Unknown to the British public, for 20 years an obscure base near Harrogate has served as one of the world's biggest telecommunications-tapping centres - and it is run, not by our government, but by America's National Security Agency.
Report by Duncan Campbell and Linda Melvern
Menwith Hill Base covers 562 closely guarded acres of the Yorkshire Moors, festooned with a remarkable array of satellite-tracking aerials. Its business for more than 15 years has been sifting the communications of private citizens, corporations and governments for information of political or economic value to the US intelligence community, and since the early 1960s its close partner has been the British Post Office. The Post Office has built Menwith Hill into the heart of Britain's national communications system - and Britain, of course, occupies a nodal position in the communications of the world, especially those of Western Europe.
The Ministry of Defence said last week that the station "exists with the full approval of the British government". They did not deny that it intercepted international civil communications on a massive scale, but a spokesman claimed that it did not listen in on calls across the Atlantic to or from Britain, "or any domestic calls in the UK". Since most of the operations of the "big ear" at Menwith Hill would presumably be concentrated on the European side of Britain's communications, the MoD does not appear to be denying any pertinent part of our description.
Every aspect of Menwith Hill's operations is shrouded in secrecy, but we have been informed that it was identified during secret Congressional intelligence hearings as the larger of two centres for tapping telephone lines in Europe. Three past and present intelligence officials confirmed the role of the base from first-hand knowledge.
One ex-NSA analyst told us he had seen a document giving the base authority for "tapping the telephone lines to Europe". A high-ranking intelligence consultant who still works for the US intelligence community told us he was aware of Menwith Hill's elaborate telephone and telex tapping facilities. He had inspected the station over 15 years ago and agreed that it was still engaged in tapping. "I know it for sure," he said. And a former British military officer who visited Menwith Hill said: "It intercepts telephone and other communications to and from the United States and Europe. Computers file intelligence dossiers on European political and trade union leaders."
The base was first planned in 1954, but did not start operations until 1960. The Post Office scheme of secret links also began in 1954. The tapping network was concealed within a Post Office plan for a chain of microwave radio towers; this system, named "Backbone", was supposed to provide emergency links if Britain was attacked. But when Backbone was completed it turned out to be feeding signals into the intelligence base at Menwith Hill instead.
Five miles south of Menwith Hill is the Hunters Stones Post Office Tower, virtually the pivotal point of more than a million route-miles of microwave radio connections. Below the ground five cables are installed in a tunnel which runs north, and one of these is the principal feed to Menwith Hill. We visited PO engineers who were replacing a manhole cover on the cable tunnel. They said that if anything went wrong with the Americans' cable "all hell would break loose". The engineers were subsequently warned not to speak to reporters. The Post Office will only say that "Hunters Stones is one of our microwave relay stations. The details of routing of circuits over the microwave network is something we don't discuss publicly."
Menwith Hill is isolated. Many of its staff live on an estate within the base or on other specially built housing estates. All their supplies come from a duty-free "PX" shop, and the base has its own water supply, generators, sewage facilities, fire station, petrol station, restaurants and entertainment facilities. The outer perimeter is guarded by Ministry of Defence police, who have no idea as to the purpose of the base. They maintain regular patrols, which question anyone stopping in the vicinity.
Although the base is said to be a joint US-British facility, the spouse of a former senior Menwith Hill official gave a different account: "There were no high-ranking Brits. They did all the menial jobs like cleaning, maintenance and electricians for the houses." The security precautions were intense: "Anyone over 12 going abroad is briefed first. I was taken to Fort Meade [NSA headquarters near Washington] and had a session with a security officer on my own. I was told that if I made friends with 'foreign nationals' - that included Brits - I was to tell my security officer. We were never to mention NSA."
The most striking feature of Menwith Hill, to the casual visitor, is the array of satellite communications aerials, tracking dishes and protective "radomes", which fill its skyline. These form part of NSA's worldwide network linking Fort Meade with bases in Germany and Diego Garcia in the Indian Ocean - and making Menwith Hill perhaps the largest known satellite communications terminal in the world.