This blog briefly explains the background to a body of domestic law called ‘assimilated law’ and looks at how it can be amended.
Before Implementation Period completion day
When the UK was a member of the European Union (EU), EU law applied in areas within EU competence and the Scotland Act 1998 required any legislation passed by the Scottish Parliament to comply with EU law.
EU law ceased to apply in the UK at the end of the withdrawal implementation period, at 11pm on 31 December 2020. This point in time is known as Implementation Period Completion Day, or “IP Completion Day”. The requirement for Scottish Parliament legislation to comply with EU law also came to an end at that point.
Assimilated law (previously called “retained EU law”)
Assimilated law is simply the name given to a body of domestic law which has its origins in the UK’s membership of the EU. “Domestic law” is used to describe the law which applies in the UK: the law of England and Wales, Scots law and the law of Northern Ireland.
At IP Completion Day, most EU laws were preserved in domestic law.
This legislation was initially known as “retained EU law”, or REUL. At the beginning of 2024, REUL that remained on the statute book was re-named “assimilated law”.
What changes can be made to assimilated law?
As assimilated law is domestic law, it is open to the UK Parliament and (within its legislative competence) the Scottish Parliament to amend or revoke it, should they wish to do so.
The Retained EU Law (Revocation and Reform) Act 2023 (“the REUL Act”) granted UK and Scottish Ministers extensive powers to make changes to assimilated law by secondary legislation – including powers for UK Ministers in devolved areas.
Further background information about REUL, and the REUL Act, can be found in SPICe blogs from July 2022 and August 2023.
The most significant powers contained in the REUL Act are due to expire later in June 2026. UK and Scottish Ministers will, however, still have the power (in section 15 of the REUL Act) to update assimilated law to reflect changes in technology or scientific developments after this date.
If Scottish Ministers exercise the power in the REUL Act to update assimilated law, this would be done by way of a Scottish Statutory Instrument considered by the Scottish Parliament.
If UK Ministers exercise the power to update assimilated law in an area of devolved competence, then the Scottish Parliament will not have a formal scrutiny role as the UK Statutory Instrument will be considered by the UK Parliament only.
Although there is no statutory requirement to seek the Scottish Ministers’ consent to such regulations being made, the UK Government has indicated to the Scottish Government that it will “seek agreement” on such instruments.
If a UK Statutory Instrument is made to update assimilated law in an area of devolved competence, then the Parliament will be notified through the Statutory Instrument Protocol agreed for Session 7.
Sarah McKay, SPICe research