GCHQ (Government Communication Headquarters) is the beating heart of the UK's spy capabilities - formally known as Signals Intelligence, or SIGINT. As such, it is tasked with monitoring communications networks for evidence of threats to British national security and traces its origins back to the famous work done at Bletchley Park during WWII where the German Enigma code was broken. Since the nature of its work has become public knowledge, it has come under increasing scrutiny regarding the nature and scope of its operations.
At the famous 'doughnut' building in Cheltenham, GCHQ is in charge of a range of clandestine intelligence operations - most notably co-ordinating the activities of listening stations such as Menwith Hill. In 1994 Jeremy Hanley told Parliament that:
"There is a significant GCHQ presence at Menwith Hill station. It is not Government policy, however, to give more detailed information on the deployment of GCHQ staff."
In 2013, it was revealed that GCHQ is aware of and can access the USA's highly controversial PRISM surveillance system, which routinely monitors online activity from data obtained from the likes of Microsoft, Yahoo, Skype, Google and Apple.
Further revelations made towards the end of the same year (trailed heavily in the US media, but receiving relatively little coverage on home soil) implicated GCHQ in a massive email surveillance program targeting the servers of both Google and Yahoo. The nature of the material obtained is, of course, unknown, and the NSA itself denied the allegation, telling journalists:
"This is not NSA breaking into any databases. It would be illegal for us to do that and so I don't know what the report is, but I can tell you factually, we do not have access to Google servers, Yahoo servers, dot, dot, dot. We go through a court order."
Despite the denials of the NSA, British Google employee Mike Hearn outlined some of the activities carried out by GCHQ, telling his readers:
"I am not American, I am a Brit, but it's no different - GCHQ turns out to be even worse than the NSA."
The Washington Post published documents released by Edward Snowden that suggested that GCHQ is being used by the US intelligence community to carry out operations that are effectively illegal under US law - primarily intercepting communications without warrants. It is thought that the UK side of operations is tasked with breaking into communication pathways between the various server networks deployed by the major ISPs and internet companies such as Google.
On November 7th 2013, the head of GCHQ was among those questioned by the Parliamentary Select Committee.
Fuck You, GCHQ The packet capture shown in these new NSA slides shows internal database replication traffic for the anti-hacking system I worked on for over two years. Specifically, it shows a database recording a user login as part of this system [Mike Hearn]
N.S.A. Said to Tap Google and Yahoo Abroad WASHINGTON — The National Security Agency and its British counterpart have apparently tapped the fiber-optic cables connecting Google's and Yahoo's overseas servers and are copying vast amounts of email and other information, according to accounts of documents leaked by the former agency contractor Edward J. Snowden. [New York Times]
How the NSA is infiltrating private networks The NSA, working with its British counterpart, the Government Communications Headquarters (GCHQ), secretly taps into the internal networks of Yahoo and Google, the two biggest Internet companies by overall data traffic [Washington Post]