Europe

Polls open in Britain's historic EU referendum

  • Britain's Prime Minister David Cameron,  foreground,  addresses Vote Remain supporters with  former Prime Minister John Major, right, during a rally in Bristol, England Wednesday June 22, 2016. On Thursday Britain goes to the polls in a referendum  on whether to remain or leave  the EU . (Geoff Caddick/PA via AP) UNITED KINGDOM OUT

    Britain's Prime Minister David Cameron, foreground, addresses Vote Remain supporters with former Prime Minister John Major, right, during a rally in Bristol, England Wednesday June 22, 2016. On Thursday Britain goes to the polls in a referendum on whether to remain or leave the EU . (Geoff Caddick/PA via AP) UNITED KINGDOM OUT  (The Associated Press)

  • Advocate to exit Europe Boris Johnson poses for a selfie photo with voters  during a whistle stop tour of the country on the final day of campaigning before Thursday's EU referendum vote, in Selby, north England, Wednesday June 22, 2016. On Thursday Britain votes in a national referendum on whether to stay inside the EU, a momentous decision with far-reaching implications for Britain and Europe. (Andrew Parsons / PA via AP) UNITED KINGDOM OUT - NO SALES - NO ARCHIVES

    Advocate to exit Europe Boris Johnson poses for a selfie photo with voters during a whistle stop tour of the country on the final day of campaigning before Thursday's EU referendum vote, in Selby, north England, Wednesday June 22, 2016. On Thursday Britain votes in a national referendum on whether to stay inside the EU, a momentous decision with far-reaching implications for Britain and Europe. (Andrew Parsons / PA via AP) UNITED KINGDOM OUT - NO SALES - NO ARCHIVES  (The Associated Press)

  • Britain's Prime Minister David Cameron and his wife Samantha smiles as they leave after voting in the EU referendum in London, Thursday June 23, 2016. Polls opened in Britain Thursday for a referendum on whether the country should quit the European Union bloc of which it has been a member for 43 years. (AP Photo/Alastair Grant)

    Britain's Prime Minister David Cameron and his wife Samantha smiles as they leave after voting in the EU referendum in London, Thursday June 23, 2016. Polls opened in Britain Thursday for a referendum on whether the country should quit the European Union bloc of which it has been a member for 43 years. (AP Photo/Alastair Grant)  (The Associated Press)

Polls have opened in Britain for a referendum on whether the country should quit the European Union bloc it joined 43 years ago.

More than 46 million people are registered to vote in Thursday's plebiscite, which asks: "Should the United Kingdom remain a member of the European Union or leave the European Union?"

Polls are open until 10 p.m. (2100GMT), with results due early Friday.

The referendum has exposed deep divisions over issues including sovereignty and national identity.

"Leave" campaigners claim that only a British exit can restore power to Parliament and control immigration. The "remain" campaign led by Prime Minister David Cameron argues that Britain is safer and richer inside the 28-nation EU.

Financial markets have been volatile ahead of the vote, as opinion polls suggested a tight race.