The prime minister will “squat” in Downing Street, rather than quit, if the Commons passes a vote of no confidence in him and tries to install a caretaker replacement, the headlines scream.
“Unless the police turn up at 10 Downing Street with a warrant for the prime minister’s arrest, he won’t be leaving,” a source threatened darkly – but anonymously of course.
So, could the Queen really end up in the extraordinary position of trying to sack Mr Johnson – and could he simply refuse to budge if she did?
The first important point is that MPs are not even close to passing the no-confidence vote that would trigger this emergency, because they cannot agree on a caretaker prime minister.
It remains most likely that Mr Johnson will be forced, kicking and screaming, to delay Brexit to avoid a Halloween crash-out and that a general election will follow.
No monarch has exercised this power since William IV kicked out Lord Melbourne in 1834 – and the palace will be desperate not to get involved – but it’s there on the books nevertheless.
However, there is a crucial difference between a no-confidence vote passing, kick-starting a 14-day hunt for a replacement, and a new leader being found who has sufficient support in the Commons.
There is no expectation on Mr Johnson to resign unless a clear alternative has emerged – whether that is Jeremy Corbyn (requiring the Liberal Democrats and others to drop their opposition) or a Ken Clarke-figure (requiring Labour to give in).
At that point, according to the institute, the Queen would have a duty to make clear, privately, that she sides with a clear instruction from MPs that they want someone else to be prime minister.
Whatever the threats from No 10 – and, remember, they never come from Mr Johnson himself, or his official spokesperson – he would surely walk out at that point?
But, yes, if he still refused, the private urgings could become an open threat of dismissal, incredible as it seems.