Hundreds had been reported, by everyone from RAF pilots over Scotland to a woman walking her dog in Norfolk.
But it wasn’t the threat of an alien invasion that tormented defence officials during this period of overhead hyperactivity at the end of the 1980s.
The sleek shape of the B2 Stealth bomber
Their theory was that our American allies had been building and testing stealth aircraft and spy planes without telling us.
In fact, in many cases they were probably right.
A series of simple, almost childish drawings produced by some of the witnesses have just been released from secret files.
And many appear to show the angular lines of a stealth fighter. Not all the sightings could be explained this way, however.
One woman claimed to have spoken to an alien with a Scandinavian accident while a series of reported sightings in London turned out to be an airship advertising the latest model of the Ford Mondeo.
Details of around 1,200 UFO sightings have come to light after seven files produced by the DI55 branch of the Defence Intelligence Staff from November 1987 to April 1993 were released by the National Archives.
The stealth bomber and fighter – aircraft that are almost invisible to radar because of their shape and the materials used to build them – are now a major element in the U.S. Air Force. Russia is also developing models.
Witnesses in Scotland saw a large diamond-shaped object in the air before it jetted off vertically at a great speed
But in the late 1980s the MoD was watching for evidence that either side was developing the technology.
And the files just released provide a fascinating insight into that obsession.
Dr David Clarke, a UFO expert and journalism lecturer at Sheffield Hallam University, said the documents showed the MoD was ‘not in the slightest bit interested in aliens’.
‘They’re only interested in the defence implications,’ he said.
This pulsing blue light was captured on camera above Shropshire by 13-year-old Harriet Rogers
‘The question is, what are the Russians testing, and could any of these sightings be something of that kind.
‘These files also show they were obsessed with the fear that our closest ally was developing spy planes and keeping them secret from us.’
This cylinder-shaped object was captured on video camera seemingly hovering in the sky above Brean in Somerset
In one case, photographs taken of a UFO hovering next to an RAF jet over Scotland, were carefully examined after witnesses said they saw a mysterious large diamond-shaped object hanging in the air for about ten minutes before it ascended vertically at high speed.
In 1989 an oilrig worker trained in observing aircraft saw a ‘perfect black triangle’ escorted by two U.S. fighters.
Other incidents recorded in the files include the report of a woman who said she was approached by an alien with a ‘Scandinavian-type accent’ as she walked her dog near Norwich in 1989, and a spate of sightings in East London in 1993 explained by the presence of a brightly illuminated airship.
Speculation: Itwas ‘fatigued’ bolts securing the 60ft blade on the turbine that caused damage here, not a UFO colliding with the 200ft structure
There are also records of sightings by crews of six RAF Tornado jets of a UFO over Germany in November 1990 which they believed to be a stealth aircraft.
But military officials appear to have paid most attention to the sighting of the diamond-shaped object next to the RAF Harrier on the A9, north of Pitlochry in Scotland, on August 4 1990.
Two members of the public took colour photos and gave them to a newspaper which in turn passed negatives to the MoD.
The ministry responded to questions by saying that ‘no definite conclusions’ had been reached, but they believed the witnesses may have had a chance sighting of a spy plane called Aurora.
Diane Bowres spotted this rare cloud shaped like a flying saucer while on holiday in Spain
Derek Burden thought he saw UFOs in the top right-hand corner of this picture, but most think they’re just reflections from the light in the room he was in
This picture of a supposed UFO sighting in Tonbridge, Kent in 2002 was sent into the local newspaper and investigated for its authenticity by UFO magazine
This UFO was spotted twice by Brian Bould’s family, hovering over Wolverhampton before New Year 2001 and in February 2001
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