Boris Johnson, the Queen and suspension of UK parliament: What happens next?
Three senior Scottish judges have ruled that Boris Johnson's decision to suspend the UK parliament was "unlawful".
A group of around 70 parliamentarians had appealed against a ruling by a judge at the court that Boris Johnson's prorogation of UK Parliament is lawful.
Judge Lord Doherty originally dismissed a challenge against the suspension - which went ahead in the early hours of Tuesday - at the Court of Session last Wednesday, saying it is for politicians and not the courts to decide.
Scottish National Party MP Joanna Cherry QC, who was among the cross-party group of politicians that brought the action, tweeted: "All 3 judges in Scotland's Highest court of appeal rule #Prorogation #unlawful! #Cherrycase succeeds.
"Huge thanks to all our supporters & our fantastic legal team who have achieved the historic ruling that #prorogation is #unlawful #Cherrycase #Brexit."
Liberal Democrats MP Luciana Berger tweeted: "As one of the Petitioners to this case, this is such an important ruling - although how awful that it's had to come to this. "
The Government said it was "disappointed" by the decision and would be appealing to the UK's Supreme Court.
Here's a look at some of the key questions following the ruling.
- When will the Supreme Court make a ruling?
The matter has been referred to the UK Supreme Court, which is expected to hear the arguments on Tuesday.
The court is likely to make a ruling later in the week.
- What happens if the Supreme Court rules prorogation was unlawful?
The Government would almost certainly have to advise the Queen to recall UK parliament immediately in such an instance.
But the UK Supreme Court could rule that their parliament was never prorogued and is still in session, meaning that there is no need to recall Parliament.
Either way - if the Supreme Court rules that the prorogation was unlawful - it is likely that UK Parliament will have to return very quickly.
Raphael Hogarth, an associate at the Institute for Government, said: "If the Supreme Court rules next week that the prorogation was unlawful, then I'd expect Parliament to be sitting again in very short order.
"The mechanics of that depend on what the court says. The court might say that UK Parliament was never prorogued at all in the eyes of the law and so is actually still sitting after all. Or, the Government might need to recall Parliament immediately."
- How would the Queen be involved?
The monarch has the power to recall UK parliament through a proclamation - which the Prime Minister would be expected to advise her to do if the prorogation was ruled to be unlawful by the Supreme Court.
If Boris Johnson refused to do so, the Queen would be plunged into an incredibly awkward position.
The UK parliamentary rulebook Erskine May notes: "When Parliament stands prorogued to a certain day, the Queen may issue a proclamation, giving notice of her intention that Parliament shall meet for the dispatch of business on any day after the date of the proclamation; and Parliament then stands prorogued to that day, notwithstanding the previous prorogation."
Could Parliament still have its break for party conferences even if it was recalled?
Yes, but this would have to be agreed by MPs who vote on whether or not to go into recess.
- What does it mean for the Brexit process?
Regardless of whether UK parliament is recalled, not a lot will change in legislative terms for Brexit before mid-October as a law designed to prevent a no-deal has already received Royal Assent.
However, prorogation has reduced the opportunities for MPs to scrutinise the Government - and has cut short the time remaining to debate Brexit in the Commons before October 31.