Across the country and around the continent on Wednesday, the final arguments were made in a breathless end to a campaign that leaves opinion finely balanced after weeks of argument.
The last set of opinion polls before polling stations opened suggested large numbers of people are heading into polling booths still undecided.
The most recent poll, carried out by Populus, had Remain at 55 per cent and Leave at 45 per cent, mirroring the result of 2014’s referendum on Scottish independence.
A TNS survey of 2,320 adults across the UK found 43 per cent intend to vote Leave, with 41 per cent voting to Remain, and 16 per cent undecided or choosing not to vote.
A poll of 3,011 people by Opinium put support for leaving the EU at 45 per cent, with 44 per cent backing Remain and nine per cent.
Pulling his final pint of the campaign on a stop in Darlington, Boris Johnson urged voters to “take back control” from Brussels, while the Prime Minister told supporters in Bristol that EU membership protected jobs and growth.
In London, Labour leaders from all corners of the UK urged their supporters to “get out on the street” and convince friends and neighbours to vote Remain in the final hours before polls close at 10pm.
Making a campaign stop at Edinburgh Airport, Nicola Sturgeon said a large turnout north of the border could keep the UK as she joined forces with former First Ministers opposition leaders of all parties to call for a Remain vote.
And from Brussels, there was a final set of warnings before a historic vote that could determine the fate of the European project, with the head of the EU Commission telling British voters: “Out is out.”
On a whistle-stop battle bus tour, Mr Cameron was joined by former Prime Minister Sir John Major, who branded the Brexit camp “the grave-diggers of our prosperity” who would have to answer for their “lies” during the referendum campaign.
Leaving the EU would be a “disproportionate” response to migration concerns and the country would live to regret it for a “long time to come”, said Sir John.
Later, at a rally in Birmingham, the Prime Minister said the referendum vote was “a choice of a lifetime”, telling voters to “think of your children and your grandchildren.
“We don’t want to cut them off from opportunity, cut them off from the world, we want to give them the best chance. That’s why we should vote Remain.”
He committed to staying in Downing Street regardless of the result, saying he would “accept the instructions of the British people and get to work on Friday morning to deliver them.”
Labour’s big hitters gathered at King’s Cross Station in London, the terminal for Eurostar services linking the UK to the continent, to fire up the party’s activists ahead of a nation-wide operation to get out the vote.
However, party leader Jeremy Corbyn was unable to resist repeating criticisms of the 28-nation bloc in appealing for Labour members to turn out and vote Remain.
Flanked by Scottish Labour leader Kezia Dugdale, Welsh First Minister Carwyn Jones, and London mayor Sadiq Khan, Mr Corbyn asked to convince friends and neighbours before polls close at 10pm tomorrow night.
“We can make this country and the world a better place if we work with other people,” he said, urging Labour supporters to “vote for jobs, rights at work and our NHS” and back Remain.
Jean-Claude Juncker, the president of the EU Commission told journalists in Brussels that a deal struck by Mr Cameron on restricting benefits for EU migrants had secured the “maximum” possible reform, and there would be “no kind of renegotiation” after Thursday’s result.
“The British policy makers and British voters have to know that there will be no kind of any renegotiation,” Mr Juncker said.
“We have concluded a deal with the Prime Minister, he got the maximum he could receive and we gave the maximum we could give.
“So there will be no kind of renegotiation, nor on the agreement we found in February, nor as far as any kind of treaty negotiations are concerned.
“Out is out.”
Responding to the comments, Nigel Farage tweeted: “Mr Juncker confirms this is Britain’s last chance saloon. We must vote to Leave EU.”
Boris Johnson dismissed the Commission president as a “unelected tinpot figure”.
The NATO Secretary General, Jens Stoltenberg, also urged voters to choose to Remain, warning that a British exit would “add to instability and unpredictability”.
“What matters for Nato, and a strong UK in a strong Europe is good for the UK and it’s good for Nato, because we are faced with unprecedented security challenges, with terrorism, with instability and an unpredictable security environment, and a fragmented Europe will add to instability and unpredictability,” Mr Stoltenberg said.
There was a boost for the Leave campaign from the continent, however, with the head of the body that represents German industry calling on the EU to quickly negotiate a free trade deal with the UK if it chooses Brexit.
Markus Kerber said it would be “very, very foolish” to attempt to impose tariffs, adding that would represent a “regression to times we thought we’d left behind in the 1970s”.
However, Mr Kerber admitted that a Brexit vote would cause “serious disruption” to the trading relationship between the UK and Germany.
Remain campaigners hailed a pro-EU letter to the Times, signed by 1,285 businesspeople employing 1.75 million workers, including 51 FTSE100 companies and 910 small businesses, who said Brexit would mean “uncertainty for our firms, less trade with Europe and fewer jobs”.
It was reported that sugar giant Tate & Lyle had told employees that leaving the EU would benefit the business and protect their jobs.
Michael Gove, the co-convener of the Leave campaign, was forced to apologise yesterday for comparing the collection of business leaders and economic forecasters supporting Remain to the Nazi sympathizers who dismissed Albert Einstein’s research in 1930s Germany.
Mr Gove acknowledged that his comment was “clumsy and inappropriate” and apologised for giving offence.
As financial markets braced for the referendum result, there was further roller-coaster trading on currency exchanges with the pound losing ground on the back of polls giving the Leave campaign a slight lead.
Last night there were reports of financial workers queuing outside foreign exchange bureaux in the City of London to cash in their Sterling.
There were signs of nerves from ordinary consumers as well, with the Post Office Travel Money service reporting a 74 per cent surge in orders for foreign currency since the weekend, compared with the same period last year.
Branch sales of foreign currency were up 48.8 per cent on Tuesday, while online purchases were up 381 per cent.