Is public support shifting towards a second referendum?

Polls have consistently shown over the past year that Britons do not think Brexit is being managed well, but that had not been matched by any appetite to re-run the referendum. More recent polls have begun to show a different picture, however.

In July, YouGov found 42% of the public were in favour of a new vote, compared with 40% who were opposed. In April 2017 just 31% of people had supported a second referendum.

Further polling for the People’s Vote campaign found support was strengthened by the prospect of no deal. In a YouGov poll of more than 10,000 people, 50% said that in the event of no-deal outcome in negotiations there should be a fresh vote.

Who is backing a new vote?

In recent months the idea of a new vote on the terms of the deal, with an option to remain, has won some high-profile political supporters as well as business donations and celebrity endorsements.

The former education secretary Justine Greening is the most high-profile Conservative backing a new vote. A number of pro-EU Labour politicians back a second referendum, including Chuka Umunna and Tony Blair, as do the Liberal Democrats and the Green party.

Celebrities including Gary Lineker, Gabby Logan and Sir Patrick Stewart have also been campaigning for another vote.

Huge donations have been made to campaigns to re-run the vote. The Superdry co-founder Julian Dunkerton donated £1m to the People’s Vote campaign, and the billionaire philanthropist George Soros gave £500,000 to the pro-EU group Best for Britain.

How would a second referendum work?

The only conceivable route to a second referendum before the Brexit deadline in March would be if Theresa May is unable to pass through the Commons any version of an exit deal that she manages to agree with Brussels. If there is no parliamentary route to break the deadlock, there could be a referendum or a general election, though both remain unlikely.

Campaigners have said the proposed vote should be a choice between May’s eventual deal and remaining in the EU – something Brexiters would never accept. Greening has mooted the idea of a “preferendum” in which voters could choose from three options in order of preference: no deal, May’s deal or remain.

What are the barriers?

There is still no majority in the Commons for a second referendum. The vast majority of MPs are likely to be instinctively reticent about the idea of a second vote and the backlash it could unleash.

Labour hopes to force a general election rather than a referendum. Time is running out for a new referendum – the legislation for the last one took seven months to get through parliament. Even if it could be expedited, it is hard to see how a vote could take place without some extension of the article 50 deadline.

What would Europe do?

The EU’s chief negotiator, Michel Barnier, has said the EU could in principle extend the article 50 deadline to accommodate a second referendum, though not without difficulty.

Any extension would have a knock-on effect on EU elections in 2019 and for any post-Brexit transition period, which must end in December 2020 at the insistence of the EU because of the bloc’s budget timeframe.

Should a second referendum lead to a remain vote, there is no guarantee that the EU would not seek to impose some conditions on Britain’s continued membership.