Again and again throughout this Brexit process I've been struck by the chasm in thinking between leading UK politicians and the viewpoint of EU leaders.

But the current state of affairs is particularly surreal.

As the UK's political class twists and turns itself into a spitting Brexit frenzy and the pound fluctuates hysterically on the currency markets, the EU has popped on its blinkers, clapped its hands firmly over its metaphorical ears and is resolutely continuing preparations for a special summit of EU leaders to sign a Brexit deal that many in the UK believe/hope could yet end up in the bin.

So far, nothing - none of the screaming headlines back in the UK - is managing to distract the EU from its focus.

This, first and foremost, is because Theresa May stands firmly behind the Brexit deal. And Europeans view her as the UK's chief Brexit negotiator.

UK cabinet ministers - even Brexit secretaries - can come and go, but as long as the prime minister remains on board, EU leaders believe the seal-the-deal Brexit summit will go ahead.

There is also zero - really, truly, honestly, not just saying it - zero-intention or appetite in Europe to start renegotiating the withdrawal deal with the UK.

For Europe's leaders, the document is the result of 19 months of intense and tense negotiations working towards something (Brexit) that none of them wants and which has already sucked up an enormous amount of time, energy and money across the European capitals in preparation.

Of course, the EU would rather the UK changed its mind and stayed in the club. But if it is leaving then this, they say, is the deal on the table.

The EU's chief Brexit negotiator, Michel Barnier, told EU ambassadors on Friday that the European Union should not start a last minute bargaining process.

The EU should protect its principles, he said: meaning standing by the backstop guarantee on the Irish border.

Brussels wants to close this chapter and move on.

But remember: we're talking about the divorce deal here. Not the future EU-UK trade deal.

Sure, EU and UK negotiators are hammering out a document this weekend to outline the kind of relationship they intend to have with one another after Brexit but - spoiler alert - when it comes to the chapter on future economic relations, expect their text to be suitably vague.

And, anyway, this document unlike the Brexit withdrawal agreement is not legally binding.

Detailed negotiations on the new EU-UK trade deal will only begin after Brexit day and the UK is legally, if not politically, free to choose - and change - the kind of economic relationship it wants with the bloc: very close à la EEA (European Economic Area),or a more arm's-length deal like Canada has.

But, since it takes two to tango in negotiations, each choice has consequences under EU law.

A Canada-like free-trade agreement can never - whatever David Davis and others promised - offer frictionless trade. And it would lead to a customs border on the island of Ireland unless a separate arrangement is agreed for Northern Ireland.

Whereas being a member of the EEA would mean the UK accepting freedom of movement and paying into the EU budget.

But the by-now hugely controversial EU-UK customs relationship outlined in the Brexit withdrawal treaty need never come about.

It is an on-paper insurance policy to avoid a hard border between Northern Ireland and the Republic of Ireland since, as already discussed, no-one knows right now what the future economic relationship will look like between the EU and the UK.

The reason it is a UK-wide customs arrangement is because Theresa May, not the EU, wanted it to be.

And, if a new trade deal is ready between the two sides before the end of the transition period - the end of 2020 - then the "backstop" customs partnership would be superseded.

If it isn't ready, the UK government could ask the EU to extend the transition period instead, though that of course has consequences too: ongoing freedom of movement, payments into the EU budget etc.

Avoiding a no-deal Brexit
The options don't look appetising perhaps but, as I have said, if the UK parliament now rejects the Brexit withdrawal deal, hoping to renegotiate a "better" (i.e more successfully cake-and-eat-it) deal, then the EU doesn't want to know.

But they would likely "freeze" the Article 50 process if the UK were to hold a general election or a second referendum.

Out of self-interest, of course.

Firstly, because the EU wants to avoid a costly, chaotic no-deal scenario and, secondly, because as France's Emmanuel Macron has said so often, they will keep the door open until the last moment in case the UK should change its mind about leaving.

But, deep down, Europeans think a nationwide change of heart is unlikely and that the Brexit deal will in the end be signed.

Which is why, in stark contrast to the UK media obsession with the current political turmoil, Brexit is far, far down the running order of evening news programmes across Europe.