Professor David Leslie is a consultant endocrinologist at Barts NHS Trust and a professor of diabetes and autoimmunity at the Blizard Institute, Queen Mary, University of London. He also sees patients privately at several locations, including The Lister Hospital and The Wellington Hospital.

Professor Leslie's specialist interests include diabetes and thyroid disorders. His research focuses on the causes of autoimmune diabetes through the study of twins and disease syndromes. He qualified and trained at Imperial College, King's College Hospital, and the Royal Victoria Infirmary in Newcastle. He furthered his expertise as an MRC Travelling Fellow at the University of Chicago, USA, and as a Wellcome Trust Senior Clinical Research Fellow at King's College and Charing Cross and Westminster Medical Schools.

Throughout his distinguished career, Professor Leslie has published 12 books and more than 250 peer-reviewed papers. He has received grants from numerous agencies, including the EU, Wellcome Trust, and MRC. In 2012, he was elected President of the Association of Physicians of Great Britain and Ireland. He also holds the title of Emeritus Professor at Central South University, China, and the University of Rome, Italy.

Professor Leslie treats a range of conditions, including diabetes, diabetes insipidus, parathyroid disease, thyroid problems, hypothyroidism, and general medical issues. His expertise in autoimmunity is widely recognised, making him a leading figure in his field.