Transforming the UK's clinical trial landscape

The UK's clinical trial regulations are changing.

The Health Research Authority (HRA) has been working in partnership with the Medicines and Healthcare products Regulatory Agency (MHRA) to amend the Medicines for Human Use (Clinical Trials) Regulations 2004.

Our goal is to create a modern, streamlined regulatory environment that maintains high standards of participant safety while accelerating access to innovative treatments.

Feedback from a public consultation in 2022 helped shape proposals to improve how clinical trials of medicinal products (CTIMPs) are run in the UK. These changes aim to make the UK one of the best places in the world to conduct clinical research.

The updated Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 have now been approved.

This page brings together everything you need to know during the implementation period and beyond.

New guidance to support researchers and sponsors

We've published new guidance to accompany the updated clinical trials regulations.

Read more in the guidance section below.

Who these changes affect

These updated regulations will impact everyone involved in CTIMPs in the UK:

  • researchers and sponsors
  • Research Ethics Committees (RECs)
  • trial participants and the public
  • healthcare professionals

Why these changes matter

The reforms will:

  • align the process for the MHRA and RECs to review and approve applications and substantial modifications
  • enhance transparency and accountability for research findings
  • reduce unnecessary burdens while upholding ethical and safety standards

Together, these improvements will strengthen the UK's position as a global leader in clinical research.

Key changes in the regulations

The following areas of the regulations have been updated.

Transparency

For the first time, it will be a legal requirement to:

  • register clinical trials in a public registry
  • publish a summary of trial results within 12 months of completion
  • offer to share a summary of results with participants (or their representative) in a format they can easily understand

Provisions for deferrals in specific circumstances, such as phase I trials involving healthy volunteers, will be available. We'll provide guidance to support researchers in meeting these new requirements.

Research Ethics Committees (RECs)

Changes to RECs will improve flexibility while aligning with international good clinical practice (ICH-GCP E6). When the new regulations come into force RECs will:

  • need at least five members that collectively possess the qualifications and experience to review and evaluate any proposed trials' scientific, medical, and ethical aspects
  • still be expected to have an appointed Chair
  • include one lay member

Guidance instead of legislation

Some areas will be supported through detailed guidance rather than new legal requirements.

We are leading work on guidance to support best practices in diversity and inclusion, and public involvement in clinical trials.

Diversity and inclusion in clinical trials

Including a wider range of participants ensures trial findings reflect the entire population's needs.

Our Public Perceptions of Research - Health Research Authority found that:

  • 88% believe trials should involve a diverse group of participants.
  • 70% support this even if it increases costs
  • 74% are in favour even if it extends timelines

We've developed a draft set of questions and supporting guidance jointly with the Medicines and Healthcare products Regulatory Agency (MHRA) for researchers to consider when they design clinical trials and clinical investigations. The answers to these questions will form the basis of an Inclusion and Diversity Plan.

This will help ensure clinical research is designed to include people who could be impacted by the findings, and that people underserved by research are not overlooked.

Following an informal consultation on the draft questions and supporting guidance in 2024, we are undertaking a pilot in which sponsors and researchers will be invited to submit a plan as part of their IRAS application. If you are planning to submit an application for a clinical trial or clinical investigation in 2025 and would be interested in taking part, please get in contact.

Public involvement

Involving the public in designing, delivering, and reporting clinical trials leads to better outcomes and builds trust.

We're updating our website to:

  • provide clear expectations for public involvement in health and social care research, including all phases of clinical trials
  • point to the wide range of resources available across the sector
  • include specific recommendations for Phase 1 healthy volunteer trials

The updates will help researchers meaningfully involve the public in all clinical trials.

Timeline of key changes

Clinical trial regulations timeline.png
A timeline of the process to update the UK's clinical trial regulations

Past milestones

What's next

  • 28 April 2026 - implementation of the amended regulations

Post-publication note

The new clinical trials regulations will now come into force on 28 April 2026.

The date was changed due to a technical issue during the final processing of the Statutory Instrument (SI) within the digital legislation platform, which meant the SI needed to be re-signed on 28 April 2025.

Support for researchers and sponsors

We're working closely with our stakeholders to ensure there is a smooth transition for the updated regulations.

To help with this we'll be producing:

  • guidance – new resources will be published throughout 2025 (see guidance section below)
  • training – online sessions, webinars and workshops will be available to explain the changes
  • frequently asked questions – answers to common questions will be hosted on this page

New guidance to accompany clinical trials regulations

We’ve now published guidance to help prepare researchers and sponsors for the changes that will happen when the new clinical trials regulations come into force in April 2026.

The guidance outlines the review and assessment processes for CTIMPs by RECs and the MHRA.

Our guidance covers the following updates to the regulations which have been a key focus for the HRA:

The guidance does not cover changes to other reviews of CTIMPs, for example study wide review. If changes are made to the way we review these types of applications or to non-CTIMP applications, we’ll share separate guidance and information with you.

If you have any comments or would like to share feedback on the new published guidance, please complete our online survey by 5pm on Wednesday 10 September 2025.

If you would prefer to provide your feedback on how our guidance is written by email, or you have any questions, please email the HRA's engagement team.

The MHRA has also published separate guidance to accompany the new regulations which you can read on their clinical trials hub.

Useful links

Sign up for updates on the clinical trial regulations

We send out regular email updates on the changes to the clinical trials regulations in the UK.

These emails included updates on the different areas the HRA is leading on, as well as opportunities to get involved and provide feedback.

You can take a look back at previous editions on our clinical trials update webpage.

Sign up to receive updates

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