Part of assimilated law. Assimilated law includes anything which, after the end of the transition period, continues to be domestic law by virtue of section 2 of the European Union (Withdrawal) Act 2018 (EUWA), as that body of law is added to or modified from time to time, and as interpreted by the UK courts (section 6(7), EUWA).

Section 2 provides that EU-derived domestic legislation, as it has effect in domestic law immediately before the end of the transition period, continues to have effect in domestic law on and after the end of the transition period, subject to exceptions.

The definition of EU-derived domestic legislation in section 1B(7) of the EUWA is broad enough to catch most UK legislation with an EU connection that was passed or made before the end of the transition period. It includes, but is not limited to, legislation made under section 2(2) of the European Communities Act 1972, such as legislation implementing an EU directive.

For more information on EU-derived domestic legislation and its interpretation following the end of the transition period, see Retained EU law toolkit: EU-derived domestic legislation and Practice note, Interpretation of retained EU law and UK-EU withdrawal agreement.