[30] In Chester v The Queen a sentencing judge of the Supreme Court of Western Australia had made a direction under s. 662(a) of the Criminal Code (W.A.) that Chester, from the expiration of the finite term of imprisonment to which he was sentenced, be detained during the Governor's pleasure. Chester had pleaded guilty to two counts on an indictment: one alleging unlawful driving of a motor vehicle without the consent of the owner or person in charge of it, and the other of armed robbery. The judge, having considered a pre-sentence report and a psychiatric report attached to the pre-sentence report, sentenced the offender to imprisonment for six months on the first count and to imprisonment for four years cumulative on the second count. His Honour also directed that the applicant be detained during the Governor's pleasure in prison at the expiration of the term of imprisonment. The direction under s. 662(a) was set aside. It was held by the High Court that the exercise of the power conferred by s. 662(a) should be reserved for those 'very exceptional cases' which do not attract the operation of s. 661 of the Criminal Code (which authorizes detention during the Governor's pleasure of habitual criminals) or for which s. 29(1) of the Mental Health Act 1962 (W.A.) (which empowers a justice to order the detention in an approved hospital of a person suffering from a mental disorder) is unlikely to be appropriate. The sentencing judge, it was held, must be satisfied 'by acceptable evidence that the convicted person is, by reason of his antecedents, character, age, health, or mental condition, the nature of the offence or any special circumstances, so likely to commit further crimes of violence (including sexual offences) as to constitute a constant danger to the community'. The stark and extraordinary nature of punishment by way of indeterminate detention, the term of which is terminable by executive, not by judicial decision (by the Parole Board in its discretion), required that the sentencing judge be clearly satisfied by cogent evidence that the convicted person is a constant danger to the community in the sense referred to, the court held (pp. 618-619).