The former UFO expert for the Ministry of Defence revealed one of his favourite ever sightings was spotted in Lancashire.
Nick Pope, who worked for the government between 1985 to 2006, compiled a list of unexplained incidents to celebrate the release of a film about alien invaders.
It includes a man who contacted the MoD in 1985 claiming to have been in contact with aliens, who wanted to establish diplomatic contact with the authorities.
And police officer Alan Godfrey who encountered a UFO the size of a bus, hovering five feet above the road in Todmorden, West Yorkshire.
His most notable sighting relating to Lancashire was a UFO flying alongside a freaky funnel cloud which was snapped moving slowly over the skies of the county in July 2008.
Pat Regan, 51, who went on to set up North West UFO Research project, took a picture of the peculiar sight while on the Rufford branch of the Leeds Liverpool Canal, near Chorley.
The incident even attracted the attention of a team of investigators from Los Angeles who flew over to interview Pat, from Ainsdale, and visited the Evening Post offices in Fulwood to talk to staff who reported on the story.
Their programme, UFO Hunters, was repeated on The History Channel earlier this week.
Mr Pope said: “Lancashire is a county that certainly seems to have a fair share of interesting sightings and incidents.
“Clearly some photos will be hoaxed but this seemed to be (taken by) someone with no prior interest in the subject, who was genuinely perplexed by what he captured.
“It’s an interesting sighting and an interesting picture.
“There are also some UFO photos and videos taken at local airshows. These are of particular concern to me because whatever you believe about UFOs, when something unidentified flies close to an aircraft, there are air safety implications.
“I investigated several such cases at the MoD, involving both military aircraft and commercial aircraft.”
Other sightings which made Mr Pope’s top 10 were retired policeman Philip Spencer who encountered an alien on Ilkley Moor, Yorkshire, in 1987 and claimed to have been abducted and a huge, triangular-shaped craft spotted over RAF Shawbury, Shrewsbury, in 1993.