Skip to main content

The government lost the Brexit case, but who won?

Dr. Dominic Burbidge is a Postdoctoral Research Officer for the University of Oxford


The Supreme Court judgement on the Brexit case made it less easy to see how the government establishes international relationships on its own, and that hampers our present ability to envisage a post-Brexit relationship with the EU.

The Article 50 case heard in the Supreme Court between 2016 and 2017 (Miller v Secretary of State for Exiting the European Union) hinged on the argument that in triggering Article 50 to start the process of exiting the European Union (EU), the government would be carrying out an action that inevitably leads to a loss of rights on the part of British and other EU citizens. As such, the action could not simply be made under powers of royal prerogative. The “royal prerogative” refers to the way the executive arm of the government is understood in the UK (helpfully explained by Professor Timothy Endicott). The royal prerogative consists in powers that the Prime Minister usually exercises on behalf of the Queen. Unlike other countries, the UK does not have a constitution that specifies what the Crown can and cannot do. The things the Prime Minister through the Queen can do are customarily understood, and then subject to change and restriction according to legislation passed in Parliament. This means there are some things that the Prime Minister can do on behalf of the Queen that are not in law, as such, but are nevertheless valid. Powers that pertain to foreign affairs and defence tend to fall in this category, and with that the making of international treaties. This reflects the way in which the Prime Minister’s office tends to represent the country internationally, and act like other executives around the world in conducting negotiations on behalf of the country as a whole. Naturally, the government thought leaving the EU fell into this category, and so was sent into disarray when Gina Miller, the lead claimant, challenged them on this very basis.


Gina Miller’s argument was that membership of the EU realises the rights of British citizens under law, and so legislation is necessary to remove those rights, not simply a decision by the Prime Minister (the argument was initially spelled out by Nick Barber, Tom Hickman and Jeff King in a blog published a mere four days after the referendum result). In other words, the extent of EU-related rights means Brexit is no longer in the domain of the executive. EU rights have been established via legislation that parliament voted on, and so it is no longer a question of the customary power of the royal prerogative.


Put simply, the claimant’s argument was that Brexit could only be done through Parliament. The Supreme Court found in her favour, saying that the government was not allowed to unilaterally trigger Article 50. Instead, Parliament therefore debated and passed the European Union (Notification of Withdrawal) Act 2017 to support the government’s action.


All that makes it clear the government lost the Brexit case, but at the end of the day who has won? And what does this mean for the government’s current ability to negotiate Brexit with the EU?


Doing things democratically


In the Brexit court hearings both sides of the debate accepted that the referendum held in the UK on membership of the EU was advisory. The term ‘advisory’ has been a bone of contention, with some arguing that holding an advisory referendum means nothing at all, and others saying that the term is merely a formality and the referendum result should be respected. I lend my voice to the latter group: the ‘advisory’ aspect was, largely, a legal provision to avoid the UK government having to immediately implement the results the very same day. As has become clear since the vote, it takes a good deal of time to negotiate terms of departure when leaving the EU, so it would have been damaging to both UK and EU interests to give the referendum result immediate effect, regardless of whether you think the UK should, overall, remain or leave.


In any case, parliamentarians felt morally bound to honour the results of the referendum they had initiated, and Gina Miller likewise avoided saying that her case was about stopping the UK’s departure altogether. The legal dispute instead fell on whether the government held the necessary powers to trigger Article 50 of the Treaty on European Union, or whether that was alternatively something that had to be done through Parliament with primary legislation.


Where is this EU that we are leaving?


Triggering Article 50 to leave the EU has no direct effect on the Human Rights Act 1998; it does not remove rights established there. So on what basis did the claimants argue that leaving the EU would affect the rights of British and other EU citizens, and thus be something the government cannot do without parliamentary approval?


The argument was that triggering Article 50 would at the very least make the European Communities Act 1972 hollow if not outright redundant, and that is not something the government could do without consulting Parliament. It is through the European Communities Act that EU law is incorporated into UK domestic law. The European Communities Act therefore facilitates numerous rights, such as the right to vote in European parliamentary elections, or some of the rights associated with freedom of movement and free trade within the EU. Those taking the government to court believed that triggering Article 50 and leaving the EU would mean these rights are automatically taken away, even though the rights had been established in part by Parliament.


