Jeremy Forrest was due to be sentenced for child abduction today, having been found guilty of that yesterday, but before mitigation he was formally charged with five sexual offences. He pleaded guilty to all five.
In mitigation, his defence counsel said that he was disgusted with himself for lying and ashamed - that what he had done was against his principles.
But the judge said that his behaviour had been motivated by self interest and he chose to ignore the "cardinal rule" of teaching.
Judge Michael Lawson QC sentenced teacher Jeremy Forrest to four and a half years for the five offences of sexual activity with a child and one year for the offence of child abduction, to run consecutively.
He told Forrest:
Your behaviour in this period has been motivated by self-interest and has hurt and damaged many people - her family, your family, staff and pupils at the school and respect for teachers everywhere.
It has damaged you too but that was something you were prepared to risk.
You now have to pay that price.
It was your duty as a teacher to stop her infatuation, not to fuel it.
Your research into what might happen to you if you were caught is proof of the deliberate nature of your behaviour.
Jeremy Forrest, who was jailed for five and a half years for abducting a 15-year-old girl and five counts of sexual activity with a child, has also been banned from working with children in the future.