18. Extended sentences of imprisonment and detention.

The court1 may impose extended sentences of imprisonment (where the offender is aged 18 or over2) or detention (where the offender is under 18) for specified violent or sexual offences3. An extended sentence of imprisonment or detention is a sentence of imprisonment or detention the term of which is equal to the aggregate of the appropriate custodial term4 and a further period (the 'extension period') for which the offender is to be subject to a licence5. The extension period must be a period of such length as the court considers necessary for the purpose of protecting members of the