Despite the popularity of mobile telecommunications there has been growing concern in the UK since the mid 1990s about possible health effects from the extremely low frequency radiation (EMF) associated with mobile phones and the masts (radio base stations) for transmitting their signals. By early 2000 there were over 300 campaign groups nationally against the siting of particular masts, and similar campaigns in a number of other countries. The campaign highlighting risks from mobile phones has not yet been subject to academic enquiry. The UK government’s reaction to the expression of concerns, particularly through the Stewart Enquiry 1999-2000, has been important in consolidating a precautionary approach in policies governing science related issues of public concern. Similar perceived risks appear likely to prove influential in framing public attitudes and government responses.