The campaigning, the debates and the rows are over and now the EU referendum is upon the UK. Millions of voters are expected to head to polling stations across Britain and Gibraltar on 23 June to have their say on the country's membership of the 28-nation bloc. The polls opened at 7am and will close at 10pm, with the results of a YouGov on-the-day survey expected to be revealed shortly after.
The electorate are being asked a simple question – whether to Remain or Leave the EU. The last time voters had a referendum on a similar issue was in 1975, when the UK voted to stay a member of the European Economic Community (EEC), a precursor to the EU.
David Cameron promised the latest referendum in his 2015 general election manifesto amid tensions within the Conservative Party over the EU and after Ukip's victory in the 2014 European Parliamentary elections.
The prime minister has promised to stay on no matter the result of the historic ballot, but Boris Johnson's leadership credentials are expected to be boosted in the event of a Leave vote.
The eve of election opinion polls were split over whether the UK would break away from Brussels or not. An online TNS survey, of more than 2,000 respondents between 16 and 22 June, put Leave on 43% and Remain on 42%.
A telephone poll from ComRes, of more than 1,000 people between 17 and 22 June, put Remain on 48% and Leave on 42%. Elsewhere, online YouGov research, of more than 3,700 people between 20 and 22 June, put Remain on 51% and Leave on 49%.
The UK has been hit with bad weather as voters went to the polls, with rain lashing Britain after an overnight thunderstorms.
Anthony Wells, Research Director at YouGov, previously told IBTimes UK: "Common sense obviously suggests that people are less likely to go out in the pouring rain, but the actual evidence doesn't back it up very well. In past elections in this country when we've had different weather in different parts of the country, it hasn't produced a big difference in turnout."