David Cameron made a last-ditch, direct appeal to voters to reject Brexit on a frenetic day of campaigning ahead of Thursday's historic vote, as polling experts said the outcome was too close to call.

In an impromptu speech outside 10 Downing Street, the Prime Minister, who knows that a vote for Brexit could spell the end of his leadership, said that it was young people, children and “those yet to be born” who would be hit hardest by the economic fallout of a vote to Leave.

Two polls showed the rival campaigns neck and neck. YouGov had Leave ahead by 51 per cent to 49, while a Survation poll had Remain ahead by just one percentage point.

John Curtice, professor of politics at Stratchclyde University and one of the country’s foremost polling experts, told The Independent: “It’s around 50-50. To cut a long story short, undoubtedly last week Leave made progress – the first significant progress of the campaign. You actually had the phone polls calling it 50-50 and you had the internet polls having Leave ahead. It’s very, very tight. You can’t call this referendum – it’s too close.”

As the rival campaigns entered the final straight, independent economists from three of Britain’s leading institutions issued a final warning that a vote for Brexit would hit wages and lead to higher retail prices and borrowing costs.

In a joint statement, the directors of Institute for Fiscal Studies (IFS), the National Institute of Economic and Social Research (NIESR) and the Centre for Economic Performance (CEP) said there had never “in our lifetimes” been such agreement among economists on a major policy issue.

All you need to know about the EU referendum

With the outcome of the vote hanging in the balance, Mr Cameron appealed to older voters to think of the next generation when alone in the polling booths on Thursday.

“I want to speak very directly to those of my generation and older,” Mr Cameron said. “I know Europe isn’t perfect. Believe me. I understand and I see those frustrations. I feel them myself. That is why we renegotiated and enhanced our special status, out of the Euro, keeping our borders, not involved in ever-closer union. We have the best of both worlds.

“So as you take this decision, whether to Remain or Leave, do think about the hopes and dreams of your children and your grandchildren. They know their chances to work, to travel, to build the kind of open and successful society they want to live in rests on this outcome.

Which celebrities support Brexit and which support Remain? Show all 30 1 /30 Which celebrities support Brexit and which support Remain? Which celebrities support Brexit and which support Remain? David Beckham (REMAIN) The former captain for the England international football team announced on Instagram that he was “voting to Remain”. He said: “We live in a vibrant and connected world where together as a people we are strong. For our children and their children we should be facing the problems of the world together and not alone.” Getty Which celebrities support Brexit and which support Remain? Victoria Beckham (REMAIN) 'I believe in my country, I believe in a future for my children where we are stronger together and I support the remain campaign.' Getty Which celebrities support Brexit and which support Remain? Daniel Craig (REMAIN) Actor He was pictured wearing a white T-shirt with the slogan: 'No man is an island. No country by itself. Vote Remain on 23rd June.' Getty Images Which celebrities support Brexit and which support Remain? Bob Geldof (REMAIN) Irish singer expresses his support for the Remain vote as he waves from a boat carrying supporters for the 'Remain' campaign in London AFP/Getty Which celebrities support Brexit and which support Remain? John Cleese (LEAVE) The Monty Python star signalled he will vote to leave the EU when he tweeted: "If I thought there was any chance of major reform in the EU, I'd vote to stay in. But there isn't. Sad." Getty Which celebrities support Brexit and which support Remain? Daniel Portman (REMAIN) Game of Thrones actor supports Reamin vote Getty Images Which celebrities support Brexit and which support Remain? Elton John (REMAIN) The singer also announced his intention to vote Remain on Instagram, sharing an image which said “Build bridges not walls,” along with the caption “I'm voting to remain. #StrongerInEurope” Getty Which celebrities support Brexit and which support Remain? Roger Daltrey (LEAVE) Former frontman of iconic rock band The Who.” I am not anti European, but I an anti the present way we are being governed in Europe,” he wrote in The Mirror. “The whole system has been corrupted by political ego and massive government overreach. The Euro being a perfect example… I do not want to be dragged into the kind of Federal State that this present EU is pushing for - with the UK's voice getting smaller and smaller. AFP/Getty Images Which celebrities support Brexit and which support Remain? JK Rowling (REMAIN) The author of the Harry Potter books has expressed concern that "racists and bigots" are directing parts of the Leave campaign. She added: “How can a retreat into selfish and insecure individualism be the right response when Europe faces genuine threats, when the bonds that tie us are so powerful, when we have come so far together? How can we hope to conquer the enormous challenges of terrorism and climate change without cooperation and collaboration?” Getty Images Which celebrities support Brexit and which support Remain? Vivienne Westwood (REMAIN) British fashion designer expressed her support for Remain vote Getty Images Which celebrities support Brexit and which support Remain? Michael Caine (LEAVE) The actor has said he is a reluctant Leaver. He said: "I don't know what to vote for. Both are scary. To me, you've now got in Europe a sort of government-by-proxy of everybody, who has now got carried away. Unless there is some extremely significant changes, we should get out." Getty Images Which celebrities support Brexit and which support Remain? Benedict Cumberbatch (REMAIN) Benedict Cumberbatch and Sir Patrick Stewart led more than 280 figures from the arts world who backed a vote to stay. An open letter pledging support for Remain was also signed by music stars Hot Chip, alt-J and Paloma Faith, authors Dame Hilary Mantel and John le Carre, and fashion designer Dame Vivienne Westwood. Daniel Craig was pictured wearing a vote Remain t-shirt with the words "No man is an island. No country by itself" emblazoned across it in a picture tweeted on the Stronger IN account. Getty Images Which celebrities support Brexit and which support Remain? Patrick Stewart (REMAIN) Actor is a leading supporter of the Remain campaign Getty Images Which celebrities support Brexit and which support Remain? Elizabeth Hurley (LEAVE) The actress said “If it means we can go back to using decent lightbulbs and choose high-powered hairdryers and vacuum cleaners if we so wish, I'm joining Brexit for sure.” Getty Images Which celebrities support Brexit and which support Remain? Stephen Hawking (REMAIN) The physicist was in favour staying, and said "progress comes from co-operation". He said: "By working together in Europe we make our economy stronger and we give ourselves more influence in the world and we provide future opportunities for young people." Numerous scientists have also voiced their support for Remain, claiming an out vote would badly damage the field. Getty Images for Breakthrough Pr Which celebrities support Brexit and which support Remain? Sol Campbell (LEAVE) – The former England international football star said he is backing Brexit so that young British sporting talent would be nurtured and given greater opportunities at British clubs. He said: "I'm looking at the sporting side - how youngsters aren't getting the opportunities at some of the big clubs and some of the big clubs are bringing in youngsters from 14, 15, 16 and becoming homegrown, which is pushing some of our youngsters out." Getty Images Which celebrities support Brexit and which support Remain? Hilary Mantel (REMAIN) Author Hilary Mantel announced her support for Remain vote Getty Images Which celebrities support Brexit and which support Remain? Bear Grylls (REMAIN) The adventurer and TV presenter said he spoke "from the heart" in backing the EU. "At such a time for the UK to retreat, run and cut ourselves loose from Europe, when there are so many challenges on our doorstep, to me just doesn't feel either courageous or kind,” he said. “Europe has many flaws, but I also believe the way to help resolve many of those tough issues is from within... I have never been a good quitter and I am so proud of the UK and our values: tolerance, kindness, respect, courage and resilience. This is why I want us to stay together and Remain in Europe." Getty Images Which celebrities support Brexit and which support Remain? Billy Bragg (REMAIN) British singer decided to support Remain campaign AFP/Getty Images Which celebrities support Brexit and which support Remain? Ian Botham (LEAVE) The former England Test cricketer and Test team captain supports Brexit Getty/Laureus Which celebrities support Brexit and which support Remain? Simon Cowell (REMAIN) Music mogul Simon Cowell announced his support of staying in EU Getty Which celebrities support Brexit and which support Remain? David James (LEAVE) The former England goalkeeper supports Brexit Getty Images Which celebrities support Brexit and which support Remain? Idris Elba (REMAIN) The actor voiced his support for Remain vote Getty Images Which celebrities support Brexit and which support Remain? John Le Carre (REMAIN) British writer supports Remain campaign Getty Images Which celebrities support Brexit and which support Remain? Paloma Faith (REMAIN) English singer supports Remain campaign Getty Images Which celebrities support Brexit and which support Remain? Perry McCarthy (LEAVE) The racing driver supports Leave campaign Rex Features Which celebrities support Brexit and which support Remain? Keira Knightley (REMAIN) The actress intends to vote for Remain campaign Getty Images for Lincoln Center Which celebrities support Brexit and which support Remain? James Cracknell (LEAVE) British athlete and rowing champion decided to vote for Brexit Getty Images Which celebrities support Brexit and which support Remain? Florence Welch (REMAIN) British singer supports Remain campaign Getty Images for Gucci Which celebrities support Brexit and which support Remain? Helena Bonham-Carter (REMAIN) The actress expressed her support for Remain vote AFP/Getty Images

