To ask the Secretary of State for Justice how many young offenders aged (a) 12, (b) 13, (c) 14, (d) 15, (e) 16, (f) 17, (g) 18 and (h) 19 years old have tested positive in screening for substance misuse in each young offender institution in each year since 2002; and how many such offenders had access to early intervention and treatment services in each such year. 
I have been asked to reply.
The counselling, assessment, referral, advice and throughcare service (CARATs) is the key non-clinical gateway drug treatment service in prisons for prisoners aged over 18. Young people's substance misuse services (YPSMS) provides a similar service for all young people (aged 15-18) in custody.
The following tables shows the number of initial assessments carried out by CARATs and YPSMS in each young offender institution (YOI) for the full financial years since 2002-03 (YPSMS data are only available from 2005-06). This gives an indication of the number of adults and young people engaged with drug treatment services in YOIs, although the level of engagement will vary according to individuals' needs. It is not possible to break down these figures by age.
Figures have been drawn from National Offender Management Service administrative data systems. Although care is taken when processing and analysing the returns, the detail collected is subject to the inaccuracies inherent in any large scale recording system. The data are not subject to audit.