The Medicines for Human Use (Clinical Trials) (Amendment) Regulations 2025 say that the chief investigator should be a ‘health care professional’ (the definition of a health care professional is provided below).
Chief investigator
The chief investigator (CI) must be a health care professional and is the lead investigator who takes responsibility for the overall conduct of the trial. In relation to a clinical trial conducted at a single trial location, this will be the investigator for that location.
In relation to a clinical trial conducted at more than one trial location, this will be a health care professional, whether or not that health care professional is an investigator at any particular location, who will take primary responsibility for the conduct of the trial.
The chief investigator’s responsibilities are set out in more detail in the UK Policy Framework for Health and Social Care Research.
Health care professional
This definition applies to both chief investigators and investigators. A ‘health care professional’ will be defined as any of the following:
- a doctor
- a dentist
- a registered nurse as defined in regulation 8(1) of the Human Medicines Regulations 2012
- a pharmacist
- a person registered in a register of ophthalmic opticians maintained under section 7(a) of the Opticians Act 1989
- a person registered in the Health and Care Professions Council register (as defined in regulation 8(1) of the Human Medicines Regulations 2012) as a member of a relevant profession within the meaning of article 2 of, and paragraph 1 of Schedule 3 to, the Health Professions Order 2001
- a registered osteopath as defined by section 41 of the Osteopaths Act 1993
- a registered chiropractor as defined by section 43 of the Chiropractors Act 1994
- a person registered under the Anaesthesia Associates and Physician Associates Order 2024
- a registered midwife as defined in regulation 8(1) of the Human Medicines Regulations 2012
Investigator
An investigator, in relation to a clinical trial, is defined as a health care professional who is responsible for the conduct of that trial at that trial location (or, if there is more than one, the trial locations) and who is, if the trial is conducted by a team of health care professionals at that location or locations, the leader responsible for that team. Investigators must be appropriately trained to undertake the role in a clinical trial.
The terms ‘investigator’ and ‘principal investigator’ are considered to be interchangeable as they both refer to the investigator who takes the lead investigator role at a trial location.