1. Department of Colorectal Surgery, Manchester University NHS Foundation Trust , Manchester , UK
2. Clinical Trials Research Unit, Leeds Institute of Clinical Trials Research, University of Leeds , Leeds , UK
3. Faculty of Medicine and Dentistry, Queen Mary University of London , London , UK
4. Bristol Centre for Surgical Research, Population Health Sciences, University of Bristol , Bristol , UK
5. NIHR Bristol Biomedical research Centre , Bristol , UK