The frog’s union flag waistcoat is disintegrating amidst the seething water. It has been clear since the Government reaffirmed its position on the backstop last month that the prospect of a clean Brexit is vanishing with it. In essence, the backstop’s implementation would mean, if Ministers’ take on it prevails, the whole UK being bound by the Common External Tarriff, and being aligned to a mass of Single Market rules.

This reading of the backstop may or may not turn out to be acceptable to the EU but, were it to prove so, the negotiation would move on to immigration, with the Commission and the EU27 arguing that if the UK is to be so closely aligned in goods it must also so be in peoples. As we have said before, such an outcome would add up less to Canada Plus, let alone Plus Plus Plus, than Norway Minus – EEA lite. The question of the direct jurisdiction of the European Court of Justice would also arise.

The absence of a White Paper setting out more of the Government’s negotiating position, the continued impasse over the customs partnership v maximum facilitation, and the sidelining of both options if the UK is to enter the backstop, point towards a climacteric in the autumn: the EU offers Theresa May not a detailed trade deal, but a vague outline proposal. The EU proposes to swap this for money – that’s to say, the £40 billion or so that the Government agreed to pay last December. They take; we give.

Brexiteers are currently divided into what James Forsyth today calls hedgers and ditchers. Hedgers believe that what matters most is getting out of the EU by March 29 next year. Better to push for a cleaner Brexit from outside the EU than within it, they say – however flawed any agreement may be. Ditchers argue that the dirty Brexit looming into view, together with this lopsided deal, could actually leave Britain worse off than it is as an EU member. Better to stay than leave in this shoddy manner.

It is far from certain that Parliament will vote for such a deal in any event. This is the background against which next week’s return of the EU Withdrawal Bill to the Commons is set. And over both it and May’s future now hovers a storm cloud which, yesterday, was no bigger than the proverbial man’s hand, but has grown this morning, and rumbles with distant thunder like a summer storm.

As today’s papers confirm, Brexiteer ministers and others have come to believe that the Prime Minister has reneged on safeguards given to them which from their point of view might render the present negotiating position recoverable. First, they claim that she has effectively given up on time-limiting the backstop. (Quite how this could be done in any event is an interesting question.) Second, they point out that the publication of the White Paper, promised for before the European Summit later this month, has been delayed.

Third, they argue that the Government has gradually crept closer to alignment than the agreement at the Cabinet committee awayday at Chequers earlier this year provided for. Finally and separately, there is intense frustration with the Chancellor who, they believe, has never believed that “no deal is better than a bad deal”, and has held out against giving the machinery of government the resources to ensure that we are Ready On Day 730 (that’s to say, at the end of transition), let alone on Day One.

So what are they going to do about it? If they no longer have confidence in May – to cut to the chase – will they actually quit? This site’s reckoning is that resignation is most likely in the following order among the most senior Brexiteers: David Davis, Boris Johnson, Michael Gove, Liam Fox. It should not be forgotten that their fellow Cabinet members Chris Grayling, Andrea Leadsom, Esther McVey and Penny Mordaunt also backed leaving the EU.

The International Trade Secretary is by instinct a strong May loyalist, and will not want to add to her troubles, even though the position on the backstop has added considerably to his. The Environment Secretary would be reluctant to face the claim, however unfair, that he has let down three colleagues in a row – David Cameron, Boris Johnson…and the Prime Minister. In any event, we must presume that his leadership ambitions are not dead. The Foreign Secretary huffs and puffs, but has not blown anyone’s house down – so far.

That leaves Davis. He is reported today to be refusing to make the case for May’s position on the backstop, presumably on the ground that without the safeguard of a firm end-date he doesn’t agree with it. There are also claims that Fox, Gove and Johnson – plus, it’s worth noting, Gavin Williamson – were sent papers relating to the negotiation later than to Davis, Philip Hammond and Karen Bradley. Yesterday, the Brexit Secretary didn’t rule out resigning: plus ca change, you may say.

It may indeed be that the Davis and the Prime Minister, forced to share negotiation policy in the manner of Love Island contestants forced to share a bed, will, if not exactly kiss and make up, at least come to an accomodation about which side each will sleep on, and how to position the ragged duvet. Furthermore, ConservativeHome understands that no discussion of the position on customs will take place in Cabinet committee today anyway.

But if trust is breaking down between the two, can it be so easily repaired? At root, there is a deeper problem. May’s point-man on Brexit is Olly Robbins. Robbins was Permanent Secretary at the Brexit Department. He and Davis didn’t get on. Robbins was moved out – but also up, into Downing Street. So Davis isn’t really master in his own negotiation. And Robbins necessarily has a civil servant’s perspective, not a politician’s – let alone a Brexiteering politician’s. Where’s Nick Timothy when you need him?

The role of Robbins, the state of the backstop, the absence of a White Paper, the prospect of a poor deal in the autumn and hesitancy over No Deal preparations meld ominously. A crisis postponed today can be a crisis present tomorrow. Were Davis to go, it is difficult to see how his Brexiteering junior Ministers, Steve Baker and Suella Braverman, could stay. The same would arguably apply to Johnson. Tory MPs would then be in leadership challenge territory, with unknowable consequences for May, the Government, and Brexit itself.