Security and privacy experts have heavily criticized an attempt by the UK, US and Australian governments to strong arm Facebook into halting its roll-out of end-to-end encryption.

Mark Zuckerberg announced a major overhaul of the social network in July following its $5bn fine from the FTC — a move which will include creating a privacy-by-design culture in the firm and extending end-to-end encryption beyond WhatsApp to Instagram and Messenger.

However, western governments are predictably dismayed at any efforts which will confound attempts by their intelligence agencies and the police to track suspects.

A widely reported open letter to Facebook from three-fifths of the Five Eyes nations demanded that the firm not continue with the encryption roll-out “without ensuring that there is no reduction to user safety and without including a means for lawful access to the content of communications to protect our citizens.”

That effectively means backdoor access for governments and law enforcers, something that the world’s leading cryptographers have repeatedly stated is not possible without undermining security for all.

Hannah Quay-de la Vallee, senior technologist at the non-profit Center for Democracy and Technology (CDT), repeated these arguments.

“Strong encryption and end-to-end security are bedrock technologies that keep information safe online. These technologies protect billions of communications every day, from the sensitive correspondence of victims of domestic violence to businesses’ financial records to our private medical information,” she explained.

“Creating a law that would mandate weaker and less secure technology is like mandating crumbling sidewalks to prevent criminals from escaping. It’s ridiculous, it won’t work, and it puts us all at far greater risk of serious injury.”

NSA whistleblower Edward Snowden also chipped in, warning that if Facebook caves to these government demands, “it may be the largest overnight violation of privacy in history.”

That doesn’t seem likely though, with a Facebook statement issued to confirm: “We strongly oppose government attempts to build backdoors because they would undermine the privacy and security of people everywhere.”

The open letter comes as the US and UK trumpeted a new “world first” data sharing agreement, that will allow law enforcers on both sides of the Atlantic to demand data from tech firms in the other country without needing to go through a lengthy liaison process with their respective governments.