The term of a detention and training order in respect of an offence may not exceed—
in the case of a summary offence, the maximum sentence of imprisonment that could be imposed (in the case of an offender aged 21 or over) for the offence;
in the case of any other offence, the maximum term of imprisonment that the Crown Court could impose (in the case of an offender aged 21 or over) for the offence.
Section 231 (length of discretionary custodial sentences: general provision), in particular, applies in determining the term of a detention and training order.
A detention and training order takes effect at the beginning of the day on which it is made, unless the court orders otherwise under section 237.