal critic of the Prime Minister in his role as Chairman of the Commons Health Committee.
Ms Truss has said she would let her rival serve in Government but the bitter nature of the race has raised questions about whether she will follow through on this offer - or if Mr Sunak would even accept.
In the same interview, he accused his rival of "promising the earth to everybody" with her tax cutting plans, which have prompted alarm among some economists.
"I don't think you can have your cake and eat it," Mr Sunak said.
"I don't think life's that simple, and I think her plan risks making the situation worse when you're borrowing that much money for tax cuts at a time when inflation's already going up."
He addressed his underdog status in the contest and claimed he was still receiving a "warm reception" despite anger among some members over his resignation.
Mr said: "If I actually spent all my time looking at the polls or reading newspapers, I probably wouldn't get out of bed in the morning to do all these things."
"There are a group of people among our members, and that is understandable, who are upset I resigned from Government," he admitted.
