The unwritten nature of the British Constitution creates a tension between the Crown, the Executive and Parliament. That tension is informed by convention and moderated by law which is why last Thursday’s judgement of the High Court is so important.
There was only one question before the Court; can the Executive use the Crown’s prerogative powers to give notice of the UK’s withdrawal from the EU? The issue is one of process.
In essence there were three principles in play before the court. The sovereignty of Parliament, the Crown’s prerogative powers generally and the Crown’s prerogative to make and unmake treaties.
The Court’s judgement starts from the premise that the Crown in Parliament is sovereign. Legislation enacted by the Crown with the consent of Parliament is supreme. So supreme that Parliament can make, repeal or amend UK law in any way it chooses. It can even bind the Crown. There is nothing superior to primary legislation, except EU law to which Parliament gave precedence through the European Communities Act 1972 (Communities because we joined three separate institutions; the European Economic Community, the European Coal and Steel Community and the European Atomic Energy Community).
Parliamentary sovereignty sits alongside the historic residual authority of the Crown. But that authority is limited because the rule of law requires that the Crown (and through it the Executive) is subject to law. In reality the Crown’s prerogative powers are limited to those actually recognised by the common law when exercised within boundaries set by the common law.
The convention on international treaties is that in normal circumstances these are reserved to the Crown in the exercise of its historic residual authority. The exercise of this power is generally exempt from scrutiny by the Courts precisely because Parliamentary sovereignty prevents the Crown prerogative from changing domestic law. As the court put it:
“…By making and unmaking treaties the Crown creates legal effects on the plane of international law, but in doing so it does not and cannot change domestic law. It cannot without the intervention of Parliament confer rights on individuals or deprive individuals of rights.”
There’s the nub of the matter.
Rights and obligations were created on the international plane when we joined the European Communities but at the same time the 1972 Act enabled European law to become part of our domestic law. So the “people” assert that Brexit affects domestic law so Parliament’s supreme and there’s no room for the Crown prerogative. On the other hand, the Executive assert that prerogative was not excluded by the 1972 Act so Parliament must be taken to have recognised the Crown’s authority to give notice because it’s operating on the international plane.
The Court said the Executive “substantially undermined” its case by maintaining that it could use the Crown’s prerogative to effect changes in domestic law. The court went on to say that Parliament intended the 1972 Act to bring European law into UK law in such a way that this couldn’t be undone by such prerogative. The Crown has no power to withdraw from treaties which are the basis for rights held by British citizens and brought into domestic law by those treaties.
The discussion now moves to the Supreme Court. I expect it to develop the themes of what Parliament intended in 1972 and to pay even more attention to the relationship between the common law and Crown prerogative. I leave you with the thought that once upon a time this was one of the causes of a civil war…