Abstract
This chapter discusses UK membership of the European Union and the Brexit process. On 1 January 1973, the UK became a member of the European Economic Community, and the UK Parliament passed the European Communities Act 1972, allowing directly applicable European laws to take effect as part of UK domestic law which had an impact on parliamentary sovereignty. In the 2016 Brexit referendum, a narrow majority of the public voted in favour of leaving the European Union and the European Union (Withdrawal) Act 2018 repealed the European Communities Act 1972 on exit day when the UK left the European Union. Brexit has made significant changes to the UK constitution including the creation of a new body of retained EU law in UK domestic law, an impact on devolution, and raising the question of whether it has been a sufficient constitutional moment to trigger a codified UK constitution.
