Maximum Residue Levels (MRLs) in GB

Following the UK’s departure from the EU, Great Britain (GB) established an independent regulatory system for plant protection products (PPPs), including the setting and review of Maximum Residue Levels (MRLs). All EU MRLs in force before 31 December 2020 were carried over into GB law, but following EU exit, GB started updating these limits independently through the Health and Safety Executive (HSE). As a result, regulatory autonomy steadily started to create greater divergence between GB and EU MRLs.

Active substance approvals, non-renewals, or MRL revisions made by the EU after 1 January 2021 no longer flow automatically into GB legislation, and GB continued to approve several actives that have been withdrawn from the EU market.

Under the Northern Ireland Protocol, EU PPP rules and MRL decisions continue to apply directly in Northern Ireland, meaning EU residue limits govern all food and feed produced, imported, or marketed there. Goods from NI may move freely into GB under the Internal Market Act 2020, but this access does not extend to PPP approvals themselves.

Learn more about EU MRLs: What are they and why are they important.

Divergence between GB and EU MRLs

Despite administrative and procedural differences, the underlying scientific and legal frameworks for active substance approvals remained closely aligned, with GB retaining the EU system almost unchanged. However, divergence developed predominantly because GB and the EU operate different approval and renewal timelines. The EU maintains a renewals system, while GB has not formally implemented one since exiting the Single Market. This has led to variations in which substances and use patterns remain approved, the conditions of their use, and the MRLs that apply.

GB’s independent evaluations have raised, lowered, or maintained MRLs differently from the EU, and because neither system updates in parallel, even small changes create divergence. New GB only pesticide authorisations have resulted in higher MRLs than those permitted in the EU. As a result, produce treated with such pesticides could not be exported to the EU or Northern Ireland unless covered by a specific scheme such as the NI Retail Movement Scheme or where import tolerances are granted.

In contrast, when GB lowers an MRL ahead of the EU, goods treated under EU authorisations may not be importable into GB unless GB grants a corresponding import tolerance. NI goods, however, retain unfettered access into GB even where EU MRLs are higher.

When the EU lowers an MRL first, GB produced goods may exceed EU limits, preventing export.

Divergence has expanded significantly as both regulatory systems update MRLs. Since 2021, more than 70 actives have undergone MRL changes in the EU, while GB has implemented over 100 MRL changes. Since MRLs are set crop by crop for each active, these changes amount to thousands of individual GB–EU differences.

Some degree of harmonisation has been achievable in this time, as both GB and the EU apply scientific risk assessments and consider Codex Alimentarius standards when setting MRLs to facilitate trade or meet domestic requirements. Nonetheless, the comparatively slower pace of EU decision making frequently increased divergence between their MRL determinations.

The EU commonly defaults an MRL to the Limit of Quantification (LOQ) representing the lowest quantifiable level using modern analytical methods, when an active loses approval and this can widen divergence. GB, where the same active may remain approved, will often retain a higher MRL based on its own scientific assessment. Any detectable residues above the LOQ become non‑compliant, effectively banning the use of the active substance for crops destined for the EU market, without suitable import tolerances in place.

Future direction of MRL assessments under the Reset Agreement

The UK–EU SPS Agreement was announced on 9 March 2026. To reduce administrative burden and costs associated with trade between the UK and the EU, the UK will align with EU Sanitary and Phytosanitary (SPS) legislation. This alignment covers a wide range of food and feed safety areas, including the regulation of pesticides and biocides.

There remains significant uncertainty around how MRLs will be handled in practice following the proposed Reset deal between the EU and GB. Key questions include whether EU MRLs that are higher than existing GB levels would be automatically accepted, and conversely, whether GB MRLs set above EU values, either through scientific interpretation, national uses, faster processing, or to support international trade, would need to be reduced, potentially creating a cycle of alignment and re‑alignment. It is also unclear how ongoing GB MRL applications will be treated, whether future applications can still be submitted, and whether GB will continue to consider Codex levels independently ahead of dynamic alignment. Additional questions remain regarding the future role of GB in EU/GB MRL‑setting, the treatment of EAMUs (extension of authorisation for minor use) reliant on higher GB limits, and how import tolerances and residue definitions will be managed across the two regulatory systems. Ultimately, the direction will depend on how both parties balance regulatory coherence with scientific independence, and whether the Reset becomes a foundation for genuine long‑term predictability.

However, as GB and the EU continue to align, divergence in MRLs is on course to reduce. For growers, traders, retailers, and regulators, this is advantageous as it decreases practical challenges, including reducing uncertainty over market access, reducing compliance costs, and possibly eliminating the need for specialist monitoring of MRLs.

How can Sagentia Regulatory help?

With extensive experience in preparing MRL dossiers, including import tolerances, Article 10 amendments, Article 12 reviews and GAP submissions, and JMPR Codex MRL setting, Sagentia Regulatory is ideally positioned to support the establishment and ongoing maintenance of MRLs. Whether you require comprehensive project support or simply targeted advice, our expert team can guide you through the submission process, identify and address data gaps, derive MRLs, assess compliance with current limits, perform risk assessments, and advise on any data generation needs.

To learn more about how we can support you, contact Sagentia Regulatory, formerly TSG Consulting, at [email protected], or reach out to your Sagentia Regulatory consultant directly: