After meetings with opposition leaders at Westminster including Jeremy Corbyn, the First Minister said Labour and the SNP were committed to finding an alternative to the Prime Minister’s Brexit plan that both parties can support.

Ms Sturgeon also held what she said were “full and frank” talks with the Prime Minister lasting half an hour, but said Mrs May failed to ease her concerns about what she claims is a “blind Brexit” deal.

“The next stage of these discussions has to be about what option the opposition can coalesce around,” she said following her talks with Mr Corbyn.

Nicola Sturgeon (right) called on a 'coalition' of MPs to defeat Theresa May's Brexit deal. Picture: PA/AFP

“That’s the responsibility of the opposition. We know what we don’t like.

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“What we now need to do is work together to come up with what would be the better alternative.”

Ms Sturgeon described the 20 minute meeting with Mr Corbyn as “friendly, cordial [and] worthwhile”, and said a common position needed to be reached in the “next couple of weeks”.

“We’re not there yet,” the First Minister said. “What we talked about today was our unity of purpose in thinking the Prime Minister’s deal was a bad deal and voting that down, and unity of purpose in not allowing this to be presented as a bad deal or no deal.

“It will be more difficult when it comes to the option that we want to coalesce around.

“That will be more of a challenge, not just for the SNP and Labour, but for all the opposition parties.”

Ms Sturgeon told journalists she was putting aside recent criticism of the Labour leader in order to find a Brexit alternative before a Commons vote expected in December.

“I don’t think his position on Brexit has shown a lot of leadership, even until very recent days, but we’ve got to look ahead now, and I’m not sitting here and telling you that I can guarantee we can get to a place where the SNP and Labour, me and Jeremy Corbyn are on the same page on this, but I feel a responsibility to have a go at that,” she said.

Talks would soon need to include Conservative rebels, the First Minister added.

“Logic would tell you in the interest of building a coalition against an alternative to the Prime Minister then the more Remain-leaning Tory MPs would need to be involved,” she said.

Earlier, Ms Sturgeon held talks with the leaders of the Liberal Democrats and Plaid Cyrmu, as well as meeting with SNP MPs.

The SNP group meeting follows disagreement over whether the party should back a second EU referendum, with the Perthshire MP Pete Wishart warning of the risk that a so-called People’s Vote could set a precedent that two ballots would be needed to secure Scottish independence.

Ms Sturgeon insisted SNP parliamentarians were “all on the same page on all of these issues”.

Lib Dem leader Sir Vince Cable said he “made it explicitly clear to the SNP and others that the priority must be stepping up efforts to build the momentum for a People’s Vote.”

Amid speculation that Labour and SNP could reach agreement on a ‘soft Brexit’ alternative to the Prime Minister’s deal, a source close to Mr Cable added: “The only thing there was full agreement on was support for a People’s Vote.”

Following their meeting, Ms Sturgeon said she believed the Prime Minister was likely to lose the Commons vote on her Brexit deal. “Perhaps if there had been more willingness to listen to different voices over the past few years, we would be in a better position now,” she said. The First Minister was shown the latest draft of the future partnership framework, which will guide upcoming trade talks with the EU, and called it “vague and aspirational”. “Effectively it amounts to the House of Commons... being asked to take a blindfold leap off a cliff.”

A Number 10 source said: “The Prime Minister urged the First Minister to listen to Scottish employers and to back the agreement reached with the EU. The truth is that SNP plans just make a no deal Brexit more likely.”

Nicola Sturgeon: SNP, Labour and Tories must form '˜coalition' to fight Brexit deal