Roughly a year ago, UK voted to leave the EU. Notwithstanding the publication of a White Paper by the UK Government, as well as of various sector-specific reports by the House of Lords’ EU Committee, it is not yet clear what ‘Brexit’ means or how it will come about – legally and constitutionally. In a recent article published on the International Journal of Legal Information (also available here), I seek to answer the latter question from the standpoint of UK and EU law. What follows is perforce merely a general indication of the content covered within the article.

The discussion begins with the domestic process before beginning the initial withdrawal negotiations, which is governed by UK constitutional law. This section is written with an international audience in mind and explains the Executive’s prerogative power to negotiate international treaties, as well as the relationship between statute and royal prerogative. The UK Supreme Court ruled in Miller that the Government could not exercise its prerogative powers and trigger Article 50 TEU without prior authorisation by Parliament by means of statute. This coheres with the normative argument presented in the paper.

The focus then shifts to the process of withdrawing from the EU, which is set out in Article 50 TEU. The principal default line is between the withdrawal agreement, which would be concluded pursuant to Article 50 TEU, and the agreement(s) governing the future relationship between the UK and the EU. The conclusion of the withdrawal agreement would require a qualified majority in the Council and the consent of the European Parliament. It is argued that the British MEPs will participate in the vote, as MEPs represent the citizens of the Union and not just the citizens of their respective countries. This would further allow EU citizens living in the UK to have at least some representation in the political process of withdrawal.

The article further examines whether ‘Brexit’ can be stopped once Article 50 TEU has been triggered. The UK Government triggered Article 50 on 29 March 2017. There is disagreement in the relevant literature as to whether the process under Article 50 could be reversed unilaterally by the UK Government or whether this would require the agreement of the EU-27. I argue that it would be very hard to believe that the other 27 Member States would seek to force the UK out of the EU against its own will, if the country were to change its mind. It is further argued that abuses of the withdrawal process could be dealt with by the CJEU by construing Article 50 such that if there were repeated attempts to trigger it that were part of a single sequence of events the two-year period should be interpreted to apply to the event as a whole.

The penultimate section of my article looks at the legal nature and substantive content of the future agreements that might be concluded between the EU and the UK. These are different from the withdrawal agreement, though the latter shall take account of the framework for the UK’s future relationship with the Union (Article 50(2) TEU). These agreements are more fully explored in two EURO-CEFG studies for the European Parliament on the impact of ‘Brexit’ on the internal market and financial services, which will be published soon.

The final section of the article examines the UK rules on ratification of such international agreements as may be concluded between the UK and the EU for the purposes of or after ‘Brexit’. There is considerable ambiguity as to degree of parliamentary involvement that would be required, and the regime under the Constitutional Reform and Governance Act 2010 may not be held to be applicable if some greater parliamentary involvement is required (eg, by the European Union Act 2011). As such, unless the latter Act were to be amended, it is argued in the literature that an Act of Parliament and a referendum may be required. Others argue that a withdrawal from the EU is not covered by the terms of the 2011 Act. In any event, it is key that the UK Parliament is not deprived of voice on the content of the UK-EU agreement.

Menelaos Markakis is a Postdoctoral Researcher at EURO-CEFG, Erasmus University Rotterdam.