THE outcome of today’s historic referendum on Britain’s future - In or Out of the European Union - is “too close to call” after eve-of-poll surveys placed Remain and Leave neck and neck.

As David Cameron and Boris Johnson made their last frantic campaign visits, criss-crossing the country, the snapshots pointed to the deciding factor being the 10 to 20 per cent of voters who claim they are still undecided.

The Prime Minister, in an emotional speech, told one last rally in Birmingham that leading figures from across the political spectrum agreed that “we are stronger, we are better off, we are safer in a reformed European Union".

Read more: Nicola Sturgeon: Remaining in EU far outweighs the supposed benefits of leaving

But the former London mayor, rallying supporters in Yorkshire, urged them to "believe in our country" and to back Brexit to make June 23 “independence day”. He suggested the campaign to get Britain out of the EU was “on the verge of victory”.

An online snapshot of 3,000 adults by Opinium Research placed Leave and Remain neck and neck with the Brexit campaign just one point clear at 45 to 44; well within the margin of error. Don’t knows were put at nine per cent.

Adam Drummond for the research body said: “This really is too close to call territory with undecided voters holding the balance of the vote in their hands.”

The Herald:

A TNS online survey of 2,320 adults put Leave two points ahead, 43 to 41, with those undecided or intending not to vote on 16 per cent.

Luke Taylor for TNS noted: “In the Scottish independence referendum and the 1995 Quebec independence referendum there was a late swing to the status quo and it is possible that the same will happen here."

But a poll by FTI Consulting gave Remain a slim lead of 51.4 per cent to 48.6 per cent, once the don’t knows were removed. Yet it put these undecideds as high as 28 per cent.

Read more: TNS poll puts Leave campaign ahead

An analysis by Glasgow University, which supplemented polling data with voters’ online searches about Remain and Leave up to June 18, so that “momentum effects” were taken into account, placed Remain on 52 points and Leave on 48.

Despite the closeness of the polls, bookies were firmly predicting a victory for Remain. William Hill trimmed its odds towards Brexit but still placed Remain on 1/4, representing an 80 per cent chance of victory, and Leave on 11/4, representing a 26 per cent chance of victory.

The markets were also pointing to a Remain victory.

The Herald:

The FTSE 100 rose 0.6 per cent to 6,261 points; the third consecutive day of gains, putting on 350 points. Sterling rose against the dollar to $1.476, its highest level since the referendum was announced earlier this year, but it was slightly down on the day against the euro at 1.301, having put on earlier gains.

In the City of London, long queues formed outside foreign exchange bureaux as people cashed in their pounds ahead of today’s vote. Markets expect sterling to plunge if it is a victory for Brexit.

The Post Office’s travel money section, which handles one in four of all UK foreign exchange transactions, said currency sales overall had surged 74 per cent year-on-year since the weekend.

Read more: Alex Salmond contrasts 'poisonous' EU campaign with 'uplifting' Scots vote

Analysts have warned that more than £346 billion could be wiped off the value of the UK's biggest companies if Britain opts for Brexit. The UBS investment bank calculated the hit to the London stock exchange could see share levels fall to between 4,900 and 5,500; a fall of around 1,000 points.

But Mr Johnson dismissed talk of a stock market crash on the back of a Brexit vote as “all part of the attempt to spook people. It will be very calm; everybody has more or less priced in either outcome”. He added: “We will continue to see robust and dynamic growth if we take control of our own destiny."

As voters head to the polls, Stronger In claimed its cause had the “most overwhelming coalition of support behind a campaign in British political history” with political leaders from all parties, former prime ministers, as well as experts and campaigners from every sector and walk of life.

Gordon Brown said if Britain wanted more, better-paid jobs and protection of workers’ rights, then “there is no road to the future that does not go through Europe” while his predecessor in No 10 Tony Blair said the historic choice was between “prosperity, influence and security as part of Europe or a reckless leap in the dark and years of damaging uncertainty”.

Earlier on the campaign trail, former Tory premier unleashed another withering attack on Vote Leave, branding its supporters “gravediggers of our prosperity,” and insisting if Britain left the EU, then “they must account for what they have done”.

Leading Outer Michael Gove was forced to make a public apology for comparing economic experts warning about Brexit with the Nazis who smeared Albert Einstein in the 1930s. The Scot admitted his analogy had been “clumsy and inappropriate”. Mr Cameron claimed the Justice Secretary had "lost it" and had made a "massive mistake" in drawing the comparison.

Meantime, Nicola Sturgeon warned Scotland's reputation on the world stage was at risk with Brexit. The First Minister urged Scottish voters, who opinion polls suggest are overwhelmingly for Remain, to turn out, saying: "Scotland can have a big impact on the final vote.”