Have we hit peak Brexit mayhem?

With 50 days left before the official date for leaving the EU, we may just have hit peak Brexit mayhem.

Can it get any worse than this? Seriously.

The cabinet has a three-way split between those who see a no-deal Brexit as economic and political armageddon, the Rudds, Hammonds, Gaukes and so on, those who would prefer a negotiated deal but secretly like the idea of a purer rupture - the Leadsoms, Foxes and Mordaunts - and those sitting in the middle with their fingers in their ears, thinking happy thoughts and hoping none of this is really happening.

"It is frustrating how many in the cabinet are just sitting this out," said one minister.

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The Labour frontbench and top team has its equivalent division, between Corbyn and his Unite-linked allies, who want Brexit, and those who'd like the UK to stay in the EU via a referendum, the Watsons and Starmers, and then slightly to one side the arch-pragmatist McDonnell, who is judging which route best secures a Labour government.

Within parliament itself, there are visceral divisions between MPs in all parties who want a referendum, others - again in all parties - who want the softest kind of Brexit, what's come to be known as Common Market ll, and those largely in the Tory party who favour the most definitive and severe break with the EU.

Even within the uber Brexiters of the Tories' European Research Group, there is now a visceral divide between those who will only support a Brexit deal if the backstop for keeping open the border on the island of Ireland is formally torn up, and those who would accept some kind of legal guarantee that the backstop could not be forever.

Meanwhile there are even tensions and splits emerging between EU 27 leaders themselves, and between the EU leaders on the one hand and the bureaucracy in Brussels on the other - laid bare by the perceptible unease at the emotive language deployed yesterday against the UK government by the president of the EU council Donald Tusk.

Is it remotely plausible that order can emerge from this utter chaos, that some kind of stable route either out of the EU or even to remain in the EU could yet transpire?

It is very difficult to see how, unless and until either May or Corbyn is prepared to call the other's bluff - and put the national interest ahead of narrower party interest.

The fundamental point is that it is now impossible to conceive of a Brexit deal which secures the majority support of MPs across the House of Commons which would not simultaneously break up either the Tory Party or the Labour Party or - more probably - both parties.

In other words, if Corbyn's and May's first choice is what they claim, namely a negotiated Brexit, then they will at some point have to agree a Brexit deal between them that brings the high probability of significant members of their own parliamentary colleagues feeling so alienated that they break away from their respective parties.

A couple of interviews are not a trend, but it was striking that last night on my show Labour's Luciana Berger pointedly did not rule out leaving Labour to form a new centre-ground party, and the Tory Brexiter Steve Baker has previously on the show been explicit that a corrupted Brexit would prompt fission in his party.

Here is the thing: the prospect of damage to both parties might offer the basis for entente between their respective leaders.

Except that the damage is unlikely to be identical and symmetrical for Conservatives and Labour.

As the TSSA research I cited yesterday shows, any kind of Brexit - except perhaps the worst kind of unmanaged anarchic Brexit - is better for the Tories' future electoral prospects than for Labour's.

Knowing that, it is very hard for May to trust Corbyn is negotiating in good faith, or vice versa.

Which leads to a conclusion that is as close to tragedy as it is possible to get in politics: if anyone tells you they know where this Brexit saga will end, they are either a blithering idiot or a criminal liar.

PS at 12.15pm

The PM’s joint statement with Juncker just now on their short talks confirms quite how much power over what kind of Brexit - if any - we face is held by Corbyn.

Because Juncker confirmed that the only concession on the backstop he can potentially offer is to change the non-binding (in a legal sense) Political Declaration, to embrace practical steps such that the backstop would be needed (if at all) for the shortest possible time.

That will not satisfy any Tory Brexiters, let alone the purists in the ERG who want the backstop incinerated.

Even so the PM has agreed to open talks on modifying the Political Declaration, with a view to meeting Juncker again to take stock at the end of February.

Has May bought herself anything of value here?

That depends on whether in just the next few days she can persuade Merkel, Macron and other EU leaders to relent and change the negotiating mandate, such that the Withdrawal Agreement will at the last be reopened.

If they won’t budge - and I cannot see them doing so - she can only get a Brexit deal through parliament with substantial Labour support.

So as I said a little earlier, it is the prime minister’s moment of truth: is she prepared to break up her party to secure an orderly negotiated Brexit, because there is no longer any alternative on offer than the no-deal Brexit she claims she does not want?