The aim of this study was to evaluate the process of a European school-based intervention programme, ‘Unplugged’, among young people and to contribute in the reduction of tobacco, alcohol and drug initiation by measuring the impact of mediating factors. The Unplugged intervention of the EU-Dap Drug Abuse Prevention network is based on a social influence approach to young people’s substance use and has already been trialled extensively across European countries, Latin-American, African and the Middle-East. 
Schools in three areas of the UK with an identified acute problem of alcohol and drug misuse (n= 214 pupils from 10 schools) were selected. Data were collected before and three months after the training. This study was designed as a one group pre-test post-test design without a control group. The impact of the training was analysed using descriptive statistics and a paired t-test. Fidelity and satisfaction forms were used to evaluate the process of the programme. 
Participants in the programme increased knowledge and risk perception about all substances. The number of girls declaring to have behavioural problems due to alcohol use was lower during post-test, which could indicate that the impact of the intervention was greater for girls than for boys. The process evaluation indicated that the programme can be feasibly implemented in UK schools, however it should be adapted for special schools such as Pupil Referral Units. 
The very small number (214) of matching records imply that databased statements are always relative; since prevalence at age 12 to 14 is low, many findings concern only a limited number of individuals.  Nevertheless, these findings contribute to the need to systematically evaluate school-based interventions, although more research is needed to ensure reliable and valid results on the effectiveness of the Unplugged school-based prevention programme for young people in the UK.