European Union (Withdrawal) Act (2018 C.16).

The Act concerns legal implications of exit of the United Kingdom from the European Union. The principal purpose of the Act is to provide a functioning statute book on the day the UK leaves the EU. It ends the supremacy of European Union (EU) law in UK law, converts EU law as it stands at the moment of exit into domestic law, and preserves laws made in the UK to implement EU obligations. It also creates temporary powers to make secondary legislation to enable corrections to be made to the laws that would otherwise no longer operate appropriately once the UK has left, so that the domestic legal system continues to function correctly outside the EU. The Act also enables domestic law to reflect the content of a withdrawal agreement under Article 50 of the Treaty on European Union once the UK leaves the EU, subject to the prior enactment of a statute by Parliament approving the final terms of withdrawal. Direct EU legislation, so far as operative immediately before exit day, forms part of domestic law on and after exit day.
The Act amends each of the devolution statutes (the Scotland Act 1998, the Northern Ireland Act 1998 and the Government of Wales Act 2006) so as to remove the requirements that the devolved legislatures and the devolved administrations can only legislate or otherwise act in ways that are compatible with EU law. It then inserts powers into each of those Acts to apply, by regulations, a temporary freeze on devolved legislative or executive competence in specified areas, so that in those areas the current parameters of devolved competence are maintained.