Primary school children should be eligible for the DNA database if they exhibit behaviour indicating they may become criminals in later life, according to Britain’s most senior police forensics expert.Gary Pugh, director of forensic sciences at Scotland Yard and the new DNA spokesman for the Association of Chief Police Officers (Acpo), said a debate was needed on how far Britain should go in identifying potential offenders, given that some experts believe it is possible to identify future offending traits in children as young as five.