VOTING against Boris Johnson’s Brexit deal today will help retain support for the SNP among backers of remaining in the European Union, according to the UK’s top pollster.

Sir John Curtice, professor of politics at Strathclyde University, added the stance – and Labour’s support for the deal – could help the SNP win a majority in Holyrood at next year’s Scottish Parliament election.

Speaking to The National, Curtice took the view that its stance to vote against the deal would result in political benefits for the SNP.

“The fact that the SNP are going to vote against the deal and Labour are going to vote for it is probably going to help the SNP to hang on to its remain support,” he said.

“I think that is probably a misjudgement by Labour at least amongst its support north of the Border – not that they have many remain voters north of the Border anyway.

“They have lost that constituency and at the end of the day if the SNP are going to be denied a majority then Labour has to recover. I think [Keir] Starmer’s decision to vote for the deal is not going to make Labour’s life any easier north of the Border.”

READ MORE: John Curtice: SNP MPs could 'gum up' Westminster until Tories agree to indyref2

He made the comments after Nicola Sturgeon’s party has been accused of effectively backing leaving the bloc without a deal this Friday by not not voting for the deal.

The First Minister hit back earlier this week at those opponents saying the two choices on offer at Westminster – the Brexit deal or No Deal – did not reflect Scotland’s wish to remain in the EU with 62% of Scots backing to stay in the 2016 referendum.

The First Minister added it was “time to build a future based on what Scotland votes for”.

Labour and the Tories will both back the deal in the landmark vote in the Commons today with the SNP and LibDems voting against.

A separate vote on a legislative consent motion on the deal will also take place in Holyrood with the SNP, Labour, Greens and the LibDems all lining up to voting against giving Westminster consent.

The National: Richard Leonard's party is set to reject the Brexit agreementRichard Leonard's party is set to reject the Brexit agreement

In what will be a deeply significant moment, and with the Tories alone is supporting consent, Holyrood will refuse to give approval to the agreement.

Ahead of the vote in the Scottish Parliament the First Minister said: “The Scottish Parliament, like the people of Scotland, has consistently voiced support for Scotland’s membership of the EU and – since the 2016 referendum – for single market and customs union membership.

“The question before the Scottish Parliament is not about this deal or no deal, but whether this deal is good or bad for Scotland.

“The Scottish Government and Scottish Parliament consistently suggested alternatives. While recognising the UK would leave the EU, we proposed staying in the single market and customs union.

“The UK Government dismissed these ideas. It disregarded Scotland’s views, values and interests. It has agreed a deal which is disastrous for Scotland.

“The UK Government’s deal will impose costs on businesses, reduce the opportunities of its citizens, and sacrifice its own international influence - in order to gain powers it will struggle to use.

“Even for the fishing industry – perhaps the only sector that genuinely believed that Brexit would deliver benefits – this deal represents a massive sell out and broken promise.

“The result is a deal which is harmful for the UK as a whole – but perhaps especially harmful for Scotland. It should not receive the Scottish Parliament’s consent.”

READ MORE: Scottish Labour to vote against Tory Brexit deal in Holyrood ballot

Scottish Greens co-leader Patrick Harvie added: “The Scottish Greens refuse to accept this false choice between a calamitous no-deal and the Prime Minister’s version, which still drags Scotland out of Europe, losing vital rights and protections as well as the ability for our students to study abroad as part of the Erasmus plus scheme.”

LibDems leader Willie Rennie said: “With our long track record of advocating membership of the European Union people won’t be surprised that the Liberal Democrats can’t support the Conservative Government’s strategy on Brexit and the last-minute trade deal they reached.”

The Tories’ hardline European Research Group, which was weighing up not supporting the deal over concerns that is would establish too close a relationship with the EU, said it would back the deal at Westminster. A self-styled “star chamber” of lawyers was assembled by the ERG to examine the 1246-page text of the agreement. They concluded it “preserves the UK’s sovereignty as a matter of law and fully respects the norms of international sovereign-to-sovereign treaties”.

They said: “The “level playing field” clauses go further than in comparable trade agreements, but their impact on the practical exercise of sovereignty is likely to be limited if addressed by a robust government.”