LONDON — It was a crime the defence characterized as a "stumble" that led to a fall.

The assistant Crown attorney called it an inexcusable breach of trust.

A conversation that award-winning London teacher Greg Stewart, 55, overheard one of his Grade 8 pupils have started a two-month process that led him to touching the 14-year-old's breast in a classroom and pleading guilty to sexual assault.

Stewart, who worked for 29 "unblemished" years at Orchard Park public school, pulled his 14-year-old pupil aside in late January 2009 and told her he'd overheard her talking about masturbation.

He advised her how to touch herself in the shower, and told her to masturbate at 11 p.m. so he could do so at the same time at his own home.

The next day, he asked her if she'd done her "homework."

Stewart, originally charged with invitation to sexual touching, sexual interference and sexual assault, pled guilty to sexual assault.

His sentencing hearing began in a London court Monday.

His victim delivered a victim impact statement that detailed a loss of self worth, a loss of friends and hardship on her family.

"I felt like I don't belong anywhere. My friends rejected me and my parents thought of me differently," the girl, whose identity is protected by a publication ban, told Justice John Skowronski.

"I was scared of going into Grade 9. I was bullied. People wrote terrible things about me on Facebook and carved things onto my locker. I didn't do anything wrong . . . Even my teachers gave me the cold shoulder."

Her grades dropped, she became depressed and her relationship with family members became strained.

Because Stewart was such a popular teacher and coach at Orchard Park, many didn't believe the charges against him, assistant Crown attorney Karen Bellehumeur told the court.

The well-liked teacher won a Prime Minister's Award for teaching excellence in 1993. Stewart's family, friends and colleagues wrote letters about his character and career to support a submission by his lawyer, Patrice Band, that he shouldn't get any jail time.

"Mr. Stewart stumbled and fell from a position of authority," Band said.

For two months, Stewart would take the girl aside and ask her about masturbation, tell her to "Google" it and told her about ways to touch herself.

On March 24, he "stumbled and fell" when he touched the victim on the breast while in a classroom with her and another pupil.

He slid his hand down the side of her body to her hip and thigh, and immediately removed it when the girl poked her friend to show her what was going on.

Later that day, he took the victim aside and apologized.

"Sorry about this morning," he told the girl.

"That's kind of weird. I'm a 14-year-old. That's wrong," she replied.

"I know. Can I do it again?" Stewart said. "Please?"

He continued to talk to her about masturbation, according to an agreed statement of facts, and told her to use a banana or candle as a sexual aid. The next day, the girl told another teacher what had gone on.

The teacher confronted Stewart, who asked to apologize to his victim.

"I'm sorry. I didn't know I was making you uncomfortable. I've had a good career here, I don't want it to end now," the girl said Stewart told her.

"I sat there and looked down and said I'd think about it," she told police.

Stewart was arrested that night.

About 15 supporters of Stewart, who turns 56 Wednesday, sat in the courtroom. Among them were his mother.

While in detention before his bail hearing, Stewart was punched repeatedly by a man who was eventually convicted o assaulting him.

"He's scared about what happened in cells. He's a broken man. He was previously gregarious and fun-loving ," Band said.

Stewart's detention before his bail hearing was "punishment paid up front, but it's punishment nonetheless," his lawyer said.

Stewart read a statement before the court, in which he apologized to the girl and her family and said he felt guilt and embarrassment.

"I am shamed and remorseful that this happened," he said. "It continues to be difficult to bear the burden of shame."

The impact of the assault in courthouse cells continues to haunt and "terrify" him, Stewart said, and he can't sleep.

Skowronski addressed the fact that the girl felt ostracized by teachers and peers.

"Fingers of blame should not be pointed at the complainant, either by immature high school students and least of all by adults. If there's someone who thinks that there's a set-up here, they're not dealing in the same reality as I am," Stewart said.

The Crown is asking for nine to 12 months in jail. Skowronski will deliver his verdict Friday.