(BBC) Counting is under way in a referendum that will decide whether the UK remains a member of the European Union.
The counting is taking place at centres around the UK in a vote widely seen as too close to call.
There is no exit poll – so the millions who cast a ballot will have to wait until results start coming in to find out how the country voted.
Flash floods in the South of England disrupted voting and led to some polling stations being relocated.
An online survey taken on polling day of 5,000 people by YouGov suggests the Remain side running at 52% of the vote, to Leave’s 48%. Ipsos Mori have released polling from Thursday and Wednesday suggesting Remain will get 54% and Leave 46%.
Ukip leader Nigel Farage has told the Press Association the Remain camp has won based on “what I know from some of my friends in the financial markets who have done some big polling”.
The referendum result, which should be known by breakfast time on Friday, could be a turning point in the UK’s relationship with Europe and the rest of the world.
If the UK becomes the first country to exit the EU it will arguably be the biggest blow to the 28-nation European Union since its formation.
A vote to remain would see Britain gain exemption from “ever closer” political union and other concessions secured by Prime Minister David Cameron in a renegotiation of the country’s membership terms.
It should become clear which way the vote has gone by the early hours of Friday morning but if it is as close as the final opinion polls of the campaign suggested, it may take until closer to 07:00 BST (06:00 GMT) for the result.
Many polling stations in the South East of England reported high turnouts despite bad weather, so declarations could be later than previously expected.
Results predicted for between 0200 BST and 0300 BST could be put back an hour or two, it was being suggested, in some parts of the region.
There were also concerns that some commuters stranded in London because of chaos on the railways might not have got home in time to vote.