The study investigates the prevalence of illicit drug use beyond that of mere experimentation, examining the 'capture-rates' of cannabis, amphetamines, ecstasy and cocaine used in a cohort of 14-16-year-old adolescents. The data are drawn from eight participating secondary schools across three boroughs in South London. The transition rate from opportunity to use to actual use was most pronounced for cannabis (with a capture rate of one in five), followed by amphetamines, then ecstasy and finally cocaine. However, regular use as a result of having ever used was lowest for amphetamines and cocaine. Age appeared to be a protective factor since the mean age of those who had never been offered either of the drugs was consistently under 15 years of age. In contrast, early onset of drinking and smoking appeared to be a risk factor in those who are offered cannabis and go on to become regular users. While the study contributes to our understanding of pathways and patterns of adolescent substance activities, there are also powerful implications for the targeting of early interventions and educational initiatives for those with early onset and rapid escalation in drinking and tobacco use.