A People’s Vote is currently the most likely option MPs will rally behind should they reject Theresa May’s Brexit Plan in a key Commons vote next month, sources at Westminster have said.

This week, Labour’s Sir Keir Starmer, the Shadow Brexit Secretary, and Stephen Gethins, the SNP’s Europe spokesman, are due to have private talks on their parties coming together to back the “best alternative plan” to what they regard as the Prime Minister’s botched Brexit deal. The talks will follow on from last week’s meeting at Westminster between Nicola Sturgeon, the First Minister, and Jeremy Corbyn, the Labour leader.

Labour’s Brexit proposal is for the UK to be in a customs union with the EU, to be as near to the single market as possible and to protect workers’ rights and privileges; the SNP’s is to keep the country in the current single market and customs union. The key point of disagreement between the two parties appears to be on the issue of freedom of movement; Labour wants restrictions, the Nationalists do not.

The Herald:

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Plus, there is the issue of optics. Labour and the SNP forming a united front on the future of Brexit will leave them open to accusations of cosying up to pave the way for the Nationalists to prop up a Labour government in a hung Parliament in return for a promise of facilitating another vote on Scotland’s future.

Indeed, Annie Wells, the Scottish Conservative MSP, said on Sunday that it was becoming increasingly clear that Mr Corbyn was “cooking up a deal” with Ms Sturgeon to get him into Downing St.

“Labour at Westminster can't be trusted to defend our Union. Labour at Holyrood are too toothless to do anything about it. Only the Scottish Conservatives at both Westminster and Holyrood will stand up against Nicola Sturgeon’s obsession with a second independence referendum," said the Glasgow MSP.

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Sources close to the Lab/SNP talks pointed out how there were currently two main alternatives: some form of customs union/single market option and staging another referendum.

One senior insider noted: “As things stand, a People’s Vote is gaining traction and seems the likelier option because it will be easier to get support from the Remainer Tories and the Lib Dems. But, as with everything to do with Brexit, things might change.”

Speculation about Labour warming to a second referendum has been stoked by suggestions that John McDonnell, the Shadow Chancellor, held talks with Tom Baldwin and Alastair Campbell, the former respective spin doctors to Ed Miliband and Tony Blair, who are now campaigning for a so-called People's Vote.

The former Prime Minister told the Andrew Marr Show "It's moving that way", adding: " I would be really surprised if the Labour Party doesn't end up in the position of supporting another vote because there's no other proposition that can get through Parliament."

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Meanwhile, it is suggested five Remainer ministers - David Lidington, Philip Hammond, Amber Rudd, Greg Clark and David Gauke - have agreed to try to get Mrs May to adopt a softer Brexit, involving a permanent customs partnership with the EU, if she fails to get her current proposal through the Commons.

Meanwhile on Tuesday, judges at the European Court of Justice will rule on a case brought by politicians across different parties as to whether or not the UK Government could unilaterally end the Article 50 process and keep Britain in the EU.

If they rule that it can, then this option could become the key alternative to Mrs May’s rejected plan; it would mean MPs and not the public voting to keep Britain in the EU.