The supreme court has ruled that Boris Johnson’s advice to the Queen that parliament should be prorogued for five weeks at the height of the Brexit crisis was unlawful.
The judgment from 11 justices on the UK’s highest court follows an emergency three-day hearing last week that exposed fundamental legal differences over interpreting the country’s unwritten constitution.
The first legal question the judges had to resolve was whether the prime minister’s decision – exploiting residual, royal prerogative powers – was “justiciable” and could consequently be subjected to scrutiny by the courts. The English high court declined to intervene; the Scottish appeal court concluded that judges did have legal authority to act.
In a unanimous verdict, the court has ruled that Johnson’s decision to prorogue parliament can be examined by judges, overturning the ruling of the high court in London.
Delivering judgment, Lady Hale said: “The question arises in circumstances which have never arisen before and are unlikely to arise again.”
Then, giving the court’s judgment on whether the decision to suspend parliament was legal, Hale said: “This court has … concluded that the prime minister’s advice to Her Majesty [ to suspend parliament] was unlawful, void and of no effect.
This means that the Order in Council to which it led was also unlawful, void and of no effect should be quashed.
“This means that when the royal commissioners walked into the House of Lords [to prorogue parliament] it was as if they walked in with a blank sheet of paper. The prorogation was also void and of no effect. Parliament has not been prorogued.”
Hale continued: “It is for parliament, and in particular the Speaker and the Lord Speaker to decide what to do next. Unless there is some parliamentary rule of which we are unaware, they can take immediate steps to enable each house to meet as soon as possible.
It is not clear to us that any step is needed from the prime minister, but if it is, the court is pleased that his counsel have told the court that he will take all necessary steps to comply with the terms of any declaration made by this court.”
Responding to the judgment, the Commons Speaker, John Bercow, said the house must “convene without delay” and that he would be consulting party leaders “as a matter of urgency”.
Lawyers for the Scottish claimants and for the businesswoman and campaigner Gina Miller argued that, in suspending parliament, Johnson was motivated by an “improper purpose” – namely avoiding parliamentary control over his policies. MPs and peers, they urged, should be recalled this week.
Government lawyers told the court, which sits in Westminster directly opposite parliament, that the justices should not enter into such a politically sensitive area, which was legally “forbidden territory” and constitutionally “an ill-defined minefield that the courts are not properly equipped to deal with”.
Despite torrential rain, the first members of the public began queueing outside for seats in the supreme court at 5.20am on Tuesday eager to be present for the historic decision.
The decision was read out by Lady Hale, the president of the supreme court. Unusually, none of the parties were provided with advance copies of the judgment due to its extreme sensitivity. Only seven of the 11 justices who heard the case were present in court.