Law | Europe | Sarah Zingel

Unlawful Prorogation: The Supreme Court v PM Boris Johnson

In this article, our new author Sarah Zingel casts an eye on the British Supreme Court's judgement on PM Johnson's failed attempt to suspend Parliament by proroguing it.

When her Majesty the Queen decided on Prime Minster Boris Johnson’s advice to prorogue Parliament for five weeks from 10th September until 14th October 2019, parliamentarians invoked the High Court of England and Wales as well as the Court of Session in Scotland to decide upon the constitutionality of that issue.[1] Whereas the High Court of England and Wales decided that the advice was not justiciable,[2] the Court of Session in Scotland ruled that de facto it was not only well able being tried in court, but more importantly, also unlawful.[3] The defeated party in each of both litigations appealed against the respective verdict. After three hearings, on 24th September 2019 the Supreme Court thereupon ruled that the advice and all the legal consequences based upon it were unlawful – hence it came to the same conclusions as the Court of Session in Scotland. In its ruling the Supreme Court found, that it was illegal to suspend Parliament´s work bearing in mind the Brexit deadline on 31st October.[4] Already on Wednesday, one day after the unanimous judgement, Parliament reconvened, but the Prime Minster intends to prorogue parliament once more – although this time for a shorter period.

The following article aims at providing the reader with a thorough understanding of prorogation as a political instrument and analyses the Supreme Court’s judgement, its legal foundations and its political consequences. 

What “proroguing” actually means:

Proroguing Parliament is no unusual event, but happens regularly. In 2016 for example, it was prorogued for four working days, whereas in 2014 it was 13 days.[5] Whenever a Queen’s Speech is in progress and a new parliamentary year is about to start, Parliament is shut down for a short period. The reason for proroguing is guaranteeing that democracy prevails and that election campaigns as well as the Queen’s Speech can be properly prepared. The Queen’s Speech is eventually delivered as a government’s agenda in order to present a number of laws, that the government appreciates being approved by parliament during their next parliamentary year. The power to prorogue parliament resides with the Queen but only on formal advice of the prime minister; an advice which she actually can´t ignore, as she is traditionally supposed to act according to the prime minister’s advice.[6] After the Queen’s Speech, Parliament reopens business.

Thus, proroguing parliament as such is no extraordinary matter. However, what is special about this particular prorogation was its supposed duration and its timing.[7] Suspending parliament’s work for about 25 working days right before the Brexit deadline on 31st October was criticized as being a political decision made by government in order to hinder parliament from debating Brexit and passing laws relating thereto. The reasoning and true motives of Prime Minister Johnson have been questioned. Instead of aiming at a Queen’s Speech being prepared, the Prime Minister and government might have had superior motives.[8]

The Supreme Court, too, thought so and came to the conclusion that prorogation was misused.

Legal aspects of the judgement:

In order to understand the reasoning behind the latest judgement of the Supreme Court, one has to understand the role and function of Parliament. The function of the Parliament of the United Kingdom of Great Britain and Northern Ireland (shortly the Parliament) is laid down by constitution. This is the sum of various written and unwritten Acts and principals based upon case law, tradition and practice. Parliament as constituted by constitution is the supreme legislative body.[9] Thus, it is responsible for passing laws throughout Acts – a sovereign capacity that can only be exercised, when Parliament meets, argues the Supreme Court. The controversial prorogation violates this constitutional principal as it prevents Parliament from gathering. In particular, the Supreme Court holds the following legal reasoning:[10]

1) First of all, the Supreme Court concludes that the courts have jurisdiction to decide upon prorogation. This conclusion is fundamental for the Supreme Court being allowed and able to decide upon the lawfulness of the Prime Minister’s advice.

Legal argument: Although prorogation might be a political tool exercised by government, respecting the separation of powers does not necessarily prevent jurisdiction from controlling the executive power. That is to say, courts are constitutionally responsible for giving effect to the law and therefore must be allowed to also consider legal disputes that contain political controversies. Government might be already accountable to Parliament, but legal accountability to the courts is thereby not restricted. By supervising the legal use of the power of prorogation, the courts ensure separation of powers, as otherwise Parliament could be unlawfully prevented from its constitutional role. Thus, the Prime Minister’s advice is justiciable.

2) Secondly, the Supreme Court establishes the standards by which the lawfulness of the Prime Minister’s advice is to be judged. The standards are sovereignty of Parliament and accountability of Ministers to the Parliament.

