A spy programme known as Project Echelon has been tapping into billions of phone calls a year for the last half-century, according to a campaigning journalist writing for The Intercept.
The scheme was jointly-run by US agency NSA and British agency GCHQ, and signalled the advent of mass surveillance by ushering in an age of "Big Brother"-style snooping, according to one source.
Starting in 1966, the project leapt into life when the NSA fronted the money for the GCHQ to build a station in Bude, Cornwall, capable of intercepting satellite communications from Intelsat, the first commercial communications satellite network.
Journalist Duncan Campbell and fellow reporter Jim Bamford located a second site in Yakima, America, that intercepted US-Asia communications.
Campbell wrote: "At the dawn of the era of mass surveillance, almost 50 years ago, the ECHELON stations at Bude and Yakima were the global mass surveillance system."
The Echelon system was automated, and able to sift through vast swathes of data from these satellites to sort and categorise it all.
Speaking to a former Lockheed (now Lockheed Martin) employee in the late 1980s who was responsible for managing NSA databases at a new site in California, Campbell learned how Echelon was spying on politicians, and his source also shared plans for the IT system underpinning the project.
He wrote: "The plans showed how ECHELON, also called Project P415, intercepted satellite connections, sorting phone calls, telex, telegraph and computer signals.
"Although the internet was then in early infancy, what was carried digitally was covered. The way ECHELON had been designed, she said, demonstrated the targeting of U.S. political figures was not an accident."
Campbell added that the scale of the operation had shocked him.
"The NSA and its partners had arranged for everything we communicated to be grabbed and potentially analyzed," he said. "ECHELON was at the heart of a massive, billion-dollar expansion of global electronic surveillance for the 21st century."
However, Campbell's expose of the spying programme in 1988 was ignored for 11 years, until the European Parliament commissioned an investigation in 1999.
Though the parliament mandated extensive action against mass surveillance in 2001, a few days later the Twin Towers were destroyed in the 9/11 terrorist attack.
"Any plans for limiting mass surveillance were buried with the victims of 9/11," wrote Campbell.
Since Edward Snowden's revelations about the NSA laid bare the extent of spying programmes against US and European citizens, public interest has spiked in privacy, and some of the documents leaked actually confirmed Campbell's reports.
