It looks as though the longest rumoured split in a major British political party since the creation of the Social Democratic Party (SDP) almost 40 years ago, will happen on Monday morning.
The reason I think this is because last night I texted the Labour MPs Chuka Umunna, Chris Leslie, Luciana Berger and Gavin Shuker asking them if they were holding a press conference at 10.30am on Monday to announce a split within their Party, and none replied.
For what it is worth, I could also have texted Mike Gapes, Angela Smith or Ann Coffey among other critics of the leadership of Jeremy Corbyn.
The mystery is not why they are leaving Labour: they are all alienated from a Labour leadership that they see as being far too slow and lacklustre in cutting out the cancer of anti-semitism, and they are furious that Corbyn has been (as they see it) ignoring the majority of Labour members and supporters who would like the Party to back a second EU referendum.
No. The mystery is why Monday, rather than in a fortnight or six weeks' time, when perhaps the UK’s EU destiny will be a bit clearer?
The point is that those running the People’s Vote campaign for a referendum have been desperately trying to persuade Umunna and Leslie to delay their split - because they think if they were to leave the Party now, that would entrench the reluctance of Corbyn and those close to him to back a referendum.
As and when Umunna and co formally leave Labour, the call for a referendum will be closely associated with those who have set themselves up as the enemies of Corbyn and his socialist project.
So the referendum-sceptics around Corbyn will tell him that conceding a People’s Vote would be to capitulate to those who want to destroy him.
So the big question for Umunna and the Labour refuseniks on Monday is whether in leaving Labour because they want a referendum they are not in practice undermining the prospect of a referendum.
PS. The decision of Umunna and co to leave Labour, because they see Corbyn as too obstructive of the party shifting to back a referendum, will not be endorsed by the People’s Vote campaign.
In fact the People’s Vote campaign will desperately try to distance themselves from the Labour splitters, because it perceives that the shadow cabinet is gently moving to the idea of a referendum and don’t want that slammed into reverse (multiple sources have told me that there is a growing enthusiasm on the frontbench for the Kyle/Wilson idea of Labour supporting May’s deal on the condition she agrees, if it is passed by Parliament, to put it to a referendum).
So the last thing the People’s Vote wants and needs is for Corbyn and the referendum-sceptics in his close circle to see Umunna as in league with them.
And if Corbyn does choose outright war with Umunna and the other refuseniks over the referendum question, the cost to him could be significant.
I asked one Labour MP who is staying in the Party for now where this will all lead.
“I guess this is up to the Party, who will inevitably react appallingly," they said.
"If they respond as they should to protect the Party and be clearer on anti-Brexit it can be fixed.
"If they don't, more will go”.