Robert Peston

Our Brexit fate is in the hands of France's president Macron – which is "not a wholly comfortable state of affairs," in the euphemistic words of a minister. What this minister means is the Prime Minister and her close colleagues are a long way from being convinced Macron will underwrite EU president Donald Tusk's proposal for the UK to be granted a year's delay to Brexit, with a break clause to allow us to leave the EU earlier if all the political and legal niceties can be completed earlier.

Pretty much everyone I meet says they want all the Brexit uncertainty to end, one way or another. But that is now impossible: even agreement - which seems remote - on some version of the PM’s deal to take us out of the EU would only be a beginning of a sort, not an end, with so much left to decide on what kind of future relationship we need and deserve with the EU. And if there is no backing from MPs for the Withdrawal Agreement that is the divorce from the EU, then we are into a series of choices whose consequences would be to lead to various forms of national and international fission.

There has been considerable and widespread cynicism about the talks between the Government and Labour about a compromise that could break the Brexit deadlock. But those close to the negotiations, led today by David Lidington and Keir Starmer, believe there is at last a "plan with a chance," of securing a positive vote from MPs for the PM’s Withdrawal Agreement, without which there can be no managed exit from the EU. It would involve a Government committing to staying in the Customs Union, "dynamic" alignment with EU rules covering workers’ rights and the environment and giving the Commons a vote on whether the whole package would be subject to confirmation in a referendum. "Is all this real?" I asked informed sources. "Yes," they said.

The magnitude of the gulf between the cabinet and perhaps a majority of Tory MPs over how to deliver Brexit was on display like an oozing wound on my show last night. The Chancellor was his normal phlegmatic, unsugaring self when revealing the government is reconciled to a long Brexit delay till at least the end of the year - and that the best the prime minister can hope for from the emergency EU council on Wednesday is that the EU’s 27 leaders would allow her a break clause, so that if a Brexit deal is fully approved on all sides earlier, the UK could leave the EU at that earlier juncture. But even so, he conceded there is now no escape from preparing to participate in European parliamentary elections, at considerable financial and emotional cost to the UK.

It is hard to overstate the magnitude of what happened in Cabinet today - because the prime minister and her senior ministers concluded over a record-breaking seven-and-a-half hours that Brexit was too hard for them to deliver on their own and they would now seek to enlist Jeremy Corbyn and Labour in finding a solution. 'There was a very significant shift to a softer Brexit,' said a senior minister. 'There is no turning back'. And there you have captured the magnitude of the risk the PM is taking. First, she is hoping Corbyn will negotiate in good faith - which may well be the triumph of hope over experience since he can legitimately query why she didn't offer proper cross-party negotiations months ago.

Labour has not tabled a motion for today’s indicative votes on a way through the Brexit mess – which feels like an important moment, perhaps because it has recognised that its proprietary version of Brexit is dead and its role instead is to work with all MPs to identify a deliverable alternative (which could be no Brexit at all) to the Prime Minister’s thrice rejected plan. Presumably the thrust of Labour’s effort in the hours ahead will be to secure support for the Kyle/Wilson call for a “confirmatory” referendum (a referendum on any Brexit deal approved by parliament). But even so, the prospect of a majority of MPs backing a people’s vote today is slim.

Some allies of the prime minister are desperate for a majority of MPs to back Ken Clarke’s motion to keep the UK in the customs union, at the close of round two of the Letwin process of the Commons bossing the government, Monday night. Yes you heard me right. They want MPs to vote for a plan that would drive a coach and whole herd of horses through the Tory election manifesto and would cleave the Conservative Party in two. To be clear, these are not ministers and officials who themselves are keen for the UK to agree a deal with the EU that would remove the requirement for customs checks to be reintroduced after Brexit. Au contraire.

Maybe I am simply in the thrall of the powerful emotions manifested by MPs in their debate on Friday, but their rejection of the Withdrawal Agreement just now feels the most significant event to date on the long and tortuous road to Brexit or revocation. Because the EU just a week ago bent its rules to accommodate the Prime Minister's request for a modest Brexit delay, and also tried to make it easier for her to ratify the deal by saying only the divorce part – the Withdrawal Agreement – would need MPs' approval to secure a postponed Brexit date of May 22 for leaving the EU. Parliament has thrown the compromise offered by the EU's 27 leaders back in their faces.

Truthfully I don't really understand why the prime minister is holding a vote tomorrow to approve the Withdrawal Agreement she negotiated with the EU - other than the symbolism of showing that on the day she originally set as Brexit day, 29 March 2019, she is still working hard to extricate the UK from the EU. Because I don't see how she wins it. It's almost irrelevant that tomorrow's vote won't be a 'meaningful vote', under the terms of the EU Withdrawal Agreement act. It is to all intents and purposes a meaningful vote: if the motion laid tonight is passed tomorrow, MPs WOULD be approving Brexit, under the terms laid down by the EU 27's leaders a week ago.

Here is the measure of today's events in Parliament: probably the least important question is whether the PM names her own departure date when she sees a rowdy meeting of Tory MPs at 5pm under the umbrella of the 1922 Committee. This is not to trivialise whether or not she confirms she would stand down on May 22nd or shortly afterwards, subject to her Brexit deal being ratified later this week. If she conveys in any way when she's going, and her colleagues have no idea whether or not she will, that's huge. But every Tory MP knows she is a short-dated Prime Minister. Whatever Theresa May says today, none of her MPs expect the leadership election that would select her successor to be held later than the summer.

This matters. I am told that the cabinet secretary Mark Sedwill and the attorney general Geoffrey Cox informed Cabinet that if at the end of the Letwin process MPs pass a motion mandating the PM to pursue a new route through the Brexit mess - perhaps a referendum, or membership of the customs union, or some other softer future relationship with the EU - the PM and government would be in breach of the ministerial code and the law if they fail to follow MP's instructions. Or to put it another way, the PM would be obliged to endeavour to negotiate with the EU the revealed will of MPs, even if that revealed will involved a Brexit delay that requires the UK to participate in May's European parliamentary elections, or is at odds with the Tories' manifesto.

A point of significant tension at this morning’s cabinet will be over whether the PM is to allow her ministers and MPs to vote with their consciences on the indicative votes today and tomorrow to find any Brexit – or no-Brexit plan – that a majority of MPs can support AND on the statutory instrument (SI) that will delay the 29 March date in law for exiting the EU. Apparently the whips want a free vote on the SI, so ministers – including some of them – can vote against it and keep their jobs. And more remainy ministers – led by Greg Clark, Amber Rudd and David Gauke – want a free vote on the indicative votes, so they can signal their support for a softer Brexit or a referendum without losing their jobs. How will the PM jump?