He was a primary school pupil when his male vice-principal first groped him in 2003, but it took the victim 12 years before he reported the incident to the police.

Now 29, the victim told the court yesterday that the abuse continued after he moved into the vice-principal's flat in Woodlands. He moved there after his alleged abuser agreed to become his guardian.

It was not mentioned in court why he made the police report only in November 2015. But by then, the victim was no longer living with the vice-principal, having moved out in 2013.

The vice-principal is on trial for three counts of committing an indecent act on a young person and six counts of having carnal intercourse against the order of nature with the victim when he was a teenager. He has been suspended from his duties.

The victim and the vice-principal cannot be named because of a gag order.

The court heard that the abuse occurred after the victim's mother was repatriated around 2002 for working illegally in Singapore. They had arrived here from China in 1999.

The victim said: "I felt helpless as I didn't know who to approach and told him about the situation. He offered to become my guardian.

"He was the only one I could turn to at that time. I regarded him as my mentor."

He said he was "honoured and privileged" that the vice-principal whom he considered a father figure had allowed him to live in his Woodlands flat for nine years,

Yesterday, the victim told District Judge Chay Yuen Fatt that he was 14 years old and in primary school when the first alleged incident occurred.

Then a vice-head prefect, he often returned to the school with some of his peers at the weekends to rehearse for a group exercise activity designed by the vice-principal. On one of the weekends, the vice-principal told him to go to the gym near the school hall to exercise, and he complied.

The victim claimed the vice-principal then "nudged" his pupil to a wall, pulled down the victim's shorts and groped him. The gym was empty at that time.

He said: "My mind was blank... I was taken aback and was shocked."

After about five minutes, they joined the others in the school hall. When Deputy Public Prosecutor James Chew asked him why he did not tell anyone about the alleged incident, he said: "Even if I told anyone, other people would not believe me."

After the victim's mother was repatriated, a distant relative who lived in Yishun became his guardian. But the victim said he actually lived with a younger cousin - also a Chinese national - in a rented room in Ang Mo Kio. It was during this time that the alleged abuse continued.

In 2004, the vice-principal offered him private tuition in his Woodlands flat. The victim would go there on weekends and after lessons, he would watch television in the man's bedroom.

He said his alleged abuser would show him articles about how it is normal for men to sexually stimulate each other. He said the vice-principal then performed a sexual act on him on his bed.

The victim said: "At first, I was uncomfortable with the articles... I thought that he was trying to help me go through puberty properly."

About a week later, the vice-principal said that he loved him very much, before sexually abusing him again in the flat.

After his Primary School Leaving Examination later that year, the victim said he received a letter from the Immigration and Checkpoints Authority stating that his distant relative could no longer be his guardian.

He believed then it could be because of his mother's repatriation. He told the vice-principal about his situation, and the older man agreed to be his guardian.

The victim moved in to live with the vice-principal, his parents and their maid soon after. He even shared a bed with the vice-principal, the court heard.

The trial continues today.