Nothing really new here, it all depends what Labour would end up offering as a choice in any second referendum. Personally, I'm coming to the opinion, in spite of the ambiguity created by McCluskey and McDonnell (and the real wishes of Corbyn), it is difficult to see the party going against the mass wishes of members and not offering a remain choice. With the liklihood of a bad deal or no deal being presented and failing in parliament, my thoughts would be that May is more likely to change her mind on a second referendum, than call a General Election..............but in the present climate, I wouldn't put my house on it!
Labour do have real problems with Europe. Any change of heart could of course badly reflect on their bedrock Brexit supporters, such is the reason they prefer sitting on the fence. However, at the core of the party (Corbyn especially) there is a dilemma. On the one side they view the EU badly, as a supporter of the maligned liberal economics and big business. Yet on the other hand there is the fear, outside the EU, of losing many of the hard gained and EU promoted, rights for workers.
I just had a wicked thought. I don't believe May would survive a rejection in parliament of her EU plans and it's not beyond belief that we could see an ironic reversal of 2016, when a leave vote saw the departure of Cameron and the replacement by a convert to Brexit. A change to remain in a second referendum could see a remainer, converted (for personal ambition?) to Brexit, then having to convert back to remain to take up the reigns of power. The one thing surely we can all agree on..........and that is, Boris would perform any number of somersaults in order to become Prime Minister!