Consideration and conclusion
49In Muldrock the High Court observed (at [50]):
"The condition of mental retardation is classified according to its severity as mild, moderate, severe or profound. Mental retardation is defined by reference to both significantly subaverage general intellectual functioning and significant limitations in adaptive functioning. Significantly subaverage intellectual functioning is defined as an intelligence quotient (IQ or IQ equivalent) of about 70 or below".
50The Court proceeded to observe (at [51]) that the fact that the appellant in that case had engaged in some paid employment, and the fact that he held a driver's licence, did not detract from an assessment of his level of retardation. The Court also observed that the appellant, like the applicant in the present case, had been in receipt of a disability support pension.
51By reference to the judgments of Young CJ and Lush J in R v Mooney (CA (Vic) 21 June 1978 unreported) the High Court cited (at [53]) the principle that general deterrence should often be given very little weight in the case of an offender suffering from a mental disorder or abnormality, because such an offender is not an appropriate medium for making an example to others. In Director of Public Prosecutions (Cth) v De La Rosa (2010) 79 NSWLR 1; [2010] NSWCCA 194, McClellan CJ at CL (at [177] - [178]) considered the principles to be applied when sentencing a mentally ill offender. Although the decision in De La Rosa was delivered after the present applicant was sentenced, his Honour's judgment reviewed a number of earlier authorities and consolidated the well established principles for which those authorities stood, and which were applicable to the sentencing of the applicant. Included in those principles was that cited by the High Court in relation to the consideration of general deterrence in the case of a mentally ill offender.
52In the present case, the unchallenged opinions of Dr Westmore included that the applicant had:
(i)a compromised level of insight into the inappropriateness of his behaviour;
(ii)an inability to read and write, other than being able to write his name and date of birth; and
(iii)an employment history which, in recent times at least, had been limited to working in services supportive of those who are intellectually disadvantaged.
53These, and the various other matters to which Dr Westmore referred, all supported his ultimate opinion that the applicant was at least mildly, if not moderately, mentally retarded. Counsel for the applicant submitted that the applicant's mental retardation was at least the same, if not greater than, that of the applicant in Muldrock. However such a comparative exercise may not be to the point. The more important consideration is that the degree of the applicant's retardation was, on any view, significant, and its relevance to sentence obvious.
54His Honour expressly stated that he had paid "careful attention" to the report of Dr Westmore before observing that in his view, it did not "answer all the unanswered questions". He then set out a number of aspects of the report as detailed in [38] above, before considering the pre-sentence report and then reaching the conclusions set out in [40]. He found that the applicant's level of intellectual functioning diminished the objective gravity of the offending "at least to some extent" and that it moderated the requirement for general deterrence "to some extent" before immediately turning to what he considered to be countervailing considerations, including the fact that the applicant posed a danger to the community.
55Although his Honour made lengthy references to the report of Dr Westmore, and although he stated that he had paid careful attention to its contents, he made only a brief reference to Dr Westmore's opinion as to the applicant's mental retardation. Although that factor was of obvious importance in determining an appropriate sentence, his Honour's reference to it passed without any further comment or evaluation.
56The significance of the applicant's mental retardation became even greater in light of Dr Westmore's unchallenged opinion that it had resulted in the likelihood of the applicant having a compromised level of insight into the wrongness of his behaviour. Clearly, Dr Westmore found some causal connection between the applicant's mental state and his offending. In these circumstances, the applicant's mental state not only meant that he was an inappropriate vehicle for general deterrence, it also operated to reduce his moral culpability.
57These matters were, on any view, important considerations in determining the sentence to be imposed. Apart from his Honour's passing reference in the terms which I have noted, there was no further assessment made of them. Moreover, to the extent that his Honour gave those matters consideration at all, he did so in somewhat qualified terms, finding that they were relevant "to some extent". Such a finding significantly understated their significance, and was indicative of insufficient weight having been given to them in the sentencing process. The evidence established that as a mentally retarded adult it was likely that the applicant had a compromised understanding of the wrongdoing of engaging in sexual acts with children. His Honour was required to assess the applicant's criminality in that context. In my view, the relevance, on the question of sentence, of the applicant's mental retardation was substantially greater than that for which his Honour made allowance.
58His Honour also described the applicant's offending (at ROS 5) as being "persistent and deliberate ... notwithstanding the interruption by (his) partner". Whilst on an objective view of the offending that description might be prima facie accurate, it failed to take into account the unchallenged evidence of Dr Westmore as to the applicant's compromised level of insight into his offending.
59For these reasons, his Honour erred in failing to properly apply the principles relevant to the sentencing of an offender who suffers from a mental illness. In particular, his Honour failed to give sufficient weight to the applicant's mental retardation in the particular respects to which I have referred. Those errors were material (see Baxter v R [2007] NSWCCA 237; (2007) 173 A Crim R 284 at [83] per Latham J).
60This ground is therefore made out.