In the context of an assessment of how surveillance, security, privacy, and trust is conceptualised in public opinion surveys, Trilateral Research carried out a study to understand the attitudes of members of the public towards the impact of surveillance technologies used to enhance public security on their privacy. These aspects are an essential, yet complex to assess for policy makers active in contexts where public trust plays a central role. This research found three issues relating to past approaches: First, past surveys do not always adequately define or conceptualise the terms they are employing. Second, surveys sometimes rely on the use of examples in lieu of definitions. Finally, and most importantly, it emerged that existing surveys do not always adequately examine the impact of the public’s trust towards the use of surveillance technologies to enhance security, but which may affect their privacy. The findings were used to inform the development of a Europe wide survey to better understand public perceptions of surveillance technologies on enhancing security.