Christopher Darler, 37, of Heyhouse Way, Chapeltown was sentenced on Monday at Sheffield Crown Court, having previously pleaded guilty to two counts of rape, sexual grooming, possession of 47 indecent videos and 44 indecent still pictures, as well as possession of prohibited images of a child, and distribution of indecent photos of a children, on 22 January.

Sentencing Mr Darler, Judge Peter Kelson described him as a “predator” and a "wolf in sheep's clothing" who took his “fantasy into the real world.”

He said Darler’s actions “undermines the trust parents and pupils place in educational institutions.”

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Christopher Darler

At the time of the offences he was the deputy headmaster and head of the social sciences faculty at Rawmarsh Community School in Rotherham.

The victim, who cannot be named for legal reasons, was not a pupil at the school. There is currently no evidence linking any pupils at the school with Darler’s crimes.

In a victim impact statement he said his interaction with Darler had left him “upset” and “scared of being home alone”.

The judge also threw out Mr Darler’s defence that his behaviour was somehow triggered by an extensive workload, which was put forward in a letter from him to the judge and in court by his defence barrister, Mr Francis Edusei.

Mr Edusei claimed the defendant’s increased responsibilities with his job had left him “unable to cope.” He admitted his client’s crimes would “follow him for the rest of his days.”

He described it as an “appalling piece of mitigation,” adding “your workload didn't turn you into a sexual predator on innocent children.

“To even raise that as a point is the most disgusting insult to all the incredibly hard-working teachers in this country. They are going to suffer in their jobs because of the damage you have done.

Darler showed no emotion throughout the hearing.

The judge added: “There was no willingness on the child’s part. He’s a child, by definition he consent in any real way. You were a predator praying on a child.”

The court heard how, as well as the grooming and rape of a 13-year-old boy, Darler had published pictures of other boys under the age of 16 for sexual gratification. A popular search term of his had been 14-year-old males.

He had used Whatsapp and another messenger app, Kik, to communicate with both his victim and another peadophile, with whom he shared images and stories about his sexual exploits.

Darler was also served with a restraining order prohibiting him from contacting or approaching the victim. A Sexual Harm Prevention Order will also ensure he will be forbidden from unsupervised contact with under-16s in future, and will not be able to delete his internet search history.

“The public need to be protected from you,” Judge Kelson added.