 In a case where a youth is jointly charged with an adult, they will both appear before the adult court, although that court may choose to remit the youth to the youth court for sentencing.A sentence of detention in a young offenders' institution (or YOI) is available to the court in respect of those between the ages of 15 and 21 years (inclusive) who have committed imprisonable offences.The relevant provisions are contained in the Criminal Justice Act 1982, which introduced the sentence to replace borstal training.