Voting has ended in a referendum that will decide whether the UK remains a member of the European Union.
Counting will get under way shortly 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.
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What to watch out for on results night
Results in full
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.
An Ipsos Mori survey for the London Evening Standard, published on Thursday, suggested the result was on a knife-edge, with 52% wanting to stay in the EU and 48% backing an exit.
The pound hit 1.49 US dollars during the day on Thursday, building on its rise all through the week after polls pointed to a narrow lead for the Remain camp.
In the late afternoon it dropped back to a 0.1% rise to 1.48 US dollars. although analysts believe currency traders are following bookmakers’ odds rather than the polls.
Follow the action on the BBC
From 22:00 BST, there will be comprehensive coverage on the BBC News website and app with live text and video streaming, reaction and analysis from BBC editors and others. There will also be an up-to-the-minute full results service and details of all local results.
BBC One, the BBC News Channel and BBC Parliament will broadcast a results show hosted by David Dimbleby alongside BBC experts and special guests from 21:55 BST. Coverage continues through the night and Sophie Raworth, Andrew Neil and Victoria Derbyshire pick up the coverage on Friday morning.
The results programme will be streamed internationally on the BBC News website from 22:00 BST.
BBC Radio 5 live will have coverage as the results come in, as will Radio 4 from 23:00 BST until the Today programme picks up at 06:00 BST on Friday.
From 22:00 GMT, television viewers outside the UK can tune in via BBC World News and BBC World News America. Listeners outside the UK can tune into BBC World Service radio for regular updates.
Referendum night – what to watch out for
A record 46,499,537 people were registered to vote in the referendum, according to provisional figures from the Electoral Commission.
Sealed ballot boxes are now being collected and transported to the venue for each of the 382 local counting areas.
These represent all 380 local government areas in England, Scotland and Wales, plus one each for Northern Ireland and Gibraltar.
Results from these areas will then be declared throughout the night, along with result totals from 11 nations and regions.
Depending on how close the poll is, the result may become clear before the final national result is officially declared by the Chief Counting Officer, who will be based at Manchester Town Hall.
The referendum followed a bitterly-fought four month campaign, which saw Mr Cameron pitted against senior colleagues in his own party, who were campaigning for Britain to leave.
A Brexit vote could deal a fatal blow to Mr Cameron’s career as prime minister, although he has vowed to stay on whatever the outcome.
He promised to hold a referendum on Britain’s EU membership ahead of last year’s general election, following relentless pressure from his own MPs and the UK Independence Party, which was taking votes – and later – MPs from Mr Cameron’s Conservatives.
He initially suggested he would be prepared to back an out vote if he did not get what he wanted from his renegotiations.
But once the date of the referendum was announced he threw himself into the campaign for Britain to remain, arguing the country would be “stronger, safer and better-off” in the EU.
Nearly all of Britain’s opposition parties, including Labour and the Scottish National Party, backed remaining in the EU, along with the majority of business leaders.
The Leave campaign – headed by former mayor of London and Conservative MP Boris Johnson – argued that the only way Britain could “take back control” of its own affairs would be to leave the EU.
The Leave campaign dismissed warnings from economists and international bodies about the economic impact of Brexit as “scaremongering” by a self-serving elite.
Immigration was a key issue in the campaign, with the Leave campaign arguing that net migration from the EU could never be reduced while the UK was signed up to free movement rules.
In an eve-of-poll interview with Telegraph, Mr Johnson, who has long been seen as bidding to be the next prime minister, claimed the vote was more important to him than his future in British politics.
“Frankly, if this is the end of my political career… I’ve done eight years as mayor of London, I enjoyed it hugely, it was a massive privilege. Fine by me.”
Courtesy of BBC