Police found more than 58,000 images, including child pornography and bestiality, on his computer

Derek Berditch, 58, who was head of music at St Joan of Arc Catholic School, in High Street, at the time of his arrest, was jailed for 18 months for possessing the "loathsome" images.

Berditch used file sharing websites to download porn films depicting the bondage and rape of children, before making them available online to other internet users, Southwark Crown Court heard.

He stored the 58,770 images on his computer in folders labelled 'pthc' - the abbreviation for preteen hardcore. 

When officers seized Berditch's computer tower from his home in Birmingham, the teacher told them: "That's the end of my career."

Prosecutor Peter Zinner told the court: "The defendant was identified as a suspect after internet service providers became aware of indecent images being distributed between various individuals. 

"Police were also concerned because, as a result of further investigation, they established that the defendant was a school teacher at St Joan of Arc Catholic School in Rickmansworth. 

"Further police work established that he was head of the music department at the school and that he was teaching pupils both at school and unsupervised at his home, with children as young as seven."

Berditch taught thousands of children at St Joan of Arc since joining the school in 1987, including pop singer Kate Nash. 

The court heard much of the material had been downloaded by Berditch over the last four years.

Officers also found on his computer tower 19 child porn films, some of which depicted children as young as six being bound and raped.

Jeremy Lynn, defending, said Berditch downloaded rafts of child abuse images because he was addicted to pornography and that he was suffering from "stress and strain".

Sentencing Berditch Judge Goymer said: "Offenders who commit this type of offence usually fail entirely to appreciate the harm they have done.

"The defendant either didn't appreciate the harm he was doing or he didn't care.

"He was more interested in pursuing his obsession with downloading these images.

"This isn't a harmless hobby such as stamp collecting and secondly, this isn't a victimless case because time and again I have to make the observation that somewhere in the world a child is being abused and exploited in order to produce images that satisfy the depraved tastes of people such as this defendant."

The judge added: "It is shameful for a teacher to engage in this kind of conduct.

"It damages the public's confidence in the profession and undermines the trust that those parents entrusted to you for the music teaching of their children, sometimes on an individual basis.

"At least they can be confident that there is nothing to suggest that you abused that trust.

"In my judgement, the scale of the offending, the quantity of the images involved, the period of time over which these offences were committed, the fact they involved the potential distribution of the images, and the fact they involved images of a most loathsome variety draws me to the conclusion that this offence is so serious that there can be nothing a prison sentence that comes with immediate effect."

Berditch, with a thick bushy beard, stood in a lavender shirt in the dock and bowed his head as his sentence was passed.

He was also ordered to register for ten years on the Sexual Offences Prevention Orders.

Berditch, of Warwards Lane, Selly Oak, Birmingham, admitted seven counts of making indecent images of children and two counts of possessing extreme pornography depicting sexual intercourse between adults and children.

He also pleaded guilty two further counts of possessing indecent images of children with a view to distribution.