What were the constitutional implications of the historic judgment given last month by the Supreme Court in relation to the Government’s purported prorogation of Parliament for 5 weeks? A full panel of eleven Supreme Court justices ruled unanimously that the prorogation was unlawful, void and of no effect. Parliament reconvened the following day. Any bills brought to an end by the prorogation (including important Brexit-related legislation) were reinstated, only to fall again in a second prorogation last week in the run-up to the Queen’s Speech. Given that legislation is needed to implement an orderly Brexit (with or without a deal), what impact has prorogation had on the legislative process?

A recap on the Supreme Court judgment

The Supreme Court had to consider two key questions: (i) whether the lawfulness of the advice to prorogue was a matter for the courts to decide (i.e., “justiciable”); and (ii) whether it was lawful i.e. what limits existed on the power to prorogue?


Not all prerogative powers will be amenable to judicial review, but the Court found that here, the issue was whether the legal limits of the power to prorogue Parliament had been exceeded, which was a question of law for it to determine. It was therefore, by definition, justiciable.


The Court found that the power to prorogue is limited by the two constitutional principles of Parliamentary sovereignty and accountability, with which it would otherwise conflict. So, if the prorogation has the effect of frustrating or preventing, without reasonable justification, Parliament's ability to carry out its constitutional functions as a law maker and the body responsible for supervising government, it will be unlawful.

Applying those principles, the Court could not discern "any reason – let alone a good reason" put forward by the Government for the decision to prorogue for a prolonged period of five weeks which it described as "not a normal prorogation in the run-up to a Queen’s speech". Notably, the Court only considered the effect of the prorogation, and not the Prime Minister's motive or purpose in seeking it.

A constitutional coup?

Some have argued that the Supreme Court overreached its remit and strayed into political matters in reaching this decision. However, the Court applied well-established constitutional principles and was careful to stress that the case was not about Brexit but instead revolved around a question of law concerning the extent of the Government’s legal powers, entirely appropriate for adjudication by the Court. The controversy surrounding the outcome is the result of the febrile political circumstances in which the case arose, which, as noted by the court, "have never arisen before and are unlikely ever to arise again", rather than of any radical action on the part of the judiciary.

A written constitution?

There have been many calls for a written constitution since this judgment was delivered, from both sides of the Brexit debate, but this decisive and unanimous decision demonstrates the existence of clear constitutional principles (not currently enshrined in a written constitution) which enabled the Court to uphold the rule of law.

Will further prorogations be permitted?

Short prorogations between Parliamentary sessions are regarded as standard business and would generally go unchallenged (as did the latest prorogation of Parliament from 8 October until the new Parliamentary session commenced on 14 October with the Queen’s Speech).

By contrast, in this case, the Supreme Court was in no doubt as to the applicability of the legal principles underpinning its decision, and as noted above, commented that the situation would be “unlikely ever to arise again”, possibly a warning that the Government would be unwise to attempt another extended prorogation. This decision makes it much more difficult for the Leavers in the Government, without Parliamentary arithmetic in their favour, to advocate prorogation as a means of circumventing Parliament’s ability to call a vote of no confidence or pass further legislation to prevent or delay Brexit (whether on a no-deal basis or otherwise) or force the Government’s hand in some other way.

Prorogation, the Queen’s Speech and the fate of Brexit-related legislation

There is still a significant amount of Brexit-related legislation awaiting approval to enable an orderly Brexit to happen, and very little time for such legislation to be submitted for Parliamentary scrutiny before the Brexit deadline of 31 October. Some significant Brexit-related bills, having been resurrected by the Supreme Court decision and the resumption of Parliamentary business, then fell in last week’s prorogation. The Queen’s Speech referred to some of these (announcing bills on Immigration, Trade, Financial Services, Fisheries and Agriculture, among others) which have been revived by the start of a new Parliamentary session. If a Brexit deal is reached, the Government will also have to pass legislation to enact it, and an extension could yet be on the cards, if only to allow for the legislative process to be completed.

However, of the estimated 800-1000 items of Brexit-related secondary legislation required to facilitate Brexit, many are still outstanding, and seem destined to pass through Parliament with minimal scrutiny under the emergency powers taken by the Government in the EU Withdrawal Act.

In these extraordinary times, further court challenges in relation to the use and potential for abuse of Parliamentary procedures cannot be ruled out.