JEREMY Corbyn's resurgent Labour “could be and should be” the vehicle to stop Brexit, Scotland's longest serving parliamentarian has suggested as cross-party forces at Westminster begin to coalesce against a hard exit.

However, Scottish MEP David Martin believes his party's leadership does not yet have a desire to fight to reverse the result of last year's narrow UK-wide vote to leave the European Union. It is the Liberal Democrats’ key policy to hold a second EU referendum on the Brexit deal.

Speaking at the European Parliament in Strasbourg, Mr Martin stressed the volatility of British politics: “The public mood has changed…If the people were asked again, they would say: we want to remain; it would still be close.

"It is only a 20 per cent chance because at the moment I do not see a political vehicle for getting that second referendum."

Asked if Labour could be that political vehicle, he replied: "It could be and it should be. But, at the moment, there is no sign that at Westminster there is a desire to perform that role."

While the Labour leadership has underlined its desire to get the best outcome from Brexit, on boosting jobs and securing tariff-free trade, the precise route-map has not been fixed. “Outcomes are what is important not mechanisms,” said a source close to Mr Corbyn.

The Labour leader will next week hold an "extended meeting" in Brussels with Michel Barnier, the EU's chief Brexit negotiator.

While John McDonnell, the shadow Chancellor, has suggested membership of the single market is not feasible, Barry Gardiner, the shadow trade secretary, last month talked of how benefits could be achieved “through reformed membership of the single market and the customs union, or through a new, bespoke trading arrangement”.

Sir Keir Starmer, the shadow Brexit secretary, has also been flexible in his outlook, saying that "unchanged single market membership is not a viable option" but also suggested reformed membership might be. He has called for the option of Britain remaining in the customs union to be "on the table" in the Brexit talks.

Lesley Laird, the new shadow Scottish secretary, has stressed on Brexit that arguing “everything is black and white is too simplistic; the public understands it is complex and will be a moveable feast”.

Mr Martin suggested there was a risk of Labour failing to deliver for Remainers, who backed the party in June and that “there is a danger that the Labour leadership, broader than just Jeremy, has taken the wrong message out of the election”.

The Scottish MEP claimed the battle inside his party was “not ideological left/right but “what was it that drove people back to us”.

He added: "I am clear it was the Remain vote that galvanised the young people behind us. There is a danger that we could disillusion them if we don't deliver for them or at least try and deliver for them."

At Westminster, it emerged more than 50 Labour MPs and peers have met behind closed doors to discuss the options for producing a soft Brexit.

A Conservative source said a similar meeting had taken place among Tory backbenchers, noting: “The 2017 and 2015 intakes get it more than the older MPs.”

During a Commons debate on Brexit and trade, Ed Vaizey, the former culture minister, questioned why the UK was "walking away" from the EU's 500 million consumers, adding Britain’s stance on free trade was "completely unclear".

Reports suggested David Cameron has telephoned Conservative colleagues urging them to back a "Norway option" ie membership of the European Free Trade Association, which means partial membership of the single market.

Such manoeuvring suggests that, with no Westminster majority for a hard Brexit following the General Election, MPs from different parties will seek to use the Repeal Bill - published next week - to soften Theresa May’s Brexit strategy in a series of votes.

Meanwhile, Mr Barnier enraged the UK Government by claiming the Prime Minister’s primary purpose of achieving “frictionless trade” after Brexit was impossible with Britain outside the single market and the customs union.

Noting how both sides were set for a “loser/loser situation,” he told the EU’s European Economic and Social Committee: “Only a combination of the customs union and the rules of the single market make it possible to trade freely without friction between our countries; you don't get the one without the other.”

In other developments:

*The CBI said Britain should remain in the single market and customs union during the two-year transitional period and until the final deal is in force;

*Donald Tusk, the European Council President, goaded Brexiteers after the EU and Japan signed an outline trade deal;

*Lord Robertson, the former Nato secretary general, warned Brexit could cost the UK its key position within the western alliance and

*Lord Hague, the former foreign secretary, warned Brexit would "undoubtedly" damage Britain’s ability to exert influence in foreign affairs and international security.