AbstractThe regime for regulating the intentional release ofgenetically manipulated organisms (GMOs) is emerging in a climate of ecological uncertainty and some public concern. Attempting a rhetorical greening of biotechnology, industry portrays GMOs as precisely reprogrammed organisms, as modest evolutionary modifications, enhancing a natural efficiency. Drawing upon those metaphors, it promises ‘environment-friendly’ products, akin to, and protective of. Nature. That portrayal is contested by those who advocate a more wide-ranging precautionary approach to regulation. Focusing on Britain, this essay explores the conflicts of value as manifest in contending concepts of GMOs and in proposals for regulating their intentional release into the environment.