NICOLA Sturgeon has promised that MSPs will have a vote on the process which triggers Brexit, although it will not amount to a veto.

The First Minister said she wanted to make it “crystal clear” that Holyrood would have its say on invoking Article 50 to leave the EU.

The UK Supreme Court is due to rule tomorrow on whether MPs should vote on Article 50.

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The UK Government wants to use executive powers alone to start the process, however the High Court last year ruled that parliament must decide the matter.

The Supreme Court is widely expected to back the lower court’s view, and Theresa May is ready to introduce a short bill swiftly after such a ruling.

The Scottish Government’s most senior law officer, the Lord Advocate James Wolffe QC, argued at the Supreme Court that Holyrood should also have a formal say on the issue, through a legislative consent motion (LCM), but accepted this could not be a veto on Brexit.

LCMs flow from the Sewel convention which says that Westminster will not ordinarily vote on devolved matters, however this is a convention not statute, and Westminster ultimately remains sovereign.

Writing in the Daily Record, the First Minister said: "No matter what the court decides, I want to make this crystal clear - I intend to make sure the Scottish Parliament has the chance to vote on the question of triggering Article 50.

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"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."

If the Supreme Court rules that MPs, but not necessarily MSPs, should have a vote on Article 50, it would be up to the UK government to decide whether to have an LCM at Holyrood.

Whether MSPs vote on an LCM or a government motion - neither is which is binding - Ms Sturgeon is likely to use Holyrood’s rejection of Article 50 to complain about the UK Government ignoring Scotland and the democratic deficit in the Union highlighted by Brexit.

SNP Brexit minister Michael Russell indicated on Sunday that his party’s MPs would vote against the triggering of article if the matter came before Westminster.

Ms Sturgeon has warned of a second independence referendum if the UK government rejects her plan to keep Scotland in the EU single market after the UK leaves it in 2019.

However the PM did not include a Scottish deal in her 12-point plan for Brexit last week.

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Ms Sturgeon also wrote in her newspaper column: "It's getting hard not to feel like the PM has her fingers in her ears when it comes to Scotland.

"This isn't some academic debate - removing us from the largest single market in the world would be devastating for people's jobs and living standards. But that seems to be of little concern to the Tories."

Scottish Liberal Democrat leader Willie Rennie said his party would vote against the triggering of Article 50 unless a further referendum on the terms of the Brexit deal was guaranteed.

He said: "The First Minister believes that the answer to the reckless nationalism of the Tories is the reckless nationalism of independence, which will only compound the chaos of Brexit further.

"Instead of giving up on the UK, the SNP should join our efforts of keeping the UK in the EU."