Boris Johnson loyalist Nadine Dorries has offered a sinister warning to Tory MPs they face losing their seats if they back a damning report which found he deliberately misled parliament over Partygate.
MPs who support the privilges committee's findings were "fundamentally not" Conservative and would be "held to account", the ex-culture secretary claimed.
A small group of fellow Johnson allies also vowed to vote against the "vindicative" report on Monday - and warned those who back it could be "given the boot" by angry, grassroots Tory members.
But Sunak allies told The Independent that Ms Dorries was "off her rocker" and urged colleagues to "show backbone" when the crunch free vote to approve the cross-party report comes on Monday.
It follows the scathing verdict which found Mr Johnson repeatedly lied over Covid-era parties, and concluded that he would have been suspended for 90 days if he had remained an MP and should have his parliamentary pass revoked.
An attempted fightback immediately begun among Boris backers, with Tory MP Brendan Clarke-Smith branding the report's findings "appalling" and vowing to speak against them "in the House on Monday".
The Bassetlaw MP tweeted: "I am appalled at what I have read and the spiteful, vindictive and overreaching conclusions of the report."
Ms Dorries said the report had "overreached" and accused the committee chair Harriet Harman of setting out her "position" before the inquiry had even began.
"Any Conservative MP who would vote for this report is fundamentally not a Conservative and will be held to account by members and the public," she warned. "Deselections may follow. It's serious."
Simon Clarke MP said he was "amazed at the harshness of today's report by the privileges committee", adding: "This punishment is absolutely extraordinary to the point of sheer vindictiveness, and I will vote against this report on Monday."
Jacob Rees-Mogg, awarded a knighthood by Mr Johnson, said the findings against his old boss were "fundamentally flawed". Another Johnson ally, Sir James Duddridge, added: "Why not go the full way, put Boris, in the stocks and providing rotten food to throw rotten food at him."
Former Tory MEP David Campbell Bannerman said: "Any Tory MP who endorses this report does not respect democracy and must face deselection."
The Brexit-backing boss of Conservative Democratic Organistion (CDO) even claimed that Mr Johnson should appeal the committee's findings via the European Court of Human Rights (ECHR).
Mr Campbell Bannerman told The Independent: "The irony of it all is Boris has a very good case to go to the ECHR to say this Stalinist show trial has imperilled his basic human rights under the convention."
Asked about the deselection threat, one scathing senior Tory told The Independent: "Nadine is off her rocker and biting the hand that put her in public life. She is making a show of herself."
Another senior Tory said colleagues should "show backbone" and ignore deselection threats made by Mr Johnson's allies. "I hope colleagues have the integrity to vote how they want - never mind those stamping their feet."
However, the former minister predicted that there would be an "even mix" of Tory MPs abstain to avoid upsetting Boris-backing constituents, and voting it through to "support the process".
As well as nervousness about angering local Tory members, The Independent understands there was some "shock" in the Tory tearoom over the harshness of the 90-day suspension that may encourage more abstentions. It is a one-line whip, making widespread absences likely.
Commons leader Penny Mordaunt confirmed that the committee's findings will be debated on Monday 19 June before a free vote - the same date as Mr Johnson's 59th birthday.
She advised MPs to read the report before taking a decision in a process she described as "painful" and "sad", adding: "But all of us must do what we think is right and others must leave us alone to do so."
Downing Street declined to be drawn on how Mr Sunak will vote, or whether he will even be in parliament to participate in it on Monday. "He intends to take the time to fully consider the report," his spokesman told reporters.
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