sentence — doing an act in preparation for, or planning, terrorist act offence contrary to s 101.6(1) of Commonwealth Criminal Code — nature and circumstances of the offence — s 16A(2)(a) — objective seriousness — fact that offender acted alone does not serve to mitigate offence — nature of terrorism offences that frequently committed by “lone wolves” — absence of factor that may aggravate offence does not operate to render less objectively serious —apparent commitment of offender to carry out plan is concerning — already come to attention of authorities in relation to access to extremist violent material, yet renewed online research within six months of police search of family home and renewed with specific purpose in mind namely commission of terrorist act — offender’s claim that did not think intervention was serious because not arrested sits uneasily with trauma offender and family experienced during search and interrogation — may have wavered in commitment but those doubts appear to have been resolved — evidence demonstrates that as at date of arrest offender persevering with stated plan — very limited period of planning — must be observed that offence not necessarily less serious than offences which have advanced beyond initial planning stages — legislative scheme premised on criminalisation of preparatory acts — depth and extent of offender’s radicalisation considerable — barbarous nature of offence that offender actively contemplating — communications with operatives — extremist nature of material which offender had been accessing over period of one year — offender’s religious and ideological motivation apparent from interview with police following arrest despite professed adherence to Australian law — no other penalty than substantial term of full-time imprisonment appropriate in order to reflect factors to which have referred — offence above low end of range of objective gravity — contemplated attack which was ideologically and religiously driven and chosen for impact such attack would have had on public holiday of great national significance — age — mental condition— s 16A(2)(m) — degree to which offender’s youth ameliorates weight to be attributed to general deterrence and denunciation is live issue — offender suffering from major depressive disorder at time of offence — impaired judgment beyond that which recognised as feature of adolescence — degree of overlap between principles attaching to sentencing of juveniles and mitigation of sentence on grounds of mental illness — both recognise that an offender’s moral culpability may be reduced for substantially the same reasons — principles of general deterrence and denunciation play somewhat lesser role in sentencing exercise — can only go so far — guilty plea — s 16A(2)(g) — offender did not plead guilty at earliest opportunity — did so after legal representatives were in position to give full and appropriate advice — considerable utilitarian value in timing of plea — assess value of plea at 20% — hardship to the offender — offender already experienced an assault whilst in custody — notwithstanding trauma and stress occasioned by that event and custodial conditions offender has adjusted satisfactorily — given offender’s exposure to bullying and assaults on basis of nature of offence, special circumstances justifying offender’s detention as juvenile offender up to age of 21 — sentence imposed 12 years’ imprisonment with 9 year non-parole period — to be detained as juvenile until turns 21