Legal argument: As already mentioned before, legal principals of the constitution are not entirely defined by written documents but are confined by common law; including the prerogative power. Thus, the standards by which its lawfulness is measured are to be found within the constitutional principals in common law regarding Parliament. As legislative authority, Parliament’s sovereignty has to be granted, but if the power of prorogation had no limit, Parliament’s sovereignty would be endangered. In addition, the constitutional principle of Minister’s accountability to Parliament plays an important role, e. g. the right of Parliamentarians to ask questions to Ministers. Lawful prorogation has to take into account and respect all those constitutional characteristics of Parliament. In case prorogation potentially frustrates Parliament’s supervisory and legislative functions, it is unlawful.  

3) Thirdly, the Supreme Court applies those stipulated standards to the controversial prorogation. It concludes, that this particular prorogation was no normal one as it prevented Parliament from fulfilling its constitutional function under the given circumstances. There was no justification for such a long-lasting prorogation.

Legal argument: Especially right before such an important event like the Brexit deadline on 31st October the only representative and democratic body of the United Kingdom has not only the obligation, but also the right to participate in the decision-making process. Suspending Parliament’s work for 25 working days presents an extreme effect upon the parliamentarian’s right to sit and debate – above all when circumstances are so exceptional. Parliament had for example shown disagreement regarding the Prime Minister’s approach to Brexit viz. leaving the European Union without an agreement. As a result, Parliament’s participation in the whole withdrawing process becomes even more important and necessary in terms of democracy. Therefore, prorogation could only be justified if there was a weighty reason. The alleged reason drawn from the provided evidence was the need for a Queen’s Speech. However, there was no explanation brought forward by government, that could justify a prorogation period of 25 working days, since a Queen’s Speech can be prepared within only a few days. To sum up, the controversial prorogation was unlawful as it conflicted with constitutional principles and as there was no reasonable justification that would still vindicate such advice or prorogation. Nevertheless, it is important to notice that the Supreme Court did not speculate about Prime Minister Johnson's intention regarding the concrete length and timing of prorogation. Deliberately the court sticked to the legal questions and facts that were brought to trial. 

4) Fourthly, the Supreme Court declares that not only the advice was unlawful, but that the prorogation itself has never taken place.

Legal argument: The controversial prorogation was based upon an Order in Council which for its part was based upon the advice. Hence, if the advice was unlawful, both the Order in Council and the prorogation were it too and were therefor of no effect. Ultimately, parliament has never been prorogued.

Political Consequences:

On the one hand, parliamentary session was already resumed on 25th September 2019.[11] On the other hand, Prime Minister Boris Johnson precludes to resign and announced that he will comply with the judgement although he deeply disagrees with its tenor. He still is eager to enforce Brexit by 31st October and considers asking the Queen once more to prorogue Parliament – though in this occasion for fewer days.[12]

Already in his first official speech after becoming Prime Minister, he pointed out, that the United Kingdom would leave the European Union on 31st October no matter whether there is deal or not. Certainly, Parliament impedes this goal. For instance, even before the failed Prorogation Parliament passed a Law issued on 4th September[13] that prevents the Prime Minister from enforcing a no deal Brexit. The Act obliges him to ask the European Union for another suspension of Brexit if a deal cannot be reached till the beforementioned deadline. One still has to wait and see, whether Prime Minister Johnson is going to outcast or adhere to the act. In order to prepare a Queen’s Speech (and perhaps in order to challenge the judgement as well as the parliamentarians), the Prime Minister might also forward another advice to prorogation. In any case further legal disputes are highly probable.  

[1] See

[2] See Gina Miller -v- The Prime Minister & Others; [2019] EWHC 2381 (QB)

[3] See Joanna Cherry and others -v- The Advocate General; [2019] CSIH 49 P680/19

[4] See R (on the application of Miller) (Appellant) -v- The Prime Minister (Respondent) Cherry and others (Respondents) -v- Advocate General for Scotland (Appellant) (Scotland); [2019] UKSC 41

[5] See

[6] See House of Commons Library Briefing Paper (No 8589, 11th June 2019)

[7] See

[8] See

[9] See

[10] See R (on the application of Miller) (Appellant) -v- The Prime Minister (Respondent) Cherry and others (Respondents) -v- Advocate General for Scotland (Appellant) (Scotland); [2019] UKSC 41

[11] See

[12] See

[13] European Union (Withdrawal) (No 2) Act 2019


Sarah Zingel

Sarah Zingel holds a Bachelor's degree in European Legal Linguistics with a focus on International and European Law from the University of Cologne. After subsequently completing her law studies, she is currently about to pass her first Legal State Examination with utmost success, specializing in criminal law and criminology. Besides her studies, she works as a research associate at a renowned Cologne law firm, primarily dealing with data protection, contract and company law. From February 2020 onwards, she will pursue a two LLM degrees in Criminology and Corporate and Commercial Law at Maastricht University.