The High Court has today given its judgment in the Article 50 judicial proceedings. The Judgment and summary are available here.

What did the Court decide?

The Court has ruled that the Government cannot lawfully use prerogative powers to trigger Article 50.

Prerogative powers are those residual powers inherent in the Sovereign and now exercised by, or on the advice of, her responsible ministers (save in a few exceptional instances).

What does this mean for Parliament?

At this stage, the implications of the Judgment for Parliament are not yet known.

The Government has said that it is “disappointed” by the Court’s Judgement and that “the country voted to leave the European Union in a referendum approved by an Act of Parliament”. It has confirmed that it will appeal.

How might an appeal work?

The Supreme Court has not yet confirmed the arrangements, but it has been widely reported that the Divisional Court has issued a certificate to declare that the case is suitable to “leapfrog” to the Supreme Court (if the Supreme Court agrees); that the Supreme Court will hear the case over 4 days in early December; and that for the first time, since the Court was established in 2009, all 11 Justices of the Supreme Court will sit to hear the case.

What if the Supreme Court dismisses the Government’s appeal?

If this were the case, the logical consequence might be that some form of parliamentary approval would be required before notice could be given under Article 50. David Davis, the Secretary of State for Leaving the European Union, has indicated in an interview to the BBC his view that an Act of Parliament would be required.

What reasons did the Court give for its decision?

The Government had argued that nothing in the European Communities Act (ECA) 1972 restricted the Crown’s power to withdraw from EU treaties using the prerogative, even though this would affect domestic legal rights. The Court rejected this claim. This means the Court disagreed that the Government retains, after passing the ECA, power under the prerogative to trigger Article 50.

The Court stated that the Government’s approach was “flawed” as it failed to acknowledge the constitutional principle that, “unless Parliament expressly legislates to the contrary, the Crown should not have power to vary the law of the land by the exercise of its prerogative powers”.

The Judgment explains that the constitution’s historical evolution, in particular the outcome of the war between the Crown and Parliament in the 17th  century, meant it would be “surprising” if Parliament had intended to leave domestic legislative rights, as implemented by the ECA in conjunction with the direct operation of European law, subject to the Crown’s prerogative powers.

Why is the European Communities Act special?

The ECA is a statute of “special constitutional significance”, according to the Judgment. Through it Parliament enabled European law to have a direct effect in the UK, a momentous change. It would “not be plausible”, the Judgement ruled, that Parliament also intended for the Government to be able to undo those changes via the exercise of the prerogative.

What’s domestic law got to do with it?

The Court took the view Parliament introduced European law into domestic law – and therefore created enforceable rights in domestic law – “in such a way that this could not be undone by Crown prerogative power”. The Court did not accept the Government’s argument that any loss of these rights could be minimised by yet to be enacted primary legislation. The exercise of the prerogative, so said the Court, would still deprive those rights of effect.

When can the courts interfere with the exercise of prerogative powers?

The Judgment states that the Government had overstated the extent to which the courts would not interfere with the Crown’s use of the prerogative in the conduct of international relations. The courts would be able to interfere where the exercise of prerogative powers in the conduct of international relations would “bring about major changes in domestic law”.

The Court’s central conclusion was that as result of Parliament enacting the ECA, and in the light of relevant constitutional principles, the Crown “has no prerogative power to effect a withdrawal” from the EU by giving notice under Article 50.

All Commons Library briefings on Brexit can be found on our Brexit Hub.

Picture credit: The Royal Courts Of Justice – The Strand – London, by Nick Garrod; Creative Commons Attribution 2.0 Generic (CC by 2.0)