Chief Judge Rozenes said that he accepted that the 50,000-odd child porn images were used by Rowbury to enable him to fantasise about himself. "(Dr Matthews) said you used the pictures to build your own sexual activities," he said. "She said you had not stopped to consider that the girls were being sexually exploited."

Chief Judge Rozenes said he would have preferred to have sentenced Rowbury after he had completed a sex offenders' rehabilitation program, so that he could have seen what difference it had made to his condition.

But the system does not allow judges to impose such programs on offenders prior to sentencing.

He said that when police searched Rowbury's home they were alarmed at the state of it. They found it unfit to live in, containing buckets of faeces and urine as well as rotting and decomposing soiled nappies.

The chief judge said that although some of the images in Rowbury's possession were of serious sexual abuse and exploitation of girls as young as five, he had not distributed or created the pictures and his use of them was different to that of most people who chose to download child pornography.