A record 46.5 million people are eligible to vote
Polls have opened across the UK in the referendum to decide whether Britain should remain in or leave the European Union.
The first people able to cast their ballot were in Gibraltar where polling stations opened at 6.00am Irish time and will close at 9.00pm.
Across the UK, polls opened at 7.00am and will close at 10.00pm. While Irish citizens aged 18 or over who are resident in the UK are also eligible to vote.
Kingston Council was forced to close two polling stations due to flooding, with voters instructed to cast their ballots at alternative locations.
Queues have also formed outside some polling stations, with voters waiting patiently in line despite the wet weather.
Nestalk.com reporter Shona Murray is at a polling station in London, and says turnout has been strong despite the weather.
On the ballot paper, voters are being asked: "Should the United Kingdom remain a member of the European Union or leave the European Union?".
They will then choose whether they want to "Remain a member of the European Union" or "Leave the European Union" by placing a cross in the appropriate box.
Party leaders and senior figures from both Remain and Leave camps cast their ballots throughout the morning.
A record number of voters - some 46.5 million - are eligible to take part in the referendum, according to figures from the UK Electoral Commission.
Counting will begin as soon as polls close.
The country has been divided into 382 voting areas, each of which will declare its own result.
This is made of 380 local authorities across England, Wales and Scotland. Northern Ireland counts as one area, as does Gibraltar.
The overall result for the whole of the UK will be announced in Manchester, but only when all 382 areas have declared.
Our special Brexit Results Programme kicks off tonight at 10.00pm until midnight, presented by Kerian Cuddihy.
Coverage continues through the night when we join LBC Radio in London, with presenters Ian Dale and Nick Ferrari.
Newstalk Breakfast begins at 6.30am tomorrow morning with reporting, analysis and real-time updates as the final results come in.