“Remember, they can’t undo the decision we take. If we vote out, that’s it. it is irreversible. We will leave Europe for good, and the next generation will have to live with the consequences far longer than the rest of us.”

Meanwhile, Vote Leave figurehead Boris Johnson pledged to publicly apologise if Britain went into recession in the wake of a vote for Brexit, as the IFS, the NIESR and the CEP issued a joint statement warning that Britain would “almost certainly” be worse off outside the EU.

Challenging Leave campaign claims that Britain’s economy would not suffer from Brexit, they said that “almost all of those who have looked seriously at this issue” were predicting lower real wages in event of Brexit, higher prices for goods and services, higher borrowing costs and higher unemployment.

“In our lifetimes we have never seen such a degree of unanimity among economists on a major policy issue,” the directors of the three institutions said in a joint statement. “The precise effect, in terms of numerical percentage, is of course uncertain. But that we would be financially worse off outside the EU than in is almost certainly true.”

Addressing some of the claims of the rival campaigns, they said that the Leave campaign’s pledge of a £10bn Brexit dividend for public services and tax cuts was “almost certainly untrue”. The claim that the UK would, after Brexit, be able to trade with other EU nations on equally good terms to those we currently have was also deemed almost certainly untrue.

Remain campaign assertions that households could be £4,300 a year worse off by 2030 were deemed to be “uncertain”, while warnings that immediate tax rises would be needed in the event of Brexit were branded “unlikely”, with the economists predicting that the Government would instead allow borrowing to rise to cover the economic costs of leaving the EU in the short-term.

Labour will attempt to rally support on the final day of campaigning on Wednesday, with leader Jeremy Corbyn and London Mayor Sadiq Khan planning to make a rare joint appearance at a London rally. Alan Johnson, leader of Labour’s Remain campaign, said that a vote for leave would “plunge our country into turmoil and uncertainty”.

Meanwhile, Michael Gove, the Justice Secretary and Vote Leave chairman, said he would “reflect” upon his position in the Cabinet depending on the outcome of Thursday’s vote.

Mr Gove faced a minor embarrassment as the campaign took a bizarre turn, with the rival camps citing the footballers who back their side. After David Beckham confirmed he was backing Remain, Mr Gove claimed that former England internationals David James and John Barnes were backing Brexit – only to be contradicted by Barnes, who said he had been misinterpreted, and in fact backed Remain.