THERESA May is willing to risk a political backlash in Scotland by ploughing on with a so-called hard Brexit and overriding any vote at Holyrood which opposes the UK Government’s strategy, Whitehall insiders have made clear.

This morning, the UK Supreme Court judges will deliver their ruling on whether or not MPs and MSPs should have a vote before Article 50, which formally begins the Brexit process, is triggered by the end of March.

The expectation at Westminster is that the 11 justices will uphold an earlier High Court ruling, which said MPs should have a vote. If this happens, it is understood the UK Government will publish a short parliamentary bill within hours of the judgement.

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However, it is not expected that the judges will say Holyrood should also have a vote; it is possible this ruling will be based on the fact that foreign relations, including those with the EU, are reserved to Westminster.

During the court hearing, Lord Keen of Elie, the Advocate General for Scotland, presenting the UK Government’s case, argued that Westminster was sovereign and the UK's relations with the EU were "not within the competence" of MSPs.

James Woolfe, the Lord Advocate, representing the Scottish Government, argued that because Brexit would have a major impact on the devolved settlement, then MSPs should have a “voice” in the process but even he accepted that any vote at Holyrood could not veto the UK Government’s strategy.

One senior Whitehall source made clear that Article 50 would be triggered by the end of March irrespective of what the judges decided or if the Scottish Parliament voiced opposition. “We’re determined to get this process underway; it’s what the UK voted for,” he declared.

Yet, Nicola Sturgeon has now made clear that, “whatever the court decides,” MSPs will be given a vote on the triggering of Article 50. The SNP leadership has indicated Nationalist MSPs and MPs will vote against triggering the Brexit process.

Read more: Former SNP leader questions Sturgeon's "pointless posturing" on Brexit

At Westminster, just one Scottish MP – the Conservatives’ David Mundell, the Scottish Secretary – is expected to vote in favour of invoking Article 50. Yet with few Tory rebels expected and the Labour leadership on board, the UK Government is expected to win any Commons vote comfortably.

Asked about the First Minister’s move on a Holyrood vote, the Prime Minister's spokeswoman said: “We have been clear that we will be getting on and triggering Article 50 by the end of March; that has been backed in the House of Commons.”

Ms Sturgeon also delivered her strongest warning yet about the possibility of another independence referendum, stressing: "If the UK Government don't start showing Scotland some respect, I'll make sure that people across Scotland have the chance to choose our own future before the Tories drag us off an economic cliff-edge."

Asked if Mrs May regarded that as a threat, a Downing Street spokesman said the PM had been very clear on her desire to preserve the Union and on the “importance of the devolved administrations being involved in the process of Britain’s exit from the EU”; hence, the establishment of a Joint Ministerial Committee[JMC] on Brexit to ensure the voices of the devolved administrations “are heard and they will be”.

Ms Sturgeon has already ruled out holding a second poll on Scotland’s future this year but some of her SNP colleagues, including her predecessor, Alex Salmond, have pointed to the prospect of there being one in 2018.

Read more: Former SNP leader questions Sturgeon's "pointless posturing" on Brexit

The Gordon MP said: “It has to be within the two-year negotiating period, so we would be talking about a year come the autumn, or something like that. You would have to have it within the two years, you would want to have the Scottish referendum before the Brexit process had been completed.”

Matters are likely to come to a head early next week when Mrs May is due to chair the plenary session of the JMC on Brexit in Downing Street; Ms Sturgeon will be in attendance.