It has been suggested that precautionary approaches to managing the possible health risks of mobile telecommunications (MT) technology may cause or exacerbate public concerns. In contrast, precautionary approaches to managing such risks in the UK have been framed as a way of reducing public concerns. This article presents evidence from a series of focus groups about the understanding of the general public of the actions taken and advice given about potential MT health risks by the UK government. Eight focus groups were conducted with members of the public that varied in their age, their awareness and concern about mast siting, and their self-reported level of mobile phone use. From the analyses, a complex picture emerged in which the understanding of the general public was not primarily framed in terms of precautionary action and advice either provoking concern or providing reassurance. People made sense of precaution by drawing upon a range of evidence from their understanding of the costs and benefits of the technology, as well as the institutional context in which MT health risks were managed. For some of those involved in protesting against mast siting, precaution was seen as confirming existing concern. Further systematic exploration of the contexts within which different responses to precaution emerge is thus likely to be instructive.