Advances in agricultural biotechnology during the 1980s produced new technological innovations in the form of genetically modified (GM) plants. Field trials and the ensuing commercialisation of these crops pressured governments to respond to new environmental risks. Although British and Canadian decision-makers developed similar policy responses to these risks in the early 1990s, stark differences emerged just a decade later. Following massive public resistance to GM crops in the late 1990s, the British government issued a moratorium on commercial planting while it conducted extensive scientific, economic and public consultation research on the risks involved. In 2004 the British government ended the moratorium on GM crops, but announced that co-existence and liability measures must be established before commercial planting can begin. GM crops have yet to be grown commercially in the UK. In contrast, the Canadian public showed little resistance to GM crops and the government considers the environmental risks to be minimal and manageable. Commercial GM crops are now grown on over ten million hectares of farmland. In recent years, Canadian policy-makers conducted a policy review and rejected the need for any revised response. This dissertation explores government policy responses to developments in agricultural biotechnology in Canada and Britain in order to better understand risk decision-making. It argues that Britain and Canada's strikingly different policy responses to the potential risks of agricultural biotechnology can be explained by emergence of a "risk society" in Britain but not in Canada. The dissertation also explores the constellation of forces that appears to have facilitated or restricted the emergence of a risk society in the two cases. The domestic political economy (specifically, institutional structures and the power of sectoral interests), regional political economy (the importance of the United States and the European Union), levels of public trust, and geographical differences in the agronomic and natural environments appear to have facilitated the emergence of a risk society in the UK, while restricting its emergence in Canada.