As I reported earlier, the UK’s Ministry of Defence has agreed to open its secret files on UFO sightings over the UK. These are five of the most controversial incidents that UFO spotters hope will be solved (don’t hold your breath!):

1. The Cosford Incident. On March 31, 1993, triangular-shaped UFOs were spotted by dozens of people in western Britain, speeding through the night sky.

The MoD’s man then running their “UFO desk”, Nick Pope, told his superiors: “It seems that an unidentified object of unknown origin was operating in the UK Air Defence Region without being detected on radar.

“This would appear to be of considerable defence significance, and I recommend that we investigate further, within MoD or with the US authorities.”

A meteorological officer said he saw a triangular-shaped craft flying at about 200ft. It made a low hum and fired a narrow beam of light which swept the ground.

Skeptics say the sightings were actually of a Russian rocket booster breaking up in the atmosphere after putting a satellite, Cosmos 2238, into orbit.

But Pope, who has since left the MoD, claims that “no satisfactory explanation” was ever found for the reports. He called Cosford the “big case” that made him believe extraterrestrials could penetrate Britain’s defences at will.

2. The Berwyn Mountain Incident. UFO believers claim that a flying saucer crashed in Wales on January 23, 1974, and that alien remains were discovered in a UK equivalent of the United States’ famous Roswell Incident.

The area was reportedly cordoned off and local villages visited by mysterious investigators, who they described as the “Men in Black”.

Police quickly set up a search team and had ten officers scouring the mountains, later to be joined by an RAF mountain rescue team from Anglesey. Their official report was that they found nothing.

During the investigation, it was discovered that there had been an earthquake at the time of the reported UFO crash. The Institute of Geological Sciences said that if the size of the tremor had been due to an impact, there would have been a clearly visible crater, yet none was found.

Skeptics say the UFO stories resulted from a combination of the earthquake, a meteor shower and the lights of poachers who were active in the mountains.

3. The Flying Cross Incident. A celebrated case championed by UFO believers was a flying saucer chased by two police officers across Devon on October 24, 1967.

The patrolmen, Roger Willey and Clifford Waycott, followed the UFO through country lanes at speeds of up to 90 miles per hour in the early hours of the morning.

But instead of being saucer-shaped, “it looked like a star-spangled cross radiating points of light from all angles,” PC Willey said afterwards.

He added: “It was travelling about tree-top height over wooded countryside near Holsworthy, Devon. We drove towards it and it moved away. It then led us on a chase as if it was playing a game with us.”

Astronomers quickly came up with an explanation for the Devon Flying Cross. They said it was a case of mistaken identity and the officers had been chasing the planet Venus which was prominent in the morning sky at that time.

4. The Manchester Incident. As a British Airways Boeing 737 carrying 60 passengers approached Manchester airport on the evening of January 6, 1995, it was apparently buzzed by a bright, fast-moving UFO.

The incident was enough to make the first officer duck instinctively as it flashed past. But air traffic controllers said they saw nothing on the radar.

The pilot told them: “We just had something go down the right hand side just above us very fast. It had lights, it went down the starboard side very quick.”

At the time of the sighting, the Boeing was descending at 4,000 ft, about nine miles southeast of Manchester. The silent UFO was moving in the opposite direction and was visible for about two seconds.

The pilots submitted a report that was investigated as a near-miss by the Civil Aviation Authority. But stargazers claim the airmen simply saw a fireball or brilliant meteor.

Leading UK UFO skeptic Ian Ridpath commented: “These kinds of cases show that pilots and policemen make the same mistakes as everyone else when it comes to misidentifying objects in the sky.

“The people who spend most time looking at the sky, amateur astronomers, report the fewest UFOs because they are less easily fooled.”

5. The Rendlesham Incident. Britain’s most famous UFO mystery began on Christmas night, 1980. There were countless UFO reports, including from aircraft passengers, of strange lights streaking through the skies over southern England.

Then at 2.50am on Boxing Day, a brilliant light was seen to fall over Tangham Woods in Rendlesham Forest by a military cop at Woodbridge NATO base near Ipswich.

Other airmen, fearing an aircraft had crashed, drove into the woods to investigate. They followed strange lights for an hour ans one said he saw an alien craft’s metallic form.

The incident was taken so seriously that police were called to the scene. Two nights later, other airmen entered the woods on a UFO hunt and reported seeing coloured lights which they followed for two hours.

They also reported higher radiation levels than normal, burn damage to trees and three depressions in the ground where a UFO had landed.

Skeptic Ian Ridpath spoke to a young forester, Vince Thurkettle, who identified the brightest light as nothing more alien than Orford Ness lighthouse, six miles away, seen through a gap in the trees. He said he had himself mistaken it for poachers’ lamps.

Ridpath says the lights seen that Christmas night across England were rocket debris from the satellite Cosmos 749 as it burned up in the atmosphere.

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