Prorogation of Parliament ruled to be unlawful

  • Insight

24 September 2019

The UK Supreme Court delivered its judgment today in respect of two appeals, one from the Inner House of the Court of Session of Scotland by the Advocate General for Scotland and the other from the High Court for England and Wales by Gina Miller, on the question of whether the recent prorogation of Parliament by the Prime Minister was lawful or unlawful. The eleven Supreme Court judges, the maximum number of judges that can hear a case in the Supreme Court, decided unanimously that the prorogation was a justiciable issue, i.e. one that the Courts can consider, and that it was in fact unlawful. In delivering the Court’s judgment, Lady Hale (President of the Court) emphasised that the circumstances surrounding the appeals were a “one-off” and that the Court was not being asked to consider when, and on what terms, the UK would leave the European Union.


On 15 August 2019, the Prime Minister’s Director of Legislative Affairs, Nikki da Costa, sent a memo to Prime Minister Boris Johnson and seven other civil servants and special advisers, recommending that the Queen be asked to approve an Order in Council to prorogue Parliament for a period of around 5 weeks starting from between 9 to 12 September 2019 with a Queen’s Speech to Parliament announcing the UK Government’s forthcoming programme to take place on 14 October 2019. The Prime Minister responded to that memo with a ‘tick’. Following a telephone call from the PM to the Queen, various Government ministers attended a meeting of the Privy Council with the Queen at Balmoral Castle at the end of August and an Order in Council was made to prorogue Parliament from those dates.

The decision to prorogue Parliament was made using prerogative powers, which are powers that lie with the Government (the Executive) rather than with Parliament (the Legislature). There is no one definition of prerogative powers, but they have been described as the residual powers of the Crown’s original authority under the UK’s constitution, which can be exercised by the monarch or by Ministers of the Crown. In the recent 2017 case of R (Miller) v Secretary of State for Exiting the European Union, the UK Supreme Court described prerogative powers as encompassing the “residue of powers which remain vested in the Crown, and they are exercisable by ministers, provided that the exercise is consistent with Parliamentary legislation”.

The appeal by the Advocate General for Scotland to the UK Supreme Court was against the Court of Session’s decision in Cherry and others v Advocate General for Scotland [2019] CSIH 49 that the prorogation was justiciable and that it had been motivated by the improper purpose of stymying parliamentary scrutiny of the Executive, and that it and the prorogation which followed it were unlawful and thus null and of no effect. The appeal to the UK Supreme Court by Gina Miller was against the High Court’s judgment in R on the application of Miller v the Prime Minister [2019] EWHC 2381 (QB) that the prorogation was not justiciable, i.e. could not be considered by a court of law.

At its hearings on the two appeals, which took place on 17, 18 and 19 September 2019, the UK Supreme Court heard a range of evidence from parties and considered that it was being asked to answer three questions, namely whether:

  • the lawfulness of the PM’s advice to the Queen in respect of the prorogation was justiciable;
  • there are limits to the prerogative power to prorogue Parliament; and
  • the prorogation in question had the effect of frustrating or preventing the ability of Parliament to carry out its constitutional functions without reasonable justification.

The Court answered each of these questions in the affirmative

In response to the first question, the Court noted that the courts have exercised a supervisory jurisdiction in relation to acts of the Government over many years and it had no doubt that it had jurisdiction to consider the existence and limits of the prerogative power to prorogue Parliament.

In response to the second question, the Court referred to two fundamental principles of the UK’s constitution – those of parliamentary sovereignty and parliamentary accountability. In terms of parliamentary sovereignty, they considered that the power of the UK Parliament to make laws that must be obeyed and would be undermined if the Government could prevent Parliament from exercising this power by proroguing it for as long as it chose to do so. In terms of parliamentary accountability, the Court considered that the accountability of the Prime Minister and Cabinet to Parliament lies at the heart of “Westminster democracy”. Thus, the prerogative power to prorogue Parliament is limited in its extent by these constitutional principles. A decision to prorogue Parliament, or to advise the Queen to prorogue, if it is taken without reasonable justification and has the effect of frustrating or preventing the ability of Parliament to legislate and to hold the Government to account, is unlawful.

