The use of competition and the associated increase in choice in health care is a popular reform model, adopted by many governments across the world. Yet it is also a hotly contested model, with opponents seeing it, at best, as a diversion of energy or a luxury and, at worst, as leading to health care inequality and waste. This paper subjects the use of competition in health care to scrutiny. It begins by examining the theoretical case and then argues that only by looking at evidence can we understand what works and when. The body of the paper examines the evidence for England. For 25 years the United Kingdom has been subject to a series of policy changes which exogenously introduced and then downplayed the use of competition in health care. This makes England a very useful test bed. The paper presents the UK reforms and then discusses the evidence of their impact, examining changes in outcomes, including quality, productivity and the effect on the distribution of health care resources across socio-economic groups. The final section reflects on what can be learnt from these findings.