Oliver Glass, who taught at St Joseph’s College in Reading, groomed the girl before having sex with her on three occasions, Reading Crown Court heard.
The ex-head of maths, 33, was sentenced to 22 months in prison after admitting the offences and he will go on the sex offenders register for 10 years.
Judge Paul Dugdale described it as one of the “most serious” abuse of position of trust cases he has had to deal with.
Glass admitted three counts of causing a child to engage in sexual activity when he was in a position of trust.
The court heard he had sent the girl explicit texts and Snapchat messages, before having sex with her in his car after a school sports day.
Laura Blackband, prosecuting, told the court: “He accepted crucially he knew it was against the law.”
In a victim impact statement the girl said she now “struggles to trust men” and Glass has “ruined” the memory of her school years.
Sally Howes QC, defending, told the court the father-of-one had been having relationship problems with his wife at the time, and has since shown “profound and heartfelt remorse and regret”.
Sentencing Judge Dugdale said Glass subjecting his victim to “rough sex” had made the offences “particularly unpleasant”.
“You used extraordinarily degrading language towards her, degrading her as a sexual partner, degrading her as a pupil and degrading her as a woman,” he said.
In a statement, the headmaster Andrew Colpus said: “We deeply regret that a former member of staff should have abused his position and betrayed the trust placed in him in such a shocking way, and we applaud his victim for having had the courage to speak out.
“The member of staff was suspended as soon as the matter was brought to our attention and he left our employment in October 2019.
“We take our safeguarding responsibilities extremely seriously, and whilst there can never be room for complacency with regards to safeguarding matters, I firmly believe the measures we have in place here are the most stringent and effective in our school’s history – they were independently reviewed last January.”

Unity News Network (UNN) Staff Writer | To find out more details about our staff, please head to the About Us section on our website.


