A paedophile music teacher is set to die in prison for his "poisonous" crime that changed his victim's life, an Adelaide court has heard.
Malcolm Winston Day, 80, pleaded guilty to grooming and abusing a 15-year-old student over many months in the early 1980s.
The District Court heard he was already serving a prison sentence for abusing another pupil in 1987.
The court was told when the abuse was revealed at the end of 1981, the victim's relationship with her parents broke down and she struggled to find support.
"I felt despised by my parents and betrayed by Malcolm Day, by the school community, and everyone around me," she said in a victim impact statement.
"I felt lonely, guilty and ashamed, and became isolated and depressed."
On top of her social withdrawal and struggles with mental health ever since, the court heard she had lost her love for classical music.
"I still grieve the loss of creating ephemeral beauty unsullied by guilt and betrayal," she said.
"Malcolm Day's selfish and disgraceful conduct changed my life."
"He poisoned my future for his own pleasure and went on to lie about it."
Apology letter suggests 'insight is lacking'
Day's defence lawyer, Stephen Ey, said given his client's age he was likely to die in prison when handed a cumulative sentence.
"He is not a serious repeat offender … he understands that the offending is serious," Mr Ey said.
But Judge Jo-Anne Deuter said an apology letter from the offender, which the victim was contemplating reading, was cause for concern.
"To the extent that it goes to — I know remorse is stated there, but the comments there would suggest insight is still lacking," she said.
Day is entitled to a sentencing discount for his early guilty plea.
Prosecutor Lucy Hurley said the offending was serious, the impact was tragic, and Day's victim had been entitled to trust him.
"Advanced age … in these sorts of matters should have little weight [in sentencing]," she said.
"He's had the benefit of living what arguably may be his best years as a free man."
Day is due to be sentenced later this month.
