Dan Wilmot and his wife were sitting on their porch reflecting on the day. It was a few minutes before 10 in the evening, the brutal sun had given way to a balmy evening and the New Mexico sky was clear when, in their words, “a large glowing object zoomed out of the sky”, hovered, and then disappeared from view at high speed.

They both ran to their garden fence to try to follow its path before it vanished.

Six days later the local daily newspaper reported – quoting the intelligence officer from the local air force base – that a flying saucer, which had crashed into scrub at Foster’s Ranch, had been recovered.

That report, in the Roswell Daily Record on this day in 1947, set off either one of the world’s greatest conspiracy theories – or a monumental and successful cover-up which makes the JFK affair look like child’s play.

The story was quickly denied. It was said to be an experimental weather balloon. And there it may well died had not that intelligence officer, Jesse A Marcel, allegedly bound for decades by official secrets, subsequently mentioned it to a ham radio correspondent who, in 1978, told Stanton Friedman, a UFO researcher. The aliens were out of the closet, or coffin.

The Roswell air base in 1947 was the centre of the United States’ atomic weapons research programme. Marcel was in charge of security, not just there but in the Pacific where tests were planned to take place. His son, Jesse Jnr, then 11, later claimed that he handled pieces of the craft. Even later it was reported that a nurse at the base said she had been present at autopsies of three creatures which had been recovered from the debris. Both Marcels are dead (but you can see their accounts on YouTube), the nurse was never identified and, as in most of these mysteries, she is said to have conveniently died in a plane crash.

In July 1997, just days before the 50th anniversary of the crash when spectators would flock to Roswell, the US Air Force released a 231-page report – The Roswell Report: Case Closed – which rubbished the theories and explained that the three aliens were crash test dummies. Closure? It was merely proof for ufologists that the state secrecy about what really happened in what was known as Area 51 was being reinforced.

When that report was issued Scotland had its own Area 51, the Falkirk Triangle, centred on Bonnybridge where, each year another 300 or so “sightings”. are reported. The first was in 1992, when  local businessman, James Walker was driving between Falkirk and Bonnybridge. He stopped when he spotted a shining, star-shaped object which was hovering over the road, blocking his path. 

Walker, who must have been exceedingly phlegmatic, said the object flew away at “an incredible speed” before he did the same. Others have reported seeing a “howling” UFO that buzzed their car, while a cigar-shaped craft was spotted landing on a golf course, probably getting in an early round. Others claim to have been captured by aliens in the Triangle, taken aboard for examination, their memories of what then happened wiped. I believe they believed it.

The Provost of Falkirk, and independent councillor Billy Buchanan, certainly does. He has written to three Prime Ministers demanding inquiries, so far with no result. “How do we know aliens aren’t walking about?” he said in 2005. How indeed? We’ve all had our suspicions of people.

But why Bonnybridge? Is it some interstellar interchange, or is the Falkirk Triangle actually a window into another dimension? Given the number of craft spotted, the council should impose some kind of congestion charge, although enforcement might be problematic. Whatever else, it’s all a handy promotion to draw visitors and custom to one of our poorer parts.

It would take more than a comprehensive debunking from the state to kill the Roswell story, of course. It had another boost  in 2012 when Joseph Beason inherited a series of colour slides from his sister who, 14 years before, had been hired to dispose of the belongings of an old woman and she couldn’t bring herself to jettison the Kodachrome.

Years passed until she got round to looking at them, projected onto a wall at home. They appeared to be immediately post-war pictures of the Allied Commander, later to become President Dwight Eisenhower, on a victory train tour, accompanied by Clark Gable and Bing Crosby. There were also contemporary shots taken in European capitals.

But it was two almost identical slides, wrapped in parchment, which sent shockwaves. They had been taken through what looked like a glass case of a small, brown creature with withered arms, shrivelled legs and a large, triangular skull with gaping eye sockets. A dead space alien.

Beason and his friend Adam Dew, a videographer, researched and found the slides had belonged to a women called Hilda Blair Ray in Arizona, a state away from Roswell. The two had the slides analysed by Kodak which confirmed they had not been tampered with and dated them to between 1945 and 1950, taking in the timeframe of the Roswell incident. But the more they researched and tried to prove a theory, the more the news started to leak out.

In May 2015, almost 7,000 people paid up to $86 to attend BeWitness, a four-hour show in Mexico City’s grandest theatre, the Auditorio Nacional, where, after innumerable speakers and ufologists, finally the slides were projected onto huge screens. 
However, just days later the alien truth was revealed. An online enthusiast, screen name Neb Lator, had examined the high-resolution image using an internet software program called Smart DeBlur Pro and had managed to decipher an indistinct placard below the case of the “alien”.

It read, “Mummified body of two year old boy”. 

Further deblurring revealed: “At the time of burial the body was clothed in a (unreadable) cotton shirt. Burial wrappings consisted of these small cotton blankets. Loaned by Mr (unreadable) San Francisco, California.”

The mummy, of a Native American child, was traced to the Chapin Mesa Archeological Museum in Mesa Verde, Colorado, where it had been on display for years. It had been discovered in a series of cave dwellings cut into Arizona cliffs in 1896 and later donated to the museum.

So had it all been an elaborate scam to make a quick buck? The two men have continued to deny it but own up to a grand mistake on their part.

Time-travelling back to 1947 and the Wilmots on their wooden porch. What did they see?

Might it have been what they wanted to see? Just days before the first “flying saucer” – not one but nine! – had been spotted when an amateur pilot called Kenneth Arnold said he saw them fly past Mount Rainier in Washington State at, he estimated, three times the speed of sound, impossible then for a terrestrial aircraft. 

He told a reporter it flew “like a saucer if you skip it across the water”. The reporter took this to mean that the objects themselves were saucer-like, and news reports across the country repeated that Arnold had seen “flying saucers”.

Suddenly, by July 4, newspapers were reporting hundreds of witnesses seeing “flying saucers” in the sky across the United States.

Or it could have been some high-altitude contraption to scan what the Soviets were up to with their atomic programme, some kind of satellite precursor? 
Or then again ...