THE Scottish courts moved a step closer to stopping a No-Deal Brexit this morning after judges said they would make a decision on sending a letter to Brussels on Boris Johnson 's behalf if the Prime Minister fails to act.

The Court of Session delayed a final ruling on the nobile officium case – brought by the SNP’s Joanna Cherry, businessman Vince Dale and QC Jolyon Maugham – until Monday 21, two days after the deadline imposed on the Tory leader by Parliament.

The Benn Act, passed by MPs last month, compels the Prime Minister to ask Brussels to push back Brexit day until January 31 if he fails to secure a deal with the EU before the end of next week’s European Council summit.

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But with Johnson and his advisers repeatedly insisting that the UK will Brexit on Halloween, come what may, the three campaigners, worried that the Prime Minister might slip out of his legal obligations, went to the Scottish court.

If successful this would effectively see the judges send the letter to Brussels on Johnson’s behalf if he fails to do so.

The Government had hoped the judges would dismiss the case, but the court said it could not rule on the matter until the political debate has "played out"

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They will reconvene after a special Saturday sitting of Parliament on October 19 when MPs will either be asked to approve any deal agreed between the UK and the EU or discuss a range of other options.

Cherry said the delay was a win for the campaigners. She tweeted: “Delighted to advise Scotland’s Supreme Court is holding off ruling on whether to force @BorisJohnson to send #Brexit #extension #BennAct letter until 21 Oct to give PM time to fulfil the promise he made to the court. A victory for us & all our supporters”.

Maugham said he was thrilled: “These cases are about keeping the Prime Minister on the straight and narrow.

“We have extracted from him a promise that he will face the music – including possible contempt proceedings.

“And the courts are likely to make good any failure on his part, including signing the Benn Act letter."

Announcing the judges' decision, Lord Carloway, Lord President of the Court of Session, said: "Until the time for sending the letter arrives, the Prime Minister has not acted unlawfully.

"If October 19 comes and goes without the Act having been satisfied, the petitioners would be entitled to return to court asking for the Prime Minister to have to comply with the Act.

"The situation remains fluid. What is known is that over the next two weeks circumstances will change.

He continued: "The courts understand that there is a limited amount of time. The political debate requires to be played out in the correct form.

"The court can only intervene if there is a demonstrable unlawfulness which it requires to correct. There has been no such unlawfulness."

Elaine Motion, a lawyer acting for the petitioners, called it an "excellent judgment ... as you would expect."

"The court have indicated that there are undertakings given by the Prime Minister that he will abide by the Benn Act and not seek to frustrate it.

"In continuing the matter to the 21st, there is a sword of Damocles over the Prime Minister's head to comply with the Benn Act, and we hope he does.

"We hope we do not have to return to court on October 21 and that politics can run its course.

"It's only if he doesn't comply with the orders that we have to come back to court."