A teacher who became obsessed with child pornography on the internet has been jailed.

Ian Clark's secret addiction was revealed after he was tracked down by police working on Operation Ore, which traced perverts who paid with credit cards to view child porn.

Among 500 images on Clark's computer were pictures of a 14-year-old boy posing indecently while wearing a school blazer.

The teenager was traced via the school badge on his blazer and another man was arrested and faces prosecution.

Clark, 34, a devout Christian with no previous convictions, is not linked to taking the indecent photographs of the boy.

But at Lewes Crown Court he admitted 16 offences of downloading indecent photographs of a child from the internet and asked for 518 offences of possessing indecent photographs of children to be taken into consideration.

The court heard Clark, of Winchester Drive, Chichester, was sacked from his job at a secondary school after his arrest.

Richard Blake, prosecuting, said Clark's home was searched in December 2002 and his computer seized.

Police found he had been sending emails calling himself "bigboy16".

He was charged with the offences in December last year when he told detectives he had viewed the indecent images but had not deliberately searched for them on the internet.

However, the images had been saved.

Terry Brookes, defending, said Clark had become secretly obsessed with pornographic images of young boys after he first obtained a computer and internet access in 1999.

The day he was arrested he turned to his church minister for support.

The minister, along with Clark's wife and members of his family and church, were in court to support him.

Clark had also asked his GP for professional help.

He had immediately stopped his voluntary work through the church, where he had been involved in music and drama activities for youngsters.

Mr Brookes said: "He was indulging in this activity and living with his shame and secret life while trying to be a good teacher, a good husband and a good Christian.

"It has all fallen down for him on this day."

Judge Charles Kemp told Clark he was a man of previous impressive character who was held in high esteem but he had to be punished for offences from which right-minded people recoiled.

Clark was sentenced to eight months in jail.

On his release he will be supervised by the probation service for two years.

He was also ordered to remain on the sex offenders register for ten years.