More than 100 Britons were among 1,000 men caught trying to pay a computer-generated child to perform sex acts online, after a Dutch children's charity set up a fake profile.
Terre des Hommes carried out a 10-week sting near Amsterdam, posing on video chat rooms as "Sweetie", a 10-year-old Filipina girl.
Some 20,000 men contacted her, with 1,000 found to have offered her money.
The names of these men - including 110 Britons - were passed to police.
When I visited the charity's operations room - in a warehouse on the outskirts of Amsterdam - I watched as a researcher logged on to a chat room as Sweetie - incredibly life-like but created by a computer.
Within seconds, like sharks, men were circling.
Of the 1,000 men who were willing to pay Sweetie to take off her clothes in front of a webcam, 254 were from the US, followed by 110 from the UK and 103 from India.
Researchers used evidence including profiles on Skype and social media to identify the suspects.
Project director Hans Guyt told a news conference in the Hague on Monday that the crime "requires a new way of policing".
"The predator won't come forward. The victim won't come forward," he said.
"We identified ourselves as 10-year-old Filipino girls.
"We did not solicit anything unless it was offered to us."
Terre des Hommes has launched a global campaign to stop "webcam sex tourism".
Managing director, Albert Jaap van Santbrink, said: "Our worst-case scenario is that the same will happen with this phenomenon as with child pornography, which is now a multi-billion industry in the hands of criminal gangs."
The charity has now handed over its findings to police and has said it will provide authorities with the technology it has developed.
But European policing agency Europol has expressed reservations about the findings.
"We believe that criminal investigations using intrusive surveillance measures should be the exclusive responsibility of law enforcement agencies," spokesman Soren Pedersen told the Reuters news agency.
Andy Baker, of the UK's National Crime Agency, also said that "tackling child sex abusers is best left to specialist law enforcement agencies".
But he praised the campaign, saying it had "widened awareness of a global child sex abuse threat".
"Working with our international law enforcement partners, we will now look at the information being passed on by Terre des Hommes," he added.
Sweetie will not be used again. She has done her job - showing the predators that they can easily become prey.