The UK's largest ever police hunt against internet paedophiles has identified over 7,000 suspects and led to more than 1,200 convictions.
Some 3,500 Operation Ore suspects have been arrested in the UK
Operation Ore was launched in May 2002 after US investigators found customers around the world were accessing images of child abuse from a Texas-based site.
Landslide Inc. was a multi-million dollar website selling pornography.
Credit card details used to access material on the site gave police direct leads on 250,000 people worldwide.
The National Crime Squad prioritised investigations into three categories.
The first - with around 1,200 names - included convicted paedophiles and those with access to children.
The second covered those in positions of authority such as police and magistrates and the third was for suspects not involved with children.
Businessmen, civil servants, lawyers and people in the media were named.
Who guitarist Peter Townshend was arrested under Operation Ore
They included Who guitarist Pete Townshend, who insisted he was merely researching the subject.
He was arrested in January 2003, cautioned and had his name put on the sex offenders' register after he admitted accessing child porn.
Those since convicted have included doctors, teachers and police.
British police forces have checked over 7,000 individuals linked to child pornography through the operation.
Of 3,500 Operation Ore suspects arrested, 1,679 have been charged and 1,230 convicted.
The longest jail term imposed as of April 2004 was 12 years.
In 102 Operation Ore cases there was evidence British children had been abused so images could be traded online.
The National Crime Squad says more than 1,300 cases are still being investigated in the UK.
Photographs or pseudo-photographs of children, apparently aged under 16, involved in sexual activity or posed to be sexually provocative are illegal.
Under the Criminal Justice Act the possession of such images is punishable by up to five years in prison.
Section 1 of the 1978 Protection of Children Act makes it illegal to take or permit such images to be taken, to distribute or show them or possess them with a view to their being distributed or shown.
Advertisements suggesting such images are available are also illegal.
The Sentencing Advisory Panel published guidance on the sentencing for offences involving indecent photographs or pseudo-photographs in August 2002.
It recommended a 10-year maximum jail sentence for the making, showing or distributing such images.
The panel identified two primary factors which should determine the seriousness of an individual offence.
These were the nature of the material and the extent of the offender's involvement with it.