By what process do EU directives become UK national law?

Question

By what process do EU directives become national law?

Do they get encoded via the normal primary legislation process of a raising a Bill, debating it and then passing an Act?

Answer 1

Just to address what may just be strange wording, an EU directive does not become UK national law, an EU directive says "we've agreed that doing X is necessary as a bloc, so all countries need to have figured out some way to implement X by time Y". Obstructionist countries may be taken to the ECJ.

An EU directive does not become UK law, it is a call for the UK to make a law, which goes through the normal law-making process of the UK. For instance, the UK legislation Water Resources Act was used to address the EU directive Drinking Water Directive

Answer 2

While EU Directives can be implemented by an Act of Parliament (as mentioned in Gramatik's answer), the European Communities Act 1972 (as amended) also grants the government the power to implement Directives via statutory instrument.

From Parliament's website:

The European Communities Act 1972 (ECA)

Section 2(2) of the European Communities Act 1972 (ECA) provides a power for subordinate legislation to be made where the EU Treaties require Member States to make provisions in their domestic law, such as for the implementation of EU directives. It also provides that other powers to adopt subordinate legislation in other Acts are interpreted as enabling them to be used to implement EU law.

Secondary legislation to implement EU law

Most EU directives and a small number of EU regulations and decisions are implemented in the UK by SI [statutory instrument] under the authority of the ECA - the majority - or another enabling Act.

Primary legislation to implement EU law

Some EU directives are implemented by primary legislation (Act of Parliament).

Regarding statutory instruments, the House of Commons briefing paper on the subject mentions that:

The vast majority of EU-related SIs (estimated at 90%) are laid subject to the negative procedure. This means they automatically become law without debate unless there is an objection from either House.

Specifically, each House has 40 days to annul any SI presented under this procedure, and the SI (and hence any EU Directive it implements) can come into force before the 40 days expires.

However, as Wikipedia mentions, objections to any SI presented under the negative procedure are rare:

Any member of either House can put down a motion that an instrument should be annulled, although in the Commons, unless the motion is signed by a large number of Members, or is moved by the official Opposition, it is unlikely to be debated, and in the Lords such a motion is seldom actually voted upon.

The last occasion on which a statutory instrument was annulled was on 22 February 2000 [...] The last time the House of Commons annulled a statutory instrument was in 1979