Boris Johnson’s decision to suspend Parliament was unlawful, the UK Supreme Court has ruled. Johnson prorogued Parliament for five weeks earlier this month, saying it was to allow a Queen’s Speech to outline his new policies. But the UK’s highest court said it was wrong to stop Parliament carrying out its duties.

The New York Times reports:

The unanimous decision, which upheld a ruling from Scotland’s highest civil court, could force the government to reconvene Parliament before Oct. 14, reopening a debate over Brexit that was short-circuited when Mr. Johnson asked the queen to suspend, or prorogue, Parliament for five weeks.

“The decision to advise Her Majesty to prorogue Parliament was unlawful because it had the effect of frustrating or preventing the ability of Parliament from carrying out its constitutional function without reasonable justification,” said Baroness Brenda Hale, the president of the court, speaking for the 11-judge panel that heard the case.

“The prime minister’s advice to Her Majesty was unlawful, void and of no effect,” she said. “Parliament has not been prorogued.”

Watch Lady Hale’s final remarks: