Perth teacher on trial for child porn

A former teacher at an elite Perth private school had more than 3000 child pornography images on his computer, a court has heard.

A trial has begun for former Guildford Grammar School teacher and navy member Jeffrey Jay McKinnell.

The 39-year-old has pleaded not guilty to one charge of possessing child exploitation material.

McKinnell claims that because he had a habit of downloading a lot of pornography, he inadvertently had the child exploitation images on his laptop.

He allegedly told police when he came across images that were potentially "dodgy" or illegal he would put them in a file called "spec" to be deleted later.

If a person accidentally downloads child pornography that was unsolicited they legally must take reasonable steps to get rid of it, prosecutor Paul Dixon told the court.

He was interested in normal porn, not "kiddie porn", McKinnell told police.

A video was played before the jury in which police arrested McKinnell on the way home from Guildford Grammar.

He chats casually saying he wants "to clear this up".

Police found only a small number of images in the "spec" file but claim 3009 images in total found on the computer was child exploitation material.

The materials tended to involve young girls on the cusp of puberty in sexually abusive situations or posing sexually and scantily clad.

"He has not been truthful, completely accurate or upfront with police," Mr Dixon said.

The prosecution alleges McKinnell has already admitted to the crimes by conceding he had not deleted files with children but defence lawyer Anthony Elliott rejected that.

McKinnell had not consciously downloaded or kept child pornography, Mr Elliott said.