Preserving and converting EU law
By only repealing the ECA, some EU law that currently applies in UK law by virtue of the ECA would cease to have effect. As outlined by the Supreme Court in Miller1, the ECA is not itself an originating source of EU law, but is rather the ‘conduit pipe’ through which EU law flows into UK domestic law.
	As set out above, section 2(1) ECA provides that directly applicable EU law (such as EU regulations) has effect in UK law without the need to pass specific UK implementing legislation. If the ECA were repealed and no further action was taken, this directly applicable EU law would cease to apply in UK law, leaving gaps on the statute book.
	Other types of EU law (such as EU directives) have to be given effect in the UK through domestic laws. As set out above, this has frequently been done using section 2(2) of the ECA, which provides ministers, including ministers in the devolved administrations, with powers to make secondary legislation to implement EU obligations. If the ECA were repealed and no further action was taken, all of the secondary legislation which has been made under it would fall away and cease to be part of the UK statute book, leaving significant gaps.
	To avoid such gaps, the Act converts the body of existing EU law into domestic law and preserves2 the laws we have made in the UK to implement our EU obligations. After this, because the supremacy of EU law will not operate on new, post-exit legislation, Parliament (and, within devolved competence, the devolved legislatures) will be able to decide which elements of that law to keep, amend or repeal once the UK has left the EU. This body of converted EU law and preserved domestic law is referred to in the Act and these notes collectively as ‘retained EU law’.
Retained EU law
(includes both categories below)
Preserved legislation
Regulations made under section 2(2) or paragraph 1A of Schedule 2 to the ECA
Other primary and secondary legislation with the same purpose as regulations under section 2(2) ECA
Other domestic legislation which relates to the above, or to converted legislation, or otherwise relates to the EU or EEA
The Act will preserve this legislation as it exists immediately before exit day. This is referred to in these notes as ‘preserved legislation’.
Converted legislation
Direct EU legislation:
EU regulations
EU decisions
EU tertiary legislation
Direct EU legislation as it applies with adaptations for the EEA
Any other rights which are recognised and available in domestic law through section 2(1) ECA (for example, directly effective rights contained in EU treaties)
The Act will convert and incorporate this law as it exists immediately before exit day into domestic law.
	This approach means that, as a general rule, the same rules and laws will apply on the day after the UK leaves the EU as before:
the Act converts directly applicable EU law (e.g. EU regulations) into UK law;
it preserves all the laws which have been made in the UK to implement EU
obligations (e.g. in EU directives);
it incorporates any other rights which are available in domestic law by virtue of section 2(1) of the ECA, including the rights contained in the EU treaties, that can currently be relied on directly in national law without the need for specific implementing measures; and
the Act provides that pre-exit case law of the Court of Justice of the European Union (CJEU) be given the same binding, or precedent, status in UK courts as decisions of the Supreme Court or the High Court of Justiciary in Scotland.