Null, & of no effect: R (on the application of Miller) (Appellant) v The Prime Minister (Respondent) and Cherry & Ors (Respondents) v Advocate General for Scotland (Appellant) (Scotland)

To adopt the description of my learned colleague in Chambers: “This is absolutely massive. Was justiciable and was unlawful. Prorogation was void and of no effect.”

Preliminary comments

The President of the Supreme Court and Lord Reed gave judgment of the Supreme Court, starting with four, preliminary comments, all worth quoting:

  1. “It is not suggested in these appeals that Her Majesty was other than obliged by constitutional convention to accept that advice. In the circumstances, we express no view on that matter. That situation does, however, place on the Prime Minister a constitutional responsibility, as the only person with power to do so, to have regard to all relevant interests, including the interests of Parliament.”
  2. “… although the courts cannot decide political questions, the fact that a legal dispute concerns the conduct of politicians, or arises from a matter of political controversy, has never been sufficient reason for the courts to refuse to consider it.”
  3. “… the Prime Minister is accountable to Parliament does not in itself justify the conclusion that the courts have no legitimate role to play.”
  4. “… by ensuring that the Government does not use the power of prorogation unlawfully with the effect of preventing Parliament from carrying out its proper functions, the court will be giving effect to the separation of powers.”

Four issues

There were four issues:

  1. Is the Prime Minister’s advice to the Queen justiciable?
  2. If it is, by what standard?
  3. Is it lawful?
  4. If not, what is the remedy?


The highest court in the land was unanimous:

“… we are firmly of the opinion that it is justiciable. … it is well established, and is accepted by counsel for the Prime Minister, that the courts can rule on the extent of prerogative powers.”

Like statutory power, “every prerogative power has its limits, and it is the function of the court to determine, when necessary, where they lie.”  The court held that political tone or context is not a good reason, by itself, for the court to “shirk that responsibility”.

Two fundamental principles of constitutional law underpin the court’s judgment.

Parliamentary sovereignty

First, “that laws enacted by the Crown in Parliament are the supreme form of law in our legal system, with which everyone, including the Government, must comply.”  This principle weighs in favour of justiciability:

“The sovereignty of Parliament would, however, be undermined as the foundational principle of our constitution if the executive could, through the use of the prerogative, prevent Parliament from exercising its legislative authority for as long as it pleased. That, however, would be the position if there was no legal limit upon the power to prorogue Parliament (subject to a few exceptional circumstances in which, under statute, Parliament can meet while it stands prorogued).”

Parliamentary accountability

Second: “Ministers are accountable to Parliament through such mechanisms as their duty to answer Parliamentary questions and to appear before Parliamentary committees, and through Parliamentary scrutiny of the delegated legislation which ministers make.”  Parliamentary accountability, too, weights in favour of justiciability:

“That principle is not placed in jeopardy if Parliament stands prorogued for the short period which is customary, and as we have explained, Parliament does not in any event expect to be in permanent session. But the longer that Parliament stands prorogued, the greater the risk that responsible government may be replaced by unaccountable government: the antithesis of the democratic model.”

Standard of lawfulness

The standard by which the lawfulness of the decision to prorogue is to be judged is as follows:

“… a decision to prorogue Parliament (or to advise the monarch to prorogue Parliament) will be unlawful if the prorogation has the effect of frustrating or preventing, without reasonable justification, the ability of Parliament to carry out its constitutional functions as a legislature and as the body responsible for the supervision of the executive. In such a situation, the court will intervene if the effect is sufficiently serious to justify such an exceptional course.”


This is a two-stage test.  First, whether Parliament’s ability to perform is frustrated.  Second, “whether there is a reasonable justification for taking action which has such an extreme effect upon the fundamentals of our democracy.”


Prorogation frustrated, and prevented Parliament’s ability to perform its legislative functions, and its supervision of the executive:

“This was not a normal prorogation in the run-up to a Queen’s Speech. 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 [from the European Union] on the 31st October.”

Ordinarily, “this might not matter”.  These are “exceptional” circumstances, however:

“A fundamental change was due to take place in the Constitution of the United Kingdom on 31st October 2019. Whether or not this is a good thing is not for this or any other court to judge. The people have decided that. But that Parliament, and in particular the House of Commons as the democratically elected representatives of the people, has a right to have a voice in how that change comes about is indisputable. And the House of Commons has already demonstrated, by its motions against leaving without an agreement and by the European Union (Withdrawal) (No 2) Act 2019, that it does not support the Prime Minister on the critical issue for his Government at this time and that it is especially important that he be ready to face the House of Commons.”

No reasonable justification

The court was “not concerned” with the Prime Minister’s “motive”, but rather, whether there was “a good reason” to do as he did.  No reason was given.  What, then, was the need for a five-week prorogation?  Accordingly, the Supreme Court gave judgment that:

“It is impossible for us to conclude, on the evidence which has been put before us, that there was any reason – let alone a good reason – to advise Her Majesty to prorogue Parliament for five weeks, from 9th or 12th September until 14th October. We cannot speculate, in the absence of further evidence, upon what such reasons might have been. It follows that the decision was unlawful.”


The court can declare that the advice given to the Queen was unlawful.  “This means that it was null and of no effect.”  The court is not precluded, however, from considering the validity of the prorogation itself.  Accordingly, the court found that:

“… Parliament has not been prorogued and that this court should make declarations to that effect. We have been told by counsel for the Prime Minister that he will ‘take all necessary steps to comply with the terms of any declaration made by the court’ and we expect him to do so. However, it appears to us that, as Parliament is not prorogued, it is for Parliament to decide what to do next.”


The Advocate General’s appeal from the Inner House of the Court of Session was dismissed.  Mrs Miller’s appeal from High Court of England and Wales – which bypassed the Court of Appeal of England and Wales by virtue of a “leap-frog” certificate – was allowed.  This judgment will have ramifications for the principles of parliamentary sovereignty, parliamentary accountability, and representative democracy for years, decades, and perhaps even centuries to come.


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