Elaine Motion

On 6 September, the Court of Session will hear arguments on the potential ‘proroguing’ of the Westminster Parliament by Boris Johnson’s government.

To prorogue Parliament would effectively involve the suspension of any further discussion on ruling out a no-deal Brexit – which Parliament has already said it does not want to consider as an option.

The Prime Minister has repeatedly refused to rule out proroguing parliament – which has prompted more than 75 politicians, represented by Balfour and Manson, to bring the case to court.

The petitioners – including SNP MP Joanna Cherry QC and new Lib Dem leader Jo Swinson – want the courts to declare that it is “unconstitutional for any Minister of the Crown, including the Prime Minister, with the intention and aim of denying before Exit Day any further parliamentary consideration of the withdrawal of the United Kingdom from the European Union, to purport to advise the Queen to prorogue the Westminster Parliament”.

The keywords are “denying before Exit Day any further parliamentary consideration” – because the petitioners are clear that parliament must be allowed to have its say. To deny it would be to deny the very sovereignty of the Westminster Parliament.

Last week at the Court of Session in Edinburgh, Lord Doherty agreed to hear arguments from both sides on 6 September – just over five weeks after the action was lodged with the court.

The petitioners are represented by the same team as brought the Wightman action, which went all the way to the European Court of Justice after referral from the Court of Session and succeeded in its argument that the UK Parliament had the right to unilaterally revoke Article 50, the mechanism invoked for the UK to leave the European Union.

Using the precedent from Wightman, the petitioners will argue that the court should state the law in advance of the Queen being asked to suspend Parliament.

It has been argued by some that if the Prime Minister asks the Queen to suspend Parliament, she faces an impossible choice – to ignore his advice and break with convention or agree to dismiss Parliament and leave the Prime Minister with the opportunity to force through a No Deal.

The petition seeks clarity before that stage is reached and to avoid a potential constitutional crisis.

The number of politicians who have come forward as petitioners show that there is widespread and cross-party support to prevent the bypassing of Parliament - and arguing that it must have its say on the prospect of the UK leaving the EU with no deal, with all the potentially damaging repercussions that could follow.

The group of petitioners includes Scottish MPS from the SNP, Liberal Democrats and Labour Party, Welsh MPS from Plaid Cymru and Labour party and a number of English independent, Labour and Green parliamentarians. The House of Commons and House of Lords are both well represented.

It is a great honour to be leading for Balfour and Manson on this case, instructing a team led by Aidan O’Neill QC and assisted by Professor Kenneth Armstrong – including the same Scottish team that went through 14 hearings and many ups and downs to win the Wightman case.

It’s also great to have the indefatigable Jolyon Maugham QC, director of the Good Law Project, on side again.