There are still big questions about a second Brexit referendum

The Labour Party has swung behind the move to put the issue of UK membership of the EU back to the people – though it is still unclear this would be supported by a majority of MPs. John McDonnell, Shadow Chancellor, said this week that the party will put an amendment down to the Prime Minister’s meaningful vote, promised by 12 March.

Labour could back the idea being offered by its backbenchers, Peter Kyle and Phil Wilson, to approve the Prime Ministers’s deal, conditional on that approval being confirmed in a referendum. Confirmation via the referendum would mean the deal was approved, where rejection would mean revocation of Article 50.  

But if that amendment succeeded, it could mean that a deal that does not command a majority in the House might live on as the only alternative to remaining in the EU. For MPs who voted against the deal or prefer the UK to leave with no deal at all, this would be unpalatable. 

Even if the Prime Minister's deal were on the ballot, people would not be sure what they were voting for

Some aspects of the Prime Minister’s deal are clear. People would know they were voting for an orderly withdrawal, a transition period ending in December 2020, a settlement on citizens’ rights, a financial settlement agreed and a final version of the Irish border backstop.

The Prime Minister’s deal would also end “vast contributions” to the EU budget and freedom of movement, as well as leave the UK outside the EU’s Customs Union and Single Market. 

But beyond that it is far from clear what the UK’s future relationship with the EU would look like under her deal. The Prime Minister herself admits it encompasses a spectrum of options.

Future relationship negotiations with the EU could even collapse. The Government could clarify what it wants during a referendum campaign but, as the UK has learnt over the last two years, the EU has its own interests to pursue, and the Government’s wishes may not be negotiable.

A new Conservative leader, or a new prime minister from another party, could change the Prime Minister’s current red lines – and the EU has made clear that this would change the possible destination. Would the vote for May’s deal carry any weight in those circumstances?

Another referendum on Brexit might not offer the resolution people seek

The selling point for another referendum is that it would settle the issue – now people know the facts. A vote to support the Prime Minister’s deal would confirm the result of the 2016 referendum, but, as set out above, still leave the nature of the future relationship unresolved.

But a second vote to remain in the EU would be as – if not more – contested as the first vote to leave. Unless Remain was supported by decisively more voters than the 17.4m who voted last time, frustrated Brexiteers would say the second referendum failed to countermand the first result.

A small margin of victory for the Remain campaign would also infuriate the losing side, as would a lower voter turnout. Regardless of the result, many Brexiteers would say that the referendum had disenfranchised all those who wanted a proper Brexit – not “May’s Brexit in Name Only”. Others would say that their version of a softer Brexit should be on offer as well.

Labour may have increased the odds of another referendum. But the odds that it would definitively answer the Brexit questions Parliament has been struggling with over the last three years are still low.