Darkest Hour pays tribute to Churchill’s outflanking of his War Cabinet, in May 1940, by the ruse of an appeal to his Outer Cabinet.  Readers will be familiar with the story.  Lord Halifax was pressing within the former for mediation by Mussolini between Britain and Germany with a view to a negotiated peace.  Churchill was careful not to rule the latter out, but it wasn’t where his heart lay.  His manoeuvre outflanked Halifax altogether.  According to his account, he told the Outer Cabinet that “I am convinced that every one of you would rise up and tear me down from my place if I were for one moment to contemplate parley or surrender. If this long island story of ours is to end at last, let it end only when each one of us lies choking in his own blood upon the ground.”  Cue applause: “quite a number seemed to jump up from the table and come running to my chair, shouting and patting me on the back”.

“Theresa May is doing the same all over again,” one cynical friend of ConservativeHome told us yesterday, “except it’s the other way round: this time, she wants to surrender.”  This was unfair to Halifax – and may illustrate the perils of applying metaphors from the struggle against Hitler to a negotiation with the EU.  But in one respect the comparison is bang on.  The Prime Minister lost her majority on the crucial Cabinet Strategy and Negotiations sub-committee when Gavin Williamson switched to support the four Brexiteer Ministers, whose position was later strengthened by the replacement of Amber Rudd as Home Secretary by Sajid Javid.  In a sentence, his broad take is that he wouldn’t have done Brexit in the first place but that, if it is to done, it must be done properly.

Since then, the sub-committee has essentially been kicked into abeyance.  Gary Gibbon reports that it is unlikely to meet before May’s equivalent of the Churchill gambit – the full Cabinet meeting at Chequers next Friday.  What will happen?

There are at least four big issues to unpick.

The first is to find a path to the free trade deals with non-EU countries that the Prime Minister herself has championed, which are a high priority for Party members and without which Liam Fox’s department will lose its sense of purpose.

The second is to sort a linked issue: how close do we want to be to the EU after Brexit in economic terms?  Are we really going to be Global Britain, or are we, when push comes to shove, a European economy after all?

In turn, the third arises from the second.  Either way, where does control of immigration fit in?  Should future EU migrants have a privileged status above other immigrants?

A fourth is what happens if the negotiation ends with no deal.  In that circumstance, will the UK pay up the £40 billion or so agreed in December’s interim deal?

Let’s look at each in turn.

The point to grasp at the start is that the route to achieving those free trade deals travels via the UK/Ireland border – or, rather, via the “backstop” agreed last December.

In broad terms, this would commit us to “full alignment with those rules of the Internal Market and the Customs Union which, now or in the future, support North-South co-operation, the all island economy and the protection of the 1998 Agreement”.  These would include the Common External Tariff, which would make those trade deals with non-EU nations difficult if not impossible.  Unpicking the backstop means agreeing an alternative with the EU.  That means first coming to a common position, the absence of which is allowing Ministers, such as Boris Johnson and Greg Clark, to push their own competing ones.  The White Paper – now on “its ninth iteration”, according to a world-weary ConHome source – has apparently still not decided between the customs partnership and maximum facilitation.

Some senior Ministers are confident that the former has been well and truly killed off.  We shall see: watch for further bits of fine-tuning before next Friday.  What might just work in narrow political terms is a trade-off whereby the Brexiteers get a bit of what they want – MaxFac, with a firm proposed end-date – and the Remainers get a bit, too: the Open Europe plan for alignment in manufactures and divergence in services.  The Home Office team is expecting immigration policy to form a further part of the discussion.  If so, look out for a clash between Clark and Javid.  The Business Secretary has urged free movement for UK workers within the EU.  That’s a way of also signalling support for the free movement of EU workers within the EU, or something so like it as to make no difference.

The stance of key Ministers will be crucial.

We know roughly where three of the main Brexiteer ministers stand.  Liam Fox is both opposed to the customs partnership and very loyal to May.  He will also perhaps be balancing off the pursuit of those future trade deals with his own ambitions: it would be surprising if he hadn’t an eye on the foreign office.  Gove is very sensitive to any question of future ECJ jurisdiction but also seems to think that an imperfect Brexit is better than none at all.  There is also no sense that Team Gove has given up on its leadership aspirations.  That pushes him in the direction of compromise with the Remain wing of the Party.  Boris Johnson is unhappy with any suggestion of alignment in manufactures per se, but the Heathrow contretemps has weakened his position.

That leaves David Davis – whose reported threats to resign helped to bring about the Chequers summit in the first place.  Crucial to the DexEU position is a determination not to be bounced by papers that it hasn’t seen in advance, duly magicked up at the summit by Olly Robbins and company.  The department is deep in conversation with Downing Street.  The detail of an Open Europe-type plan would be crucial.  What would happen when new EU regulations are applied?  What about the right to diverge, implicit in May’s “baskets” – and the legal underpinning necessary?   What would happen to agriculture?  (The IOD has floated a partial customs union including some processed agricultural goods.)  Ministers are also “fighting trench warfare with officials on conditionality and the financial settlement”.

“If Liam and David aren’t happy, then there will be problems,” ConHome is told.  But that is to assume that the Prime Minister will have a majority in Cabinet for whatever she settles on – assuming, of course, that key decisions aren’t kicked further into touch (which would be very risky indeed given the timetable).  She probably will do, not that anything so crude as votes are likely to be taken.  But this week’s blue-on-blue Ministerial action is a brutal reminder of May’s political weakness.  She cannot rely on Javid or Jeremy Hunt.  And there are other Brexiteers in Cabinet: Chris Grayling, Andrea Leadsom, Penny Mordaunt.  One thing is for sure: both sides will brief immediately after the meeting that they “won”.

If the Cabinet agrees a plan, the EU may reject it wholesale.  If it doesn’t, a further question arises for Brexiteers: is a Norway Minus deal – which trades off some migration control for curtailed trade freedoms, plus close alignment to the EU model – worth having?  Is a messy Brexit better than none?  Either way, the Prime Minister will rely next week, as she strives to inch her position forward, not on Churchillian rhetoric, but on grinding mastery of detail.