The defendants responded that triggering Article 50 would, in fact, be business as usual. Whenever rights are established that depend on international agreements, there can be a separate negotiation of those international agreements that does not need to be approved by Parliament. It may be that some rights and benefits that are diplomatically obtained receive articulation and affirmation in UK domestic law, but that does not in itself bind governments throughout the world to honour such rights. For example, through the European Communities Act you may have the right to stand in European parliamentary elections in France, but if France leaves the EU you would lose that right, regardless of what UK law says. In the same way, for implementing international agreements, national law reflects what has been agreed on; it is not domestic law that keeps parties in agreement but the international agreement they have already committed themselves to. As Professor Mark Elliott argued when reporting on the case:


The European Communities Act [ECA] ‘simply assumes binding EU obligations: it does not make them permanent or transfer the executive’s function in contracting those obligations to Parliament. Just as it is inaccurate, or incomplete, to say that the UK joined the EU by means of enacting the ECA 1972, that Act’s repeal is not a necessary component of Brexit, if Brexit is understood to mean the extrication of the UK from its EU Treaty obligations.’


In contrast, to hinge the argument against the government explicitly on rights, Lord Pannick for the claimants took as the clearest example the right to vote for Members of the European Parliament, as established through the European Parliamentary Elections Act 2002. As Lord Pannick explained, ‘That right is simply frustrated in its entirety by the giving of notification [to leave the EU]. Parliament’s consideration of that right is simply pre-empted by the notification and its consequences’. The idea here was that you lose your right to vote, and that is something Parliament wanted to give you, not just the EU treaties.


The example is interesting, because it opens up the core democratic dilemma involved in membership of the EU, and how that democratic participation relates to national sovereignty. As Robert Craig highlighted with respect to discussion of the European Communities Act, Lord Pannick felt there to be ‘some “irony” in the fact that the desire to restore national sovereignty over those rights “was the reason why the defendant wishes to give notification to withdraw, and they are the very reason why he cannot use prerogative powers to do so”’. On this reasoning, the argument that the UK should exit the EU was based on the idea that the EU is too involved in legislation affecting citizen rights, and so we needed to assert parliamentary sovereignty and leave. But parliamentary sovereignty is ultimately expressed through legislation, not the government’s powers of royal prerogative, so you have to respect parliamentary sovereignty in leaving and do it through legislation.


That view is not quite correct, however. While it is true that Parliament is sovereign, and that Parliament expresses its sovereignty through legislation, that is not to say that parliamentary sovereignty renders all non-legislative government action unlawful. Parliamentary sovereignty means that Parliament can determine anything going on in the country if it so chooses, but the Brexit court case was about whether the government can go ahead in triggering Article 50 given that Parliament has made no objection to following through on the referendum result.


As established by Professor John Finnis in a recent series of policy papers, exiting the EU only leads to a loss of treaty rights (rights established in international treaties), not statutory rights (rights established through parliament voting on domestic legislation). Just as with a double-tax agreement between different countries, the Crown can negotiate the terms of these and exit any relationship that is not favourable to British interests regardless of how tax law in the UK stands at any one time. In the same way, the government can make or unmake European treaties, and subsequently start a separate process for deciding upon the best domestic legislation to reflect these international obligations.


Doing international treaties


The government, under the royal prerogative, enjoys freedom to negotiate international treaties, and this means every stage cannot be legislated by Parliament in a practical way. As MPs were well aware when voting for the European Union Referendum Act 2015, if the UK voted leave, we would bind ourselves to that outcome in a way that was constitutionally consistent with existing government practices for entering into and leaving international treaties. Those existing practices are executive-led.


The fact that the government lost the court case, however, shows how much our relationship with the EU is believed by judges to be an inextricable part of the way the UK’s constitutional order should ideally operate. The Miller judgment made our EU commitments best understood as a domestic commitment, not an international one. This means it is less easy to see how the government establishes international relationships on its own, and that hampers our present ability to legally envisage a post-Brexit relationship with the EU.


We have gotten used to having the EU do all the heavy lifting in organising international affairs. But in a democratic system that supports self-government and the rule of law, who wins if the government loses its ability to effect a referendum result?