Labour's negotiations on a Brexit pact with the Government may well be pronounced dead today - partly because the party is launching its EU elections manifesto tomorrow and would presumably need to say something about a possible pact other than "don't know".

To be clear, there are more talks between the two sides this evening. But those involved tell me they have no expectation a breakthrough will be seized from the jaws of futility.

Simultaneously Labour's leadership is consulting "all the elements" in and connected to the party, so there's no great backlash from MPs or union leaders as and when the hopes of a Brexit compromise are officially abandoned - which could happen tonight.

Corbyn is, for example, meeting loyalist MPs later. And presumably the general secretaries of the big unions will be contacted.

European Union flags fly outside the Houses of Parliament in Westminster. Credit: PA

One outstanding question is whether the party should now help the PM at least create the impression a process still exists to deliver Brexit, by providing assurances it won't be wilfully destructive, as and when she introduces the Withdrawal and Implementation Bill to the Commons.

But given the sheer number of Tory and Labour MPs who hate the Withdrawal Agreement that will be enshrined in that bill - the Tories mainly because of the hated backstop, Labour MPs largely because they want a confirmatory referendum - it is difficult to see what Corbyn could deliver to May that would move her Brexit plans any meaningful distance from the mortuary.

Labour have been trying to find a deal with Theresa May's Conservative party. Credit: PA

Also, Corbyn and his closest colleagues are acutely aware that for them to allow May to claim any kind of Brexit victory - or even to credibly claim a victory is achievable - could benefit only her party; Labour's vote ahead of the EU elections would continue to haemorrhage.

For what it's worth, some Labour candidates fear the party's number of MEPs will halve to around 10 - compared to their earlier expectation of Labour topping the poll if it had unambiguously backed a referendum. They anticipate a significant swing to the Greens, especially in London and the south.

Can Corbyn stop the rot? There's no sign he shares the view of his remain-y candidates about how best to do so, since the manifesto launch will be in Brexit-y Kent - which shows he still thinks it is not just an unsustainable stunt to ride both the leave and remain horses.