In a memorable quotation from the 1999 Hollister Lecture at Northwestern University, Illinois, Sir Cyril Chantler said “Medicine used to be simple, ineffective and relatively safe. Now it is complex, effective but potentially dangerous”.1 For 50 years the dangers have been recognised, initially as diseases directly related to medications2 and subsequently as hospital induced complications in which an early study showed that 20% of patients admitted to hospital were damaged by the care process. This was regarded as the price of medical progress.3 Neither the medical profession nor departments of health were prepared to address the issues. However, by the 1970s in the USA the insurance industry was crumbling under the weight of a growing number of claims of alleged medical negligence. To reveal the size of the problem the Californian Medical Association commissioned a group of doctors to develop a method of case record review. They showed that about 1% of patients admitted to hospital suffered an iatrogenic event as a result of negligence.4 Ten years later the Commissioner of Health of New York State asked Harvard Medical School to re-examine the issues. The resulting study showed that defects in medical treatment caused disabling injuries in 3.7% of patients admitted to hospital.5 The insurance industry had temporarily stabilised and neither study made much impact.