Reform UK would not take Liz Truss in the party - despite a string of senior Tories jumping ship in the last few days alone.
GB News understands the former Prime Minister would not be accepted in Nigel Farage's ranks, with the party chief having publicly denounced claims Reform was becoming "Conservatives 2.0."
Farage has confirmed talks with serving Tory MPs - but has remained coy about the chances of an imminent defection, saying candidates are "watching and waiting".
The Reform leader also said he would be "picky" about which Conservatives he would accept, after welcoming ex-Welsh Secretary David Jones and former Tory chairman Jake Berry in the last week.
One insider said that hiring the ex-PM would be a 'non-starter'
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He added that Truss linking up with the surging Reform would spark "a lot of internal debate".
While one insider told the Mail that hiring the ex-PM would be a "non-starter" as she has "far too much baggage in the public's mind".
Former Home Secretary Suella Braverman is also said to be unwelcome in the party, despite her husband Rael switching blue for turquoise last year.
She is "not a team player", one source claimed, adding: "Her record shows she is just too disruptive."
And today, Mr Braverman released a cryptic one-word message on social media after reports emerged that his wife may be barred from joining Reform.
"Awkward," he said.
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Farage has confirmed talks with serving Tory MPs - but has remained coy about the chances of an imminent defection
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In January, GB News revealed that defection talks with potential joiners had been ruthless after influential conservative commentator Tim Montgomerie and former Tory donor Nick Candy joined Reform's ranks.
Then-chairman Zia Yusuf revealed that the series of defections came without any outreach whatsoever.
"We aren't going to take everyone who wants to join," an insider said. "Some just aren't for us."
A source closely connected to Reform also told Britain's News Channel: "Other former Tory MPs were milling around, so they're clearly discerning about who they are bringing in."
Kemi Badenoch has voiced her fury about her party's departures
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But Conservative leader Kemi Badenoch has voiced her fury about her party's departures.
Ex-Tories who went on to join Reform "were never Conservatives to begin with," she said.
"If there are people who call themselves Conservatives, who like that policy platform, my view is that they were never Conservatives to begin with," Badenoch blasted.
"We need to be the authentic, centre-right Conservative Party, and if people don't like personal responsibility, living within our means, strong borders and making sure that we don't bankrupt ourselves on net zero, then we don't mind if they go to Nigel Farage's party."