A new treaty between the UK and the US will force Facebook to share encrypted WhatsApp messages with British police, according to reports.

The accord, which is expected to be signed in October, would require social media firms to build “back doors” into messaging apps in order to assist with investigations, Bloomberg and The Times reported. The new deal, which also covers Facebook’s Messenger platform, would mean that any individuals suspected of serious offences like paedophilia or terrorism would be subject to police warrants for their private messages.

Facebook-owned WhatsApp introduced end-to-end encryption to “every form of communication” on the app in 2016 in order to prevent messages and images from being seen by anyone other than the person sending and the person receiving them.

In order for police to have access to messages sent across WhatsApp, Facebook would need to backtrack on numerous privacy pledges to its users by completely redesigning how messages are sent and received.

Security back doors essentially act as secret access portals, whereby the social media companies and law enforcement agencies would have the keys to decrypt data sent and received by users of the messaging apps.

Facebook birthday: 15 defining moments for the social network Show all 15 1 /15 Facebook birthday: 15 defining moments for the social network Facebook birthday: 15 defining moments for the social network Facebook is born On 4 Feb, 2004, 19-year-old Harvard student Mark Zuckerberg launched a website called 'TheFacebook' from his dorm. Within 24 hours the college social network had more than 1,000 users Wikimedia Commons Facebook birthday: 15 defining moments for the social network Winklevoss twins sue Zuckerberg Within one week of launching, fellow Harvard students Cameron Winklevoss, Tyler Winklevoss and Divya Narendra accused Zuckerberg of stealing their idea. It would be four years later when the resulting lawsuit was finally settled Facebook birthday: 15 defining moments for the social network Open for business The social network finally opened it platform to everyone on 26 September, 2006. The move proved the catalyst in supercharging the site's already explosive growth PA Facebook birthday: 15 defining moments for the social network Billion-dollar bid Yahoo offered $1 billion to buy Facebook in September 2006 but Zuckerberg turned it down. 'I don’t know what I could do with the money,' Zuckerberg reportedly said. 'I’d just start another social networking site' Reuters Facebook birthday: 15 defining moments for the social network In the money In September 2009, almost five years since the site launched, Facebook turned a profit for the first time Getty Images/iStockphoto Facebook birthday: 15 defining moments for the social network Taking the lead Facebook overtook MySpace in 2010 to become the world’s most popular social network Facebook birthday: 15 defining moments for the social network Taking on the tech giants In 2011, Google launched its own social network that it hoped would knock Facebook from its perch. Despite its initial success, Google+ ultimately failed and will be shut down completely in 2019 Getty Facebook birthday: 15 defining moments for the social network Facebook goes public On 18 May, 2012, Facebook went public. The initial public offering raised $16 billion – the third largest in US history Facebook birthday: 15 defining moments for the social network Gobbling up the competition Facebook acquired Instagram in April 2012 for $1 billion, consolidating its position as the world's leading social network Reuters Facebook birthday: 15 defining moments for the social network One billion users On 4 October, 2012, Zuckerberg announced that Facebook had hit 1 billion users. 'If you’re reading this: thank you for giving me and my little team the honour of serving you,' he wrote in a blog post Getty Images Facebook birthday: 15 defining moments for the social network Expanding its empire In February 2014 Facebook acquired the messaging app WhatsApp for $19.3 billion REUTERS/Dado Ruvic Facebook birthday: 15 defining moments for the social network Two billion users In June 2017, Facebook passed the 2 billion user milestone REUTERS/Dado Ruvic Facebook birthday: 15 defining moments for the social network Privacy scandal On 17 March 2018, news broke that UK firm Cambridge Analytica had harvested data from around 87 million Facebook users for the purpose of political profiling in the build up to the 2016 US presidential elections Shutterstock Facebook birthday: 15 defining moments for the social network Record profits Despite the scandals and subsequent #DeleteFacebook campaign, Facebook posted record profits just before its 15th anniversary, the equivalent of $7.37 from each of its 2.32 billions users iStock/Independent Facebook birthday: 15 defining moments for the social network Unhappy users A study found that people are happier when they don’t use Facebook, adding to mounting evidence surrounding the impact social media has on mental health Rex Features

Privacy advocates argue that introducing such tools would make them vulnerable to abuse from hackers, or even from people within the companies or law enforcement agencies.

Following various privacy scandals involving user data, Facebook chief executive Mark Zuckerberg announced a new “vision” for the company earlier this year that puts privacy at the centre of the social network’s products.

“Privacy gives people the freedom to be themselves and connect more naturally, which is why we build social networks,” he wrote in a blog post at the time.

In response to the latest reports, Facebook stood by Mr Zuckerberg’s comments that privacy is a human right and should not be compromised.

“We believe in the right for people to have a private conversation online. End-to-end encryption helps protect that right and is fundamental to the value we provide to over a billion people every day,” a Facebook spokesperson said.