A teenager who took part in multiple riots while in youth detention has been sentenced to an adult prison after spending 36 consecutive days locked down in "traumatising and hopeless" conditions.
The 17-year-old boy, who has an extensive record of criminal offending, faced Perth Children's Court last week to be sentenced on charges including assaulting public officers, aggravated home burglary, car stealing and reckless driving to escape police pursuit.
President Hylton Quail heard the boy was involved in a major riot at the Banksia Hill detention centre on New Year's Eve.
Months later, he "terrorised" residents of a suburban housing complex when he climbed onto rooftops and threw tiles at police.
He was arrested and later remanded at Unit 18, a standalone facility for challenging youth detainees at the maximum-security Casuarina adult prison.
The court heard details of a riot on March 31 in which the boy grabbed hold of a female officer and helped pull her to the ground while another detainee attempted to take her keys.
Prosecutors said the boy had threatened to kill another inmate who had attempted to surrender during the struggle.
An officer was also robbed of her keys by other detainees during another disturbance at Unit 18 involving the boy and 12 others in April which caused extensive damage.
Judge Quail noted the boy had spent 111 days in Unit 18 and for 94 of those days, he had been locked in his cell for more than 20 hours.
He said the teenager endured 36 consecutive days of "what amounts to unlawful solitary confinement" between April 16 and May 27.
"Surrounded by food scraps, always threatening and attempting self-harm in a traumatising and hopeless environment," the judge summarised.
"(He) is a prime example of a boy who, when treated badly in custody through never-ending lockdowns, deprivation, solitary confinement in his cell with nothing to do and no stimulation, reacts badly out of frustration and anger."
The state applied for his sentence to be served in an adult prison which could better manage his behaviour, noting he was days away from his 18th birthday and eligible under Western Australia's young offenders legislation.
Judge Quail granted the application and ordered the boy to serve one year and 11 months with eligibility for parole after half that term.
He told him he could not remain at Unit 18 because he was a risk to others but also to himself, given his history of self-harming.
AAP understands the teenager, along with several others around the same age, was sent to the maximum-security Hakea Prison and initially placed in crisis care.
A Department of Justice spokeswoman said the Children's Court had the power to sentence and remand youths aged 16 and over to adult prisons.
The court was told the boy had been briefly left in a wheelchair after crashing a stolen motorbike into a car and had been lucky to survive the incident.
"When you're out in the community - and it's not going to be that far away - you are going to have to make choices," Judge Quail said.
"Next time, (you might) kill yourself when you crash, or you will crash into somebody and kill them.
"Either way, your life will be over. Because you will go to jail for a very, very long time, and it will be a wasted life."
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