Britain's leading anti-EU politician, UKIP leader Nigel Farage, claims the Government rigged the vote in favour of Britain staying in the EU.
After seemingly conceding defeat within seconds of the polls closing in the EU referendum, Mr Farage said that the Government's decision to extend the deadline for voter registration by 48 hours may have handed the Remain campaign victory.
He said in a press conference that he hoped he was wrong and that Leave proved triumphant in the poll. "What has dominated this campaign is an issue Westminster finds very difficult to talk about. An issue for which I have been demonised. That issue, if we do vote to Remain, is not going to go away. The eurosceptic genie is out of the bottle.
"My sense of this is the government's registration scheme, getting two million voters on in the 48 hour extension maybe what tips the balance. I hope I'm wrong. I hope I am made a fool of. But either way, whether I am right or wrong, if we do stay part of this union it is doomed, it is finished anyway.
"If we fail tonight, it will not be us that kicks out the first brick from the wall but somebody else."
He added: "We are running them close, they have been scared, they have behaved pretty appallingly. Win or lose this battle tonight, we will win this war, we will get our country back, we will get our independence back and we will get our borders back."
Mr Farage made the extraordinary statement after voting came to an end following a day in which storms and torrential rain disrupted much of the south. However, it is not thought to have deterred people from coming out to register their view at the ballot box.
Pro-EU Labour MP CHuka Umunna also said he was"'reasonably confident" that his side has won. The Pound soared on the news, spiking in value by around a cent against the dollar. A YouGov poll for Sky News published put Remain on 52 per cent and Leave on 48 per cent.
The outcome of the referendum is too close to call, according to pollsters, but a series of final surveys conducted before voting began today showed the Remain campaign in the lead.
Earlier in the day Mr Farage said: "It's been an extraordinary referendum campaign, turnout looks to be exceptionally high and looks like Remain will edge it. Ukip and I are going nowhere and the party will only continue to grow stronger in the future."
According to TV reports he later "un-conceded" and then re-conceded.
Meanwhile, Boris Johnson reportedly conceded defeat to a random man on the Tube.
According to the Daily Telegraph Mr Johnson told a man on the Tube that the Vote Leave campaign had lost the referendum.
Mr Umunna said he still believed the outcome would be "close". "If I was forced to call it I am reasonably confident that Remain gets a result."
Boris Johnson hijacked his own daughter's graduation earlier by unveiling a Brexit banner with just hours to go until polls close in the historic EU referendum
As his 22-year-old daughter Lara was enjoying her big day at St Andrews University in Fife, Scotland, the leading Vote Leave campaigner waved a poster with the words: "Last chance to vote."
But one student defied the ex-London Mayor by marching up to collect her degree with a Remain poster of her own as voters went to the polls across the country.
Millions of Britons defied the wet weather to queue in torrential rain and even wade through deep water to vote in the EU referendum.
Several polling stations were closed in London because of floods as Britain was finally having its say on whether to stay in the EU or cut our ties with Brussels after a gruelling 10-week campaign.
Thundery showers caused chaos across London and the south of England overnight and could potentially push the result towards a Brexit because polling data is clear that Leave voters are less likely to be put off by the bad weather than Remain voters.
Long queues snaked down the road from many polling stations as voters rushed to have their say when the polls opened.
David Cameron voted in Westminster with his wife Samantha this morning with the final EU referendum polls making the contest too close to call.
An exclusive survey for the Daily Mail and ITV News, gave the Remain camp a lead of six points, by 48 per cent to 42 per cent - but 11 per cent of electors said they were still undecided.
The In camp are ahead of Leave by 52 per cent to 48 per cent, according to an Ipsos Mori survey for the Evening Standard this afternoon. To add further uncertainty to the outcome, 12 per cent of those polled said they could switch sides as they head for the polling booth.
But according to an online poll by Populus the Remain campaign is at 55 per cent compared to Leave on 45 per cent.
Today's EU vote is a historic day for Britain because it is only the third nationwide referendum ever to take place in the UK. A record 46.5million are registered to vote.
It emerged today that senior Tory ministers on both sides of the EU debate are planning to calm the markets by backing Mr Cameron staying as Prime Minister whatever the outcome of the result.
They hope to shore up his support despite some Tory backbenches publicly revealing they will attempt to force him out of Downing Street because of his aggressive "Project Fear" strategy during the referendum campaign that they blame for creating bitter divisions in the party.
Kiwi expats watch votes closely
Last-minute polls indicated that the campaign to keep Britain within the EU was slightly ahead.
Expat New Zealander Glenn Hughes, from Tauranga, said he cast his vote at a tube station in North London on the way home from work.
Mr Hughes, 34, who moved to the UK in 2013, said that he voted "Remain", because he was inspired by the positive campaign and its emphasis on London's multiculturalism.
The "Leave" campaign was comparatively muted, he said.
"People aren't afraid to say on the street 'I'm Remain' but I haven't seen anyone walking around with stickers on their chest saying 'Exit'."
Most New Zealanders supported Britain staying in the EU, he believed.
"If we stay in the EU it's easier to travel, which is part of the reason why I'm over here anyway."
He said there was a strong sense of expectation on London's streets, and people were aware of the significance of today's result.
"Everywhere you go there's advertisements and posters and shops have put up in the front window which way they are voting."