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 Cambridge University and King’s College Hospital, London in 1990 and completed his gastroenterology training within North West London.  He 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.

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, 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.

  • Professional experience

    • Consultant Gastroenterologist, Imperial College Healthcare NHS Trust, London (2006 - present)
    • Director, West London Bowel Cancer Screening Centre (2007 - present)
    • National Endoscopy Lead – BCSP, Public Health England (May 2019 - present)
    • Professional Clinical Advisor, Endoscopy London QA, Public Health England (2009 - 2019)
    • Locum Consultant, Gastroenterology & General Medicine, Hillingdon Hospital, Middlesex (Apr 2002- Jul 2002)
  • 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

    • BA, University of Cambridge (1986)
    • MB BChir, University of Cambridge (1989)
    • MA, University of Cambridge (1989)

    •  MRCP (UK), Royal College of Physicians (1993)
    • MD, University of London (2002)
  • Professional membership

    • Member of British Society of Gastroenterology
    • Member of American Society of Gastrointestinal Endoscopy
    • Member of St Mark's Association
    • British Medical Association
    • Royal College of Physicians of London
    • UK Capsule Endoscopy Users Group
    • Member of NICE Guideline Development Group - Colorectal Cancer
  • 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
    • Hon Senior Lecturer, Imperial College, London (2002 - 2005)
    • Director of National Colonoscopy Training Courses - St Georges National Training Centre
    • Regular faculty at endoscopy training courses – St Mark’s National Training Centre
    • Examiner for Bowel Cancer Screening colonoscopy accreditation assessments
  • Publications and conferences

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

    • Runcorn Travelling Fellowship 2002

 Diseases, Medical Tests and Treatments

  • Abdominal pain
  • Acid reflux
  • Barrett's oesophagus
  • Bloated stomach
  • Blood in stool (rectal bleeding)
  • Bowel cancer
  • Bowel cancer screening
  • Capsule endoscopy
  • Chronic diarrhoea
  • Coeliac disease
  • Colitis
  • Colon cancer
  • Colonoscopy
  • Colorectal cancer
  • Constipation
  • Crohn's disease
  • Diarrhoea
  • Digestive diseases
  • Diverticular disease
  • Dysmotility
  • Dysphagia
  • Endoscopic mucosal resection (EMR)
  • Endoscopy
  • Food allergies
  • Gastrointestinal bleeding
  • Gastrointestinal endoscopy
  • Gastroscopy
  • Helicobacter pylori
  • Indigestion (dyspepsia)
  • Inflammatory bowel disease (IBD)
  • Iron deficiency
  • Irritable bowel syndrome (IBS)
  • Oesophagitis
  • Polypectomy
  • Polyps
  • Rectal cancer
  • Rectosigmoidoscopy
  • Stomach cancer
  • Stomach ulcer
  • Ulcerative colitis

Make an appointment


  • Bupa Cromwell Hospital
    8 Pennant Mews W8 5JN - London (Central London)
    (+44) 02078989995
  • OneWelbeck Digestive Health
    1 Welbeck Street W1G 0AR - London (W1G Marylebone London)
    (+44) 02078664214


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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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Capsule endoscopy: how long does it take to pass?

Capsule endoscopy is a technique that allows visualisation of the entire gastrointestinal tract to enable doctors to diagnose conditions such as coeliac disease and inflammation of the gut. Expert gastroenterologist Dr John Martin explains how the procedure works and how long the capsule takes to pass.

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How to relieve symptoms of IBS

The cause of irritable bowel syndrome (IBS) is not entirely understood. In IBS, the gut appears normal, with no inflammation or any abnormal findings on investigation. IBS is sometimes called a “functional” disorder because symptoms are thought to be caused by the way in which the gut works, for example, the passage of food through the gut may be either too slow or too quick. In addition, the gut may be oversensitive to distension by either gas or food content, causing pain or discomfort. The symptoms of IBS may be exacerbated by certain foods or stress. Here to tell us more about IBS and how we can manage it is Dr John Martin.

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What should I know about a colorectal cancer screening?

Colorectal cancer is the second commonest of cancer deaths in the UK, affecting 1 in 18 men and 1 in 20 women. However, the disease is entirely preventable by the early removal of non-cancerous growths (polyps), which are detected through screening tests. Expert gastroenterologist Dr John Martin explains more...

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  • 10/10 for everything.
  • Dr Martin is a life saver. Can’t recommend him highly enough.
  • I was extremely impressed by Dr Martin and his team. From my arrival to the excellent facilities I was put at my ease and made comfortable.
  • Fantastic brand new and sparkling clean facility with extremely helpful, polite and reassuring staff!
  • Excellent!!
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