Part A
The main facts of the Miller case1 was the UK government’s question to trigger Article 50 of the
Treaty on the European Union2, leading to the UK Parliament to pass the European Referendum Act,
triggering a referendum on 23rd June 2016. The referendum produced a majority in favour of leaving
the EU. Later the UK government proposed to exercise its prerogative powers to leave the EU by
serving the notice of withdrawal from the European Union under Article 50 of the Treaty on the
European Union. There had been concerns over the limits of prerogative power of ministers and
whether the government had breached Parliamentary sovereignty by making constitutional
arrangements without the authorisation of an act of Parliament. Although, by the terms of the 1972
Act3, the prerogative power to withdraw from international treaties was not excluded. The issue of
the right to legislate without the regard of the devolved legislatures (Northern Ireland, Scotland, and
Wales) was also discussed as the Supreme Court had chosen to dismiss the issue of devolution,
whilst raising the question of the authority of constitutional conventions within the UK, such as the
Sewel Convention. Overall, the ratio of this case established that the Secretary of State did not have
the power of royal prerogative to give notice to trigger Article 50 of the Treaty on the European
Union for the United Kingdom to terminate its membership with the European Union.
Part B
The Miller case has revealed a number of problems with the UK constitution, in which this essay will
discuss the issues of the royal prerogative and parliamentary sovereignty; the issue with devolution
being dismissed; and why these issues have occurred due to the nature of our uncodified
constitution.
One problem of the constitution revealed by the case is the extent to which royal prerogative can be
exercised. An important prerogative power that the ministers may exercise is the power to make
diplomatic relations, in conducting foreign policy and treaty-making; Lord Neuberger suggests that
terminating treaties is a matter of the treaty-making prerogative 4. In this light, the Secretary of State
was entitled to exercise the power of withdrawing from withdrawing from the EU and proceeding
with the Notice of withdrawal without an Act of Parliament or legislation. The issue arising is that
ministers’ intentions are not law and cannot presume that they will become law as highlighted by
Lord Browne-Wilkinson in R v Secretary of State for the Home Department, Ex p Fire Brigades Union 5,
1
R (on the application of Miller and another) v Secretary of State for Exiting the European Union [2017] UKSC 5
2
Consolidated Version of The Treaty on European Union [2012] OJ C326/13
3
European Communities Act 1972
4
R (Miller) v Secretary of the State for Exiting the European Union [2017] UKSC 5, per Lord Neuberger, para [54]
5
R v Secretary of State for the Home Department, Ex p Fire Brigades Union [1994] 2 AC 513, 552, per Lord
Browne-Wilkinson
, as these are matters for parliament to decide as the supreme legislative body; issues must be
resolved with existing law. As there was no prior Act of Parliament or legislation to authorise the
withdrawal from the EU, it could be suggested that the Secretary of State acted unlawfully and
challenged Parliamentary sovereignty. There is also the possibility that the prerogative power of
decision-making potentially alters rights of citizens. Professor Wade presents the argument that
exercising prerogative powers in treaties cannot alter the domestic rights in the UK, but Payne rebuts
this by arguing that ‘even a treaty that has not been incorporated into domestic law may lead to a
particular interpretation of a statute’6. Taking Payne’s argument, the prerogative power exercised to
withdraw from the EU may have a domestic impact on the UK suggesting that limits should be placed
on the extent on prerogative powers. However, in JH (Mincing Lance) Ltd v Department of Trade and
Industry, Lord Templeman states that the ‘government may negotiate, conclude, construe, observe,
breach, repudiate or terminate a treaty’7, demonstrating that subject to parliamentary sovereignty,
ministers are able to exercise their prerogative power in terminating treaties without prior legislative.
As a result, the Miller case has revealed that ministers exercise their prerogative power that
potentially alters domestic law despite the lack of prior authorisation from Parliament, all suggesting
that there needs to be a limit to prerogative powers.
In continuation, the case has revealed a problem with the authority of Parliamentary sovereignty.
Parliament is the supreme law-making body and the ultimate political authority of the state, which
all other bodies must abide by. The UK government attempting to put in the Notice for withdrawal of
the European Union without an act of Parliament was a clear breach of Parliamentary sovereignty.
Usually, ministers are not to exercise their prerogative to displace provisions made in an act of
Parliament and ministers act unlawfully if they proceed with legislation that has not been authorised
by parliament, therefore, the Secretary of State had acted unlawfully by triggering Article 50.
However, in the dissenting judgement made by Lord Reed, suggested that there is ‘no legal
requirement for the Crown to seek Parliamentary authorisation for the exercise of power’ 8 (the
Crown being the ministers who hold royal prerogative); this follows the principle established in
Blackburn v Attorney General and the Tin Council 9 that prerogative decisions do not need to be
authorised by Parliament. This goes against the fundamental principle of Parliamentary sovereignty
as the supreme law-making body and that the government should not act without the authority of a
Parliamentary act. In addition, Parliament had made the agreement to the 1972 Act 10, therefore it is
6
S. Payne, ‘The Royal Prerogative’ in M. Sunkin and S. Payne (eds) The Nature of the Crown (1999, Oxford:
OUP), pp 84-5
7
JH (Mincing Lane) Ltd v Department of Trade and Industry [1990] 2 AC 418, 476
8
R (on the application of Miller and another) v Secretary of State for Exiting the European Union [2017] UKSC 5,
per Lord Reed, para 161
9
Blackburn v Attorney General and the Tine Council [1971] EWCA Civ J0510-2
10
European Communities Act 1972
