Jeremy Corbyn was today accused of betraying his second referendum promise by 'plotting' with Tories who want a super-soft Brexit that would tie the UK to Brussels.

The Labour leader has discussed the Norway-style deal being proposed by senior Conservatives including Nick Boles and Oliver Letwin who want Britain to be in permanent customs union with the EU.

The meeting, which was also attended by Labour remainers, was meant to last around 15 minutes but went on for over an hour.

24 hours earlier Corbyn loyalist Ian Lavery reportedly ripped into Labour MPs now pushing Mr Corbyn towards a new EU vote and told Mr Corbyn: 'If we back a 2nd referendum you will never be Prime Minister', according to The Sun.

And hinting that he could back a softer Brexit deal Mr Corbyn said last night: 'I left both meetings more certain than ever that we can find a way to work across Parliament to force the Government to back a sensible Brexit plan that protects jobs and more determined to achieve it'.

But his response has caused a backlash among second referendum supporters with one critic saying: 'The party leader is undermining the party's second referendum stance by plotting with the Tories' - another Labour supporter said: 'It's a betrayal'.

Norway’s arrangement with the EU forces it to accept the free movement of people - ruled out by Labour’s 2017 manifesto.

Jeremy Corbyn discussed the idea of a Norway-style deal with the EU with a cross-party group of MPs - but was accused of betrayal by those who want a second referendum

Tory Remainers Nick Boles and Oliver Letwin are pushing for the softest possible Brexit based largely on Norway's relationship with the EU - and Labour loyalist Ian Lavery has warned Mr Corbrn he'll never be PM if he backs a second referendum

Mr Boles was in an upbeat mood following yesterday's meeting with Jeremy Corbyn, which is likely to annoy supporters of a second referendum

His optimism was shared by Mr Kinnock, who said there was 'a strong and growing cross-party consensus for a pragmatic, bridge-building Brexit'

But in a surprise move, the Labour leader discussed the idea with a cross-party group of MPs calling for the softest possible Brexit as an alternative to a second referendum.

What is the Norway-plus Brexit senior remainers are pushing for? MPs from across parties have been mooting the idea of a Norway model keeping Britain in the customs union like the Scandinavian country. It would effectively keep the UK in the single market, with a customs bolt-on to avoid a hard Irish border, and backers say it would keep Britain close to the EU while cutting contributions to Brussels. However, critics say it has the drawbacks of keeping free movement, - and tightly limiting the possibilities for doing trade deals elsewhere. The EU is also thought to have concerns about a country the UK's size joining the EEA, while other states in the group might be resistant. Advertisement

Tories last the meeting were joined by Labour MPs, Lucy Powell and Stephen Kinnock.

Nick Boles said he was 'happy' after the talks about the so-called 'Common Market 2.0 proposal' and tweeted last night: 'For months now we have been meeting with senior MPs from all parties in search of a cross party Brexit compromise'.

In a separate development last night, the House of Lords voted for plans that would force Theresa May to seek a permanent customs union with the EU after Brexit.

The moves underline fears at the top of Government that Parliament will seize control of the Brexit process if Mrs May’s deal is rejected for a second time on March 12.

Chief Whip Julian Smith warned the Cabinet on Tuesday that Parliament would ‘try to force the Government into a customs union’ if the deal is defeated next week. Mrs May is considering a public warning on the issue tomorrow in the hope of pressuring MPs into supporting her proposals.

A Whitehall source said the PM could make a major speech ‘framing next week as the moment of decision for the country’.

Yesterday’s talks involved Mr Corbyn, Tory ex-ministers Sir Oliver Letwin and Nick Boles and Labour backers of the Norway plan, Stephen Kinnock and Lucy Powell.

Mr Kinnock said the meeting involved talks about a Norway-style deal, adding: ‘There is a strong cross-party consensus for a pragmatic, bridge-building Brexit.’

Sir Oliver, working with Labour’s Yvette Cooper, is leading a push for Parliament to take control of the Brexit process.

Former Tory leader Iain Duncan Smith said last night it was ‘astonishing’ that senior Conservatives were willing to work with Labour’s hard-Left leader on plans that would undermine Government policy.

With just five days until the crunch vote on May's Brexit deal, estimates suggest Mrs May is well short of the votes needed to win on Tuesday

Labour's Stephen Kinnock and Lucy Powell, a former shadow minister, was the fourth MP in the group which met with Mr Corbyn on Wednesday to discuss their soft Brexit plan

In a separate development last night, the House of Lords voted for plans that would force Theresa May to seek a permanent customs union with the EU after Brexit

Last night, peers backed an amendment to the Customs Bill by a majority of 66 that would require Mrs May to seek a permanent customs union with the EU after Brexit. An alliance of Labour, Lib Dem, cross bench and some Tory peers defeated the Government by 207 votes to 141.

Labour’s trade spokesman in the Lords, Lord Stevenson of Balmacara, said: ‘Ministers must drop their red lines on Brexit and embark on a fresh approach to the negotiations with the EU based around a Customs Union that protects jobs, secures opportunities for our industries, and removes the need for a hard border in Ireland.’

Ministers had been resigned to losing last night’s vote, but No10 indicated it would seek to overturn the demand in the Commons, where MPs have already voted twice to reject a permanent customs union.

Mrs May’s spokesman said: ‘The PM has been clear about the importance of the UK being able to have its own trade policy.’

Norway is not in the customs union but is a member of the EU’s single market, and has to accept free movement, pay into the EU budget and accept EU laws. Senior Tories warn that making the UK a rule-taker undermines the idea that the UK is taking back control from the EU.