This section applies where the court imposes a sentence of detention in a young offender institution in the case of an offender who is subject to a relevant detention and training order.
If the offender has not at any time been released for supervision under the detention and training order, the court may order that the sentence of detention in a young offender institution is to take effect at the time when the offender would otherwise be released under the relevant detention and training order (see section 248(5)).
Otherwise, the sentence of detention in a young offender institution takes effect at the beginning of the day on which it is passed.
In this section “relevant detention and training order” means—