We have witnessed some astonishing developments in the three years since the Brexit referendum in June 2016. The previous Prime Minister resigned after losing three House of Commons votes on her Brexit deal, one of which was lost by a record margin. The work of the Westminster Parliament has ground to a halt. It is important to note that that has had significant implications for this Parliament in areas—such as social security and no-deal preparations—in which we require co-operation to deliver our own commitments.

In recent weeks, the United Kingdom Government has also lost control of the House of Commons and now, even with the support of the Democratic Unionist Party, it has no workable majority. The Prime Minister has yet to win a single vote in the Commons since he took office.

All of that is extraordinary and unprecedented, but none of those extraordinary events compares with what has happened today. Today’s judgment of the Supreme Court may be about the prorogation of another Parliament, but the circumstances giving rise to it, and the implications of it, are of enormous significance to this Parliament and the people of Scotland. Indeed, that is why the Lord Advocate intervened in this case, on behalf of the Scottish Government.

Let me turn to the terms of the judgment. The UK Supreme Court has this morning upheld the judgment of the inner house of the Court of Session. It has ruled—and has done so unanimously—that the British Prime Minister acted unlawfully by suspending the UK Parliament. The president of the court, Lady Hale, said:

“the effect upon the fundamentals of our democracy was extreme”.

We should not allow the chaos and unprecedented events of the past three years to diminish or obscure the gravity of what the court has decided today. For the sake of democracy, we must not allow the abnormal and unacceptable to become normal and acceptable. It is truly historic and unprecedented in our modern democracy that a Prime Minister has been held to have broken the law in order to frustrate or prevent

“the ability of parliament to carry out its constitutional functions”.

It is hard to think of another democratic country in which there has been a more damning verdict on the behaviour of a Prime Minister. The judgment could not be starker. The Supreme Court said:

“It is impossible ... to conclude ... that there was any reason—let alone a good reason—to advise Her Majesty to prorogue Parliament for five weeks”.

This is not a technical or narrow defeat for the UK Government. It is not just about, for example, the detail of an act of Parliament. It is a defeat on justiciability, on lawfulness and on remedy, and it is in terms that call into question the UK Government’s commitment to basic democratic values and the rule of law.

Let us be clear: a Prime Minister with no electoral mandate and no parliamentary majority tried to shut down Parliament. He tried to prevent the UK Parliament from holding the UK Government to account, from exercising its democratic functions, from challenging the Government, from scrutinising its actions, from holding committee meetings, and from questioning him and other ministers. In other words, he sought to prevent Parliament doing all the things that give meaning and life to the term “parliamentary democracy”.

The Supreme Court mentioned the vital role that such scrutiny has in our system of government. The judgment even noted that, in the advice that was sent to the Prime Minister, the importance of

“consultation with the Scottish Parliament and the Welsh Assembly” was not mentioned anywhere.

The statutory instruments that are required to prepare the statute book for European Union exit, which this Parliament has to consent to under a protocol that is otherwise honoured by the UK Government, were made instead under an emergency procedure, without the consent of the Scottish ministers or the scrutiny of this Parliament.

“This was not a normal prorogation”,

the Supreme Court ruled.

“It prevented Parliament from carrying out its constitutional role for five out of a possible eight weeks between the end of the summer recess and exit day.”

That is scrutiny that cannot be got back.

The Supreme Court observed that

“Nowhere” in the evidence

“is there a hint that the Prime Minister, in giving advice to Her Majesty, is more than simply the leader of the Government seeking to promote its own policies.”

Nowhere is there a hint that he has “a constitutional responsibility”.

That behaviour on the part of a Prime Minister shames his office, shames the UK Government, shames the Conservative Party and demonstrates beyond doubt that Westminster politics is badly broken.

We should pay tribute to the campaigners in England and in Scotland—led, of course, by Joanna Cherry MP—who brought the court actions. Let me do so now on behalf of the Scottish Government. Indeed, it speaks volumes that, in his initial reaction to the ruling, the Prime Minister accused those who brought the actions to have the prorogation declared unlawful of trying to “frustrate” Brexit. Not only is that argument wrong, it is also a remarkable argument from a Prime Minister who also claims that the prorogation had nothing whatsoever to do with Brexit.

Now, of course, we must look forward. In my view, four things should happen. First, there must be a clear recognition that the person who is responsible for this fiasco is the Prime Minister. 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—it is Boris Johnson who must now resign. 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. However, no Prime Minister should believe that they can act with impunity and remain in office when they have acted unlawfully in the manner and the circumstances that were set out so clearly by the Supreme Court today.

Before he became Prime Minister, many of us said that Boris Johnson was not fit to hold office. Many argued that his past comments should have ruled him out of running even to be leader of the Conservative Party. Those are—of course—political views, and they will be contested. However, the view that he should resign today is not just about politics; it should be the conclusion of anyone who believes that parliamentary democracy, accountability and the rule of law matter.

Secondly, the court has ruled today that the UK Parliament is not legally prorogued. It must, therefore, return to business as soon as possible. To that end, I welcome the statement from the Speaker of the House of Commons a short while ago that it will do so tomorrow. Never in recent times has it been more important for all of us that the UK Government is held to account, and it is right that that work will restart immediately.

Thirdly, the UK Government must make it absolutely clear that it will respect and adhere to the Benn act—the European Union (Withdrawal) (No 2) Act 2019—which is designed to prevent a disastrous no-deal crash out of the European Union. There have been alarming whispers that the Tories are looking for technical loopholes or are prepared simply to ignore the law and press ahead with their no-deal plans.

After today, we need a clear and unambiguous statement that the law will be respected, and that the UK Government will ask for an extension to prevent a catastrophic no-deal Brexit on 31 October. Ultimately, this is—of course—about the fundamentals of our democratic system. However, it is also—never let us forget—about people’s jobs and living standards, the health and wellbeing of our communities and our place in the world. It is about maintaining the hard-won and precious peace in Northern Ireland, and it is about respecting the wishes of the people of Scotland and the views of this Parliament. It is also about avoiding the disruption that we know will take place, and that the UK Government knows will take place, in both the short and long term, if any Brexit—but especially a no-deal Brexit—is allowed to happen.

Fourthly, in my view, this UK Government should be removed from office as soon as possible. There is, in truth, no functioning UK Government right now, and, as of today, we know beyond doubt that, to the extent that it is functioning at all, it is a Government that is prepared to ride roughshod over democracy and the law. It is impossible to have confidence in this Prime Minister or the Government that he leads. Therefore, as soon as the risk of it being used to force through a no-deal Brexit on 31 October has been removed, there must be a general election.

This is an important time to take action but also to reflect. Our Scottish Parliament has been reconvened for 20 years. Its reconvening was a vital step in restoring Scotland’s political voice. Today in this chamber, we need to make it clear that all of us, regardless of party, stand up for democratic values, that we condemn a Prime Minister who was prepared to act unlawfully to shut down Parliament and that we will continue to do everything that we can, as a Parliament, to make Scotland’s voice heard and to protect our citizens from the damage of Brexit.

We should also resolve not to allow our Parliament or the people of Scotland to remain at the whim of an extreme, out-of-touch, law-breaking UK Government. We should instead resolve that the better—the best—foundation on which to build the future of our country is as an independent member of the European family of nations.