Scottish appeal court judges have declared Boris Johnson’s decision to suspend parliament in the run-up to the October Brexit deadline is unlawful.
The three judges, chaired by Lord Carloway, Scotland’s most senior judge, overturned an earlier ruling that the courts did not have the power to interfere in the prime minister’s political decision to prorogue parliament.
Lawyers acting for 75 opposition MPs and peers argued Johnson’s decision to suspend parliament for five weeks was illegal and in breach of the constitution, as it was designed to stifle parliamentary debate and action on Brexit.
The judges failed to issue an interdict, or injunction, ordering the UK government to reconvene parliament, prompting a row over whether the decision meant MPs could go back to the House of Commons.
The court issued an official summary of its decision declaring the prorogation order was “null and void”, but Carloway said they were deferring a final decision on an interdict to the UK supreme court, which will hold a three-day hearing next week.
Jolyon Maugham QC, the legal campaigner whose Good Law Project funded the legal action, said he and Aidan O’Neill QC, the group’s lawyer, believed this meant prorogation was suspended with immediate effect unless the UK government won a court order reinstating it.
The UK government will appeal at the UK supreme court against the latest ruling, which also contradicts a decision in Johnson’s favour by senior English judges last week.
The supreme court has already scheduled an emergency hearing on both the Scottish and English cases for 17 September, alongside a third challenge brought in the courts in Belfast.
The three Scottish judges, who will issue their own reasonings in full on Friday, said the prorogation was unlawful “because it had the purpose of stymying parliament”.
Parliamentary scrutiny of the executive was “a central pillar of the good governance principle enshrined in the constitution”.
The court’s summary concluded Johnson’s prorogation request to the Queen and her decision to accept it “was unlawful and is thus null and of no effect”.
Maugham said: “Our understanding is that unless the supreme court grants an order in the meantime, parliament is unsuspended with immediate effect.
“I’m relieved that my understanding of the functioning of our democracy – that allows parliament to exercise its vital constitutional role – has been vindicated by Scotland’s highest court.
“This is an incredibly important point of principle. The prime minister mustn’t treat parliament as an inconvenience.”
A UK government spokesperson said: “We are disappointed by today’s decision and will appeal to the UK supreme court. The UK government needs to bring forward a strong domestic legislative agenda. Proroguing parliament is the legal and necessary way of delivering this.”
Keir Starmer, the shadow Brexit secretary, said: “I welcome the court’s judgement. No one in their right mind believed Boris Johnson’s reason for shutting down parliament.
“I urge the prime minister to immediately recall parliament so we can debate this judgement and decide what happens next.”
House of Commons authorities had no immediate response when asked if the Speaker would be able to declare parliament is back in session, with a spokeswoman saying the ruling was being looked into.
The Liberal Democrat leader, Jo Swinson, tweeted: “Scottish judges have found in favour of 75 MPs (including me and other Liberal Democrats). We argued that Boris Johnson’s parliament shutdown is illegal, and designed to stifle parliamentary debate and action on Brexit.”