Objective: To review the principles underlying medical student selection from the perspective of the imperatives of widening access policies. Setting: A recent government initiative has increased the number of medical school places in Great Britain. A priority is to widen access to sections of the community hitherto inadequately represented in medical schools, including applicants from disadvantaged areas and lower socio-economic groups, in order that the social characteristics of the population of future doctors better reflects society as a whole. Outcome: An analysis of evidence upon which medical student selection policies and practice have evolved in order to: (1) provide guidelines to shape programmes aimed at raising aspirations to a career in medicine in target groups under-represented in medical schools; (2) establish a template for flexible and inclusive selection and admission policies; and (3) increase the representation of students from diverse backgrounds. Conclusions: It is possible to define a set of principles to increase the diversity of the medical school class with respect to both academic and personal qualities thereby widening access to students from disadvantaged communities and those with broader backgrounds of experience.