Voting is under way in a historic referendum on whether the UK should remain a member of the European Union or leave.
A record 46,499,537 people are entitled to take part, according to provisional figures from the Electoral Commission.
Polling stations opened at 07:00 BST and will close at 22:00 BST.
It is only the third nationwide referendum in UK history and comes after a four-month battle for votes between the Leave and Remain campaigns.
In common with other broadcasters, the BBC is limited in what it can report while polls are open but you can follow the results as they come in across the BBC after polls close on Thursday evening.
The referendum ballot paper asks the following question: “Should the United Kingdom remain a member of the European Union or leave the European Union?”
Whichever side gets more than half of all votes cast is considered to have won.
Kingston upon Thames Council in south west London has moved two polling stations after they were inundated with water.
The Electoral Commission estimates a final result “around breakfast time” on Friday.
The last nationwide referendum took place five years ago, when voters rejected an attempt to change the way MPs are elected.
The first one was in 1975, when the country was asked whether the UK should continue to be a member of what was then called the European Economic Community.