Research registration and research project identifiers

Last updated on 29 Jan 2024

All research should be registered in a publicly accessible database.

For clinical trials, it is a condition of a favourable ethics opinion. It is good practice for all other studies.

Registering trials reduces research waste. It prevents duplication and means that more people can find out about studies to join.

Trusted information about health and social care studies should be publicly available for the benefit of all, and registration is the first step.

You can read more about this on our transparency pages.

Registration of clinical trials

It is a condition of a Research Ethics Committee (REC) favourable opinion that a clinical trial is registered. You should register your trial before the first participant is recruited and no later than six weeks after.

A ‘clinical trial’ is:

  • a clinical trial of an investigational medicinal product
  • a clinical investigation or other study of a medical device
  • a combined trial of an investigational medicinal product and an investigational medical device
  • any other clinical trial to study a novel intervention or randomised clinical trial to compare interventions in clinical practice. For example, research involving:
    • trials of surgical interventions
    • radiotherapy
    • imaging investigations
    • mental health investigations or therapies
    • physiological investigations
    • trials of products not defined as medicines or medical devices (for example nutritional)
    • complementary or alternative therapies

For the purposes of this condition, a ‘public registry’ is any registry on the World Health Organisation (WHO) list of primary registries or the International Committee of Medical Journal Editors (ICMJE) list of registries which facilitates public access to information about the UK trial.

We ask sponsors to use either or ISRCTN as these both feed in to Be Part of Research, an online service run by the National Institute for Health and Care Research (NIHR) that helps members of the public understand what research is and what it might mean to take part, as well as showing what research is currently happening across the UK.

The use of one of these registries helps bring us closer to having a full record of all UK clinical trials in a single place.

Please note that for trials taking place in both the EU and the UK, registration with the EU Clinical Trials Information System (CTIS) will not satisfy the condition for registration as it does not support visibility of UK trials. Furthermore, CTIS is currently a ‘data provider’ to the WHO and not a primary or ICMJE approved registry.

The sponsor is responsible for ensuring appropriate arrangements are made for making information about the research publicly available before the first participant is recruited and no later than six weeks after. If your trial is already registered when you complete your IRAS application, you should include your registration number. If you register after submitting your IRAS application, you should email the REC and with your registration number as soon as possible. You should ensure you keep the record in the registry up to date.

If you make amendments to your study, update the record in the registry as needed.

If the sponsor decides to abandon a clinical trial before it commences (before any trial procedures such as patient screening / consent set out in the protocol have been initiated), then the trial will not need to be registered.

Registration of trials submitted through combined review

We’ve partnered with ISRCTN Registry to register trials submitted through combined review on behalf of sponsors.

All clinical trials of investigational medicinal products (CTIMPs) and combined trials of an investigational medicinal product and an investigational medical device (IMP/device trials) submitted on or after 1 January 2022 for combined review in the new part of IRAS will have study information sent directly to ISRCTN for registration.

However, if you tell us that you have registered, or will register, on then in your application you can ask your study not to be registered with ISRCTN.

The lawful basis for processing the data for this purpose is official authority under the NHS Care Act 2014 (see our privacy notice).

ISRCTN will be in touch with you to ask for some additional information to finalise the registration. ISRCTN will also let us know the registration number for your trial, so you don’t need to email us.

You should ensure that the record in the registry is kept up to date as the study progresses.

For more information see the HRA-ISRCTN Registry partnership questions and answers pages.

Registration with

If a trial approved through combined review is registered, or will be registered, on, you can request that it is not automatically sent for registration with ISRCTN.

To let us know that you have or will register on, you’ll need to make this clear in your IRAS application. You should do this in section c of the study information section of your combined review application in IRAS. This is not a deferral request. Your study will be published on the HRA research summaries webpage. If you have not included your registration number in your IRAS application, you should email it to the REC and, as soon as possible.

Registration of research tissue banks

It is a condition of favourable ethics opinion that all research tissue banks are registered on the UK Clinical Research Collaboration (UKCRC) Tissue Directory. The research tissue bank should be registered no later than six weeks after favourable opinion, or six weeks after the research tissue bank holds tissue with the intention to provide for research purposes.

Registration means having added details of the types of tissue samples held in the tissue bank. We monitor registration details as part of annual progress reporting. Your research registration reference number should be entered in your dataset on the Integrated Research Application System (IRAS), so that this can be included on your application form(s).

See the Research Tissue Bank webpage for further information.

