The Scottish Seven elected politicians who brought a legal challenge to Brexit to find out if the UK Government can reverse Article 50 have won the right to have their case heard in Scotland’s highest court.

In an unexpected development, the Court of Session will now hear their case after three judges led by the Lord President, Lord Carloway, overturned an earlier decision by judge Lord Doherty that the the case should not proceed because the question of stopping the Article 50 withdrawal was “hypothetical and academic”.

With Andy Wightman of the Scottish Greens the leading name on the court papers, the Scottish Seven yesterday won their appeal against that decision. The others in alphabetical order are Joanna Cherry QC MP (SNP), Ross Greer MEP (Scottish Green), Christine Jardine MP (Lib Dem), David Martin MEP (Labour), Alyn Smith MEP (SNP), and Catherine Stihler MEP (Labour).

All of them will have to vote on whether to accept the final Brexit deal either in the Scottish Parliament, the UK Parliament or the European Parliament.

Giving the judgement on behalf of himself, Lord Menzies and Lord Drummond Young, Lord Carloway wrote: “The court is conscious that the petition proceeds at the instance of members of the Scottish, United Kingdom and European Parliaments and relates to a matter of very great constitutional importance; that being the United Kingdom’s relationship with the European Union. The petition is presented by responsible counsel and agents. The court has therefore elected to take quite some time to consider the petition and the written and oral arguments in an attempt to identify what potentially relevant facts are averred and what possible legal argument may be hidden in the petition’s many paragraphs. This is, however, an exceptional course and it is not one which a court should follow in the ordinary case.”

As well as this criticism of the length and complexity of the legal challenge, Lord Carloway was critical of the arguments put forward, saying the petition had “significant problems” and calling the position of the UK government “ambiguous”.

He said that if the petition was “shorn of its rhetoric and extraneous and irrelevant material and reduced, after adjustment, to a manageable size”, then “a case of substance – albeit not necessarily one which is likely to succeed - can be discovered”.

Lord Carloway added: “The issue of whether it is legally possible to revoke the notice of withdrawal is one of great importance. On one view, authoritative guidance on whether it is legally possible to do so may have the capacity to influence members of parliament in deciding what steps to take in advance of, and at the time of, a debate and vote on the EU Withdrawal Bill.

“After all, if parliament is to be regarded as sovereign, the government’s position on the legality of revoking the notice may not be decisive.”

He concluded that there was “a point of substance, albeit one heavily concealed” in the case, “which should be argued in the normal way”. The judge said he would allow some time for the two sides to formulate their arguments before further hearings in the Scottish courts are set.

The action is being crowdfunded by Jo Maugham QC of the Good Law Project. He tweeted last night: “This was not the result I wanted. I wanted to lose and go to the Supreme Court. But it is hugely politically significant that the Scottish Court of Appeal has acknowledged that Parliament can vote to Remain - whatever the Government pretends.”