The Supreme Court is rebuilding our constitution

The Supreme Court’s unanimous decision today, that Boris Johnson’s decision to advise the Queen to prorogue parliament for five weeks was unlawful, would not have been predicted by most legal commentators a month ago (it certainly wasn’t by me). The general view was that even if a prorogation decision was justiciable (capable of being considered by a court at all) the courts would not wish to delve into the merits of what was a decision of high politics.

What changed? I think two things did. First, the duty of candour did its work. This duty is often not appreciated: it requires the government—when faced with the judicial review challenge—to put its cards on the table by explaining its reasoning candidly. That has two key aspects. Documents necessary to explain that reasoning must be produced. And the explanation of the reasoning which is usually (but not invariably) produced must be in the form of a witness statement and therefore must be true, on pain of contempt of court.

In the present case there was no witness statement. And the documents left a gaping hole: they simply failed to explain why, in order to obtain a Queen’s Speech in October, such a long period of prorogation was required. There was some public concern that there might be other documents, in the form of officials’ (and for these purposes government special advisers are officials) WhatsApp messages or private e-mails, that might have explained the true purpose (and if so, would have been disclosable). But in the end the gaping hole spoke for itself: there was simply no coherent reason, that the government was prepared to own up to, why the prorogation took the form that it did.

The second was the realisation that maintaining the orthodoxy that prorogation was not justiciable left a nuclear weapon in the hands of an executive to shut down parliament whenever it felt like it. In past eras, judges might not have been troubled by that: the informal conventions of political life (backed up by the fear that what you did to the opposition would in turn be done to you) would be enough to restrain any misuse of that power. But, as a Downing Street spokesman managed unsubtly to remind everyone by making it known that if this prorogation were struck down the prime minister might well prorogue again, these conventions (and that fear) are not what they were.

Those two factors opened the door for the Supreme Court to take a spectacular turn. Like all spectacular turns in case law, it was not unheralded. The Court has in a number of cases—including UNISON (on employment fees), Miller 1 (on triggering Article 50), and Evans (on ministers’ powers to refuse information requests even after losing in court)—articulated and based its judgments on fundamental constitutional principles taken rather more from the modern democratic and law-based reality of our constitutional arrangements, than from anxious examination of medieval cobwebs. This move was perhaps inspired by, and certainly symbolised by, the court’s move from the deteriorating false Gothic Gormenghast of the Palace of Westminster to a brand new and modern building of its own on the opposite side of Parliament Square.

So the Supreme Court started its thinking by asking itself what fundamental aspects of our constitution were at stake. And it drew the answer to that question (see in particular paragraph 55 of the ruling) from the realities of our democratic life, namely that that it depends on the principle that the government holds office by virtue of having the confidence of the Commons and, critically, on its accountability to parliament. Prorogation potentially threatens that, if misused: and since misuse undermines accountability to parliament, accountability to parliament could not be the cure for any misuse. And when it turned to the question of whether there had been misuse, the gaping hole in the government’s reasoning sank Johnson's ship, chased by the devastating criticism (paragraph 60) that nowhere in the documents recording his decision was there a hint that the prime minister had a constitutional responsibility—a savage criticism of a serving prime minister by a senior court that, as far as I can recall, is unprecedented.

Standing back from the immediate impact of all this, where are we? In a key paragraph (39) the Supreme Court explains that the fact that the UK constitution is unwritten doesn’t mean that it doesn’t have one. In particular, our constitution gives the courts the task of upholding its values and principles. But what are those values and principles? The Supreme Court has been busy finding them. But there must be a case for opening up that discussion: should our constitution’s values and principles be left for wise judges to discern among the ill-sorted heap of material left to us by our ancestors, or should they be set out in a document of which we all, as citizens, can be said to be authors?