THE SNP would push for an immediate Commons motion to set up a People’s Vote if MPs rejected Theresa May’s take-it-or-leave-it Brexit deal, Ian Blackford has insisted, stressing how Westminster would have to “exert its authority over the Government”.

The declaration from the SNP’s leader at Westminster came as he today travelled with fellow opposition party leaders to Brussels to meet Michael Barnier, the EU’s chief negotiator, to put forward their case for Britain staying in the customs union and single market.

The Nationalists have made clear that they will seek to vote down any deal the Prime Minister agrees with the EU27, which falls short of their red line on customs union and single market membership.

But Mr Blackford explained that if that option was not available and Mrs May failed to get a take-it-or-leave-it deal through Westminster, rather than the country moving to World Trade Organisation rules in a no-deal scenario, Westminster had to “exert its authority over the Government at that stage” and push for a People’s Vote.

The Highland MP dismissed the suggestion that a bad Brexit would be a boon to the independence cause.

“The last thing that any of us want to do is to end up in a situation that ends in chaos and you are playing with fire if you are going down that road because you are playing with people’s jobs; you can’t do that and nothing is further from our minds,” declared the party leader.

He explained that if a deal were voted down, then there had to be mechanisms such as a confidence vote in the Government but he stressed the “preference in such a scenario” would be a motion to establish a People’s Vote, which he described as a “safety blanket”.

“We have to take whatever action that is going to protect the interests of the people of Scotland,” said Mr Blackford, who insisted a second referendum would involve voters making a simple choice between accepting the Government’s deal or staying in the EU.

Today, together with Sir Vince Cable, the Liberal Democrat leader, Liz Saville Roberts, Plaid Cymru’s Westminster leader and Molly Scott Cato, the Green Party MEP for the South West of England and Gibraltar, Mr Blackford will have talks with Mr Barnier.

“While the UK Government clearly still has no plan to break the Brexit impasse and Labour fail to act as an effective Opposition, it has been left to the 'unofficial Opposition' to speak up for a deal that would protect jobs and livelihoods. I am grateful to Mr Barnier for meeting with us.

“Any Brexit deal that falls short of staying in the single market and the customs union will not get through Parliament. It’s time for Theresa May to drop the jargon, quit playing games and act to protect our economic future,” said the Highland MP.

Sir Vince added: “Our ‘unholy alliance’ has provided a sensible counterpoint to the hard-line Brexiteers who have pushed the Conservatives and Labour’s frontbench into senseless and fudged positions. It is vital Michel Barnier and the European Commission know that there is another view in Parliament[for a People’s Vote], one that has cross-party support and that can get the EU and the UK out of this mess.”