Robert Jenrick has told Tory members there will be no deal with Nigel Farage if he is elected leader of the party to replace Rishi Sunak.
The former home office minister, who resigned because he did not think Mr Sunak was strong enough on the Rwanda deportation flights, has emerged as the leading candidate of the right in the leadership race.
Speaking at an event in Upminster in Essex this week, Mr Jenrick told party members that he plans to win back Tory voters who defected to Farage’s Reform.
But unlike fellow right-winger Suella Braverman – who is leading in support among party members but struggling to get enough MPs to nominate her – Mr Jenrick said there would be no deal with Mr Farage.
In June, Ms Braverman suggested the Conservatives should welcome Mr Farage into the party as there was not much difference between the Tories and Reform.
Mr Jenrick’s rebuff came after it emerged that Reform fears his nomination most of all and hopes his rival Tom Tugendhat, associated more with the centrist One Nation members of the party, wins instead.
A number of sources claimed that former Tory MP turned Reform UK MP Lee Anderson said Mr Jenrick “would provide the biggest problem”.
Mr Anderson denied this and told The Independent: “None of them worry us. Just look at their majorities.”
But allies of Mr Tugendhat believe he can follow in David Cameron’s footsteps in the leadership election, arguing that he could win the leadership race by establishing himself as the frontrunner at the party conference.
The former prime minister, now Lord Cameron, was the unexpected victor of the 2005 contest, despite starting behind the bookies’ favourite, David Davis.
But a star-making speech, delivered without notes at that year’s gathering of the party’s rank-and-file, transformed his electoral fortunes.
As the standard bearer of One Nation Tory MPs, Mr Tugendhat could still struggle to win over more right-leaning Conservative members if he makes it to the final two.
An ally of Mr Tugendhat said: “One thing people misunderstand about the membership is how much they want to win power. Yes, they are more to the right at the moment. But what they will be looking for is a candidate who can win and who can make sure they are back in No 10 sooner rather than later.
“They also realise they made a mistake with Liz Truss and are determined not to do that again. They will be looking for a winner and for whoever establishes themselves as that person – like David Cameron did.”
Ms Truss lasted less than two months as prime minister before she was ousted by her own MPs. She was replaced by Rishi Sunak, but he announced his intention to step down as leader after a disastrous general election result earlier this month.
He is staying on as interim leader while the party spends the next four months choosing his successor.
Mr Tugendhat and Mr Jenrick have both secured the backing needed to get through to the next stage, before nominations close on Monday afternoon. Former home secretary James Cleverly has also got the necessary nominations, as has former work and pensions secretary Mel Stride.
Ex-business secretary Kem Badenoch, who has accused rivals of playing dirty tricks against her, and another former home secretary, Priti Patel, are also expected to be on the ballot paper.
MPs will whittle down the list of contenders to a final two, before allowing the party membership to choose.
Before that stage, however, there will be a “beauty parade” at the party’s annual conference, during which the applicants will try to establish themselves as the frontrunner for the job.