1. National Centre for Bowel Research and Surgical Innovation, Centre for Digestive Diseases, London, UK
2. Pragmatic Clinical Trials Unit, Centre for Primary Care and Public Health, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University London, London, UK
3. Gastrointestinal Physiology Unit, University College Hospital, London, UK
4. National Centre for Bowel Research and Surgical Innovation, Centre for Primary Care and Public Health, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University London, London, UK
5. The Sir Alan Parks Department of Physiology, St Mark's Hospital and Academic Institute, Harrow, UK