New documents have been released which detail the role of a special MoD unit responsible for investigating UFOs.
The role of Britain's UFO desk officers is shown in records released by the National Archives.
The 6,700 pages include a detailed briefing on UFO policy from the officers who worked for the Defence Intelligence Staff to then Prime Minister Tony Blair and a sighting of a UFO allegedly seen hovering above Chelsea Football Club.
The desk officers also set-out their thoughts on the possibility of the existence of alien life and discussions about how the Ministry of Defence could harness extra-terrestrial weapons.
Among their many tasks was the handling of hundreds of Freedom of Information requests from people looking for information about reported UFO sightings.
Officers were also expected to provide briefings on the Ministry of Defence's official position on extra-terrestrial life and maintain regular contact with UFO experts.
According to the files, a hotel owner in Wales once complained to her MP after a UFO landed in a field "from which two tall silver-suited 'faceless humanoids' emerged and began "making measurements'."
The desk also claims to have once investigated an earthly visit by three "men in black” but the perception there were top-secret teams of scientists scurrying around the country like the X-Files was "total fiction".
The documents are being released after a Freedom of Information request by Dr David Clarke, author of 'The UFO files' and a lecturer at Sheffield Hallam University.
He said: "These records allow us to look behind the scenes of what must have been one of the strangest jobs in Whitehall."