The Conservative Party’s “motivation”, observed the late MP and diarist Alan Clark, at “all times and in both the corporate and individual context” was its “appetite for power”.

It’s that appetite that explains both its remarkable electoral success over the past century or so, and also its ability endlessly to adapt, sacrificing both policy and principle to that end: acquiring and exercising power.

Doubtless that was the motivation behind the recent “snap” election and, in an individual context, the determination of Theresa May to try and protect her premiership since. It seems, however, an increasingly quixotic aspiration.

As William Hague once perceptively remarked, the Conservative Party is an autocracy tempered by regicide, so as soon as the Prime Minister appears unsalvageable to her colleagues, then they’ll be characteristically brutal in removing her.

Before last week’s Grenfell Tower fire, Mrs May’s position looked to have stabilised, her appearance before the party’s 1922 Committee having demonstrated a spirit sadly lacking during the election campaign. But then the Prime Minister’s inept (rather than unfeeling) response to that tragic incident once again brought all her weaknesses to the fore.

Today, as planned, the Brexit negotiations begin in Brussels, and although they’re preliminary in nature – substantive talks won’t get going until after the German federal elections in September – Mrs May is hardly in a strong position to make an impact.

As with Chamberlain after Munich, Eden after Suez and Thatcher after that first leadership ballot, it’s now only a matter of time. Even if May gets through Wednesday’s Queen’s Speech, she might not survive a Commons vote on her government’s plans due on 28 June.

And rather than resolve the Conservative Party’s decades-long obsession with Europe, it’s now clear last year’s European referendum has simply exacerbated the problem. Even a strong Prime Minister would struggle to reconcile competing demands over Brexit, and Mrs May is self-evidently not a strong Prime Minister.

Some ministers maintain that any backtracking on “Brexit means Brexit” at this juncture would erode public trust even further, while others are using the election result to push for membership of the Customs Union, the European Economic Area or a compromise Boris Johnson and Ruth Davidson are calling “open Brexit”.

But neither the Foreign Secretary nor the Scottish Conservative leader envisage remaining in the Single Market or Customs Union, just that the UK should aim to maintain as much “access” to them as possible. A noble aim, just one without any detail. Like the DUP, who support Brexit but oppose a hard border in Ireland, they want to have their cake and eat it.

The rhetoric at least recognises another essential truth of Conservative tradition, that what the historian Robert Blake called “stern and unbending Toryism” rarely pays political or electoral dividends. The choice is between delivering change according to abstract dogma or in accordance with the will of the electorate.

Now it isn’t unreasonable to interpret the recent election as some sort of kickback against the prospect of a “hard” Brexit, but when both Labour and the Tories essentially want the same outcome from the negotiations, that makes any major compromise virtually impossible.

If Conservatives were to take the long view, then the path ahead might look a little clearer. Dump May, elect a caretaker successor and then initiate another general election. This might produce a similarly precarious minority Labour government, but wouldn’t it be better to let Jeremy Corbyn take the rap for Brexit and associated economic turbulence before riding to the rescue in a few years’ time?

Incumbent Prime Ministers and governments, of course, don’t think in those terms. If they had, then John Major might have lost in 1992 and avoided his party’s subsequent defenestration in 1997. Yet a change of leader can improve apparently grim situations: think Macmillan after Eden in 1956, or Major following Thatcher in 1990.

If there is Tory leadership election sometime soon, meanwhile, it will have a conspicuously Scottish dimension for the first time in the party’s long history. “Both the Scottish Conservatives and the DUP are keeping the Conservatives in power,” observes a senior figure. “Anyone who became UK leader would have to be acceptable to the Scottish Tories, and that’s not Boris Johnson.”

During last year’s leadership election, the Scottish Conservative Party floated the idea of UDI from London, but only if Johnson emerged victorious, conscious that a posh, English and not entirely serious PM would play badly north of the border. Ironically, for all her faults Mrs May proved “acceptable” to the Scottish party. In fact, her “now is not the time” declaration in relation to a second independence referendum might end up one of the few bright spots in her political obituaries.

Over the past week, Ruth Davidson has been the focus of the sort of gushing profiles that Nicola Sturgeon once enjoyed when London-based progressives viewed the First Minister as their political saviour a couple of years ago. Not only is the idea of Ms Davidson as UK Tory leader or PM far-fetched, but it reflects how bad things are at Westminster. The grass, as they say, is always greener.

And the Scottish Tory leader, of course, has her own “appetite for power”, an ambition to lead the largest party, and therefore become First Minster, after the next Holyrood elections in 2021. That I’m able to write such a sentence without inviting ridicule speaks to how much things have changed since 2015.

But while considerably more likely in light of the ongoing Scottish Tory “fightback”, Davidson now has competition. Just as the SNP failed to detect a Corbyn bounce until it was too late, nor did the Conservatives. “That changes the next Holyrood election,” says another well-placed Tory source, “we’re no longer unchallenged as the main Unionist party”.

So if Brexit proves a disaster and the economy tanks, Scottish Labour could capitalise and experience a revival of its own (just think of all those Glasgow constituencies where it’s breathing down the SNP’s neck). Ruth Davidson might be more popular than Kezia Dugdale at the moment, but the latter could find her voice as quickly as Sturgeon lost hers. Political cycles now last months rather than years and nothing, as Francis Urquhart put it in the original “House of Cards”, “lasts forever”.