1. Department of Medicine, Imperial College London, SW7 2BU, UK
2. College of Medical & Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
3. GKT School of Medical Education, King's College London, London, SE1 1UL, UK
4. Barts & The London School of Medicine & Dentistry, Queen Mary University of London, London, E1 2AD, UK