A secret policy that gives the government permission to carry out mass surveillance of Facebook, Twitter, YouTube and Google users in the UK has been uncovered.
The legal loophole was uncovered in the wake a challenge by several privacy and civil liberties groups, which featured a witness statement by Charles Farr, the UK government's director general of office for security and counter terrorism.
The 50-page document featuring Farr's statement claims UK residents could lawfully have their social networking site communications monitored because these are classed as "external communications" under the Regulation of Investigatory Powers Act (RIPA).
According to RIPA, external communications are defined are those that are sent and received outside of the British Isles, but do not include those sent and received within its borders.
"A person conduction a Google search for a particular search term in effect sends a message to Google asking [the company] to search its index of web pages. The message is a communication between the searcher's computer and a Google web server," Farr explained.
Because Google's largest European datacentres are not located within the British Isles, the likelihood is this correspondence between the Google web server and the user will be classed as an external communication.
And the same could apply to Facebook, YouTube and Twitter users, if the communications they have with those sites are facilitated by overseas datacentres and web servers.
"A user located in the British Islands posting a message on Twitter will communicate with a Twitter web server forming part of Twitter's datacentre infrastructure," Farr continued.
"That datacentre infrastructure is largely based in the United States; so the communications may well be external' for the purposes of RIPA."
The witness statement has been published by Privacy International and forms part of the government's defence case about the scope of its surveillance activities in the wake of the Edward Snowden revelations, which is being handled by the Investigatory Powers Tribunal.
In a statement on the Privacy International website, the civil liberties group hit out at the definition of social media posts and Google searches as "external communications".
"By defining the use of platforms' [like this], British residents are being deprived of the essential safeguards that would otherwise be applied to their communications simply because they are using services that are based outside of the UK," the statement reads.
The revelation has prompted an outpouring of contempt from several other privacy groups, including Amnesty International.
Michael Bochenek, senior director of international law and policy at Amnesty, said: "British citizens will be alarmed to see their government justifying industrial-scale intrusion into their communications.
"The public should demand an end to this wholesale violation of their right to privacy."
