Data are not held centrally on the numbers of 21-year-olds who are transferred from young offender institutions into the secure adult prison estate. Offenders who reach their 21st birthdays towards the end of their sentences normally remain in the young adult estate. Those who have a substantial time still to serve are normally transferred to the secure adult estate soon after reaching 21. Careful guidelines are observed on the management of such transfers.
In exceptional and rare circumstances, an 18 to 21-year-old sentenced offender can be held in an adult prison as an adult on an individual basis (under section 43(2)(c) of the Prison Act 1952) and is managed by local establishment management, where appropriate the offender manager and only when agreed by the Prison Service Area Manager.