Randomised controlled trials are the gold standard for testing the efficacy and safety of health interventions, especially medications, and researchers in the U.K. are required to gain approval from ethics committees, the regulatory body (Medicines and Healthcare products Regulatory Agency) and local NHS research governance departments for such trials. Although research governance is important to reassure trial participants that their rights and interests are protected, current practice is impeding research and presents a genuine threat to the U.K. and to the NHS's ability to deliver high-quality evidence on which doctors can base clinical decisions and improve the delivery of care. This article discusses recent experience of running large-scale clinical trials and suggests measures that could improve the current situation.