There are often scientific uncertainties and ambiguities surrounding novel industrial technologies. This makes regulatory processes problematic. An examination of the literature on mobile phone technology in the UK shows that whilst government and the telecommunications industry research has not found any clear evidence of ill effects on human health, other studies conducted more or less independently show a more mixed picture. The aim of this paper is to advocate a more open-ended regulatory process when investigating issues that exhibit scientific uncertainty. This process encompasses the views of a wider body of experts and lay persons. In the presence of uncertainty and ambiguity we believe that the precautionary principle is a useful tool with which to examine issues such as mobile phone technology.