A legal bid to challenge the suspension of parliament has succeeded at the highest appeal court in Edinburgh.
A "major showdown" at the UK's Supreme Court has been predicted after Scotland's highest civil court ruled Boris Johnson's suspension of Parliament is unlawful.
It comes after three judges at the Court of Session in Edinburgh on Wednesday found in favour of a cross-party group of politicians who are challenging the Prime Minister's move.
Last week, Judge Lord Doherty had dismissed a challenge against the suspension of Parliament, saying it was for politicians and not the courts to decide.
The UK Government plans to appeal against the ruling and Nick McKerrell, a lecturer in law at Glasgow Caledonian University (GCU) now expects a showdown at the Supreme Court.
"This was a pretty unexpected judgment from the Inner House of the Court of Session and strongly overrules the findings of Lord Doherty's ruling last week," he said.
"The Lord President - the top judge in Scotland - said the decision to suspend Parliament could only be reviewed if its purpose was to 'stymie parliamentary scrutiny'. He believed this was the true reason.
"This was because of the length of time and the documents released showing the political discussions around prorogation that took place.
"The other two judges supported this. Significantly, all argued that in most normal circumstances the decision to prorogue could not be reviewed by the Courts which shows how exceptional this situation is.
"Ultimately then the court said the decision to suspend Parliament is 'null and is of no effect'.
"However, this will now be appealed to the Supreme Court of the United Kingdom in London next Tuesday. This will now be a major showdown."
Scottish Greens Parliamentary co-leader Patrick Harvie said: "We'll all need to study the detail of this ruling but it seems clear that the criticism of Boris Johnson's decision to shut down Parliament has been vindicated, and we therefore support the demand to recall Parliament.
"It's extraordinary that the UK Government - even one which has descended ever further into minority status - should have the power to replace the Prime Minister, set the parliamentary agenda and even force MPs to pack up and go home to avoid being held to account.
"No Scottish Government would have the legal ability to act in this dictatorial manner.
"The present crisis has highlighted the urgent need for a modern, democratic constitution which prevents the abuse of power by dangerous extremists like Boris Johnson."