Dr John Martin is a highly-experienced gastroenterologist and endoscopist based in London and holds an NHS Consultant post at Imperial College (ICL). He is an expert in colorectal cancer screening, therapeutic and diagnostic colonoscopy and has 25 years' experience of managing all aspects of gastroenterology including abdominal pain or discomfort, reflux disease, diarrhoea and constipation, rectal bleeding, irritable bowel syndrome, Crohn’s disease and ulcerative colitis. 

Graduated from Cambridge University and King’s College Hospital, London in 1990, Dr Martin completed his gastroenterology training within North West London. In 2002, he was awarded an MD from the University of London in bowel cancer screening and became a consultant at Chelsea and Westminster Hospital before joining Charing Cross Hospital in 2006. Dr Martin refined his skills in colonoscopy to ensure they are always safe, high-quality and comfortable for his patients. 

Dr Martin teaches colonoscopy both within the NHS Trust and also at national screening centres. He is a bowel cancer screening accredited colonoscopist and an examiner for BCSP colonoscopy accreditation. He has authored numerous peer reviewed publications.  

Dr Martin is director of the West London Bowel Cancer Screening Centre; he is the national advisor to Public Health England on endoscopy within the Bowel Cancer screening service and chairs the national advisory committee on quality and safety of endoscopy within screening. He forms an integral part of numerous other professional bodies and has been widely published in peer-reviewed journals.