Publication of the research summary

We publish details about each research study reviewed by a REC in the UK in our research summaries pages. The information is taken from the IRAS application reviewed by the REC. We publish:

  • REC details: REC name, REC reference, REC opinion and date of REC opinion
  • study identifiers: IRAS ID, registration numbers, Human Tissue Authority (HTA) storage licence (research tissue banks only)
  • basic study information: short title, research type (for example, ‘research database’)
  • contact name and email address
  • full title
  • research summary
  • sponsor organisation name
  • establishment organisation and address (research tissue banks and databases only)
  • research programme (research tissue banks and databases only)
  • samples or data collection arrangements (research tissue banks and databases only)

Deferral of registration on a public registry and publication of the HRA Research Summary

We recognise that commercial sensitivity may be a concern in some sectors and so it is possible for applicants and sponsors to submit a request to defer registration of clinical trials on a publicly accessible database.

You can also request to defer publication of the HRA Research Summary. This can be included in a request to defer registration or requested separately.

Deferrals are valid for 12 months. Sponsors can continue to apply to extend the deferral period by 12 months at a time until the study comes to an end. They can then request an extension of the deferral for a specified period, nominated by the sponsor, up to a maximum of 30 months in total from the end of the study (the definition of the end of the study should be documented in the protocol. For most clinical trials this will be the date of the last visit of the last participant).

Where a deferral is agreed we:

Deferral of research summary on the HRA website

Where a deferral is agreed, a minimum research summary will still be published in the research summaries database. At the end of the deferral period, we will publish the full research summary.

Deferral of registration on a publicly accessible database (for clinical trials)

If a deferral is agreed, we expect the sponsor to follow best practice and publish a minimal record on a publicly accessible registry, this applies to any deferrals approved after 31 January 2022. When the deferral period ends, the sponsor should publish the full record on the same registry, to fulfil the condition of the REC favourable opinion.

The HRA deferral policy does not apply to the publication of summary results. However, whilst a valid deferral is in place we do not expect summary results to be made public and the HRA will not publish the summary results on the research summaries pages.

How to request a deferral

If you are using combined review, you can submit a deferral request in the new part of IRAS, by answering the deferral question in part c of the study information question set.

For other clinical trials not submitted via combined review, you can request a deferral by emailing with the following information:

  • IRAS ID and REC reference
  • clear justification for the request

We will confirm whether the deferral has been agreed and provide information about the deferral, including the end date.

After a deferral is agreed: next steps

If we agree a deferral request we will publish a minimum research summary in our research summaries database after the REC final opinion is issued.

For clinical trials, where deferral is approved after 31 January 2022, you should follow best practice and register your trial on a publicly accessible registry, within six weeks of recruitment of the first participant, with minimum fields. When you have done this, email to let us know the registration number. If you would like to request an extension to a deferral, you should email at least ten working days before the end of the deferral period and include:

  • IRAS ID and REC reference
  • clear justification for extending the deferral period

We will review requests on a case-by-case basis and will contact you to let you know whether the extension has been agreed and the extended deferral end date.

Minimum Fields

Where a deferral is agreed, minimal fields will still be published in the research summaries pages, and clinical trials sponsors should follow best practice and register minimal fields on a publicly accessible database.

The minimum fields for research summaries of studies with a deferral are:

  • REC name
  • REC reference
  • REC opinion
  • date of REC opinion
  • short title, title of the Research Tissue Bank or title of the Research Database
  • study duration (for projects only, not applicable for Research Tissue Banks or Research Databases)

For clinical trials, where deferral is approved, the minimum information that we expect to be published on a registry is:

  • registry number
  • investigator name and site address
  • sponsor name and address
  • REC decision and date of decision
  • nature of clinical trial (for example, bioequivalence in 24 healthy volunteers)
  • date of start of trial
  • date of end of the trial in the UK, EU member states (if applicable) and globally (if applicable)
  • date of start of recruitment
  • date of end of recruitment
  • justification of deferral

There is more information about registering clinical trials with minimum fields on the ISRCTN Registry website.

Any questions?

If you have questions about the deferrals policy or process, email

Project identifiers, including the IRAS ID

The IRAS ID is the unique identifier, which is generated by IRAS when you first create a project.

The IRAS ID will be used by everyone involved in the project, whatever the type of health and social care research and the approvals required. Stakeholders across the UK have agreed to adopt the IRAS ID as the common study identifier. This will enable traceability across a whole study lifecycle, from funding through to delivery and dissemination. It will enable data sharing with organisations across the research landscape and streamline services for users. IRAS Help has more information. 

All available project reference numbers should be entered into your IRAS dataset so that they may be included on your application form(s).

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