The chair of the powerful Tory 1922 Committee is meeting Liz Truss in No 10, as pressure grows on him to advise her to quit.
The prime minister was not scheduled to have a meeting with Graham Brady – but Downing Street confirmed he had been escorted in through the back door.
The sudden talks come as the number of Tory MPs calling for Ms Truss to resign reached 13, following the meltdown of discipline over Wednesday night’s fracking vote.
One cabinet minister, Anne-Marie Trevelyan, refused multiple times to say that she will survive until the next general election, as her authority crumbles further.
The most likely way that the prime minister will be forced out is if Sir Graham informs her that she has lost the support of her MPs – the private news that triggered Boris Johnson’s departure.
It had been thought that the failure of MPs to agree on a unity candidate to replace her might keep her in office a bit longer, but support appears to be draining away.
Asked if Ms Truss getting ready to accept her time is, her official spokesman said: “There are no plans for any change in prime minister.”
Downing Street said the meeting was requested by the prime minister herself, suggesting she might be seeking to assess the strength of her remaining support – but that is a question normally asked of the chief whip.
Ms Truss needs to survive in her job for a further 75 days to avoid being the shortest-serving prime minister in history, but that looks increasingly unlikely.
Some Conservative MPs – in despair at the meltdown of the government, on a day when the home secretary was also sacked – want Ms Truss to be forced out within hours.
Charles Walker, a former chair of the 1922 Committee, said: “The grown-ups in our party, and a few do exist, need to meet in a papal conclave over the next 24 hours and decide on a coronation.”
And Crispin Blunt, a former minister, said: “It’s plain what is required. We need to effect a change, frankly, today in order to stop this shambles.”
Simon Hoare, the chair of the Commons Northern Ireland committee, said: “Can the ship be turned around? Yes. But I think there is about 12 hours to do it.”
The veteran Tory MP Gary Streeter said Ms Truss must be forced out as the first step to avoiding “slaughter at the next election”, tweeting: “Sadly, it seems we must change leader.”
The spokesman put a brave face on the chaos, saying said: “The prime minister acknowledges yesterday was a difficult day and she recognises the public wanted to see the government focussing less on politics and more on delivering their priorities.
“That is also what the prime minister wants. You saw her take action yesterday and make a number of difficult decisions.”
Referring to the sacking of Suella Braverman, he added: “She ensured the public can take confidence in the importance of the ministerial code.”
