Dr Martin


  • Colonoscopy
  • Capsule endoscopy
  • Inflammatory bowel disease (IBD)
  • Polypectomy
  • Irritable bowel syndrome (IBS)
  • Bloated stomach

Dr John Martin

GMC: 3336920

Dr John Martin graduated from Girton College, Cambridge and King’s College Hospital, London in 1990 and completed his gastroenterology training within North West London.  He is a highly-experienced gastroenterologist 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.

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.

Dr Martin is Director of the West London Bowel Cancer Screening Centre, is a professional advisor to Public Health England on the quality and safety of Bowel Cancer Screening within London and is a member of 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.

  • Professional experience

    • Consultant Gastroenterologist, Imperial College Healthcare NHS Trust, London (present)
    • Director, West London Bowel Cancer Screening Centre (present)
  • Public positions

    • Professional advisor to Public Health England on maintaining endoscopy quality within Bowel Cancer Screening
    • Member of advisory committee to NICE on colorectal cancer management guidelines
  • Education

    • Trained as a gastroenterologist in North West London
    • King’s College Hospital, London (1986)
    • Cambridge University, Girton (1983)
  • Professional membership

    • Member of British Society of Gastroenterology
    • Member of American Society of Gastrointestinal Endoscopy
    • Member of St Mark's Association
  • Teaching posts

    • Teaches colonoscopy within Imperial College Healthcare NHS Trust
    • Teaches at at national screening centres
    • Colonoscopy teaching faculty at St Georges National Endoscopy Training Centre
  • Publications and conferences

    • Numerous papers, chapters and articles written on his subject field

 Diseases, Medical Tests and Treatments

  • Capsule endoscopy
  • Colonoscopy
  • Inflammatory bowel disease (IBD)
  • Polypectomy

Make an appointment


  • Bupa Cromwell Hospital
    8 Pennant Mews W8 5JN - London (Central London)
    (+44) 02078989995


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Is bloating ever a sign of something serious?

Bloating is a common sensation that many of us have experienced. While it's very rare that it's a sign of something serious, it's valuable to know when to see a specialist for advice. Dr John Martin, a gastroenterologist, explains the causes of bloating so that you know when to seek medical help.

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Dysmotility: a focus on the oesophagus

Oesophageal dysmotility is a condition in which the muscles in the oesophageal wall fail to contract as they should. This may result in discomfort and/or difficulty in swallowing. Dr John Martin is an expert in treating dysmotility of the intestine, and here he explains in detail about causes and treatment of dysmotility in the oesophagus.

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Intestinal dysmotility: causes and treatments explained

Intestinal dysmotility is a common condition that causes a wide range of different symptoms with variable severity. Dr John Martin, a gastroenterologist with expertise in all aspects of gastroenterology, explains what this condition is and the treatment options you may be offered.

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What to expect after a colonoscopy?

Have you been told that you need a colonoscopy? A colonoscopy allows your doctor to take a look at your colon and rectum to find cancer or polyps. It is a safe examination with very few risks. Dr John Martin tells us a bit more about what to expect after a colonoscopy and what recovery looks like.

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The pros and cons of a virtual colonoscopy

Colonoscopies after the age of 50 become a regular procedure to check inside the colon for abnormalities. Nowadays, a virtual colonoscopy is available to patients and offers a non-invasive and less aggressive alternative to a regular colonoscopy. But what happens during the procedure and can it offer more reliable results? Dr John Martin, a leading gastroenterologist in London, explains what a virtual colonoscopy is and why it might be right for you.

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Colon polyps and the polypectomy procedure

Polyps are abnormal growths within the colon that vary in size from a few millimetres to several centimetres. Most of these are not cancerous, but some have the potential to develop into a cancer. Because of this risk, your doctor will very likely recommend that these are removed via a polypectomy. Here gastroenterologist Dr John Martin talks you through all you need to know about polyps and having a polypectomy.

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