Britons were voting on Thursday to decide the future of their country and Europe in a referendum on European Union membership that has divided the nation and is being nervously watched by financial markets and politicians across the world.
Opinion polls taken before the vote indicated the outcome is far too close to forecast.
Prime Minister David Cameron called the vote under pressure from his ruling Conservative Party and an increasingly powerful anti-EU party, hoping to put to rest decades of debate over Britain’s place in Europe and its ties with Brussels.
Most polls put the “Leave” and “Remain” camps neck-and-neck at the end of a campaign that was dominated by immigration and the economy, and shaken by the murder of a pro-EU MP, though late on Wednesday two showed a swing to “Remain”.
The “Leave” campaign says Britain’s economy would benefit from a Brexit, or British exit from the EU. Cameron says it would cause financial chaos.
Traders, investors and companies are preparing for volatility on financial markets whatever the outcome of a vote that both reflects, and has fuelled, an anti-establishment mood also seen in the United States and elsewhere in Europe.
Finance leaders from the Group of Seven leading economies will issue a statement stressing their readiness to take all necessary steps to calm markets if Britain votes to leave, government officials with direct knowledge of the preparations said.
Britain’s AAA credit rating could be swiftly downgraded by Standard and Poor’s after a vote in favor of leaving the EU, S&P chief sovereign ratings officer Moritz Kraemer told German daily newspaper Bild.
Much will depend on turnout, with younger Britons seen as more supportive of the EU than their elders but less likely to vote.
“Go out and vote remain for a bigger, better Britain inside a reformed European Union,” Cameron told “Remain” campaigners on Wednesday.
His main rival, former London mayor Boris Johnson, whose decision to support “Leave” galvanised its campaign, told voters this was the “last chance to sort this out”.
Sterling rose to its highest so far this year against the U.S. dollar late on Wednesday after one poll pointed to a clear lead for “Remain” and betting markets priced in an 80 percent chance Britain would not leave.
Polling stations for 382 local counting areas opened at 6:00 a.m. GMT and close at 9:00 p.m. GMT, with most of the results expected between around 1:00 and 3:00 a.m. GMT on June 24.