The maximum term of detention in a young offender institution that a court may impose for an offence is the same as the maximum term of imprisonment that it may impose for the offence in the case of a person aged 21 or over.
The minimum term of a sentence of detention in a young offender institution is 21 days.
Section 231 (length of discretionary custodial sentences: general provision), in particular, applies in determining the term of a sentence of detention in a young offender institution.
For further provision about the term of a sentence of detention in a young offender institution, see—
section 265 (special sentence for certain offenders of particular concern);
section 268 (extended sentence).
section 268B (serious terrorism sentence).