I have written before on this blog about the European Union (Withdrawal) Act 2018, including a short, ‘1,000 words’ piece giving a general overview of the legislation, which will form the constitutional centrepiece of the UK’s post-Brexit legal arrangements — subject, of course, to the possibility that it will need to be adapted in the short-term if a withdrawal agreement is ultimately approved by Parliament. Stephen Tierney and I have now completed a substantial article on the Act, focussing on its constitutional implications. The article will be published in the January 2019 edition of the journal Public Law. The following abstract of the article gives a flavour of the issues that are considered in it: 

The European Union (Withdrawal) Act 2018 forms the centrepiece of the UK’s domestic legal preparations for its departure from the European Union. The Act aims to capture and domesticate large swathes of EU law so as to safeguard legal continuity upon Brexit. This paper examines the process by which the Act was passed by the UK Parliament and its substantive constitutional implications, which are likely to be far-reaching. Membership of the EU has had a monumental impact not only upon the substantive law of the UK, but also upon the development of fundamental constitutional doctrines, principles and practices over more than four decades, affecting our understanding of parliamentary supremacy, the relationship between Parliament and Government, the constitutional authority of the courts and the creation and development of devolved government. The implications of the Act go far beyond the immediate task of retaining and reordering the domestic effect of EU law. The paper assesses the deeper consequences which the Act signifies for four dimensions of the constitution: the rule of law and legal certainty, parliamentary supremacy, the relationship between Parliament and government, and the UK’s territorial constitution.

A full pre-publication draft of our article can be downloaded here.