Constitutional and Administrative Law

For nearly half a century the UK’s Constitution was part of the most globally significant supranational legal order. The UK, like other member states, granted the European Union (EU), or shared with it, competences over entire areas of law making, in order to secure the benefits of harmonisation of rules across the member states. Such deep cooperative commitments within this supranational order are maintained by binding rules, and throughout its membership UK policy makers struggled to reconcile to this loss of freedom of action. After the UK joined the European Economic Area (EEA), a nationwide referendum was held which approved this decision. Over four decades later, amid growing discontent within the Conservative Party over the UK’s EU membership, David Cameron as Prime Minister renegotiated the terms of the UK’s membership and called a referendum on whether the UK should remain part of the EU based on these terms. In June 2016, a majority of referendum voters voted to leave the EU. This chapter explores what the EU is, the consequences of the UK’s membership of the EU for its constitutional order between 1973 and 2020, the process of the withdrawal from the EU and the post-Brexit relationship between these orders.