Supreme Court’s case Cherry/Miller: What’s Next?

27 Sep 2019

Public Law and Judicial Review

By Sam Fowles

Sam was part of the legal team who represented Joanna Cherry QC MP and other MPs in Cherry/Miller v Prime Minister. This article was originally published in the UK Constitutional Law Association blog.

Yesterday the Supreme Court handed down its unanimous judgement in Cherry and Others v The Advocate General and Miller v the Prime Minister. The court found that the Prime Minister’s decision to prorogue parliament was unlawful and, consequently, null and void. This article aims to identify some of the immediate constitutional and political impacts of that decision.

The decision

Four key points underpin the court’s reasoning.

  • First, the matter of justiciability. All parties accepted that the court was entitled to determine the existence and extent of prerogative powers. The government parties, however, argued that, where the power was exercised within its lawful bounds, it was not justiciable. Cherry and Miller argued that, even within lawful bounds, the ordinary principles of judicial review applied. The question of justiciability formed the cornerstone of the government’s case. Ultimately, however, the court decided it on entirely uncontroversial terms. The court found that it was only necessary for it to determine the extent of the power to prorogue and whether the Prime Minister had strayed beyond this. It was not necessary for the court to determine the question of justiciability on ordinary judicial review principles.
  • Second, the court found that the extent of the prerogative power was defined by constitutional principle. In particular, parliamentary sovereignty (that parliament may make or unmake any law) and parliamentary accountability (that the government is accountable to parliament). The extent of the power therefore was that the Prime Minister was not entitled to use it to prevent parliament from performing its constitutional duty without a proper reason.
  • Third, any prorogation will interfere with parliament’s constitutional duty. As Sir James Eadie QC (for the Prime Minister) conceded in argument, the effect of prorogation is to prevent parliament from either legislating or holding the government to account. Ordinarily prorogation is for a limited period, uncontroversial, and necessary to end the parliamentary session. In the instant case, prorogation had the effect of preventing parliament from performing its constitutional role at a time when the UK was about to undergo a fundamental and irreversible constitutional change. The court found that the Prime Minister had raised no good reason for this interference and had, consequently, strayed beyond the bounds of the prorogation power.
  • Fourth, the effect of the court’s finding was that prorogation was void ab initio. This point split the Miller and Cherry claims. Lord Pannick QC (for Gina Miller) had argued that a mere declaration that prorogation was unlawful was sufficient. He declined to request a further remedy. Aidan O’Neil and the Cherry team, by contrast, argued (in written submissions) that the effect of a ruling that prorogation was unlawful is that that prorogation was void ab initio. The court preferred the latter interpretation.

Constitutional impact

The Cherry/Miller decision, while undoubtedly politically controversial, was not constitutionally radical. It strengthens and clarifies, rather than alters or develops, the constitution. The most constitutionally progressive part of the decision is that it required the court to grapple with the twin principles of parliamentary sovereignty and accountability in practice. As the court found, if there was no limit on the power to prorogue parliament, then the government would be able to free itself of accountability at will.

The essence of the decision, however, was rooted in the deep-seated principle of parliamentary sovereignty founded on the democratic mandate. This is a principle recognised from the time of Coke and Blackstone, in The Case of the Proclamations (1611) 12 Co Rep 74, through Jackson v Attorney General 1 AC 262, and the first Miller [2017] UKSC 5. In Cherry/Miller, the court clarified this principle and certainly took a robust approach to its defence. But clarifying and defending the keystone principle of the constitution can hardly be considered radical moves.

Perhaps the most significant aspect of the judgement in constitutional terms was the clarification of the principle of parliamentary accountability as a constitutional principle rather than a constitutional convention. In the first Miller case the court found that constitutional conventions are not enforceable in law. It is clear from the Cherry/Miller decision that a bright line must be drawn between constitutional conventions and constitutional principles. While the former are not justiciable, the latter are both justiciable and must form a core part of any court’s reasoning on constitutional questions. This may influence the framing of constitutional challenges in future.


The effect of prorogation is that bills which have not yet received Royal Assent are, in effect, discontinued. They must start from the beginning of the legislative process in the next session (even where they have already received a second reading or passed the committee or report stages). In the instant case, this meant that 12 bills were discontinued. These included the Domestic Abuse Bill and the Divorce, Dissolution, and Separation Bill (which would have provided for “no-fault” divorce).

The effect of the Supreme Court’s decision is that the prorogation in question never happened. The Prime Minister’s advice to the Queen was unlawful. This meant that the Order in Council which provided for prorogation was also unlawful. The Lords Commissioners, who carried out the prorogation ceremony in the House of Lords, did not, therefore, have any lawful authority to prorogue parliament. In Lady Hale’s words, it was “as if the Commissioners had walked into Parliament with a blank piece of paper”.

This means that, in law, parliament has not been prorogued. It follows that the inevitable impacts of prorogation have no effect. This includes the discontinuance of legislation under consideration. The bills in question are, therefore, still under consideration and can continue to progress through the legislative process as if prorogation had never happened.

It might be argued that the status of the live bills is a matter for parliament and thus falls under parliamentary privilege (as set out in Article IX of the Bill of Rights). The Supreme Court was clear, however, that Article IX does not provide a shield for the effects of prorogation. The wrongful act occurred outside parliament, the fact that its inevitable consequences reached into parliament does not save those consequences from the taint of unlawfulness. It may be that the Speaker rules that the relevant legislation must begin again in the new session, but this is a decision that the Speaker must take ab initio.

A second prorogation

It has been suggested that the government will seek to prorogue parliament again. This comes with a number of risks. In oral argument before the Supreme Court, Lord Keen QC and Sir James Eadie QC indicated that the government would not rule out using the Prorogation Act 1867 to prorogue parliament a second time. This option is now not available to the government. The 1867 Act applies only where parliament is currently prorogued. The effect of the Supreme Court’s decision is that parliament is not prorogued. The powers in the 1867 Act are consequently not available to the government in this instance.

The Supreme Court made clear that a short prorogation to facilitate a Queen’s Speech was unlikely to go beyond the extent of the prorogation power. The court also, however, highlighted the unique situation in which the UK currently finds itself. The “cliff-edge’ Brexit deadline of 31 October (and the fundamental and irreversible impacts that must follow) create a unique set of circumstances. It follows from the court’s reasoning that even a relatively short prorogation may be unlawful. If, for example, parliament was prorogued in advance of 31 October, with the effect of stymieing legislation relating to Brexit, then parliament will have been prevented from discharging its constitutional duty and the prorogation would, consequently, be unlawful unless properly justified.

This may be a moot point, however. A second prorogation may be timed in such a way that, by the time the courts have ruled on its legality, the 31 October deadline has expired. Any unlawful effect will consequently be achieved and the courts will be powerless to provide a meaningful remedy.

For this reason, the Supreme Court’s judgement may only be the first step in attempts to control the prorogation power. The newly returned parliament may choose to legislate to impose further controls or even assign the power to prorogue to itself. As the Supreme Court pointed out, it is easier to determine the limits of a power when that power is controlled by statute. The courts can apply the law, as clarified in Cherry/Miller but, ultimately, only parliament can provide clarity.