Surgeon Rear Admiral Lionel John Jarvis, CBE, KStJ, QHS, FRCR, DL is a British consultant radiologist.

Lionel Jarvis trained at Guy's Hospital University of London, graduating in 1977 before joining the Royal Navy.

During this tenure Jarvis was the Defence Consultant Advisor in Radiology from 1995 to 2002, responsible for worldwide diagnostic imaging for all UK armed services.

Jarvis was then promoted to Surgeon Rear Admiral on 2 June 2008,[3] and became the Assistant Chief of the Defence Staff for Health, responsible for managing oversight of UK and NATO military operations and healthcare delivered worldwide.

He established clinical and organisational governance in the hospital's early years, achieving external accreditation with Joint Commission International.

Jarvis has co-authored a number of publications relating to the effects of climate change on the medical world; a topic which he is passionate about.

As well as serving on the Faculty Board of Clinical Radiology, on the UK National Information Governance Board, as part of the Academy of Colleges Information Group, and on a number of other national academic UK committees, Jarvis was the Chairman of the IT Committee of the Royal College of Radiologists.

[8][9] In the same year Jarvis was also appointed as an Officer Brother (OStJ) of the Most Venerable Order of the Hospital of Saint John of Jerusalem.