Beginning in 1959, the translation of measles vaccination from the laboratory to the clinic was a difficult journey. From the very start, the decision over whether to administer experimental measles vaccines to children in Britain had been a fraught one. At various moments, experts and officials advising both the Medical Research Council (MRC) and the Ministry of Health argued over the relative risks of measles vaccines. Although the decision was finally taken in 1968 to begin Britain's first national campaign to vaccinate against measles, it was not without its risks. In 1969, less than one year after the start of the campaign, reports reached the Ministry of Health of children suffering from serious neurological reactions following the use of Burroughs Wellcome's Wellcovax. Following an investigation carried out by the Ministry of Health, the decision was taken to withdraw the vaccine from future campaigns. Yet despite this troubled journey, only rarely did internal tensions reveal themselves in public. Indeed, set to become another therapeutic scandal, the story of Wellcovax is remarkable for its disappearance from the public's view. In charting the history of measles vaccination and the British state, this thesis examines the management of medical risk. It shows how leading British scientific institutions, such as the MRC and the Ministry of Health, attempted to understand, control and communicate the risks of medical innovation. In particular, through situating the decision making process in the wider political context, this thesis examines the relationship between the state and the public sphere. I argue that central to the state's management of experimental and medical risk was a desire to prevent public conflict. Decisions over which risks to respond to, how to respond to them, and how to communicate them to the public, were all made under the spectre of potential controversy. Through politically aware decision making and carefully constructed representations of science, the MRC and Ministry of Health attempted to control scientific, political and public perceptions and debate on the subject of measles vaccination. A story of knowledge, power and at times deception, this thesis examines the relationship between science, society and the state.