Senior officials said the UK received 12 million tips over child sex abuse images and suspicious activity from the social network last year, and that if the “taps get turned off” fewer offenders will be arrested and more children could be at risk.
The NCA’s warning came as one of the UK’s most prolific paedophiles, David Wilson, was jailed for using Facebook to target up to 5,000 children while posing as a teenage girl.
In March 2019, Mark Zuckerberg announced that Facebook was working towards end-to-end encryption on all its messaging services that would “prevent anyone – including us – from seeing what people share”.
Rob Jones, the NCA’s director for threat leadership, said Facebook’s plans would risk “abuse spiralling out of control in a hidden space that is created”.
“It poses an existential threat to child protection,” he told a press conference.
“It creates a private space where people like Wilson can masquerade as children, engage with children, groom them and develop either coercive control and make them abuse themselves and send images to them, or meet them in the real world and abuse them themselves.”
Wilson, who posed as a teenage girl on numerous fake Facebook accounts to dupe boys as young as four into sending him sexual images.
The Norfolk roofer, who lived with his mother, contacted up to 5,000 children globally and was sent content by around 500 victims. Several were then blackmailed into sending more extreme footage, and forced to abuse younger siblings or friends.
Priti Patel called the case “a chilling reminder of how crucial it is that tech companies play their part in combating child sexual abuse”.
“It is vital that Facebook do not press ahead without amending their current end-to-end-encryption plans, otherwise sick criminals like Wilson could still be abusing children with impunity,” the home secretary added.
Chief Constable Simon Bailey, the national policing lead for child protection, said: “The information from Facebook was crucial in bringing Wilson to justice. Which is why I am concerned about Facebook planning to introduce further encryption and privacy protections, making it harder for us to prevent exploitation and find child sexual abusers like Wilson.”
The NCA said Wilson was one of the most prolific paedophiles they had ever investigated, mainly used Facebook Messenger for his abuse.
Mr Jones believes he would not have been caught if the service had been encrypted while Wilson was targeting victims.
He said the predator was identified through a “cyber tip” regime that currently sees more than half of referrals come from Facebook.
The NCA estimates that there is a minimum of 300,000 people who present a sexual threat to children in the UK.
Around 4,500 offenders were arrested and 6,000 children safeguarded in 2020, and Mr Jones said an “awful lot” of investigations stemmed from the cyber tip regime.
“There will be a lot less referrals and a lot less arrests [if Facebook encrypts its services],” he added. “We know a large number of Facebook users are seeking to identify children to abuse them.”
He voiced additional concerns that more paedophiles could be drawn away from other platforms to Facebook if its services are encrypted, causing a wider fall in referrals to the NCA.
“There is a potential domino effect where offenders will coalesce where they think they are safe,” Mr Jones said.
“We’re not asking for anything more than we currently have. This isn’t about privacy or security on their networks, we’re asking to maintain a position where Facebook can access their own material and report the unlawful abuse of children to the NCA and international law enforcement”
Mr Jones said the NCA had been in discussions with Facebook about its concerns but was unhappy with current assurances.
“I implore them to not create a risk and fail in their duty of care,” he added. “They must explain how they mitigate the risk from those new measures.”
Facebook said it would still be able to make metadata available to law enforcement and continue sending cyber tips based on user reports, and evidence from profile photos and group descriptions.
“Child exploitation and grooming have no place on our platforms,” a spokesperson said. “Facebook has led the industry in developing new ways to prevent, detect, and respond to abuse and we will continue to work with law enforcement to combat criminal activity.
“End-to-end encryption is already the leading technology used by many services to keep people safe online and, when we roll it out on our other messaging services, we will build on our strong anti-abuse capabilities at WhatsApp. For example, through a combination of advanced technology and user reports, WhatsApp bans around 250,000 accounts each month suspected of sharing child exploitative imagery.”