Everybody seems to me to be asking the wrong question about Labour's brexit policy.
All of the focus is on whether or not we should be backing a second referendum but, with respect, this is almost irrelevant.
A significant number of Labour MPs will not vote to hold a second referendum, whether or not that becomes Party policy, and no more than a handful of Tory MPs will ever support a second vote, so there is no prospect of that proposition securing a House of Commons majority.
I should note, in passing, that there might have been some prospect of the Kyle/Wilson plan coming to fruition whereby the government conceded a second referendum in exchange for Labour support for the Withdrawal Agreement but it is clear that, with Mrs May's departure, the always very faint prospect of this has gone.
However, it is also clear that there is no majority in the current House of Commons for leaving the EU without a deal or any appetite at all on the part of the EU to remove the backstop. So, if we discount the farcical idea of proroguing Parliament, and the equally improbable eventuality of the EU throwing us out, one of two things will eventually happen. Either Mrs May's deal will pass, making a referendum irrelevant, or there will be a general election.
And the key question to be asked is not whether Labour would back a second referendum now but rather what Labour's policy would be at that General Election. It makes simply no sense for that policy to be a "better Brexit" (whatever that is) plus a referendum on that better "Brexit" with an option to remain. Why, if the government had been elected on a promise to Brexit, better or otherwise, would they then wish to give the public the opportunity to reject the government's own policy? How would the Labour Party anticipate campaigning in such a referendum? Against the "achievement" of its own government?
The truth is that calculated ambiguity may be a tactic for opposition but it is inconceivable as the position of a government. The Labour Party manifesto will have to say whether or not we support remaining in the EU. And if, advised by the first referendum, we don't, logically it should say that we would leave. And if we say we would leave, we will also have to say what we will do if the EU refuse to renegotiate the Withdrawal Agreement or at least to concede in full the changes we seek (whatever they are). Would we then leave on the best terms available or would we stay in? I point out that, if it is the latter option, the EU would have no incentive to renegotiate at all.
But of course things are not even as simple as that. For, even with the grip Corbyn and his allies currently have on the organs of the Party, I find it difficult to see how they would engineer a situation where the Labour Party manifesto committed us to leaving at any price. Most candidates wouldn't stand for it and most activists wouldn't work for it. "They did in 2017!" I hear you protest but 2017 was a long time ago and, frankly, nobody thought for a moment we had any chance of getting elected in 2017. Next time will be different (possibly).
Now you might think that the solution was, on a circular argument.........another referendum! But think through the logic of that. The only conceivable options in that other referendum would be Mrs May's deal or remain. But we are on record as denouncing Mrs May's deal as a terrible deal (albeit in rather unspecified ways) and have voted against it as consistently as the hardest of ERGers. Our manifesto could (surely) not say "we will let you have a vote and encourage you to vote to stay but if you don't we will go away and implement this terrible deal."
In the end leaving or remaining is a binary choice. Either Labour is for one or the other. There is no third way.
And by the way, pretty much everything I say above applies with equal force to the Lib Dems. Except that I am in no doubt about what their manifesto will say. "Bollocks to Brexit" works. "Bollocks to Brexit (subject to a referendum)" doesn't.
And also, by the way, Labour has a (relatively) easy way out of this dilemma. They could vote for the deal currently on offer (with some cosmetic changes to the political declaration) and defuse the car crash coming. They would then have to resign themselves to this Parliament going full term but by 2022 it might all just seem a long time ago and in any event a fait accompli. For what it's worth, if you listen carefully to Rory Stewart, that's what I believe, as PM, he would anticipate explaining calmly and logically as is his wont, behind closed doors to my own Party's leadership.
For if, by the time of the next election, we haven't left the EU, that's as much of a problem for Labour as it is for the Tories.