Senior Conservatives believe James Cleverly was booted out of the party’s leadership contest by mistake.
The former home secretary became the latest candidate to be ejected by Tory MPs in a major shock on Wednesday.
Cleverly had been widely thought to be a shoo-in to make the final run-off when he came top of the MPs’ ballot the day before.
But he was beaten by Kemi Badenoch and Robert Jenrick, who will now battle it out to replace Rishi Sunak.
The result left many Tories baffled, not least those in Cleverly’s own campaign team.
He had comfortably topped Tuesday’s ballot with 39 votes, well ahead of Jenrick on 31 and Badenoch on 30. Tom Tugendhat came last with 20 votes and was removed from the contest.
In the fourth and final MPs’ vote 24 hours later, Cleverly slumped to 37 votes, leaving him last behind Badenoch on 42 votes and Jenrick on 41.
Initial claims that Cleverly’s own team had allowed some of his supporters to vote for Jenrick in order to remove Badenoch from the race were described to HuffPost UK as “fucking bollocks” by a source on his campaign.
One Tory source said: “It’s far more likely that some pro-Cleverly people thought he was in and tried to be clever.”
That theory was backed up by former Conservative chancellor George Osborne, who told his Political Currency podcast: “The most plausible explanation I’ve heard is that, rather than this being some elaborate cunning plan, it was a total cock up.
“In other words, some supporters of James Cleverly thought he was sufficiently far ahead that they could vote for either Kemi or Robert in order to basically knock out the person they thought was most likely to be a challenge to James.
“So, if you thought Kemi was a stronger candidate you voted Robert, and if you thought Robert was a stronger candidate you voted Kemi. But the net result of all of this is not enough people voted for James Cleverly.
“And I spoke to the people running James’s campaign, and they’re claiming this wasn’t their doing, but this was all freelancing by some of their supporters.”
One former cabinet minister said: “What a duplicitous bunch our MPs are - too driven by stopping others rather than voting positively for any candidate.”
The result means that whoever wins, the Tory Party is set to lurch further to the right.
Tory members have until October 31 to vote for their preferred candidate, with the winner due to be announced on November 2.