
On 23 January 2025, the UK Government published its third report on assimilated law (PDF). The report sets out the progress made in revoking and reforming assimilated law between June and December 2024. It also describes the government’s plans for further reform up to 23 June 2026, the 10th anniversary of the Brexit referendum.
What is assimilated law?
Assimilated law replaced retained EU law (REUL) from 1 January 2024. REUL was a special body of EU-derived domestic law created by the European Union (Withdrawal) Act 2018 to ensure consistency and legal certainty in the law as it applied before and after the UK’s exit from the EU.
The Retained EU law (Revocation and Reform) Act 2023 (the REUL Act) gave ministers powers to amend, revoke or replace REUL more easily. In 2023 the government said it intended to use these powers to remove “inefficient and bureaucratic REUL from the UK statute book” and optimise regulatory reforms after Brexit.
Most of the powers in the REUL Act apply in the same way to assimilated law as they did to retained EU law until the end of 2023, although the EU law principles of interpretation do not apply to assimilated law.
Retained EU law and assimilated law dashboard
The retained EU law and assimilated law dashboard was published in June 2022. It provides a public record of REUL and assimilated laws identified by government departments, and the actions taken to retain, reform or revoke them.
The dashboard was last updated in January 2025 and now lists 6,901 pieces of assimilated law. The table below shows the changes made since the previous update in June 2024.
Status | Assimilated laws as of 23 December 2024 | Assimilated laws as of 23 June 2024 |
---|---|---|
Unchanged | 4,417 (64%) | 4,370 (65%) |
Repealed | 1,484 (21.5%) | 1,461 (22%) |
Amended to make substantive policy changes | 806 (11.7%) | 798 (12%) |
To be confirmed (TBC) | 89 (1.3%) | 4 (0.06%) |
Expired | 62 (0.9%) | 61 (0.9%) |
Replaced by new legislation making substantial policy changes | 43 (0.6%) | 41 (0.6%) |
TOTAL | 6,901 | 6,735 |
According to the government’s third report on assimilated law (PDF), its departments identified 166 pieces of assimilated law between June and December 2024. This may account for the increase from four to 89 in assimilated laws whose status is yet to be confirmed.
The report’s executive summary states that 40 pieces of assimilated law were revoked or reformed between June 2024 and December 2024, giving a total of 2,395 since Brexit. However, this total includes 62 pieces of law which simply expired. Overall, the levels of unchanged assimilated law have remained steady at around 65%.
Reform of assimilated law since June 2024
Only two statutory instruments (SIs), the most common form of secondary legislation, have been made using powers in the REUL Act since June 2024. The Aviation Safety (Amendment) Regulations 2024 updated assimilated law to take account of changes to international air safety standards. The Vehicle Drivers (Certificates of Professional Competence) (Amendment) Regulations 2024 eased requirements for HGV drivers and others who need to obtain a Driver Certificate of Professional Competence and who only intend to drive in the UK. In both cases, the changes pursued similar objectives to the assimilated law being updated or replaced.
A further nine SIs amending assimilated law were made using powers in other domestic legislation.
When the government uses powers in section 14 of the REUL Act to change assimilated law, it must ensure that the overall effect of the changes does not increase the regulatory burden. The same requirement does not generally apply when the government uses powers in other domestic law to change assimilated law.
Future reform: Powers in existing legislation
The government aims to reform assimilated law based on its objectives to “reset” UK relations with the devolved governments and the EU, and to create a regulatory framework which supports innovation, economic growth, investment and high-quality jobs.
Unlike the previous government it has not set a quantitative target (PDF) for how many assimilated laws it wants to revoke or reform.
Using the powers in the REUL Act, it is planning to introduce 10 SIs by June 2025 that amend, revoke or reform assimilated laws.
One of the SIs (related to the coordination of social security) will “restate” the principle of supremacy of certain assimilated law (PDF) to ensure it has priority over other inconsistent domestic legislation. This principle applied to REUL but does not generally apply to assimilated law. Reapplying the principle would be for a limited purpose, to ensure the government can recover debts, such as an overpaid benefit, under any post-Brexit social security agreements the UK makes with EU countries.
Further SIs in areas such as procurement, competition, biosecurity, climate change and energy, road transport, aviation security, medicines and clinical trials will be made under other Acts of Parliament and assimilated law.
Future reform: New powers
There are four bills currently before Parliament which the government says are relevant to the future reform of assimilated law:
- Product Regulation and Metrology Bill [HL]
- Employment Rights Bill
- Data (Use and Access) Bill [HL]
- Finance Bill
Until they are enacted, the scope and purpose of any powers to reform assimilated law in these and other bills will remain uncertain. Powers in the Product Regulation and Metrology Bill would make it easier to update assimilated law that regulates goods. This would allow the UK to keep pace with changes made to EU product regulations, including those which continue to apply in Northern Ireland as part of the Brexit settlement.
This might suggest a change in approach, with the current government being more willing to align with EU rules where this would reduce divergence and regulatory friction within the UK’s internal market. The existing powers in the REUL Act are less “alignment-friendly” because they cannot be used to amend assimilated law in ways that increase the overall regulatory burden.
Further reading
Commons Library research briefing, A shift in approach? Assimilated law reform and the change of government
Commons Library research briefing, The end of REUL? Progress in reforming retained EU law
Commons Library research briefing, Retained EU Law (Revocation and Reform) Act 2023
About the author: Leigh Gibson is a senior EU policy specialist, working for the Parliament, Public Administration and Constitution Hub.
Photo by: Lena Kristin Müller on Unsplash