If in doubt, blame Corbyn. So much of the strategy employed by so many of the players in British politics can be distilled to that mantra. Theresa May is one of them.

Addressing a very sweaty meeting of the 1922 Committee this evening, the prime minister warned Conservative MPs that if they rebelled against her on Brexit, their reward would be a Labour government.

Is that threat enough to cow would-be rebels? Listen to any of the members of the government payroll who dutifully spun tonight’s meeting as a triumph for the prime minister and you would assume so.

Robert Buckland, the solicitor general, sought to play down the infighting as the “Tory family talking to each other”. One cabinet minister spoke of a “strong coming together”, and claimed the prevailing mood within the party was “to get behind the prime minister and deliver the best possible deal”.

Meanwhile Brandon Lewis, the Tory chairman, preached unity alongside Geoffrey Cox, a pro-Leave backbencher and QC. Lewis insisted the Conservative Party was a “very wide tent”. Cox claimed the much-maligned Chequers blueprint amounted to a “giant leap out of the EU”.

All very pleasant but sadly simply untrue, as a rival briefing from Jacob Rees-Mogg taking place just yards away illustrated. The ERG chair stopped short of inciting mutiny but made clear his displeasure. “The statement today gave me no reassurance,” he said.

He went on to warn that moves by Downing Street to brief Labour MPs on the Chequers proposals – in the hope of winning their support in the vote on the final deal – could split the party “from the top”.

Though he said he did not expect a confidence vote in the prime minister, his words nonetheless spoke to divisions in the party that can’t and won’t be healed with seven rounds of table-banging for the prime minister and a knowing gag about her love of walking holidays.

Who are we to believe? Lewis or Rees-Mogg? It’s hard to escape the conclusion that the former’s consoling niceties no longer hold true. The Tory tent’s impressive width is irrelevant when May has chosen a pitch that won’t accommodate it.

In that respect, the resignation of Chris Green, the Bolton West MP and parliamentary private secretary to Chris Grayling’s junior ministers, was almost as significant as Boris Johnson's.

I know, me neither. To quote his fellow backbencher Simon Hart: “Your [sic] a pps Chris. It is not relevant and nobody gives a fuck.” Only it is. Green’s decision to resign from the payroll after the prime minister had invoked the spectre of a Corbyn government and spun the Chequers deal as the “giant leap” described by Geoffrey Cox underlines the scale of the challenge she faces.

Gestures such as these, and barbed comments from quixotic backbenchers like Philip Davies, who gave the most overtly negative speech of the evening at the ‘22, cannot be ignored. There might not be a confidence vote tomorrow, this week, or this month, but the fight ahead will still define her premiership and determine whether it can survive beyond the medium term.

After the meeting, the most accurate description of May’s predicament came not from one of her own MPs spinning in the narrow corridor outside Portcullis House’s Boothroyd Room but, rather surreally, from former Lib Dem leader Tim Farron. As Cox spoke of his giant leap, Farron, who inadvertedly found himself caught up in the lobby's huddle, quipped that Buzz Aldrin’s first words on the Moon were more apt: “Magnificent desolation.”

That sums up May’s problem. No matter how sincere the agreement that a Corbyn government is something nobody in the Conservative Party wants to see, the visceral dislike many of her backbenchers will take to any Brexit deal she proposes defies all logic. For them, no price is too high for magnificent desolation. There might only be a handful of them, but a handful is all that's needed to bring down a minority government. Graham Brady’s postbag might be much lighter than expected but for May, the worst is yet to come.