The legislation provides that if the offender fails to abstain from alcohol and drugs and does not attend treatment during the prescribed period, then the original prison sentence may be imposed. The provision applies when drunkenness or drug addiction is a necessary part of the offense, a custodial sentence would be appropriate for the offense, the offense is not serious enough to require a general deterrent penalty, and the offender is a habitual drug or alcohol user. The provision and its implementation have been criticized by judges, magistrates, barristers, solicitors, treatment staff, police, and clients. Underlying the criticisms are assumptions that clients often continue to abuse drugs and alcohol despite the order, many clients who do not comply with the order are not returned to the sentencing court for further action, many clients commit other offenses during the diversion period, and most orders are made by city and suburban magistrates' courts. Empirical research, however, indicates that section 13 is more effective than its critics believe. It is sufficiently effective to warrant its retention. This article suggests legislative and administrative changes that can improve the section's operation. 38 notes.