The 23,000 consultants who work in the National Health Service are crucial to its success or failure. As well as delivering medical care and treatment to patients, and supervising its delivery by junior colleagues, consultants are responsible for a range of important non-clinical duties such as teaching, management, and clinical audit. However, in addition to their work for the NHS, approximately 16,000 consultants maintain private practices, which raises a number of important issues including that of equity.