A paedophile ring that streamed live child abuse from the Philippines over the internet has been broken up after an operation by UK police and their counterparts in Australia and the US.
The National Crime Agency says 17 Britons have been arrested in Operation Endeavour, which spanned 14 countries.
Three other inquiries into men who pay to see abuse via webcams are under way, with 139 Britons among 733 suspects.
The NCA say it is an "emerging threat", particularly in developing countries.
It said: "Extreme poverty, the increasing availability of high-speed internet and the existence of a vast and comparatively wealthy overseas customer base has led to organised crime groups exploiting children for financial gain."
The Philippines investigation, which began in 2012, saw British officers work alongside the Australian Federal Police and US Immigration and Customs Enforcement.
Five of the 17 UK suspects arrested have been convicted; one will face no further action, and two are dead. Nine more are still being investigated.
Operation Endeavour has also resulted in 29 arrests in other countries, including 11 people suspected of facilitating the abuse in the Philippines.
Suspects have been identified in Australia, the US, France, Germany, Canada, Hong Kong, the Netherlands, Sweden, Norway, Taiwan, Denmark and Switzerland.
In the Philippines, some 15 children aged six to 15 were rescued after being identified as victims.
Payments by customers totalling more than £37,500 were uncovered by the investigation, with relatives getting paid for abuse of the children in some instances.
The investigation began in 2012 after Northamptonshire Police carried out a routine visit at the Kettering home of registered sex offender Timothy Ford, where they found a number of indecent videos on computers and a collection of DVDs recorded from webcams.
'Every link in chain'
The force contacted the UK's Child Exploitation and Online Protection Centre (Ceop) - now part of the NCA - leading to the launch of the global investigation.
Analysis of the digital media seized led to the identification of suspects and the child victims, and the Philippine National Police became involved.
Ford was sentenced in March last year to eight-and-a-half years in prison for his role in the case.
Detectives found records of money transfers to the parents of five children whose abuse he had paid to watch.
Among the other Britons convicted over the Philppines abuse was Michael Eller, 68, from Berkhamsted, Hertfordshire, who was jailed for 14 years last December.
Thomas Owen from Merseyside was jailed in July 2013 for seven years after being convicted as a result of the investigation.
Ceop deputy director Andy Baker said: "This investigation has identified some extremely dangerous child sexual offenders who believed paying for children to be abused to order was something they could get away with.
"Being thousands of miles away makes no difference to their guilt. In my mind they are just as responsible for the abuse of these children as the contact abusers overseas.
"Protecting the victims of abuse is our priority and that means attacking every link in the chain, from dismantling the organised groups who are motivated by profit through to targeting their customers."