A teenager is on the Sex Offenders' Register after apparently searching the internet for pictures of girls his own age but being inundated with child pornography.

The 16-year-old says he unwittingly received material from paedophiles after he left his computer on all night to download the pictures of teenage girls.

But, he says, when he awoke he realised he had downloaded pornography involving children as young as three.

I had assumed he was downloading music, I never thought to warn him about paedophiles

Teenager's mother

His attempts to clear the pictures from his PC failed and he was arrested in a police raid, taken to court and charged, his mother told The Daily Telegraph newspaper.

Cyber detectives had traced him and when they knocked on his door in March last year were amazed to discover their suspect was a schoolboy, still studying for his GCSEs.

The youth's mother told the newspaper: "At 7am there was a banging on the front door - half a dozen people were outside including uniformed police with a search warrant.

"I assumed they had the wrong house but they stormed in and took away our computer."

School chaperone

Following his arrest the teenager was seen by a psychiatrist, social services were called in and he had to be chaperoned to and from school.

His mother said: "I became paranoid that I would come home to find anti-paedophile graffiti all over the house.

"Whenever I saw the police nearby I thought they were going to search us again.

"When I saw him spending hours on the computer I had assumed he was downloading music, I never thought to warn him about paedophiles."

In the crackdown in which the boy was arrested 45 addresses were raided by police and five teenagers were among those held.

The youth's mother said: "The vast majority of teenagers caught in these raids will only have stumbled on the material by accident."

Internet caution

Her son pleaded guilty in court and is currently completing a 12-month supervision order.

His details will be on the Sex Offenders' Register for two-and-a-half years.

An estimated five million youngsters use the internet and a quarter of all children use chatrooms.

Experts have warned that children sitting alone in their bedrooms and having on-line conversations with strangers are easy prey for paedophiles.

They have urged that computers are moved from children's bedrooms into family rooms.