Latest EU referendum poll of polls: Brexit just one point behind Remain on final day of campaigning

Leaders of the Leave and Remain sides have been crossing the country all day in a frenetic final push for the winning line.

YouGov's latest EU referendum poll of polls has Leave on 44 per cent, Remain on 45 per cent and Don't Know on 11 per cent, suggesting last-minute campaigning could yet be crucial.

The bookmakers disagree, however, with most of the major gambling outlets offering odds of 3/1 on Brexit and 1/4 on Remain.

• MORE: Boris Johnson in Wolverhampton on final day of campaigning

• MORE: George Osborne insists immigration CAN be cut if the UK votes to remain

Prime Minister David Cameron joined political rivals on a battle-bus tour to promise a "bigger, better Britain" if voters back continued EU membership while Leave standard-bearer Boris Johnson flew across the country to tell voters that June 23 can be "independence day".

Mr Cameron insisted he expects to remain Prime Minister even if voters choose Brexit, telling the BBC Radio 4 Today programme: "I will accept the instructions of the British people and get to work on Friday morning to deliver them."

Mr Johnson agreed that the PM should "stay under any circumstances".

Meanwhile prominent Leave campaigner Michael Gove was forced to say sorry after comparing economists who have warned of the dangers of Brexit to scientists in the pay of the Nazis who smeared Albert Einstein in the 1930s.

After a scathing slapdown from Mr Cameron - who said his old friend and Cabinet colleague appeared to have "lost it" - Mr Gove acknowledged that his comment was "clumsy and inappropriate" and apologised for giving offence.

The Economists for Remain group issued a warning from more than 175 experts, including 12 Nobel Prize winners, that Brexit would make a recession "significantly more likely". The Leave campaign was based on "dangerous fantasies" and misleading claims about the impact of immigration, they said.

The group's organiser, Oxford University academic Eric Beinhocker, said: "It may be inconvenient for Michael Gove, but the independent IMF and OECD and the 12 Nobel laureates and over 175 UK economists who signed our statement all say the same thing: Brexit would hurt growth and jobs, raise prices, and leave less money for Government services."

Mr Cameron rejected Leave claims that Britain would be "shackled to a corpse" if it chose to stick in the EU, telling supporters in Bristol the Remain case could be summed up in the single word "Together".

"If we want a bigger economy and more jobs, we are better if we do it together," said Mr Cameron.

"If we want to fight climate change, we are better if we do it together. If we want to win against the terrorists and keep our country safe, we are better if we do it together."

Mr Johnson, however, said it was "time to break away from the failing and dysfunctional EU system", telling activists in Maldon, Essex: "I do think that we are on the verge, possibly, of an extraordinary event in the history of our country and indeed in the whole of Europe.

"It's all going to be about getting our supporters out to vote and if we do it I really think tomorrow can be independence day."

Criss-crossing the country by plane, Mr Johnson signed autographs and posed for selfies with supporters in a number of locations but was heckled by 17-year-old Will Taylor in Ashby-de-la-Zouch, who said: "I'm annoyed that I can't vote and as a young person it's my future."

Mr Cameron was joined in Bristol by Labour's former deputy leader Harriet Harman as well as his predecessor as Tory PM 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.

"If our nation does vote to leave, we must respect their decision, but if they vote to leave on the basis of half-truths and untruths and misunderstandings, then pretty soon the grave-diggers of our prosperity will have some very serious questions to answer,"

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".

The BBC reported that sugar giant Tate & Lyle had told employees that leaving the EU would benefit the business and protect their jobs.

The Leave campaign highlighted comments from Markus Kleber, head of the BDI - or federation of German industries - who urged the EU to agree a free trade deal with the UK after Brexit, warning it would "very, very foolish" to attempt to impose tariffs on the departing former member.