By Estelle Shirbon and Michael Holden
LONDON (Reuters) – The United Kingdom’s Supreme Court ruled on Tuesday that Prime Minister Boris Johnson’s decision to shut down parliament in the run-up to Brexit was unlawful, a humiliating rebuke that thrusts Britain’s exit from the European Union into deeper turmoil.
The unanimous and stinging judgment by the court’s 11 judges undermines Johnson’s already fragile grip on power and gives legislators more scope to oppose his promise to take Britain out of the EU on Oct. 31.
Opposition leaders demanded that he should resign immediately for misleading Queen Elizabeth, who had officially suspended parliament on his advice.
Parliament, where Johnson has lost his majority and he suffered repeated defeats since taking office in July, is now set to be reconvened three weeks early, giving opponents more time to challenge, amend, or block his Brexit plans or even bring down his government.
“The decision to advise Her Majesty to prorogue parliament was unlawful because it had the effect of frustrating or preventing the ability of parliament to carry out its constitutional functions without reasonable justification,” Supreme Court President Brenda Hale said.
In its historic ruling, the court said Johnson had not given any reason – “let alone a good reason” – for suspending the legislature for five weeks.
“The prime minister’s advice to Her Majesty was unlawful, void and of no effect,” said Hale, adding that parliament was therefore not suspended and it was up to the speakers of parliament’s two chambers to decide what to do next.
John Bercow, the speaker of the House of Commons, where a majority of lawmakers oppose his plan for an Oct. 31 Brexit even if he has failed to secure a divorce deal, said the chamber would convene on Wednesday.
“I’ve instructed the House authorities to undertake such steps as are necessary to ensure that the House of Commons sits tomorrow and that it does so at 11.30 am (1030 GMT),” he said.
Sterling initially hit a day’s high of $1.2479 after the ruling before falling back to stand at $1.2454 at 1045 GMT, up 0.2% on the day and only slightly stronger than before the court decision.
Johnson declined to answer questions as he attended a meeting of business leaders in New York but had said ahead of the verdict he would not resign if he lost the case.
He is due to meet world leaders later at the United Nations General Assembly. The government declined immediate comment.
More than three years after the United Kingdom voted by 52%-48% in a referendum to leave the European Union, the future of Brexit remains mired in confusion, with options ranging from a turbulent no-deal exit to abandoning the entire endeavor.
The country is deeply divided and the court ruling was eagerly awaited, from pro- and anti-Brexit protesters gathered outside parliament to people watching on television in homes and offices.
Johnson’s reaction to the damning ruling could be crucial. He now faces a hostile parliament and the EU which says his proposals for a Brexit deal are far too meager for a proper divorce deal.
Parliament was suspended, or prorogued in the formal term, from Sept. 10 to Oct. 14. The prorogation was approved by Queen Elizabeth, Britain’s politically neutral head of state, on the advice of the prime minister. Buckingham Palace had no immediate comment.
Johnson, who took office in July after Theresa May stepped down over her failure to win parliament’s support for a withdrawal agreement, had claimed the suspension was necessary so that a new legislative agenda could be laid out and that it had nothing to do with thwarting opposition to a no-deal Brexit.
His lawyer had told the court he might even prorogue parliament again. However, after the ruling, opposition lawmakers demanded Johnson’s resignation.
“I invite Boris Johnson, in the historic words, to ‘consider his position’,” Labour Party leader Jeremy Corbyn told delegates at Labour’s annual conference in Brighton.
A Labour spokesman would not comment on whether the party would put forward a vote of no confidence in Johnson.
Liberal Democrat leader Jo Swinson said Johnson was unfit to rule and that she would return to Westminster to fight to stop Brexit altogether. Scotland’s First Minister Nicola Sturgeon said if he did not resign he should be forced out.
Former Conservative Prime Minister John Major, who joined anti-Brexit campaigners and opposition lawmakers in the legal challenge against the prorogation, said parliament should be recalled to receive Johnson’s “unreserved apology”.
“No prime minister must ever treat the monarch or parliament in this way again,” he said in a statement.
By Estelle Shirbon and Michael Holden