Police around the world have taken down a global child abuse ring in which paedophiles in at least 38 countries gained 'loyalty points' for uploading abuse videos to a dark web website and paid in bitcoin to download others.

More than 250,000 horrific videos, stored on a computer server in South Korea and available through a website called 'Welcome To Video', were sold to paedophiles around the world through the dark web, with more than a million clips downloaded.

The site was uncovered by Britain's National Crime Agency during its investigation into one of the UK's most prolific paedophiles, Matthew Falder, who is serving 25 years in prison for 137 offences linked to the sexual abuse of children.

The US Department of Justice has now charged South Korean suspect Jong Woo Son, 23, with running the website, as police forces around the world move in on those who have been using the site.

So far, 337 suspects have been arrested globally, with 18 investigations in the UK and seven British men already convicted. American authorities have raided the homes of 92 people and today released the names 34 people arrested or charged in the U.S.

British paedophiles Dr Matthew Falder and Kyle Fox were among hundreds of sex offenders around the world using the sick website, which was based in South Korea

Welcome to Video, the site used by paedophiles around the world, has now been shut down and replaced with this message

Arrests have been made in 38 countries including the UK, Ireland, America, South Korea, Germany, Spain, Saudi Arabia, the United Arab Emirates, the Czech Republic and Canada.

The man suspected of being behind the website, Jong Woo Son, was arrested in South Korea and is currently serving an 18-month sentence in his own country.

It is thought American authorities will now attempt to extradite him to face justice in the U.S. The site has also been removed from the dark web.

The site was uncovered when police arrested Cambridge graduate Dr Matthew Falder, a geophysicist from an affluent family who led a secret life trading images of child sex abuse.

He later admitted 137 offences, including voyeurism, encouraging child rape, and sharing images showing the abuse of a newborn baby, and has been jailed for 25 years.

During the investigation into Falder, the National Crime Agency (NCA), Britain's equivalent of the FBI, found a link to the website, which then sparked a global investigation.

The subsequent police probes led to the arrest of Kyle Fox, who filmed his sexual attacks on a five-year-old boy and a one-year-old girl. He appeared on footage on the 'Welcome to Video' site, raping a young girl.

Fox, from the upmarket London commuter town of Epsom in Surrey, was later jailed for 22 years.

The NCA uncovered Welcome To Video during its investigation into the geophysicist Dr Matthew Falder. His computer is pictured

Police today released an image of what the website looked like. It included a message telling users not to upload adult porn

One of the screenshots shows a points system. In order to download the videos hosted on the site, the user had to spend 'points'. These points could be acquired by either uploading videos or purchasing using bitcoins

The British NCA's Nikki Holland said today: 'Dark web child sex offenders – some of whom are the very worst offenders – cannot hide from law enforcement.

'They're not as cloaked as they think they are, they're not as safe as they think they are.

'The NCA is relentless in pursuing them and we have specialist capabilities, which we use for all UK law enforcement, to unmask them and help take down sites like Welcome To Video.

'I'm immensely proud of the role we played in catching some very depraved and dangerous global offenders and for beginning the work that eventually caught Jong Woo Son.'

The US Justice Department's Assistant Attorney General Brian Benczkowski said today: 'Darknet sites that profit from the sexual exploitation of children are among the most vile and reprehensible forms of criminal behavior.

'This Administration will not allow child predators to use lawless online spaces as a shield.

'Today's announcement demonstrates that the Department of Justice remains firmly committed to working closely with our partners in South Korea and around the world to rescue child victims and bring to justice the perpetrators of these abhorrent crimes.'

Details of the investigation were released at a press conference at the U.S. Department of Justice today, which was attended by officials from the UK and South Korea

US attorney Jessie Liu added: 'Children around the world are safer because of the actions taken by U.S. and foreign law enforcement to prosecute this case and recover funds for victims.

'We will continue to pursue such criminals on and off the darknet in the United States and abroad, to ensure they receive the punishment their terrible crimes deserve.'

Following the announcement, Andy Burrows, of children's charity, the NSPCC, said: 'There is no such thing as just looking at child abuse images. Every single one is a crime scene, and every time someone clicks on one they are hurting a child.

'Online abuse is one of the greatest threats to children and law enforcement are having to do incredibly tough work to bring these offenders to justice.

'If we are to disrupt these criminals we can't just leave it to police to track them down and pick up the pieces after abuse has taken place. We need the platforms where children are being groomed and abused to be regulated so they are safer, and tech needs to change to protect the child.'