1. A biometric system comprising: a biometric capture unit for capturing biometric data from a user; and control means for producing a biometric template there from and for analyzing the template to determine if the enrolment measurement may be susceptible to allowing false acceptances when in use, by using the template as a test template against which templates created from biometric measurements obtained earlier from other sources are compared, and a decision as to whether or not to accept the enrolment measurement is made dependent on the number of false accepts detected.