Britain's spy agency GCHQ has secretly gained access to the network of cables which carry the world's phone calls and internet traffic and has started to process vast streams of sensitive personal information which it is sharing with its American partner, the National Security Agency (NSA). The sheer scale of the agency's ambition is reflected in the titles of its two principal components: Mastering the Internet and Global Telecoms Exploitation, aimed at scooping up as much online and telephone traffic as possible. This is all being carried out without any form of public acknowledgement or debate. One key innovation has been GCHQ's ability to tap into and store huge volumes of data drawn from fibre-optic cables for up to 30 days so that it can be sifted and analysed. GCHQ and the NSA are consequently able to access and process vast quantities of communications between entirely innocent people, as well as targeted suspects. This includes recordings of phone calls, the content of email messages, entries on Facebook and the history of any internet user's access to websites - all of which is deemed legal, even though the warrant system was supposed to limit interception to a specified range of targets. The existence of the programme has been disclosed in documents shown to the Guardian by the NSA whistleblower Edward Snowden. Britain's technical capacity to tap into the cables that carry the world's communications ... has made GCHQ an intelligence superpower. A total of 850,000 NSA employees and US private contractors with top secret clearance had access to GCHQ databases.