Britons are about to decide finally whether to stick with the European Union, ending decades of debate over the country's place in Europe and a bitter referendum campaign that has left the country deeply divided.
The outcome of Thursday's vote on the EU will reshape Britain's future, either as a stand-alone country or part of a 28-member union plagued by problems but with ambitions to expand. And there will be ramifications around the world, as financial markets react and global trade patterns face potential realignment.
With polls showing the referendum too close to call and undecideds down to 10 per cent, the two main combatants in the campaign – Prime Minister David Cameron and Conservative colleague Boris Johnson – crisscrossed the country on Wednesday in a last-minute effort to make their case. Both tossed aside their usual arguments and appealed directly to Britons' sense of national pride.
Mr. Cameron spoke of his deep patriotism and praised Britain as "arguably the most successful multiethnic, multifaith, opportunity democracy anywhere on Earth," adding that a vote for Remain would prove the country isn't inward-looking.
Mr. Johnson said voting to leave was a chance "to believe in ourselves" and to "once again stand on our own two feet."
No effort was spared and throughout the day there was a steady stream of endorsements, name-calling and counterclaims.
The Remain side invoked Winston Churchill and pulled out a letter signed by nearly 1,300 business leaders who support staying in the EU. Landmarks in Britain and across Europe, including the Eiffel Tower in Paris and the Tate Modern in London, were lit up with Union Jack colours and "Vote Remain."
Vote Leave brought out endorsements from celebrities and brushed aside comments from business people backing Remain, saying the British people and not elites will decide the outcome.
Just how Britain would restructure its relationship with the EU if it votes to leave has been a major question throughout the campaign.
Under the EU Treaty, Britain would have to give notice of withdrawal and then both sides would have at least two years to work out a new arrangement. But this has never been done before and it's not clear what kind of a deal could be struck, how the process would work and how easy it would be to negotiate.
On Wednesday, some EU leaders warned it will be difficult.
"This would be irreversible," said French President François Hollande, who hinted that Britain would lose tariff-free access to Europe. Jean-Claude Juncker, who heads the European Commission, which is the EU's executive body, warned that "out is out" and said there would be no renegotiation of Britain's terms of membership.
Britain, too, would face upheaval. A vote for Brexit would leave Mr. Cameron facing a caucus revolt as nearly half of Tory MPs support leaving the EU. He has vowed to stay on, but many question how he could negotiate Britain's exit, given his strident campaigning for the Remain side. And while the Tories are divided, most other MPs back staying in the EU, meaning that it won't be easy getting approval for legislation to quit the EU.
Even a vote to remain has complications. Mr. Cameron would have to reassemble a badly split cabinet and repair fractured party relationships, and he could still face a call to resign from his own MPs. He has also promised to push for more reforms at the EU if the Remain side wins, but Mr. Juncker has made it clear that the EU has gone far enough.
On top of that, the referendum campaign has opened rifts in the country over immigration, globalization and nationalism.
The campaign "has been unpleasant. I think it's been hateful. It has depressed me significantly," Tim Farron, leader of the Liberal Democrats and a Remain supporter, said in an interview. He added that the campaign has brought out a dark kind of nationalism that crosses party allegiances.
Nonetheless, he has kept campaigning hard for Remain.
"This is massive," he said of the importance of the vote. "We hear what [Canadian Prime Minister] Justin Trudeau says, we hear what [U.S. President] Barack Obama says, that we, in one sense, are North America's voice at the EU table. We are in many ways the junction between North America and the European Union."
But Tory MP Dominic Raab, who supports Vote Leave, indicated that Britons are tired of being told what to do by elites and said this is an opportunity for "Britain to put the Great back into its title."
"It's not what politicians like me say that counts, it's not what the elite and the establishment say that counts," he said. "It's what the British people say."