In the UK, there is great concern about the perceived increase in plagiarized work being submitted by students in higher educations. Although there is much debate, the reasons for the perceived change are not completely clear. Here we present the results of a 2-year trial of the JISC Plagiarism Detection Service (PDS) involving hundreds of students. The effectiveness of the service in detecting plagiarized material and in acting as a deterrent are discussed. Although an increased number of cases of plagiarism were detected during the trial, the relative contributions of the electronic detection system and increased staff awareness remain unknown. (Contains 2 figures.)