Paedophile Philip Thompson, 27, the "librarian" for a worldwide internet child-abuse ring, was today given an indeterminate prison sentence of a minimum of 45 months at Teesside Crown Court.
The unemployed loner lived a quiet life with his mother in Gooseport Road, Stockton-on-Tees, using his benefits to collect films and memorabilia.
However, unknown to the outside world, the self-taught computer expert used his skills to moderate an invitation-only website featuring borderline images of children.
The gateway website served two purposes - to show the users had a perverted interest in children and to show their commitment.
Once they had signed up, members would link up - often using instant messaging programmes - to use more secretive online environments.
It was here that thousands of sick images and videos, as well as information about vulnerable children, were exchanged.
Thompson, who told police he was the "librarian" for the site, was caught with a massive archive of nearly 250,000 perverted images on his computer, of which more than 3,000 were of levels four and five - the worst kind of child abuse images.
Thompson was unmasked when child abuse officers from Scotland Yard began investigating the site he ran and their inquiries led to him.
The police have so far identified 360 suspects worldwide, of which 130 were in the UK. To date 50 arrests have been made in Britain, including a police community support officer and a lecturer.
It emerged after sentencing that 15 British children have been saved from the clutches of paedophiles after Thompson was unmasked and his online activities stopped.
The international network was infiltrated by law enforcement officers and dozens of suspects arrested.
The investigation involved the largest deployment yet of undercover officers in the UK for a child protection inquiry.
Detective Sergeant Becky Driscoll, of Cleveland Police, said Thompson thought he was operating "below the radar".
"He was integral. He played a key role. He was trusted by others members of this site, so much so that he stored horrific images of child abuse on their behalf," she said.
"He described the 250,000 child abuse images as his collection. He was prepared to share that with acquaintances he found on his forum.
"This site would have existed without him, but it would not have been operating as effectively."
Detective Chief Superintendent Mark Braithwaite, the force's head of crime, said: "Thompson was a critical piece of this network.
"He was, essentially, the librarian for a myriad of images that were distributed to like-minded individuals both in this country and elsewhere.
"This was an extremely sensitive and highly complex investigation, requiring excellent teamwork between Cleveland Police, the Child Exploitation Online Protection (Ceop) Centre and the Metropolitan Police Service along with other police forces in the UK.
"I hope this result acts as a deterrent and sends out a clear warning that activity such as this will not be tolerated."
Jim Gamble, chief executive of the Ceop, added: "This website, whilst appearing to operate on the margins of legality, was clearly a front for the sinister, sexual abuse of children and an image trading ground for paedophiles.
"There is a simple message for those individuals like Thompson, who think they can go to this website - or indeed any space on the internet - and discuss their sexual interest in children and share images.
"You leave a digital footprint. We will track you down and hold you to account."