Lord Pentland’s judgement said there was no doubt the PM accepts he “must comply” with the law.
A judge has dismissed a legal bid to force Boris Johnson to delay Brexit to avoid a no-deal.
The prime minister has promised he will comply the so-called “Benn Act” passed against his wishes by MPs last month, which forces him to seek a Brexit extension if he does not pass a deal through parliament.
But he has also said Brexit will definitely happen on 31 October – not explaining how this is possible given the legislation.
So campaigners – led by businessman Vince Dale, SNP MP Joanna Cherry QC and Jolyon Maugham QC – launched legal action at the Outer House of the Court of Session.
They wanted a judge to order that Mr Johnson had to send a letter to Brussels asking for the delay.
They also wanted to try and stop the prime minister finding a way around the law, including getting the judge to ban Mr Johnson from asking EU leaders to veto the request.
Their case was dismissed on Monday afternoon.