I’m told by a senior Labour source not to expect a grand announcement on a second Brexit referendum when the Shadow Cabinet meet at 1.30 on Wednesday afternoon. It is an incredibly sensitive subject for a party completely split on Brexit.
It is now "inevitable" that a second, or "confirmatory", referendum on ANY negotiated deal will become official Labour policy, we understand. The preference of Tom Watson and shadow Brexit spokesperson Keir Starmer is that policy would include Labour campaigning to Remain.
I’m also told those in the shadow cabinet pushing for a second referendum want it confirmed as party policy before the Tories elect a new leader at the end of July.
However, it's unclear what that would mean in practice.
For instance, does ANY deal include one negotiated by a Labour government?
"Yes", a Labour shadow minister told me. "Any proposed deal negotiated with the EU."
So that would mean, as one Labour MP against a second referendum put to me: "If we win the election we’re then trying to have a referendum on our own deal (and presumably campaigning against it)?"
I put this to a senior Labour source in favour of the party becoming a referendum-and-remain party.
They told me one option being floated is holding a referendum immediately after Labour wins a general election, before Labour attempted to negotiate its own deal. If the public vote to Leave (again), they would then go to the EU and negotiate a deal to leave.
But what would the leave option be on the ballot paper in such a referendum? Theresa May's deal? No deal?
"That needs to be decided", I was told.
From this conversation and others with Labour ministers, the party is far from clear on how the ‘referendum-and-remain' policy the party is set to adopt would work if Labour were in government.
One thing Labour's divided shadow cabinet does agree on, I'm told, is a reluctance to put 'No Deal' on the ballot paper in any public vote, because of the "chaos" leaving without a deal would course, particularly on security.
So, a Labour government is unlikely to ever hold a No Deal or Remain referendum. Can it really hold a referendum where the question is Theresa May's failed deal v Remain?
We may be expecting some clarity on Labour's support for a second referendum, but how exactly it would work in reality remains as clear as mud.