THERESA May’s Government has suffered a humiliating defeat in their attempts to derail a Scottish court case seeking to determine whether the UK can unilaterally reverse Brexit.

In a development that will infuriate Brexiteers, the European Court of Justice (ECJ), which they detest, could now find against the UK Government which would mean that Scotland’s top court could ultimately decide whether or not Article 50, the process for leaving the EU, could be reversed.

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The case has gained new importance because of the possibility of ‘no Brexit’ as admitted by the Prime Minister last week. If the Scottish case is won, the House of Commons could theoretically revoke Article 50 though doing so without another referendum or general election would be very unlikely.

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On Tuesday morning the UK Supreme Court rejected an application from ministers who wanted to stop Europe’s top court from giving guidance on a case brought by Green MSPs Andy Wightman and Ross Greer, the SNP’s MEP Alyn Smith and MP Joanna Cherry, and Labour MEPs David Martin and Catherine Stihler, and the lawyer Jolyon Maugham QC.

The National:

Delighted: The SNP's Joanna Cherry

Joanna Cherry told The National: “I am delighted with this important decision as it vindicates both Scots law and EU law.

“We already know that Article 50 can be revoked with the agreement of the other EU countries. The purpose of our legal challenge is to see if Article 50 can be unilaterally revoked by the UK Parliament.”

The Court of Session in Edinburgh ruled in September that the question of whether Article 50 could be revoked without permission from the EU’s other member states should be referred to the ECJ.

The UK Government have fought the case all the way, and told both the Court of Session and the UK Supreme Court that there was no point in the case going to the ECJ as it was immaterial to know if Britain could reverse the decision because ministers had no intention of doing so.

The Supreme Court said the Court of Session’s ruling was “preliminary” and it would still have to reach a “final judgment” on the matter after the European Court has given its guidance.

A statement issued by the Supreme Court said: “As both this court and the (ECJ) have made clear, the preliminary ruling is merely a step in the proceedings pending before the national court – it is that court which must assume responsibility for the subsequent judicial decision.

“It will therefore remain for the Court of Session to give judgment in the light of the preliminary ruling, any relevant facts which it may find and any relevant rules of domestic law. It is only then that there will be a final judgment in the proceedings.”

The ECJ is due to hear the case on November 27.

A Government spokesperson said: “We are disappointed by the decision of the court and it remains a matter of firm policy that we will not be revoking Article 50.”

Maugham tweeted: “The best, the really compelling, the objective evidence that all options are still on the table is the desperation with which Government acted to try and block MPs from seeing the clear path to Remain.”

Stihler tweeted that she was “pleased to see the Supreme Court has refused permission to appeal. Looking forward to our case being heard at the ECJ a week today.”

Wightman said it was a “welcome ruling” and added: “The question as to whether the UK Parliament can unilaterally revoke Article 50 is becoming more relevant as the chaos around Brexit shows no sign of being resolved.

“It is vital that Parliament is informed of all of its options.”