'A 16-year-old schoolboy who raped a teacher has been given a life sentence at the Old Bailey.
The judge told the youth that he had violated the teacher's classroom - her place of safety - and had left her "physically and mentally scarred".
He said he agreed with a doctor who said his behaviour suggested that he had planned or rehearsed the rape in a fantasy.
The youth, who had pleaded guilty to rape at an earlier hearing, will be eligible for parole after serving four-and-a-half years.
But he will not be released until doctors consider he is no longer a danger.
The teenager, from south London, was 15 when he attacked the 28-year-old teacher on her second day at a central London school in September last year.
Brendan Kelly, prosecuting, said the teacher was in her classroom when she was grabbed round her neck and pulled to the back of the room.
The court was told that the 5ft 11in, powerfully-built teenager head-butted and threatened to kill the woman as she fought him off.
But she was overpowered by the pupil and sexually assaulted. After the attack, the teacher ran naked to the headteacher's office.
Describing the impact of the assault on the victim, Mr Kelly said: "The effect of this attack upon her has been devastating.
"Since the incident she has been unable to teach. She anticipates that once 'all this' has been put to bed she proposes to go back on a trial period - not to the school in question, she will go to another school.
"Her confidence has been devastated, her social life equally has been devastated.She lives in fear of returning to her vocation."
Judge Moss lifted a court order protecting the youth's identity but stayed this until Friday afternoon after the defence said it wanted the decision reviewed by the High Court.
He ordered that Westminster City Boys School, central London, where the teacher was attacked after working only two days in September last year, could be identified.
After the case, the teacher said: "I was very glad to be alive because I did not think I would be.
"I honestly thought that I was going to be murdered, on top of everything else."
She said she is now trying to rebuild her life. '
Make you feel all nice and safe, doesn't it?
he could be out in as little as four years. It makes me feel sick.