“NOT Scott!” will have been the cry yesterday as news broke that, hot on the heels of the resignation of Robert Courts as a parliamentary aide to the Foreign Office, Scott Mann, the Tory MP for North Cornwall, is standing down as a parliamentary private secretary at the Treasury.

Or perhaps, like a normal human being with a life, you’ve never heard of these two stars of the political firmament. By the time you read this, Algie ffeatherstonehaugh-Marjoriebanks (pronounced “Pole”) might even have quit as bag carrier to the deputy under-secretary of the parliamentary committee on health and safety compliance in local government stationery acquisition without it having made much difference to your life.

Still, heedless of the consequences, or as their predecessor out of the door Boris Johnson would no doubt put it, fiat thingummyjig ruat caelum, they’re gone. Yet while Tory MPs standing down from unimpressive government jobs may not be a marmalade-dropper in any households but their own, it doesn’t mean that Theresa May isn’t toast.

Lots of pro-Brexit Tory MPs are unhappy with Mrs May’s “Chequers Deal” – with reason. First and foremost, it’s not a deal with anyone except the remaining members of the Cabinet, and there is no chance that, as it stands, it will be the deal the UK finally agrees with the EU.

Even Leavers who take the pragmatic view that they could just about live with the proposals as marginally better than no deal (or no Brexit, as the PM is now attempting to frame it) are unlikely to subscribe to a watered-down version, which is what they must imagine they’ll end up with.

There are easily enough of them to get the 48 MPs (15 per cent) needed to write to Sir Graham Brady, chairman of the 1922 committee, to trigger a leadership contest. Even more worrying for the PM, however, will be backbenchers who – though not themselves hardline Brexiters – spent the weekend listening to constituency party activists.

We can guess their views. Last month, 13 per cent of activists wanted Mrs May to go immediately, and a further 50 per cent wanted her gone before the next General Election. And that’s Tories.

At the weekend – specifically, since the Chequers masterplan was unveiled and then promptly rubbished by everyone from the Eurosceptic Jacob Rees-Mogg to the Europhile Lord Mandelson – the latest poll put the Tories on 36 per cent (down six points in a matter of days) and Ukip, effectively dead and buried this time last week, back up to eight per cent support. Fifty-six per cent of voters – including those who think her plan is better than the other options – think the Prime Minister is making a dreadful job of handling Brexit.

Those Tory backbenchers will now be thinking not of the numbers needed to trigger a leadership vote, or whether Mrs May can muster the numbers to win it, or the fact that there is no Commons majority for a hard Brexit (the calculation behind the shift from an assurance that “no deal is better than a bad deal” to her implied threat of “Chequers or no Brexit”). They will be thinking of their own majorities.

The majorities in their constituencies, that is, since Mrs May threw away the perfectly workable parliamentary majority the Tories had until she called the election, and then ran such an atrocious campaign that she was lucky to beat Lord Buckethead (0.4 per cent of the vote in her seat), who at least had a more genial and natural appearance.

The Prime Minister’s colleagues know that they are going to get thumped if a) they don’t deliver Brexit or b) they can’t deliver Mrs May’s Brexit (which stands no chance of being delivered) or c) they do deliver Mrs May’s Brexit, because it’s the worst of all possible worlds.

Then, with Labour on 40 per cent, there’s the danger of a government run by crackpot Marxist apologists for terrorism whose own Brexit agenda is even less coherent than Mrs May’s, and whose imbecilic economic policies make the SNP’s look relatively cheap and prudent.

It’s a compelling argument – almost as compelling as the one for saving their own skins – for Conservative MPs to push the Prime Minister under the bus, and kick her as hard as they can as they do so. As I am sure they will.

But not yet.

The problem is the arithmetic. All the arithmetic. There’s still, despite attempts to claim otherwise, a clear popular majority for Brexit (and one which would probably strengthen if there were another referendum). There’s still, in the Commons, no majority for a Brexit with no deal. But, given many Labour MPs’ fears of their voters – many of whom are more vociferously pro-Leave than grassroots Tories – and the stance of their leadership (in so far as one can work it out), there’s no majority for anything else. And all this before the EU just says “No” to whatever might be cooked up.

It’s such a mess that it’s difficult to get rid of the Prime Minister although – and to some extent, bizarrely, because – the mess is almost entirely of her own creation. Had she understood the arguments for Brexit, had she taken soundings on the relative merits of different kinds before invoking Article 50, were she, in short, any bloody good at her job, we wouldn’t be here.

But while everyone wants rid of her, her backbenchers have the problem that they could trigger a party vote of confidence in her leadership, but might well not win it. The rules would then prevent another contest for a year. Meanwhile, a vote of confidence in the Government is not really in the opposition’s interest.

Besides, who would want the job? Boris, obviously, but he is much less popular with Tory MPs than he is with Tory voters – and there are signs they’re going off him, too. David Davis and Michael Gove are admired by many activists, but they’re not electorally popular. Even fans of Mr Rees-Mogg concede he has no ministerial experience, while Ruth Davidson isn’t eligible, since she’s not an MP. Some think Sajid Javid might be the best bet.

Mrs May, in other words, owes her survival to date to the fact that there’s no point stabbing her in the back until there are other, better, and better-thought-through options. And at the moment, most politicians seem to be terrible at providing those for anything at all, not just their choice of leader.