British and European politicians are plotting to block the UK's exit from the EU.

On a chaotic day in which the Labour Party went into meltdown, a campaign was started to force a second referendum.

Tony Blair, Nicola Sturgeon, some pro-Remain MPs and a senior German official said a rethink was needed now the consequences of quitting the Brussels club were clear.

They were joined by Sir Richard Branson, who has called on Parliament to take a second look at the EU referendum result.

The Virgin Group founder accused Leave voters of opening 'a Pandora's Box of negative consequences' for Britain based on 'false promises' by the Boris Johnson-led Brexit campaign.

SNP leader Nicola Sturgeon delivered the most explicit threat – saying Scottish MSPs have to give their 'legislative consent' and she would advise them to veto it

Tony Blair was among those said a rethink was needed now the consequences of quitting the Brussels club were clear

It came as at least 21 Labour frontbenchers resigned in a bid to replace Jeremy Corbyn with a pro-EU party leader.

The plotters hope a general election can be held later this year before the start of the formal process of quitting. Last Thursday's referendum could then be reversed.

In further developments:

Theresa May prepared to take on Boris Johnson for the right to win the race to succeed David Cameron as prime minister within the new few months;

Mr Corbyn, who sacked Hilary Benn for disloyalty, claimed he was going nowhere, despite failing to even secure the backing of his own deputy, Tom Watson;

George Osborne announced he will give a statement today to 'provide reassurance about financial and economic stability';

The Chancellor, who had not been seen since the referendum result, is to stay in post to 'protect the national interest';

In a surprise move, talks have also begun for him to join a Boris Johnson leadership 'dream ticket' alongside Michael Gove;

A petition calling for a second referendum was placed under investigation after 77,000 signatures were found to be fraudulent.

Meanwhile, top figures in Brussels have questioned whether Britain will ever quit the union, with a senior diplomat saying the divorce process will probably be delayed and then ditched.

Iain Duncan Smith said the Europhiles were 'bad losers' yesterday.

Mr Duncan Smith said the bid by the political elite to frustrate the will of the people was an 'anti-democratic joke'.

'There is a lot of bad losing here from the Europhiles,' the former Tory leader told the Mail. 'This was one of the biggest turnouts since the war and there is no justification for a second referendum whatsoever.'

But Philip Hammond, who campaigned for Remain, insisted yesterday that Britain would have to sign up again to the European single market or face catastrophic consequences.

Sir Richard Branson (pictured) also called on Parliament to take a second look at the EU referendum result

Left: Peter Altmaier said that, if Britain left, it would be 'a difficult watershed with many consequences'. Right: Labour MP David Lammy called on Parliament to 'stop this madness'

Iain Duncan Smith said the Europhiles were 'bad losers' and the bid by the political elite to frustrate the will of the people was an 'anti-democratic joke'

The Foreign Secretary said this could mean having to accept continued freedom of movement.

A string of senior figures in Britain and Europe yesterday attempted to undermine the democratic will of the British people by sabotaging Brexit.

BRUSSELS DON'T BELIEVE THE UK WILL GO THROUGH WITH DIVORCE Top figures in Brussels don't believe Britain will go through with leaving the EU, with diplomats questioning whether the UK will ever trigger the formal divorce process. A country leaving the union must formally notify the European Council, setting the clock ticking on a two-year period to negotiate its split. But a senior EU diplomat said last night that he believes the UK will never actual embark on the move and will end up staying in the union. 'We want London to trigger Article 50 now, to have clarity. I expect, as we can't force them, for them to take their time,' the diplomat said. 'And I would not exclude, it's my personal belief, that they may never do it.' Advertisement

SNP leader Nicola Sturgeon delivered the most explicit threat – saying Scottish MSPs have to give their 'legislative consent' and she would advise them to veto it.

German Chancellor Angela Merkel's chief of staff said politicians should 'have the possibility to reconsider the consequences of an exit'.

Peter Altmaier said that, if Britain left, it would be 'a difficult watershed with many consequences'.

He added that Britain could apply to rejoin the EU later 'but that would take a long time'.

Tony Blair also said a second referendum on the UK's membership should not be ruled out.

He said the nation needs to 'see the consequences' of Brexit as they play out in the coming weeks.

The former prime minister said it was difficult to see a second poll at the moment, but 'there will be a lot of people in the country who will say 'let's have a look at this and see what we are going to do' and Parliament will want to look at it.'

Tory grandee and arch Europhile Lord Heseltine said he was appalled by the result of the referendum with voters 'sold a fool's promise'.

He also suggested there will need to be a general election in order for Parliament to sign off on Brexit.

Philip Hammond, who campaigned for Remain, insisted yesterday that Britain would have to sign up again to the European single market or face catastrophic consequences

'Every indication is that there is a 350 majority in the House of Commons in favour of remaining in Europe,' Lord Heseltine said.

'The only realistic prospect of persuading the House of Commons to pass amending legislation would be after a general election or another referendum.

'That is why the fight back begins today.'

Writing on his blog, Sir Richard - an active campaigner for Britain staying in the EU during the referendum campaign - urged the public to keep up the pressure on MPs to hold a second referendum on Britain's EU membership and said Parliament should consider a re-run.

He wrote: 'The decision over the UK's future was based on false promises that pushed a minority of the UK's total voting population (17 million out of 46 million) to vote the way it did.

'Two years before Brexit will even become reality, according to EU rules, it is already having massive consequences on the UK economy, and on society. Brexit has fractured the country more than any other event in recent memory.

'Based on the misrepresentation made by the Leave campaign, Parliament needs to take the petition of more than three million people to call for a new referendum seriously. The alternative is to watch a rapid decline of Britain's health and wellbeing.'

Labour MP David Lammy called on Parliament to 'stop this madness' and to vote against the decision to leave the EU.

In a statement on his Twitter feed, the former minister said: 'Wake up. We do not have to do this.'

Tim Farron, the Liberal Democrat leader, said his party would not 'roll over and give up' over the issue, pledging to fight the next general election on a manifesto promise to take Britain back into the EU.

Lord Heseltine (left) said he was appalled by the result of the referendum with voters 'sold a fool's promise'. Tim Farron (right), Liberal Democrat leader, said his party would not 'roll over and give up'

The hopes of some Europhiles have been raised by the fact that Mr Cameron has not triggered so-called article 50.

This is the formal mechanism which a country must use to give Brussels two years' notice of its intention to quit the EU.

During the bruising referendum campaign, the PM said he would invoke article 50 immediately in the event of a Brexit vote, but has failed to do so.

At a special Cabinet meeting today, there will be 'initial discussions about the administrative process needed to move forward'. But No 10 insiders said 'decisions around Article 50 are a decision for the next PM'.