A study was conducted to investigate the body movements of participants waiting to be interviewed in one of two conditions: preparing to answer questions truthfully or preparing to lie. The effects of increased self-awareness were also investigated, with half of the participants facing a mirror; the other half facing a blank wall. Analysis of covertly obtained video footage showed a significant interaction for the duration of hand/arm movements between deception level and self-awareness. Without a mirror, participants expecting to lie spent less time moving their hands than those expecting to tell the truth; the opposite was seen in the presence of a mirror. Participants expecting to lie also had higher levels of anxiety and thought that they were left waiting for less time than those expecting to tell the truth. These findings led to the identification of further research areas with the potential to support deception detection in security applications.