Revealed: How the government probed Britain's greatest UFO mystery
Declassified government files have revealed how Ministry of Defence (MoD) officials launched a top-level probe into a diamond shaped aircraft seen hovering above a Scottish village.
Officials were so alarmed by the object, which was captured on camera, that they broke with established procedures and referred the sighting to ministers.
They also overrode rules prohibiting investigations into UFO sightings not considered an immediate threat to national security, and spent more than a year trying to crack the still unexplained mystery.
According to the files, the Ministry of Defence first became aware of the existence of the craft when the Daily Record newspaper presented it with six colour photographs of the object. The UFO seen by two men, one of whom captured it on camera, as it hovered in daylight near the A9, at Calvine, north of Pitlochry, on August 4, 1990.
The witnesses said it hovered for about 10 minutes – during which time military aircraft were also seen making a series of low-level passes – before moving upwards, out of sight, at great speed.
The files show that officials established from the photographs that the military craft were Harrier jets even though, intriguingly, none were operational in the area at the time. Dr David Clarke, a university journalism lecturer and UFO expert, said: "This is the most tantalising of all the UFO reports. This shows how the MoD was worried about what the hell they were going to say. They had no idea what it was. They couldn't even identify where the Harriers had come from. It is a real mystery. It is one that can't be explained. They took it very, very seriously."
The files show that a year after the original photographs were taken, the MoD tasked experts to produce line drawings of the UFO which would give officials an idea of scale.
Even the creation of the drawings was shrouded in strict secrecy. One undated document suggests "very special handling" because of "sensitivity of the material". It also orders "minimum handling by listed personnel".