A Japanese musician who boasted about abusing mentally-ill classmates when at school has quit his role as part of the creative team for the Tokyo Olympics opening ceremony after outcry at his appointment.

Keigo Oyamada, better known by his stage name Cornelius, was last week named as one of the music composers for the opening ceremony after a career spanning more than 25 years.

That announcement saw two interviews he gave to Japanese music magazines in 1994 and 1995 resurface, in which he described inflicting horrific abuse on his peers when at school.

He described locking a disabled classmate in a box, taping a cardboard box around his head and pouring chalk inside, wrapping him in a mattress and kicking him, making him eat his own faeces, and forcing him to masturbate in front of other students.

Following widespread criticism of his Olympic role, Oyamada released a statement apologising “from the bottom of my heart” for his actions, but declined to step down.

Tokyo Games organisers also insisted they wanted Oyamada to remain involved.

“At the moment, he has made a full apology,” said Tokyo 2020 chief executive Toshiro Muto on Saturday. “He is sorry for his past actions and he has said that he wants to act with high morals.

“It is true that the organising committee was not aware of what Oyamada had done in the past. However, we have heard Oyamada’s apology and we are hoping that he will continue to contribute to the Tokyo Games.”

Keigo Oyamada apologised 'from the bottom of his heart'

Credit: GETTY IMAGES

However, after sustained criticism from within Japan and worldwide, Oyamada finally relinquished his position on Monday.

In his initial apology delivered last week, Oyamada, 52, said: “In past magazine interviews, I spoke of my thoughtless remarks and actions towards my classmates in my school days and people with disabilities at neighbouring schools without reflecting on what I did at the time. I take it seriously that I deserve to be criticised.

“I sincerely apologise to my classmates and their parents who have been hurt by my words and actions, and I feel deep regret and responsibility for not being a good friend in school life, which is supposed to make good memories, but being in a position to hurt them.

“When I was a student and at the time of the interview, I couldn’t imagine the feelings of the victims. I think I was very immature.”