Moderate Conservatives are threatening to throw out their ballot papers after Kemi Badenoch and Robert Jenrick were selected as the final two candidates in the battle for the Tory leadership.
A supporter of James Cleverly said moderate members told him they were putting their ballots "in the trash" after the surprise departure of their candidate, considered the most centrist.
Both Mr Jenrick and Ms Badenoch are seen as on the right of the party. Mr Jenrick vows to withdraw from the European Convention on Human Rights, while Ms Badenoch has taken a stand against the 'woke' policy.
It raises the prospect of a damaging division in the party, with those at the center feeling they have no say in its future direction.
It is believed Mr Cleverly has no intention of backing Ms Badenoch or Mr Jenrick in the near future.
It comes as a blame game broke out over Mr Cleverly's shock elimination from the race on Wednesday. Furious Tories accused MPs of "freelancing" in a deceptive game of tactical voting, while others pointed the finger at Grant Shapps, Cleverly's campaign manager, who famously puts his supporters on a spreadsheet.
A Cleverly supporter said: "There is a huge amount of disappointment among members with the outcome of the final vote.
"This morning I have already had a dozen members tell me they are going to throw their ballots in the trash because they are being denied their vote."
The MP said many were angry that Mr Cleverly had been eliminated, even though there was general agreement that his leadership speech had been best received among activists at the Tory conference.
"Not only did James have a good conference, perhaps more importantly, the others didn't," he said.
"If the party is trying to persuade young people and women to vote for the party again, it seems like suicide to downplay maternity benefits like Kemi did.
"If the party stands for the rule of law, why should we talk about special forces carrying out extrajudicial killings, as Robert did?
"They both had bad conferences and showed they couldn't hold their ground under fire."
It comes as the Tory Reform Group, which represents those in the party's centrist 'one nation' wing, refused to back either of the final two candidates.
The TRG, whose president is Lord Clarke, the former chancellor, said it could not support either remaining candidate because they had both used rhetoric that is "a far cry from the party at its best".
The group describes itself as "the home of One Nation Conservatism since 1975", and its senior members include Sir John Major and Damian Green, the former de facto deputy prime minister.
In a statement, the group said: "TRG members were consulted throughout the process and the results clearly show that neither candidate has received widespread support from the majority of our members.
"Both have used rhetoric and focused on issues that are far removed from the party at its best, let alone the One Nation values we cherish and uphold. Therefore, the TRG board has unanimously concluded that we cannot support either candidate."
Some of the TRG sitting MPs have expressed their support for one of the remaining candidates.
Battle for leader
Nigel Huddleston, the shadow Chancellor of the Exchequer, has backed Ms Badenoch, while John Lamont, Scotland's shadow secretary of state, has thrown his support behind Mr Jenrick.
A source in the Cleverly campaign said they believed he would take time to consider his future and would not endorse either candidate anytime soon, if at all.
Both Mr Jenrick and Ms Badenoch have indicated he would be given a key post in the shadow cabinet if they win.
But one supporter said: "I wouldn't be surprised if he takes the opportunity to take some time off in the backseat.
"His wife has just recovered from a serious illness, which shows how precious family time can be."
One MP said he was irritated by the way the other two candidates had tried to portray Mr Cleverly as a "limp-wristed, flower-arranging Lib Dem", saying: "He supported Truss and Boris."
It comes as Mr Jenrick used his first major speech since making the last two to suggest Ms Badenoch would create "unnecessary drama" if she were elected leader.
Speaking to the Policy Exchange think tank in central London, he said the Tories "exist to serve our country in government, not to do battle on Twitter".
He said the party must show voters that it offers "a serious plan, not unnecessary drama."
"They need to see that we are focused on what they really care about and not going down rabbit holes," the former immigration minister added.
His comments were seen as a swipe at Ms Badenoch, who attacked her critics on social media, including David Tennant, the former Dr Who actor.
Mr Jenrick also denied claims that MPs in his camp had been involved in vote trading to ensure he made it to the last two of the leadership elections.
He said: "We have not exchanged votes. We have worked relentlessly to convince colleagues to get as many supporters as possible into Parliament."
On Thursday evening, Mr Jenrick was backed by Sir Jacob Rees-Mogg. The former business secretary said he was best placed to reverse Tory fortunes in the wake of the party's historic election defeat.
Sir Jacob lost his seat in North West Somerset to Labor in July in a near-extermination that saw the Conservatives reduced to just 121 MPs.
Speaking on his GB News programme, he said: "I have decided to back Robert Jenrick because he understands the scale of the challenge facing the Conservatives and has the courage to do something about it."
The endorsement is a boost for Mr Jenrick as Sir Jacob is seen as a pillar of the Tory right.
Like the former immigration minister, he has also called on Britain to withdraw from the European Convention on Human Rights (ECHR) and significantly reduce immigration.
