John Thompson had escaped a prison sentence in July despite pleading guilty to sexually assaulting his victim, Daily Mail reported. He accused the schoolgirl of pinning him down on a bed after flirting with him.
Thompson narrowly avoided jail and was instead ordered to undergo a sex offender treatment programme.
The lenient sentence sparked fury among child protection charities who branded it "despicable".
Despite his let-off, Thompson was back in the dock last month after he failed to comply with the same order. He was yet again given a second chance to change his "appalling attitude". Now, having again failed to attend the sex offender treatment programme, he has been sent to prison.
Thompson remained adamant that the girl was a liar, demanded that she be punished and threatened to sue her for making the allegations, the hearing was told.