EU referendum: New opinion polling approach puts Brexit vote result on 'knife-edge'

The UK's referendum on its membership of the EU will come down to a "knife-edge" on 23 June, according to unique survey of voting intentions. The new polling approach from NatCen Social Research predicts that the result of the historic ballot will be 53% for Remain and 47% for Leave.

The research, based off the polling lessons learned from the 2015 general election, was conducted over the internet and by phone, with a randomly selected sample of respondents. The survey, of more than 1,600 people between 16 May and 12 June, comes with just two days before the referendum.

"Our survey provides valuable insight into how to interpret the divergent results that have been produced by internet and phone polls throughout the referendum campaign," said Professor John Curtice, a senior fellow at NatCen.

"It strongly suggests that the truth may well lie in between the two. This implies that, in the final days before the vote, it may well be reasonable to split the difference between the online and phone polls. However, it is important to remember that the outcome looks so close that any lead should be treated with caution."

But the prediction for a Remain victory at the referendum falls in line with other recent opinion polls, which have registered a swing away from Leave as the vote looms. The latest telephone survey from Survation, of more than 1,000 people between, put Remain on 45% (+3) and Leave on 42% (-3), with 13% of respondents undecided.

NatCen's findings come ahead of the last final major TV debate of the EU referendum, with Vote Leave campaigner Boris Johnson facing his successor as Mayor of London, Labour's Sadiq Khan, as part of the BBC One's live 21 June event at Wembley Stadium.

The 'Great Debate', hosted by David Dimbleby, will also see Labour MP Gisela Stuart and former Conservative minister Andrea Leadsom represent Leave alongside Johnson, while Scottish Tory leader Ruth Davidson and TUC general secretary Frances O'Grady join Khan for the Remain side.