The Supreme Court has ruled that it was unlawful for the prime minister to advise the Queen to prorogue Parliament. All 11 judges who heard the case reached a single, unanimous decision: in the eyes of the law, the prorogation never happened. MPs now return to Westminster.
It is an extraordinary decision, with far-reaching implications for the UK system of government and the balance of power between its three branches: executive, legislature and judiciary.
The court had two questions to decide. First, the judges had to determine whether the prorogation was justiciable: was it the role of the court to rule on whether the prime minister’s decision was lawful?
The Supreme Court decided it was. It is a question of law, the Supreme Court said, where the limits of the power to prorogue lie. If the power had no legal limits at all, then the prime minister would be able to suspend Parliament for as long as he pleased – and that, said the court, would be inconsistent with parliamentary sovereignty.
Second, the court had to decide whether this particular prorogation was lawful. The court did not take a view on Boris Johnson’s motive for prorogation; instead it focussed on the prorogation’s effect.
Because this prorogation was so long, and took place in the immediate run-up to the date on which the UK is scheduled to leave the EU, the court decided that prorogation had 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.” The prorogation could not be justified by the prime minister’s desire to bring forward a new legislative agenda in a Queen’s Speech, the court said, because he could have achieved that with a much shorter prorogation.
The first rule of the constitution is that Parliament is sovereign: Parliament alone makes laws, and the rest of us must follow them.
However, the Supreme Court’s account of Parliament’s constitutional role goes much further than that, and goes much further than previous judgments.
It said that a second constitutional principle – ministerial accountability to Parliament – is just as fundamental to our constitution. Ministers answer parliamentary questions, appear before committees, and submit secondary legislation to scrutiny by parliamentarians. All of that protects citizens from the arbitrary exercise of executive power.
That Parliament performs those roles might, before this judgment, have been thought a statement of convention or common practice. It is now clear that Parliament’s role in holding the government to account is part of our constitutional law – and if the government threatens that accountability, then the courts will move to protect it. In the long term, this may be the judgment’s biggest contribution to our understanding of the UK constitution: the court has fortified executive accountability to Parliament with the force of law.
Because Parliament is sovereign in the UK, and the UK has no codified constitution, the Supreme Court does not perform the most politically sensitive role of many other supreme courts around the world: to rule that laws passed by the legislature are “unconstitutional”.
Nevertheless, the Supreme Court has approached this case armed with the toolkit of a constitutional court. The judges appealed to first principles as much as statutes or judicial precedents in order to reach their decision.
The court said that the prime minister’s decision had “an extreme effect upon the fundamentals of our democracy”. It explained the importance of Parliament’s scrutiny functions by noting that the support of MPs is the government’s sole source of “democratic legitimacy”. It noted the risk that, in a long prorogation, “responsible government” would be “replaced by unaccountable government”, which it described as “the antithesis of the democratic model”.
The court did not have to approach the case in this way. It could have focussed more narrowly on precedent and legal doctrine. The judges’ language and reasoning – as well as their ultimate conclusion – shows that the Supreme Court now sees itself as more than a court of last resort whose job is to resolve the hardest legal quandaries.
It considers itself a guardian of democracy in the UK, policing the boundaries of constitutionally proper behaviour. Any ministers tempted to defy constitutional norms or conventions should beware: the Supreme Court has put them on notice.