A legal battle over Boris Johnson’s decision to suspend parliament for five weeks ahead of the Brexit deadline will be heard by the UK’s highest court on Tuesday.
The Supreme Court in London will hear appeals from two separate challenges brought in England and Scotland.
The prime minister has insisted that the five week ‘prorogation’ of parliament is to allow the government to set out a new domestic agenda in a Queen’s speech when MPs return on October 14.
But those who have brought the legal challenges have accused Johnson of trying to avoid scrutiny from MPs in the run up to Brexit.
The Supreme Court – which will sit as a panel of 11 justices for only the second time in its 10-year history – must reconcile contradictory judgements issued by the English and Scottish courts.
While the Court of Session in Edinburgh ruled Johnson’s decision was unlawful, saying it was motivated “by the improper purpose of stymying parliament”, the High Court in London dismissed a challenge by businesswoman Gina Miller.
The court found that the length of the prorogation was “purely political”.
Miller’s case was supported by former prime minister Sir John Major, shadow attorney general Baroness Chakrabarti and the Scottish and Welsh governments, who are all interveners in the Supreme Court case.
Meanwhile, a cross-party group of around 75 MPs and peers, led by SNP MP Joanna Cherry QC, was responsible for the Scottish challenge and the subsequent appeal.
The Supreme Court hearing is scheduled to last until Thursday.
The Key Players
Boris Johnson
The Queen prorogued parliament on Boris Johnson’s advice on August 28 after Commons leader Jacob Rees-Mogg, Lords leader Baroness Evans and chief whip Mark Spencer flew to Balmoral for a Privy Council meeting.
In a handwritten note dated August 16, the prime minister said that parliament sitting in September was “rigmarole introduced ... to show the public that MPs were earning their crust, so I do not see anything especially shocking about this prorogation”.
The prime minister told the BBC he will “wait and see what the judges say” before deciding whether to recall parliament.
Gina Miller
The investment fund manager and campaigner first came to public prominence in 2016 when she launched a legal challenge against Theresa May’s decision to use the royal prerogative to trigger Article 50.
The High Court ruled that the prime minister did not have the power to trigger Article 50 without the authority of parliament, a ruling ultimately upheld by the Supreme Court in January 2017.
However, Miller’s most recent challenge to Johnson’s decision to prorogue parliament was dismissed.
Sir John Major
Sir John served as prime minister between 1990 and 1997, taking over from Margaret Thatcher.
In July, after Johnson refused to rule out prorogation, Sir John told BBC Radio 4′s Today programme that it would be “utterly and totally unacceptable” for any British premier to shut down parliament.
The former PM said he would bring a judicial review against any attempt to do so and intervened in Miller’s High Court case in September. His lawyers have been given permission to make oral submissions at the Supreme Court hearing.
However, Major himself controversially prorogued Parliament ahead of the 1997 general election, which prevented a report on the cash for questions scandal being considered by MPs.
Baroness Chakrabarti
The peer was director of civil liberties organisation Liberty from 2003 to 2016.
Following her appointment in 2016 as the chairwoman of an inquiry into anti-Semitism in the Labour Party, Baroness Chakrabarti was nominated to the House of Lords and subsequently appointed Labour’s shadow attorney general.
Joanna Cherry
Joanna Cherry, a barrister-turned-MP and the SNP’s justice and home affairs spokeswoman, is the lead claimant in the proceedings brought in Scotland.
The case is brought by a total of 79 petitioners, including Lib Dem leader Jo Swinson, Green Party MP Caroline Lucas and Plaid Cymru’s Westminster leader Liz Saville Roberts.
On Tuesday Cherry said she is “cautiously optimistic” that the ruling by the Scottish judges will stand.
She told BBC Radio Scotland: “I’m cautiously optimistic that it will stand.
“I think that Scotland’s supreme court reached the right decision here for the right reasons and I’m cautiously optimistic that at least a majority of the UK Supreme Court justices will follow.”
Raymond McCord
The victims’ rights campaigner, whose son was murdered by loyalist paramilitaries in 1997, is one of three individuals bringing a legal challenge in Belfast, arguing that a no-deal Brexit would damage the Northern Ireland peace process.
Unlike in England and Wales and Scotland, cases in Northern Ireland cannot leapfrog straight to the Supreme Court, so McCord’s case was heard by the Court of Appeal in Belfast on Monday - and he has also been given permission to intervene at the Supreme Court.
Supreme Court justices
For only the second time in the court’s history, an 11-strong panel of justices will hear the joined cases - the first time being Miller’s Article 50 case.
The panel will be headed by Supreme Court president Lady Hale and also includes deputy president Lord Reed, who will become president in January when Lady Hale retires.