UFO investigator Nick Pope, who formerly ran the Ministry of Defence’s project on the subject, has insisted that “compelling” evidence of extraterrestrials is out there, but has been covered up by the government.

He told BBC Radio Scotland Show, Tales of the Unexplained, he insists that the best picture of a UFO he ever saw was that of a “diamond-shaped metallic craft” suspended in the sky over the village of Calvine in Perthshire.

The highland incident, which occurred near Pitlochry, was spotted by two men, who reportedly saw the 25 metre craft hover for 10 minutes before charging up into the heavens at great speed. Not before the onlookers managed to obtain a colour photograph however, which was sent to the Ministry of Defence.

Military planes were visible in the background and seemed to be escorting “or even chasing” the UFO, Pope told BBC Radio Scotland

After experts told Pope that they believed the photo was genuine, the UFO expert, who worked at the Ministry of Defence from 1991 to 1994, blew up the mysterious picture and pasted it on the wall in his office.

However the picture was taken down by the head of his division, recalls Pope, and it was suggested to him that putting up such pictures was inappropriate. The mystery photo then never reappeared, even when the MoD declassified and released the files in later years.

“I suspect that certain people thought that this was some secret prototype aircraft, a next-generation stealth that maybe nobody should be seeing.” he told BBC Radio Scotland.

It’s not the first time that Scotland has been a target for UFOs. In 2010, it was revealed that authorities in Bonnybridge, Scotland repeatedly wrote to Downing Street due to the high levels of sightings in the area.

One of the most high profile UFO encounters that occured in a remote part of Scotland is to be made into a movie released this year. It tells the story of Garry Wood and Colin Wright, who claim they were abducted along the Edinburgh to Ayr road.

Nick Pope can be heard on BBC Radio Scotland at 2pm on Thursday.