LONDON — The gloves are off in the U.K. government’s deepening spat with tech giant Meta.

On Wednesday, Britain’s Home Secretary Suella Braverman unveiled a fresh campaign aimed at making the Mark Zuckerberg-led tech giant rethink its plan to roll out end-to-end encryption on Facebook and Instagram — a move she says will hamper the police’s ability to catch pedophiles.

At a background briefing for reporters on Tuesday, Home Office officials used graphic language to describe the types of child sexual abuse material that they say risks going undetected if Meta goes ahead with its plans. A video put together as part of the campaign features a victim of child sex abuse appealing directly to Meta chief Mark Zuckerberg to rethink plans to roll out encryption.

The National Crime Agency has estimated that making messages on Facebook Messenger and Instagram end-to-end encrypted will wipe out more than 85 percent of the platforms’ reports of online child sexual abuse material.

Meta, which aims to finalize the encryption rollout by the end of the year, has said it plan to continue policing its platforms for grooming and the sharing of child abuse content. It will do this by, for example, watching for suspicious behavior from accounts and providing a range of controls to help kids avoid harm.

But Braverman said she’s not yet been convinced that these measures will make up for the shortfall in reports that the encryption changes are expected to bring about, prompting her to write to the tech giant in July asking it to stop its encryption rollout if it can’t give stronger assurances.

“Meta has failed to provide assurances that they will keep their platforms safe from sickening abusers,” Braverman said in a press release. “They must develop appropriate safeguards to sit alongside their plans for end-to-end encryption.”

“We don’t think people want us reading their private messages so have spent the last five years developing robust safety measures to prevent, detect and combat abuse while maintaining online security,” said a Meta spokesperson.

The company on Wednesday also published an updated report setting out these measures, such as restricting people over 19 from messaging teens who don’t follow them and using technology to identify and take action against malicious behaviour.

A new front in the encryption fight

The campaign, which is also backed by a slew of child protection groups and law enforcement bodies, is just the latest round of a bruising battle between U.S. tech companies and the U.K. government over encryption that has largely centered on Britain’s new draft internet rulebook, the Online Safety Bill.

The bill, which passed its final parliamentary hurdle Tuesday, would empower Britain’s comms regulator Ofcom to force tech companies to monitor messenger apps for illegal child abuse content. That’s proven controversial, with dozens of cryptography experts saying that the powers would effectively undermine end-to-end encryption — tech that enables only the sender and receiver to view messages.

Tech execs like Signal’s Meredith Whittaker and WhatsApp’s Will Cathcart have suggested they’d rather have their encrypted services blocked in the U.K. than undermine privacy for millions of users on their apps. 

But Ofcom officials have previously said there’d be a high bar for them to mandate monitoring on encrypted apps, while any order for Meta to scan its messenger apps for content would prove highly contentious for the regulator. 

That’s what’s prompted the U.K. government to lobby for Meta to rethink its plans in the first place.

“We urge companies looking to introduce end-to-end encryption to their services to think carefully about the impact on younger, vulnerable users,” said Susie Hargreaves, chief executive of child protection group the Internet Watch Foundation in a statement.