Gabriel is a Belfast-born medical graduate who trained first in general practice and then in public health. He has held senior public health positions both in Northern Ireland and in England and has had extensive experience at top levels in both the Department of Health and the NHS. He has managed many serious NHS clinical failures and played a leading role in the development of clinical governance in the NHS. His contribution to public health has been particularly in the areas of performance management, sexual health, tobacco, obesity, the built environment and sustainability. He is a trustee of the Soil Association and a non-executive director of the National Treatment Agency for Substance misuse. Gabriel has made significant contributions to policy development and the professional literature in medicine and public health, has edited one book and is the joint author of a standard textbook of public health.