NICOLA Sturgeon has insisted Boris Johnson must resign as she accused the Prime Minister of bringing shame on his office, his party and the UK Government.

The First Minister said it was “truly historic and unprecedented in our modern democracy that a Prime Minister has been held to have broken the law”.

She added: “It is hard to think of another democratic country where there has been a more damning verdict on the behaviour of a Prime Minister.”

Ms Sturgeon addressed MSPs just hours after the UK Supreme Court ruled Mr Johnson had acted unlawfully by suspending Parliament for five weeks ahead of Brexit, upholding an earlier decision by Scotland’s Court of Session.

She insisted the explosive judgment was of “enormous significance” to Holyrood and the people of Scotland, and called on opposition MPs to move a vote of no confidence in the Prime Minister.

She said: “It was Boris Johnson who took the decision to prorogue Parliament.

“It was Boris Johnson who acted unlawfully, and I do not say this lightly, but it is Boris Johnson who must now resign.”

She added: “It is of course possible for a Prime Minister to continue in office if they are unpopular.

“It is even possible for a Prime Minister to survive in office if they are not competent.

“But no Prime Minister should believe they can act with impunity and remain in office when they have acted unlawfully in the manner and in the circumstances set out so clearly by the Supreme Court today.”

Ms Sturgeon continued: “The view that he should resign today is not just about politics – it should be the conclusion of anyone who believes parliamentary democracy, accountability and the rule of law matter.”

A No 10 source insisted Mr Johnson will not resign following the damning Supreme Court judgment, which saw all 11 justices agree unanimously that the five-week prorogation was “void and of no effect”.

The First Minister told MSPs the chaos and unprecedented events of the last three years should not “diminish or obscure the gravity of what the court has decided”.

She said: “For the sake of democracy, we must not allow the abnormal and the unacceptable to become normal and acceptable.”

She called on the UK Government to make clear it will adhere to legislation aimed at preventing a no-deal Brexit on October 31, which was passed by MPs earlier this month.

Earlier, she posted a picture on social media of her Cabinet gathered in front of a television in Bute House, her official residence in Edinburgh, to watch the Supreme Court ruling.

Elsewhere, Scottish Tory acting leader Jackson Carlaw said the judgment was “as profound as any made by any court in my political lifetime”.

He said: “The judgment of the courts must be respected by Government, all the more so when it may not like the result.”

Mr Carlaw, who is standing in as leader following the resignation of Ruth Davidson, urged MPs to work to get a deal with the EU.

Scottish Greens co-leader Patrick Harvie insisted the whole of the UK Government must be held responsible.

Scottish Liberal Democrat leader Willie Rennie said: “The Prime Minister should resign. He is not a fit and proper person.”