We have entered a dangerous phase.
London4Europe Committee member Michael Romberg worries about a stitch-up by the two main party leaders - even though only one of the parties' membership largely support Brexit while the other party's members are overwhelmingly for Remain.
Obviously Theresa May wants Brexit, as does her party. But so does Jeremy Corbyn.
In his September 2018 party conference speech Jeremy Corbyn abandoned Labour's six tests which had just been reaffirmed by the party and reached out to Theresa May: "If you deliver a deal that includes a customs union and no hard border in Ireland, if you protect jobs, people’s rights at work and environmental and consumer standards – then we will support that sensible deal."; he could not bring himself to mention the referendum directly.
True, in the indicative votes Labour did whip in favour not only of pro-Brexit options but also for a confirmatory referendum on any deal. But when front-bench allies of Corbyn rebelled against the last element of that whip no action was taken; not much of a whip if you are a pro-Brexit rebel.
In the second set of indicative votes, Corbyn's personal letter only urged Labour MPs to back the pro-Brexit motions. Otherwise a referendum was presented as an option only to stop No-Deal or a damaging Tory Brexit.
That is all consistent with Corbyn's statements of December 2018 [if Labour win a general election Brexit would go ahead] February 2019 [Labour amendment based on customs union not six tests; referendum only to stop Tory Brexit] and April 2019 [Labour to end freedom of movement]. Support for Brexit was the basis of the 2017 election manifesto.
The two pro-Brexit leaders of the main parties might agree on a Brexit model
As regards the policy substance that would not be difficult.
Both accept the withdrawal agreement and anyway it's not up for discussion.
The backstop's "single customs territory" is more or less a temporary customs union. There are only three ways to exit the customs provision of the backstop: a permanent customs union; a border in the Irish Sea which would threaten "our precious union" (and the DUP's blood-red line); and a combination of as yet uninvented technology and as yet undeveloped management procedures (it’s national unicorn day on 9 April). Were it not for the need to appease the ERG's fantasies Theresa May would presumably have headed for the permanent customs union long ago.
Differences between the two leaders on a strong single market relationship (but ruling out freedom of movement - so not that strong), protection of workers' rights, consumers and the environment are no more than rhetorical.
They don’t even have to be explicit about ruling out a referendum – prevarication would do it. Given the logistics - especially if you throw in a citizens’ assembly - you will not have much change from the year that President Tusk is proposing. So after a few more weeks of faffing about the option would have fallen away without a further extension.
What will keep the leaders apart?
Both party leaders share a concern to keep their parties together and both wish to be in No 10 - but those considerations point in different directions for each. It is hard to believe that personal chemistry would make them soulmates. There is a complicated blame game going on in which the EU is also a player. Domestic party politics make cross-party agreements of any sort risky. The habit of deriding each other across the despatch box will be hard to break.
So there is a good chance that that they will not be able to agree. Let's hope that politics as usual prevails.
What should bring them together?
A referendum, of course.
Theresa May cannot get her deal through the Commons. If she adds Kyle-Wilson, a referendum, it will pass. She would annoy the ERG - but perhaps annoy them less than by agreeing to a customs union.
Jeremy Corbyn cannot expect to get his deal through his pro-Remain party without the risk of the party splitting. His reputation for honesty has tanked with the electorate due to prevarication over Brexit. Pro-Corbyn sentiment has led members to overlook a lot of pro-Brexit statements. But at some point soon, Labour actually has to take a firm stand. It is hard to believe that going all-out for Brexit will win him enough points for honesty to overcome what he loses on policy. As in 1975, a referendum could avoid the split in the party that could otherwise occur.
That is why it is so important that Chancellor Philip Hammond said that a referendum is a perfectly credible proposition. And that the DUP are at last waking up to the risk that Brexit - a desirable in their book - presents to the only thing that actually matters to them - the Union.
Even more important is the conversion of Emily Thornberry MP (Islington South) to a referendum. She had previously issued mischievous teases that she wanted "a people’s vote but I want it to be a big and proper people’s vote, which is a general election." Some in Labour deride her pro-referendum message as just positioning for the party leadership; but even if that is all it is, it is still a clear signal of what the membership wants. So congratulations to EM-affiliated Islington in Europe - and campaigners in Remain-Labour, Labour against Brexit and Labour for a People's Vote - for succeeding in persuading one of their MPs to come out for the cause. Let's all hope that they are equally successful with Thornberry's constituency neighbour.
We have to hope that party politics prevents Jeremy Corbyn from stitching up Brexit with Theresa May. We need a referendum.
The London4Europe blogs page is edited by Nick Hopkinson, Vice-Chair. Articles on this page reflect the views of the author not necessarily of London4Europe.