More interesting revelations from this week's release by the UK Ministry of Defence of secret documents pertaining to the UFO subject...though in this case, it is crop circles. One of the mysterious themes propagated (pun not intended) in the crop circle mythos is that of 'black helicopters' being present at the scene of newly-formed glyphs. According to the latest MoD documents released, that was simply the military sight-seeing:
The MoD tried to stop military helicopter crews photographing crop circles for fear that this contradicted the official line that they had no interest in the phenomenon.
In 1991, the Centre For Crop Circle Studies wrote to the MoD, saying aircraft had hovered over fields where the patterns had appeared and on at least one occasion taken pictures. This concerned the MoD so much that they wrote to Army and Navy chiefs, asking them to ensure this did not happen again.
But both services refused, saying they would "not be taken seriously" by air crews if they issued such an edict and suggesting the department was being "over-sensitive towards the UFO lobby".
The documents also reveal a dialogue between the MoD and British Prime Minister Margaret Thatcher regarding the circles, as well as one strange case in which a circle was said to be formed by four 'bright' whirlwinds (interesting note about the "swishing" sound, given my own research...although in this case that's probably a likely sound with a windstorm in fields of crops).