A final YouGov poll suggests that 7% of UK Independence Party (Ukip) supporters voted to remain in the European Union.
The poll, released after polls shut at 10pm on Thursday, puts Remain ahead with 52% of the vote.
Ukip leader Nigel Farage told the Huffington Post UK that he believes the Government’s extension to voter registration swung the referendum to Remain.
The survey results have left many shocked and rather confused.
If the poll is accurate, it would be a hammer-blow for Boris Johnson, whose backing of a Leave vote helped widen a split at the very top of the Conservative Party.
While the survey is not a traditional exit poll, YouGov accurately predicted the Scottish Referendum in 2014 using the same method of asking a targeted group of people which way they voted on the day of poll.
Joe Twyman, head of political and social research at YouGov, said: “Today YouGov conducted a survey, going back to the same people we spoke to yesterday to find out how they actually voted. The survey found a small move to Remain and based on these results we expect the United Kingdom to continue as a member of the European Union.
“Remain are on 52% with Leave on 48%.
“The results are close and it too early to call it definitively. But these results, along with the recent trends and historical precedent, suggest a Remain victory is the more likely outcome.”