Boris Johnson suspended parliament because he wished to “evade control” by MPs and no other prime minister “has abused his power” in such a way for the past 50 years, a lawyer for anti-Brexit campaigner Gina Miller claimed at the start of one of the highest-stakes constitutional cases ever heard in the UK.
The Supreme Court began hearing two contrasting but linked appeals on Tuesday, including one from Ms Miller, on the issue of whether the prime minister acted lawfully in advising the Queen to prorogue parliament for five weeks until October 14. If the justices find against the UK government, Mr Johnson will have to answer the charge that he misled the monarch.
It is only the second time in the court’s 10-year history that the 11 judges have sat together and it signifies the constitutional importance of the case, which is being livestreamed.
London’s High Court had ruled that Mr Johnson’s action in proroguing parliament could not be reviewed by the courts — or that it was non-justiciable — and so the action was lawful.
By contrast, the highest court in Scotland, which has a separate legal system, ruled that Mr Johnson’s actions in suspending parliament could be examined by the courts and found his action was unlawful and “clandestine” and had been aimed at stymying parliamentary scrutiny of the government.
A key battleground in the case is whether the Supreme Court decides that the case is justiciable or whether it falls into a “forbidden area” of high policy and politics where the courts do not tread under the UK’s unwritten constitution. The government argues that the prorogation cannot be reviewed by the courts.
David Pannick QC, acting for Ms Miller, told the Supreme Court on Tuesday that the “exceptional length” of the five-week prorogation was “strong evidence” that Mr Johnson’s motive was “to silence parliament for that period because he sees parliament as an obstacle to the furtherance of his political aims”.
“No other prime minister has abused his powers in the manner in which we allege in at least the past 50 years,” he told the court. He added that one “remarkable” feature of the case was that Mr Johnson had not submitted a signed witness statement to the court responding to allegations that his motives for proroguing were “improper”, which would enable him to be cross-examined.
“We say the case cries out for an answer in a witness statement,” Lord Pannick said.
Lord Pannick added that Mr Johnson’s advice to the Queen was “motivated or at least strongly influenced by the prime minister’s desire to prevent a risk of parliament damaging government policy” and “silencing parliamentary scrutiny”. He said: “It means parliament cannot legislate and it cannot inform itself for the purposes of legislating by the asking of parliamentary questions.
He likened government ministers to being a junior partner in a constitutional hierarchy in which parliament was the senior partner. “The junior partner, the executive, cannot use its constitutional power in effect preventing a superior body from performing its constitutional function, particularly when the constitutional function is the scrutiny of the junior partner.” he said.
Mr Johnson’s action in suspending parliament meant the government had the “inevitable effect of avoiding parliamentary scrutiny” at a vital time and as such the case should be within the remit of the courts, he argued.
He added that the legal question was whether the prime minister had exercised the prerogative powers for a legitimate legal purpose. “The rule of law demands the court answers it and does not say ‘it is not for us’,” he said.
Lady Hale, president of the Supreme Court, told the start of the hearing on Tuesday that both cases raised “serious and difficult questions of law” that the court would decide. She said the court was not being asked to decide political issues such as how or when the UK leaves the EU.
The case exposes the growing strain around Britain’s partly codified, unwritten constitution that has been built up over hundreds of years and which includes political conventions and prerogative powers.
Aidan O’Neill QC, barrister for Joanna Cherry and 70 parliamentarians who are bringing the Scottish case, claimed in his written arguments that the Scottish court decision was correct and the reasons for the government’s motives in prorogation should be examined by the courts.
“It is an administrative power that has, in this case, been used abusively by the executive” which “falls squarely” within the court’s remit, he said. He argued that English law should be “brought up to the standards by which the executive is called to account under Scots law”.
As well as the two cases, the Supreme Court will also hear supporting arguments this week by interveners, including the Scottish and Welsh governments, Belfast victims campaigner Raymond McCord and former Conservative prime minister John Major. The latest hearing has generated huge public interest, with a full public gallery and about a hundred protesters gathered outside the court.
The case continues.