It’s almost become a Sunday-morning ritual: tales of Tory leadership intrigue followed by a firm rebuttal from a relatively sensible Cabinet minister.

And so it proved yesterday morning. One Sunday newspaper revealed that Conservative MPs had urged Foreign Secretary Boris Johnson to back a “dream team” comprising him as Prime Minister, Michael Gove as deputy and Jacob Rees-Mogg as Chancellor.

Coming just days before Michel Barnier arrives at Downing Street to discuss a two-year transition period and a two-day Cabinet meeting later this week to (finally) thrash out a negotiating position on Brexit, the whole thing is clearly destabilising for an already embattled Theresa May. “We’re in a situation now where it could all end tomorrow,” says one UK Tory insider, “on the other hand it could go on for weeks.”

In response, Home Secretary Amber Rudd told the BBC the Cabinet’s Brexit committee was “more united” than the hard-liners believe. She expressed confidence the Government would “arrive at something which suits us all”, although given how fractious Conservatives are at the moment, that seems like wishful thinking.

“It’s totally f***ing mental,” says one Tory MSP. “We wish they’d all just shut up.” Party leader Ruth Davidson must be wishing hardest of all. With good reason, she generally declines to offer a running commentary on each new chapter in the ongoing Tory psychodrama, for this one has the potential to re-toxify the Scottish Conservatives.

Ever since the EU referendum in June 2016, and particularly since the “snap” general election a year after that, Davidson’s voice has been a prominent counterweight to the hard-liners attempting to pressurise Mrs May into walking away from Brussels with no deal.

But her strategy of trying to nudge the UK Government in a softer direction, a sort of internal opposition, depends upon Mrs May – however weakened and embattled – remaining in place. Davidson managed to obtain a UK-wide profile when taking on Boris Johnson at Wembley Stadium, so there are obvious problems if BoJo ends up becoming Prime Minister.

“Given how Remain Ruth was and how bad her relations are with Boris,” says a Scottish Tory insider, “him becoming PM could kill off any prospect of further progress for the Scottish Tories; a hard-Brexit Tory coup could quickly re-toxify the party.” No wonder Davidson is remaining tight-lipped, she’s most likely hoping this apparent coup – like so many others to date – will fizzle out.

According to reports, Johnson told the plotters to “rally round” Mrs May, while adding that he’d be “ready” for a future contest and that the “cavalry is coming” to block any plan for a new customs union. In other words, the Foreign Secretary is clearly keeping his options open; the question is if anyone will actually resign and demand a vote of confidence.

I reckon the odds are still against it, but there’s only so much speculation of this sort Mrs May can survive. If the Cabinet meetings later this week produce more fudge instead of clarification, then already-emboldened Brexiters could make the next, altogether more destructive, move.

Naturally, speculation continues to swirl that the leader of the Scottish Conservatives could ride to the rescue, although that ignores the not insignificant point that she isn’t an MP and, even if she were, the path to the leadership wouldn’t be easy. “I am not going to be replacing Theresa May,” she told Vogue magazine in an interview published last Friday. “I’ve got a job to do in Scotland. I wouldn’t leave it to go and do another job.”

Asked about the possibility of the Conservative “brand” becoming re-toxified following Brexit, Davidson side-stepped the question by expressing worries “much greater” than that, of a global “culture war” in which it’s not “a question of left versus right any more” but one “of open versus closed”. Now that was all very interesting, but domestic affairs are surely the Scottish Tory leader’s more immediate concern.

And Davidson is clearly conscious she has to maintain – ironically for a Unionist – distance from the UK Tory party. Yesterday another Sunday newspaper reported that she’d “banned” senior UK Cabinet ministers like Boris Johnson and Liam Fox from the forthcoming Scottish Tory conference in Aberdeen, fearing they’re “toxic” north of the Border. Only the Prime Minister and Scottish Secretary David Mundell will speak.

This caution is understandable, for otherwise the Scottish Tories believe their strategy for the next three years is going to plan. Strategists aren’t unduly concerned about recent polls showing the party in third place behind Richard Leonard’s Labour Party (council by-election results continue to be good) and, usefully, the SNP’s planned tax rises have handed the party a much-needed alternative narrative to simply opposing a second independence referendum.

A leadership election – or even worse, another “snap” general election – would obviously disrupt this Scottish Tory sweet spot, most destructively if Boris emerged as the new PM. But the very fact so much speculation surrounds the Foreign Secretary actually counts against him – almost every Conservative Party leader since Sir Alec Douglas-Home in 1963 has emerged from left of field.

Ruth Davidson has been lucky thus far, able to forge productive relationships with, at first, David Cameron, and now Theresa May. And given the parliamentary arithmetic, she could emerge as an important power broker in any future contest. Under that scenario, says one senior UK Government source, “there would be a stop-Boris candidate”. “Unity, vision and decisiveness would be the key attributes in that contest, everything May is not – but then neither is Boris.”

There’s a sense amid all this intrigue that matters must soon come to a head: “either everybody signs up to the negotiating position”, says one minister, “or they’ll have to leave the Cabinet”. Ruth Davidson won’t be alone in hoping that if it comes to that, the cards will fall in a certain way.