Brexit just got more complicated. In a landmark ruling, the High Court ruled that the Secretary of State for Exiting the European Union can’t use the royal prerogative to activate Article 50.
The European Communities Act 1972 is at the heart of the court’s decision. This Act incorporated the law of the European Communities (the precursors of the European Union) into Britain’s domestic law. This is significant because, once Article 50 is invoked, the British people will inevitably lose rights that are part of British law because of the 1972 Act. It has long been axiomatic that the Crown can’t use its prerogative powers to change the law. Therefore, the court held that the Government lacks the power to give notice under Article 50.
I’m not terribly surprised by the court’s decision. The more I thought about the claimants’ case, the more compelling it seemed. The notion that Crown can’t unilaterally tinker with the statute book is one of the fundamentals of the British constitution. Parliament settled this question in 1689 when it declared “[t]hat the pretended Power of Suspending of Laws or the Execution of Laws by Regal Authority without Consent of Parliament is illegal.” The EU laws in this case can only be abrogated by Parliament.
The High Court’s decision has provoked a strong reaction from members of the Leave camp. Many have accused the judges of trying to subvert the will of the British people. For example, Iain Duncan Smith told the Telegraph that “when we passed an Act to give the British people a referendum, we passed sovereignty back to them to make that decision [to leave the EU].” There’s one major problem with this argument: Constitutionally speaking, the Queen-in-Parliament is sovereign, not the British people.
The European Union Referendum Act 2015 did not change this fundamental fact. Parliament could have ceded its authority over this matter to the British people—for example, it could have included a ‘Henry VIII clause’ in the 2015 Act that would automatically allow the Crown to amend or repeal EU-related legislation by statutory instrument in the event of a Yes vote. But in the absence of such a provision, Parliament is ultimately responsible for deciding whether Britain remains in the EU.
The outrage from Leave campaigners is more than a little ironic. Many of them claimed that leaving the EU was the only way to safeguard Parliament’s sovereignty, so it’s a bit rich for them to castigate the High Court for upholding that very doctrine!
The Government has promised to appeal, but I would be very surprised if the ruling were overturned. The limits on the royal prerogative are too firmly entrenched.
 Both the Government and the claimants argued that notice under Article 50 can’t be revoked, and the High Court accepted this proposition. However, over at the UK Constitutional Law Blog, Aurel Sari has argued that the UK could, in fact, withdraw its notice.
 Section I of the Bill of Rights 1688.
 Henry VIII clauses are actually quite common. The Government usually justifies them on the grounds of expediency. Highly technical legislation often requires numerous changes to other statutes, and the full extent of these changes might not be apparent when the bill is going through Parliament. In theory, a Henry VIII clause allows the Government to avoid wasting Parliament’s time. The downside is that, once a Henry VIII clause has been enacted, Parliament has little control over how the Crown uses that power. Statutory instruments are subject to much less stringent parliamentary oversight, and peers and MPs can’t amend them.