The final question considered was whether this prorogation had the effect of frustrating or preventing the ability of Parliament to carry out its constitutional functions without reasonable justification. The Court noted that this was not a prorogation in the usual circumstances of the period running up to a Queen’s Speech in Parliament. The Court considered that the effect of the prorogation was in fact to prevent Parliament from performing its constitutional role for five weeks out of the eight week period between the end of Parliament’s summer recess and Brexit day on 31 October. In reaching its view, the Court indicated that it was not necessary to consider whether the Prime Minister’s motive or purpose was unlawful.

The key differences between proroguing Parliament and ‘in-recess’

Addressing the UK Government’s suggestion that the prorogation was not for very long, over and above the usual period of a party conference recess, the Court pointed to key differences between what happens (or rather doesn’t happen) when Parliament is prorogued and what can and does happen when Parliament is simply in recess:

"While Parliament is prorogued, neither House can meet, debate or pass legislation. Neither House can debate Government policy. Nor may members ask written or oral questions of Ministers or meet and take evidence in committees. In general, Bills which have not yet completed all their stages are lost and will have to start again from scratch after the Queen’s Speech. During a recess, on the other hand, the House does not sit but Parliamentary business can otherwise continue as usual."


The Court considered that such a prolonged and complete suspension of parliamentary democracy in light of the approaching date for Brexit represented exceptional circumstances: i.e. a fundamental change in the UK’s constitution. In the Court’s opinion: “Parliament, and in particular the House of Commons as the elected representatives of the people, has a right to a voice in how that change comes about. The effect upon the fundamentals of our democracy was extreme.”

The Court held that no reasonable justification for taking action with such an extreme effect had been presented to the Court by the UK Government and that Nikki da Costa’s memo of 15 August did not explain why it was necessary to stop parliamentary business altogether for 5 weeks, when the usual period to prepare for a Queen’s Speech was between 4 to 6 days.

The Court ruled that the Prime Minister’s advice to the Queen to prorogue Parliament “was unlawful because it had the effect of frustrating or preventing the ability of Parliament to carry out its constitutional functions without reasonable justification.”

Prorogation of no effect

In addition to the Prime Minister’s advice to the Queen being unlawful, void and of no effect, the Court also decided that the Order in Council following that advice was unlawful, void and of no effect and should be quashed. The Court considered that the prorogation was not a “proceeding in Parliament” and so not beyond the scope of the Court’s jurisdiction. Whilst the prorogation might take place in Parliament in the presence of Members of both Houses of Parliament, it is not a decision of those members; rather, it is something imposed upon them by the UK Government. For that reason, the Court agreed in its own judgment with the opinion of the three judges who previously heard the Cherry case in the Inner House of the Court of Session, the prorogation was void and of no effect – leading to their conclusion that Parliament had not in fact been prorogued at all.

What next?

In terms of what follows next, it has been confirmed that Parliament will sit again on 25 September 2019, which will mean further scrutiny of the UK Government’s actions, the possibility of further legislation being introduced and also the possibility of an early election under the provisions contained in the Fixed Term Parliaments Act 2011, depending on what MPs decide to do and how the UK Government responds. The UK Government has indicated through its legal representatives that it will abide by the Supreme Court’s ruling. As the current law stands, if a Brexit deal cannot be agreed between the UK and EU by 19 October 2019, and if MPs don't vote in favour of leaving with no deal, the Prime Minister will be legally obliged to ask the EU for a Brexit delay. Whether he does so remains to be seen and failure to do so would inevitably result in another legal challenge. There is no guarantee that the EU would agree to such a request in any event. The PM will be considering his options at this time.

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