A crossparty group of UK parliamentarians is set to bring a legal challenge in the Scottish courts over whether the next UK prime minister can advise the Queen to suspend the UK parliament in order to pursue a no-deal Brexit.

Some UK parliamentarians fear that the amendment passed last week could still leave a way open for Boris Johnson to “prorogue” Parliament to prevent MPs from blocking a no-deal Brexit.

Seven MPs, including new Liberal Democrat leader Jo Swinson, and five peers are preparing to apply for a judicial review.

The group’s letter to Lord Keen, Advocate General for Scotland, can be read here.

The legal case, backed by a crowdfunding effort, is being brought in Scotland because the Court of Session in Edinburgh sits throughout August, while the High Court in London is in recess next month.

Those bringing the challenge would like the court to have issued its decision before the UK parliament returns on September 3. 

They want to ask the Court of Session to issue a declaration that the new prime minister cannot lawfully advise the Queen to suspend parliament ahead of October 31 — the date when the UK is currently due to leave the EU.

Boris Johnson, expected to be named new Tory leader on Tuesday and named prime minister on Wednesday, has so far declined to rule out “proroguing” parliament to pursue a no-deal Brexit.

Anti-Brexit barrister Jolyon Maugham QC, founder of the Good Law Project, is co-ordinating the legal challenge with a crossparty group of MPs and wants the Scottish court to clarify the law well in advance of any move to prorogue parliament by a new prime minister. 

Maugham said: “If the Prime Minister asks the Queen to suspend Parliament she faces an impossible choice.

“Either she ignores his advice and breaks with convention or she dismisses Parliament so the Prime Minister can use her prerogative to force through No Deal.

“Both options explode the notion of the UK as a modern, functioning democracy.

“We will ask the Courts to assist Her Majesty by ruling on that choice.”

In a press release, the Good Law Project said: “Parliament is not an inconvenience to be bypassed.

“That’s what a cross party group of MPs and Peers has today said to the Government’s legal representative in Scotland, informing him that in seven days they will sue for a court guarantee that the Prime Minister cannot close down Parliament in the run up to 31 October 2019.

“The cross-party group includes Scottish MPs from the SNP, Liberal Democrats and Labour Party; Welsh MPs from Plaid Cymru and Labour; and a number of English independent, Labour and Green parliamentarians.

“It also includes Jolyon Maugham QC of the Good Law Project, which is backing the action.

“The action will be brought before the Court of Session – which sits through August – and is for a ‘declarator’ that the Prime Minister cannot lawfully advise the Queen to suspend Parliament …”

Joanna Cherry QC, SNP MP for Edinburgh South West, another of those bringing the challenge, said: “The Tories have steadfastly ignored the democratically expressed will of Scotland’s voters and parliament to stay in the EU.

“Now we face a no deal Brexit with potentially catastrophic damage to Scotland’s economy, society & culture.

“It is unconscionable that the incoming PM should simply do away with the Westminster Parliament in order to fulfil this slow motion car crash.

“Therefore we must take all steps we can to prevent prorogation.”

Swinson said: “Liberal Democrats will do everything we possibly can to stop the next Tory Prime Minister from crashing the UK out of the EU.

“That is why I am adding my name as a petitioner to this important case.

“Proroguing Parliament so as to crash the UK out without a deal would be catastrophic for our NHS, jobs, and our environment.

“Even entertaining the idea is reckless and demonstrates the degree to which Boris Johnson will always put his own career ahead of the future of our country.

“Liberal Democrats will continue to work cross-party to stop Brexit.

“This legal challenge is one of the many ways in which we will fight to ensure that the Tory government do not ride roughshod over our Parliament and democracy.”