U.K. Court To Rule On Parliament Suspension

The UK's highest court is due to hand down its historic ruling on the legality of the five-week suspension of parliament.

Prime Minister Boris Johnson, who has been accused of an unlawful "abuse of power", will be in the United States when the Supreme Court announces its findings on Tuesday following an unprecedented hearing last week.

Eleven justices have been asked to determine whether his advice to the Queen to prorogue parliament, for what opponents describe as an "exceptionally long" period, was unlawful.

Boris Johnson is under pressure to apologies for his comments. Image: Getty Images.

The prime minister advised the Queen on August 28 to prorogue parliament for five weeks, and it was suspended on September 9 until October 14.

Johnson says the five-week suspension is to allow the government to set out a new legislative agenda in a Queen's Speech when MPs return to parliament.

But those who brought legal challenges argue the prorogation is designed to prevent parliamentary scrutiny of the UK's impending exit from the EU on October 31.

The Supreme Court heard appeals over three days arising out of separate legal challenges in England and Scotland, in which leading judges reached different conclusions.

The Queen approved the suspension. Photo: Getty

At the High Court in London, Lord Chief Justice Lord Burnett and two other judges rejected campaigner and businesswoman Gina Miller's challenge, finding that the prorogation was "purely political" and not a matter for the courts.

But in Scotland, a cross-party group of MPs and peers led by SNP MP Joanna Cherry QC won a ruling from the Inner House of the Court of Session that Johnson's prorogation decision was unlawful because it was "motivated by the improper purpose of stymieing parliament".

Miller has appealed against the decision of the High Court, asking the Supreme Court to find that the judges who heard her judicial review action "erred in law" in the findings they reached.

The justices have been asked to determine whether Johnson's advice to the Queen was "justiciable" - capable of challenge in the courts - and, if so, whether it was lawful.

During last week's hearing, Lord Pannick QC, for Miller, told the packed court that Johnson's motive for a five-week suspension was to "silence" parliament, and that his decision was an "unlawful abuse of power".

He argued that Johnson's reasons for advising on a suspension of that length "were improper in that they were infected with factors inconsistent with the concept of parliamentary sovereignty".

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But Sir James Eadie QC argued on the prime minister's behalf that the suggestion the prorogation was intended to "stymie" parliament ahead of Brexit was "untenable".

Miller's case is supported by former prime minister Sir John Major, shadow attorney general Baroness Chakrabarti, the Scottish and Welsh governments, and Northern Irish victims' campaigner Raymond McCord.

The decision sparked rallies across the UK. Photo: Stefan Simanowitz via Twitter

The justices have also been asked by the Westminster government to allow an appeal against the decision in Scotland.

Depending on the legal basis upon which the judges reach their conclusions, parliament may have to reconvene if Johnson, who has refused to rule out a second suspension, loses the case.

Documents submitted to the court revealed three possible scenarios in the event the court rules the suspension was unlawful, two of which could see the prime minister make a fresh decision to prorogue parliament.

The other outcome could see the court order parliament to be recalled.