Mr Haunch, now 72, of Sutton, south London, denies 16 offences, including rape and indecent assault, between June 1975 and September 1983.
Prosecutor Richard Barton said the girl kept it a secret until two years ago.
He said the grooming began when Mr Haunch told the girl’s mother she needed extra help with her schooling.
“It’s the Crown’s case that this was a lie that he used as a ruse to allow him to take the girl up to his room so she was able to repeatedly visit him on her own,” he said.
School chapel ‘assaults’
He added that “at no stage” did he give her extra tuition. “Instead, over the months and years, he gradually groomed her.”
Mr Barton said the accused offered the girl praise, threats and rewards and at one point threatened to kill her parents if she ever disclosed what happened.
He would ask her to play games with sexual themes, said Mr Barton, and in what he described as the most serious incident he said Mr Haunch invited the girl to the school chapel, where she was repeatedly sexually assaulted by different men while he looked on.
The court heard that Mr Haunch was arrested after she alerted relatives two years ago.
He allegedly rejected the girl’s claims but admitted “a very serious error” with a boy pupil, which had led to his dismissal from the school.
After his sacking, the court heard, the teacher wrote a letter to the boy’s parents, saying how ashamed he was.
The case was not referred to the police at the time, but the boy later told police he had been abused by Mr Haunch.
Source : bbc