LEADING figures from four main parties are joining forces to “call time” on what they describe as the Leave campaign’s “con-trick” on the British people over trade, spending, workers’ rights and environmental protection.

At a campaign event today in London, David Cameron will join Harriet Harman, the former Labour deputy leader, Tim Farron, the Liberal Democrat leader, and Natalie Bennett, leader of the Greens, to unveil a dossier that they say exposes the Brexit campaign’s deception.

In what is tantamount to a vow, the Prime Minister and his fellow campaigners will say that they will “guarantee that, if Britain votes to remain in the EU, businesses, workers and young people will continue to benefit from our membership of the world’s largest free-trade single market".

Read more: Corbyn brands criticism of his EU campaigning unfair as Prescott asks "where's Labour?"

They will add: "EU law will continue to deliver valuable rights for workers and Britain will stay at the top table in dealing with issues like climate change and terrorism."

Both Nicola Sturgeon and Jeremy Corbyn have made it clear they would not share a platform with Mr Cameron.

But on Thursday the First Minister will enter the EU fray, promising to give a Scottish perspective to the debate when she appears in a live head-to-head event on ITV, expected to face Boris Johnson.

The Herald:

Matthew Elliott, for Vote Leave, branded the cross-party declaration “desperate stuff from an increasingly desperate campaign” and accused No 10 of panicking.

It comes as a new poll by TNS UK suggested that the outcome of the referendum is still too tight to call.

The Leave campaign was slightly ahead, at 43 per cent, with Remain at 41 per cent. A total of 16 per cent of the 1,213 adults surveyed were still undecided.

Meantime, the Out camp launched its own new offensive, claiming Britain would have to pay for the next eurozone bailout as well as a higher EU budget and, new figures showed, the UK would have to pay a post-referendum bill of £2.4 billion.

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Mr Johnson described it as a “triple whammy of woe,” but Labour’s Chuka Umunna, for Stronger In, branded the claims “nonsense,” noting how Britain’s special status in Europe meant it was protected from paying into eurozone bailouts,

As Sir John Major launched an excoriating attack on the Leave campaign, branding it “deceitful” and dismissing Mr Johnson as a “court jester”, leading Brexiter Michael Gove claimed leaving the EU would reduce net migration to below 100,000 although he did not give a timescale. Also, the Scot suggested divorce from Brussels would take at least five years as “we would still be part of the bloc by 2020”.

Today on a visit to Northern Ireland, Chancellor George Osborne will warn Brexit would trigger a “profound economic shock” for the UK region, that cross-border checks with the Republic would have to be implemented and he will question whether the common travel area with Ireland could be maintained.

The Herald:

In a separate development, Venki Ramakrishnan, president of the Royal Society, warned of a negative impact Brexit would have on scientific research.

He said: “If the UK chooses to leave the EU on June 23, it will affect funding and the mobility of scientists and their collaborations. It would also impact our ability to influence the policy and regulations that can affect an international undertaking like science.”

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Elsewhere, the Electoral Commission has warned the public this is their last chance to register to vote in the June 23 poll as the deadline falls midnight tomorrow. Since the launch of the election watchdog’s public awareness campaign in mid-May more than 1.35m people have applied to register to vote online at www.gov.uk/register-to-vote.