Facts
In June 2016, a referendum produced a majority in favour of the UK leaving the European Union. The government planned to give notice of withdrawal under Article 50 of the Treaty on European Union using the royal prerogative, the power to conduct foreign affairs and make and unmake treaties, without first obtaining an Act of Parliament.
Gina Miller and others brought judicial review proceedings, arguing that the government didn't have power to do this. The Divisional Court agreed with them. The government appealed to the Supreme Court. References from Northern Ireland raised further questions about devolution.
Issues
- Could the government give notice under Article 50 using prerogative powers, without parliamentary authority?
- Did the devolved legislatures have to consent before notice was given?
Decision
The Supreme Court held, by eight to three, that an Act of Parliament was required before notice could be given. It held unanimously that the consent of the devolved legislatures wasn't legally required.
Reasoning
The limits of the prerogative. The majority, in a joint judgment, explained that ministers can't use prerogative powers to change domestic law, whether common law or statute, unless Parliament has authorised them to. That principle goes back to the Case of Proclamations (1611) 12 Co Rep 74.
The effect of withdrawal. The European Communities Act 1972 made EU law a direct source of UK law, for as long as the UK remained a member. Withdrawing from the EU would inevitably cut off that source of law and remove rights that UK citizens enjoyed under domestic law. That was a fundamental constitutional change, which only Parliament could make.
Constitutional statutes. The majority described the 1972 Act as having a constitutional character, recognising the concept of constitutional statutes discussed in Thoburn v Sunderland City Council [2002] EWHC 195 (Admin).
Conventions. The Sewel Convention says Westminster won't normally legislate on devolved matters without the consent of the devolved legislature. It had been referred to in the Scotland Act 2016. But the Court held that this didn't turn it into a legal rule. Conventions operate in the political sphere; the courts can recognise them, but can't enforce them.
The dissent. Lords Reed, Carnwath and Hughes would have held that the 1972 Act only gave effect to EU law while the UK was a member, so withdrawal didn't remove anything Parliament had guaranteed.
Why it matters
Miller (No 1) is a leading authority on:
- the limits of prerogative power, and its relationship with parliamentary sovereignty;
- constitutional statutes; and
- the legal status of conventions, building on Attorney General v Jonathan Cape Ltd [1976] QB 752.
It led directly to the European Union (Notification of Withdrawal) Act 2017.
How it comes up in exams
Use Miller (No 1) when a problem asks whether the government can act using the prerogative:
- Does a prerogative power exist for this purpose?
- Would using it change domestic law or remove statutory rights? If so, Parliament's authority is needed (Miller; Case of Proclamations).
- Has a statute displaced the prerogative in this area (Attorney General v De Keyser's Royal Hotel Ltd [1920] AC 508)?
- If a convention is involved, remember that it's politically, not legally, binding.
Frequently asked questions
What was decided in Miller (No 1)?
The Supreme Court held by eight to three that the government couldn't give notice under Article 50 of the Treaty on European Union using prerogative powers alone. An Act of Parliament was needed, because withdrawal would change domestic law and remove rights created by Parliament.
What did Miller say about the prerogative?
That the prerogative can't be used to change the law of the land or to frustrate the purpose of an Act of Parliament. The government can't, by itself, remove rights that Parliament has created.
What did Miller decide about the Sewel Convention?
The Court unanimously held that the Sewel Convention, under which Westminster doesn't normally legislate on devolved matters without the devolved legislature's consent, is a political convention. The courts can recognise it but can't enforce it, even though the Scotland Act 2016 refers to it.
What happened after Miller?
Parliament passed the European Union (Notification of Withdrawal) Act 2017, which authorised the Prime Minister to give notice under Article 50.