Mr Gregory Thomas is a Consultant Colorectal Surgeon at St Mark's Hospital (The National Bowel Hospital), London. 

His specialist interests are in pelvic floor disorders (faecal incontinence, constipation, anal pain, post obstetric injuries, rectal prolapse), proctology (haemorrhoids, fissures, fistula, skin tags), abdominal wall hernia and diverticular disease.

He qualified from Imperial College School of Medicine (St Mary Hospital) in 2003 with a distinction in surgery and an intercalated BSc from Imperial College, London. His basic surgery training was undertaken at St Mary Hospital and in the Northwest London region.

Mr Thomas received specialist general and colorectal training in Southwest London and Surrey. He undertook two years of research into pelvic floor disorders at St Mark Hospital (a world renowned hospital for bowel disorders) and was awarded a post-graduate research degree (MD) from Imperial College, London. He has maintained a strong ongoing research interest in this field. He has published over 50 peer reviewed papers and text book chapters on pelvic floor and colorectal disorders. He has presented widely on these subjects at national and international meetings.

He was awarded a travelling fellowship from the Association of Coloproctology of Great Britain and Ireland in 2016, and has spent time at the  Cleveland Clinic Hospitals in Florida and Ohio, and at the Centre Hospitalier Universitaire de Nantes, France. He received the FRCS from the Royal College of Surgeons of England in 2016. Mr Thomas spent a further year at St Mark's Hospital as a Resident Surgical Officer for higher post graduate training. He was previously a consultant colorectal surgeon at Ashford and St Peter's NHS Trust in Surrey.