A predatory teacher gave a student a master key to his prestigious Melbourne private school to develop trust and control before repeatedly sexually abusing him, sometimes on school grounds.
Former Ivanhoe Grammar School teacher Graeme Keith Harder, 60, also had a key to the student's locker and would leave him "long and powerful" notes about his feelings during the period of abuse in the 1990s.
The former Year Nine co-ordinator continued at the school until March this year when he was charged with 33 historic sex offences.
Victorian County Court Judge John Carmody on Thursday said Harder was a charismatic and powerful person who used enticements like school trips, alcohol and other privileges to gain his victim's trust.
The first incident occurred on a school trip to the Victorian coast where Harder used the excuse of an ill student to invite the victim, then aged 15, into his bed.
After performing sex acts on the boy he told him it was "very normal in other countries".
He later abused him on other school trips, at his home, on the school grounds and once in a car on the side of a freeway.
The victim was teased and ostracised by his friends because of the perception about his relationship with the teacher, Judge Carmody said.
"He felt he was trapped without the skills and knowledge of how to get out of it," Judge Carmody said.
During a recorded conversation with the victim in March this year, Harder said he didn't feel as though he had exploited the student and that they had had a "really fantastic" relationship.
He said it was a high point of his life.
Harder has been jailed for five years, with a minimum of three, after pleading guilty to 12 charges of sexually penetrating a child under his care.
Judge Carmody said the offending was "grave and serious" and a gross breach of trust of the student, his family and the school.
