Four men have admitted running a paedophile ring that sent millions of indecent images around the world.
The men circulated the material to 46 countries, investigators discovered.
Ian Frost, 35, and Paul Rowlands, 34, both of Lincolnshire, Paul Frost, 37, of Sheffield, and Ian Sambridge, 32, of St Albans, admitted charges relating to the gang at Nottingham Crown Court.
Lincolnshire Police said 132 children had been removed from danger since the ring was uncovered.
Rowlands, also of Woodhall Spa, pleaded guilty to distributing, making and possessing indecent images of children.
Paul Frost and his brother Ian, from Woodhall Spa, and Sambridge admitted distributing indecent images of children.
Lincolnshire Police said as well as the 132 children in the UK being protected, a number of paedophiles had been taken out of positions of trust, including teachers, doctors, youth workers and police officers.
The investigation, codenamed Operation Alpine, began after intelligence from Germany was forwarded by the Child Exploitation and Online Protection Centre (CEOP) in 2005.
Officers executed a search warrant at Ian Frost's home in 2006 in the hamlet of Martin Dales in Woodhall Spa, which he shared with Rowlands.
They found a powerful computer system which allowed users to share and view up to 3 million images, ranging from the lowest severity to the most extreme.
Officers also found a similar system being run by Paul Frost, also an IT worker, from Woodhouse in Sheffield, South Yorkshire. Sambridge, a legal adviser, was running another.
Over seven years the group is thought to have made around £2m from subscriptions, even though they did not appear to have extravagant lifestyles.
Officers found 1,310 individual packages had been sent to 46 countries around the world by the computer systems.
Of those receiving the illegal content involving indecent images of children, there were 211 in the UK - 38 of which have been dealt with to date.
The largest number of subscribers were based in the US, officers said.
They are due to be sentenced next month.