Supreme Court rules that Government cannot invoke Article 50 under the Royal Prerogative
The Supreme Court has this morning given judgment in the case of R(Miller) v Secretary of State for Exiting the EU  UKSC 5. In summary, the Court has (by majority of 8 to 3) dismissed the Government’s appeal against the Divisional Court’s judgment , and has ruled that the Government has no power under the Royal Prerogative to invoke Article 50 TEU. An Act of Parliament is now required to authorise the executive to trigger the Article 50 process. As regards the additional devolution arguments made on behalf of Northern Irish citizens and the devolved Governments of Scotland and Wales, the Court has unanimously held that UK ministers are not legally compelled to consult the devolved legislatures before triggering Article 50.
The Supreme Court’s judgment can be found here.
The press summary can be found here.
A transcript of Lord Neuberger’s summary given in open court can be found here.
All the parties’ written cases can be found here.
The judgment, 96 pages long and containing detailed dissents from Lords Reed, Carnwarth and Hughes, will be discussed in detail by Gerry Facenna QC , Anneli Howard and Jack Williams at a forthcoming Monckton seminar this Thursday. More details here. For now a few matters are particularly noteworthy.
First, the Court’s judgment clarifies the proper framework for analysing prerogative powers. After establishing that a relevant prerogative power exists (see  and ), the next stage is to determine the extent of that prerogative power. This comes before any question of abrogation by statute arises. Thus, the Court delimits prerogative powers generally, and the foreign relations treaty prerogative specifically, in confirming that executive powers cannot change domestic law (see, in particular, -). It was therefore unnecessary to consider subsequent questions of whether the relevant prerogative power had been excluded or abrogated by statute, or whether its purported exercise was otherwise unlawful, once the Court found that domestic law and rights would be affected if Article 50 were triggered by prerogative power (see  – ). As the Court stated, “rather than the Secretary of State being able to rely on the absence in the 1972 Act of any exclusion of the prerogative power to withdraw from the EU Treaties, the proper analysis is that, unless that Act positively created such a power in relation to those Treaties, it does not exist” ().
Second, the Supreme Court upheld the Divisional Court’s two-pronged reasoning that prerogative power does not extend to either changing domestic law or affecting domestic rights (see ). This may have significant consequences for the use of prerogative powers in the international sphere where domestic or acquired rights would be affected, and is of potentially wider application than if the Court had confined its analysis to circumstances where acts on the international stage result in changes to the (domestic) constitutional framework. It may, combined with the findings in relation to the principle of legality (), have implications for what the authorisation bill needs to cover.
Third, the judgment lays to rest the heated academic debate as to whether a preliminary reference was required on the reversibility of Article 50 for the purposes of this litigation. The Court stated, in accordance with the Secretary of State’s own case, that the reversibility of otherwise of an Article 50 notification “would make no difference to the outcome of these proceedings” (). As such the Court was prepared to proceed on the assumption that an Article 50 notification was unilaterally irrevocable (as all parties in the litigation agreed was prudent), without deciding the issue or expressing any views either way on the matter.
Finally, the Court’s ruling on the Sewel Convention reiterates that constitutional conventions are a political constraint only which, whilst playing an important role in the operation of the UK constitution, are not for the Court to police in terms of their scope and application (see  – ). The reservations for ruling on the scope of a convention may be slightly surprising to some (the courts have previously ruled on the nature and scope of conventions, if not enforcing them).
Anneli Howard is instructed by Mischcon de Reya to represent Mrs Gina Miller, the First Respondent.
All views are entirely personal and do not represent the views of other Members of Monckton Chambers or clients.