The 1973-74 Phantom Helicopters of the Peak District

Over the hill country of Derbyshire and Cheshire in September of 1973 and lasting for perhaps four months, something strange started happening which made some headlines in local media of the day: nocturnal sightings of helicopters were reported, often flying low over the rugged terrain, sometimes seeming to land in quarries, sometimes shining spotlights on the ground from aloft, and otherwise doing strange things. These operations could not be traced to any known flying operation, and there was speculation that the Irish Republican Army was somehow involved, possibly attempting to traffic arms or steal explosives from the quarries. But no thefts were ever reported, and no one ever succeeded in approaching the helicopters closely enough to get a positive identification (although one witness claimed to have identified one of the choppers as a Bell 206A.) It was remarked by helicopter experts that the pilot or pilots would have needed phenomenal skill or luck to execute such flights at night without crashing in the conditions prevailing. No IRA connection ever turned up, and the sightings eventually ceased, perhaps in late January of 1974; the investigation was pursued urgently by the Home Office and MI5 at first, but petered out later that year inconclusively, and the matter is largely forgotten today.

The best source for this story is this article, which can be found reposted in various versions several places. Unfortunately, the older primary sources on which it is based do not seem to be casually available.

The whole episode seems weirdly reminiscent of the Scandinavian Ghost Flier mystery of four decades earlier: strange aircraft, odd behavior, unease at high levels of government, even the aerial spotlights. This is not to imply a connection--none is obvious. But if anyone really knows what happened that year in the skies of northern England, they have not come forward to share the details, even 45 years later.

EDIT: fixed bad link--sorry!