A trainee maths teacher whose collection of child pornography was discovered by a pupil, has been jailed for three and a half years.
Fan was given a jail term and banned from working with children
Kai Ho Fan, 24, from Brighton, had admitted making indecent films and distributing indecent images.
Lewes Crown Court heard his interest in child porn began as "idle curiosity" and became a "morbid compulsion".
He was put on the sex offenders' register indefinitely and banned from working with children for life.
A pupil found the assistant maths teacher's computer memory stick at Longhill School, Brighton, in April.
He took it home, plugged it into his own laptop, and found footage of an eight-year-old girl being indecently assaulted by a man.
Annabel Maxwell-Scott, prosecuting, said the boy then looked at a video he thought related to PlayStations, but found two people having sex, one of whom he recognised as Fan.
Police were alerted after the pupil told his mother.
Detectives seized two laptops, hard-drives and discs, and found 2,165 indecent pictures and videos featuring children from the age of two to about 12.
One showed what police believed was a genuine rape.
Jeffrey Lamb, defending, said Fan, of Hollingdean Road, was "remorseful" and "contrite" and both needed and wanted help.
He said Fan's decision to become a teacher was not to gain access to children or to act out scenes shown in the images and films he downloaded.
Judge Anthony Scott-Gall told Fan: "The prevalence of child porn over the internet increases almost on a daily basis and as it increases so does the depravity reflected.
"People like you add to the ever-widening circle of disgusting material that corrupts."
After the hearing, Det Insp Mick Jones said: "Kai Ho Fan went to great lengths to put himself in a position where he had access to children to which he poses a considerable risk.
"Every indecent image of a child involves a victim.
"People like Fan create a demand for more victims to be found."