18:30

A judge at the court of session in Edinburgh has rejected a bid by the anti-Brexit campaigner, Jolyon Maugham, that questioned the legality of Boris Johnson’s new withdrawal deal.

The basis of the legal challenge by the QC and director of the Good Law Project was that the newly agreed deal contravened legislation – originally amended by hardline Brexiters to stymie the backstop arrangement – that prevents Northern Ireland forming part of a separate customs territory.

But Lord Pentland, who heard submissions on Friday morning and delivered his ruling at 5pm the same day, said Maugham’s argument was “weak”, adding that his petition was “of doubtful competency”. In his ruling, Pentland said:

It is a cardinal principle of constitutional law that the courts should not intrude on the legitimate affairs and processes of parliament.

Responding to the ruling, Maugham accepted that he had been mistaken in bringing the action in haste.

We had to make a decision to issue proceedings for interim remedies quickly or not at all; once the withdrawal agreement reaches parliament it becomes impossible to challenge. That was a difficult decision to make. It is difficult to move quickly and accurately and, the court has found, I got that decision wrong.

Lord Carloway, Scotland’s most senior judge, has already cleared time for an emergency hearing in the court of session at noon next Monday, as part of an earlier action by Maugham along with the SNP MP, Joanna Cherry, and Dale Vince, the millionaire owner of the Ecotricity green energy company. Carloway could issue court orders forcing Johnson to send a letter to the EU asking for an extension to article 50 until 31 January, as required by the Benn act.