NINETY-SIX per cent of child porn images for sale worldwide are photos and videos of children taken in the US and Europe.

But because of a sharp rise in people sharing child porn online for free in peer-to-peer networks, the situation is beginning to shift.

This is because some people now trading illegal images of children are sourcing them personally, mostly after grooming children over the internet.

Traditionally, some organised crime gangs were involved in arranging for images of children being raped to be taken, which were then sold on websites. But international police crackdowns on these websites have curtailed this activity.

In 2000, Texan Thomas Reedy was handed down the world's longest ever sentence – 1,335 years – for running a multi-million-dollar website trading in images of child porn. His sentence was later reduced to 180 years. The Who's Pete Townshend was placed on the sex offenders' list in the UK after it was established he had accessed images on Thomas Reedy's website.

"Reedy made millions and millions of dollars from child pornography. He sourced the images from criminals in Russia and Indonesia, who also made millions," says John Carr of the European NGO Alliance for Child Safety Online (eNACSO).

A few years later in 2004, a child porn ring was dismantled in the Ukraine. Police raided a child pornography ring operating in the cities of Kiev, Kharkiv and Simferopol. The ring had operated since 2001, and used a modelling agency as a front.

Over 1,500 girls aged eight to 16 were said to have been used by the ring. Pornographic and erotic materials produced by the ring were distributed over the internet to various countries. The so-called agency, known as Ukrainian Angels Studio, streamed on the web and had a number of different domains. Two leaders of the agency were taken into custody but have since been released. Most of the parents of the girls refused to press charges.

"The parents of those children were being paid $100," adds Carr. "Some of them certainly knew what was being done to the kids."

At present, some 48% of child porn images for sale originate from the US, 48% are taken in Europe while the other 4% are from other parts of the world, according to Carr.

In terms of photos being shared on peer-to-peer networks, the images are coming from all over the world.

"A lot of the images being shared are from the US and Europe. It's linked to population density and access to technology," says Steve Racioppo, chief operating officer at US software company TLO, which produces data on computer downloading and sharing of child porn images on peer-to-peer networks.

"We're seeing more images from China but there has never been a huge number from Africa." The reason for this, says Carr, is simple: "Generally, the demand is for white Caucasian children. And the perpetrators looking for the pictures are overwhelmingly white males."