The looming votes on James Wharton's Private Member's Bill for an EU referendum are likely to present the last opportunity ahead of the general election for MPs to put on record whether they support giving people a say on Britain's membership of the EU. The prospect is already stoking signs of collapse in the unpopular positions of the anti-referendum parties.
A small but notable shift in Labour policy on an EU referendum was exposed recently when a leaked Labour document revealed not just that there would be no party whip when the EU Referendum Bill comes before Parliament next Friday, as is customary for private members' bills, but that "Labour will abstain on the Bill".
The briefing was smoked out by an "Email your MP" campaign launched by the People's Pledge just 48 hours beforehand, as Labour MPs then contacted party headquarters to ask how they should respond to questions from constituents about their voting intentions on July 5.
So when did Labour's policy on an EU referendum shift from opposition to abstention? Perhaps it was after MPs voted on John Baron MP's pro-referendum amendment to the Queen's Speech. The vote showed that, with full Conservative and DUP support, coupled with that of a few MPs from other parties, a future majority for an EU referendum could depend on just a handful of Labour MPs - many fewer than are known to support an EU referendum.