The government's spy agency GCHQ has been able to snoop on what citizens are doing on the world's most popular social media websites, including YouTube and Facebook, in a programme called ‘Squeaky Dolphin'.
Documents obtained by NBC News, and leaked by former National Security Agency (NSA) contractor Edward Snowden, reveal that GCHQ showed off its abilities to the NSA in 2012.
NSA employees were shown how GCHQ could monitor YouTube activity in real-time, collecting addresses from videos that were being watched, as well as user information, which it could then analyse. At the time, Facebook and Twitter users were also snooped on, but Facebook has since encrypted its data. Google's YouTube and Blogger are not encrypted.
The presentation obtained by NBC is dubbed ‘Psychology A New King of SIGDEV' (Signals Development), and explains how the programme is a "broad real-time monitoring of online activity", covering websites ‘liked' on Facebook, and Blogspot/Blogger visits.
Both Google and Facebook have denied that they gave GCHQ permission to access the data, and have claimed that this is the reason more and more services are being encrypted.
According to the presentation, the data collected was analysed in real-time using data analytics firm Splunk's Dashboard.
GCHQ showed how the software works, with a pie chart that highlighted 20 trending YouTube video tags, as well as Facebook and blog posts on 13 February 2012, in advance of an anti-government protest in Bahrain the following day.
Experts told NBC that although specific users were not identified, this could have been possible if GCHQ had access to such data.
But GCHQ has denied any wrongdoing, suggesting that its work is in accordance with UK law.
The operation could be a part of the wider ‘Tempora' programme, published by the Guardian last year which found that GCHQ was tapping into fibre-optic cables to get access to global internet traffic and phone calls, and processing information from around the world which it is sharing with the NSA.