Former ministers Philip Hammond and Amber Rudd are understood to be the two leading candidates to succeed Mr Johnson under the plan. One Cabinet minister said: “It would be a legal coup. There is nothing we can do to stop it.” Ministers have picked up rumours of the plot circulating in the Commons, where MPs are sitting despite the Tory conference going ahead in Manchester. They believe a cross-party group of lawyer MPs want to launch a legal action aping the attempt to impeach US President Donald Trump in Washington by the opposition in Congress.
And while an ancient impeachment procedure dating back to the Middle Ages is now thought to be obsolete, senior Tories believe the plotters could use an emergency Commons motion to try to force the Prime Minister out of office instead.
They are understood to be planning to use Mr Johnson’s threat to defy the so-called Surrender Act designed to block a no-deal Brexit as the pretext for tabling the motion.
It would require Speaker John Bercow to allow the use of an emergency motion – under Commons standing order 24 – for the impeachment process.
The motion would be worded to demand the sacking of the Prime Minister while recognising that his successor must be another Tory MP because the party is the largest in the Commons.
The Cabinet minister said: “Bercow has bent the rules to allow SO24 motions to be used in this way. It is a constitutional outrage. He is completely out of control.
“If this coup succeeds it would be a disaster for democracy.”
Ministers believe the use of emergency motions to try to force the Government’s hand during the Brexit debates is unprecedented and directly at odds with constitutional practice.
“We know Bercow has overruled advice for the Commons clerks that S024 debates should not be used in this way but he has told them to f*** off. That’s the way he operates,” the Cabinet minister said.
Impeachment is an ancient procedure for Parliament to launch a prosecution against an individual suspected of “high crimes and misdemeanours”.
The first recorded use of the procedure in England was in 1376, when Lord Latimer, the Lord Chamberlain was impeached for taking bribes and pocketing fines.
It was last used in 1806 against Lord Melville for misappropriation of public funds but ended in his acquittal.
Around 70 impeachments have taken place in Parliament, with about a quarter being launched during the English Civil War.
In 1967, a Commons committee ruled that the procedure was outdated and should be abolished.
And in 1999, a report from Parliament’s Joint Committee on Parliamentary Privilege concluded: “The circumstances in which impeachment has taken place are now so remote from the present that the procedure may be considered obsolete.”
However, the plotters are understood to be using the emergency motion procedure to bring impeachment back.
The plotters are understood to want one of the leading pro-Brussels rebels who have been stripped of the Tory whip to replace Mr Johnson in Downing Street.