Cast your mind back to 1991. Quite an eventful year. Saddam Hussein invaded Kuwait, Nelson Mandela was elected president of South Africa, the USSR disintegrated and gave way to democracy. Yet there was one, overriding topic of conversation in the air. What was causing strange patterns to appear up and down the land?

   Hardly a day passed during that long, hot summer, without more reports from riled farmers that their crops had become victim to the unexplained phenomena. By night, whole swathes of corn, wheat and other crops, were becoming flattened, the morning light revealing mysterious patterns. Some were small, simple designs; others were larger and more complex. Whatever was occurring had caught the public imagination.Thousands came from all corners of the globe, each hoping to see a crop circle for themselves. Or better still, to witness one being made.

   Not even the prime minister escaped the furore. In one of the more notable cases, a crop circle formation, consisting of several circles, had appeared in the then Prime Minister John Major's country residence. It had materialized inside the security fence, amidst anti-terrorist security. The press speculated. One headline read: "NOW EXPLAIN THIS." Had aliens landed at the PM's holiday home? Or had clever hoaxers beaten anti terrorist security? Neither apparently. An official statement was issued attributing the design to "poor soil conditions."

   The rabid, media, feeding frenzy was being fed daily by the appearance of yet more formations, accompanied by stories of UFO sightings and abductions. But summer drew to a close, September set in and farmers began to fell their crops. Media interest began to ebb.

   Later that month the headlines exploded. Two men had come forward, Doug Bower and Dave Chorley, both of whom claimed to have been responsible for the creation of every crop circle that had appeared since 1976. The duo, both in their sixties, described to the international media how they had "fooled the world for the last fifteen years." But fifteen years of running around in the middle of the night, jumping over barbed wire fencing and eluding vigilant landowners was taking its toll. They weren't "getting any younger"; the time had arrived to finally come clean on their nocturnal tomfoolery.

   To back up their claims, the men demonstrated their method in front of the worlds press. Cameras rolling, they got to work. Using nothing but a metal stake, a piece of string and a small wooden plank, the team had managed to produce a perfect circle in less than half an hour. The press had their circle and the public had its explanation. The party, or so it seemed, was over.

   The ET brigade and a hardcore of researchers remained resolute and public disbelief did little to dampen their spirits. Although national newspapers had stopped running stories on the UFO link, many people still supported the idea, explaining the phenomena as being down to alien visitation. An enthusiastic, American tourist, enamoured with the ET theory, produced a huge formation of his own, spelling: 'TALK TO US.' Further distress befell the relevant farmer when only a few days later more of his corn became victim, only this time to a large tract of ancient Hebraic text apparently fashioned as a reply.

   Despite ridicule and a hostile press, researchers asserted that a great deal of questions remained to be answered. In many peoples' eyes, Doug And Dave's story was all too inadequate in accounting for some of the more curious anomalies evident in around 20% of crop circles. These, amongst others include:

   A bending at the node (elbow) on the stork of plants within a formation. Nobody has been able to explain how this is possible, as standing on corn, or oil seed rape, would invariably cause the stems to snap. Laboratory analysis has often shown affected plant matter to have undergone molecular change, the cell walls becoming swollen and expanded. The ground underneath crop circles often appears considerably dehydrated, the soil appearing broken and cracked, even after heavy rain. Radiation levels within a crop circle have been measured as being 10 times above average.

   Even if Doug and Dave did somehow manage to produce the above effects they have never offered an explanation how. Neither have they endeavoured to account for their methods in creating some of the complex designs.

   Following the most reputed formation of 1996, the triple Julia set fractal; an engineering company was asked to replicate the design. They replied that due to the complex mathematical structure of the pattern, the preliminary groundwork alone would take 11 days and use metal stakes in order to map the design. It would also have incurred a cost of over £5000. No evidence of stakes being used was there on Windmill hill that day!

   More evidence of Doug and Dave's mendacity became apparent during a television interview with the surviving member of the duo, Doug Bower. When pressed to give technical data he was unable and tried to skirt around the issue. A leading researcher, Colin Andrews, also present on the show, asked Mr Bower how he could account for 2300 recorded formations, when he had claimed responsibility to only 200. This forced him to back down on his original claim that he had been responsible for all the formations since 1976.

   There were still, as researchers had maintained, a great deal of questions that two men, a piece of string and a stick, could not answer, especially after the debunking of the most widely accepted, sceptical theory to date. During the 1980's, well before Doug and Dave surfaced, Dr Terrence Meadon, a distinguished scientist, formulated what had become known as the 'plasma-vortex theory' in an attempt to explain the phenomena. Meadon postulated that previously unrecognised vortices were forming high above the ground and suddenly descending in a lightning type strike, thus explaining the spiral swirl displayed by a great deal of crop circles. His theory won considerable support. From their lab in Japan, Dr Y.H. Ohtsuki and Prof. H. Ofuruton corroborated Meadons' claims by producing similar vortices using electrostatic discharge and microwave interference. Further evidence was provided in the form of research by Prof. H. Kikuchi, also of Japan, who provided theoretical models of Dr Meadons' plasma vortices.

   As satisfactory as this theory appeared to be, it rapidly began to lose face, as it could not account for the complex pictograms, that by this time had started to appear on the scene. These were more than the familiar lone circles of the 1980's. Groups of circles linked together by lines and curves increasingly appeared. They formed geometrically complex patterns, many of which drew reference to ancient religious symbols, such as the Celtic cross and the Jewish Star of David. All at once, Dr Meadon's plasma vortex theory was in dire need of revision. The idea that simple vortices could create such intricate glyphs seemed ludicrous.

   Many more theories surfaced, each vying to offer an adequate explanation where Dr Meadon could not. All sorts of interesting propositions came to light. Everything from earth energy, to military experimentation were explored as a possible cause. Crop circle researchers, of whom some had been researching the phenomena since the seventies, were emerging more and more into the public eye.

   Large-scale surveillance operations were mounted at Alton Barnes and Bratton castle, two of the areas most accustomed to hosting crop circle formations. Some of the fields in these areas were affected year after year. High tech equipment was used. Cameras were set up, alongside sound recording equipment and an infrared trip wire system.

   The Bratton castle operation appeared to pay dividends early. In what was to be a three-week exercise, a formation had appeared on only the second day at the foot of the ancient hill fort. Although the creation of the circle was not caught on film, excited researchers hastily rushed down to the scene, amongst them photographers and journalists all keen to get a slice of the action.

   All concerned were then confronted with what was little more than an amateurish hoax. A simple design presented itself. The corn had been crudely and hurriedly trampled down. Left in its centre, as though on purpose, lay a ball of wire and a horoscope game. Disappointed by the hoax, the media presence dwindled, leaving only the hardcore of researchers and a few steadfast onlookers.

   Several days on and only 440 yards from the hoaxed attempt, something altogether more compelling had cropped up. In a well-documented incident a whirl motion had been seen by two of the researchers through night vision lenses. The movement of this whirling motion lasting for some 15 seconds, defining the shape of a question mark. An observation was made of the field the very next day revealing a question mark design imprinted firmly into the corn.

   This was one of many alleged sightings that had increasingly been coming to light. Members of the public and researchers alike had been claiming to have seen strange light shows, hours before the appearance of a new formation. Farmers too had often told stories of their herd animals behaving in an agitated manner or refusing to enter a certain part of the field, in which a new formation would show itself the next day.

   Some eyewitness reports involved larger numbers of people and attracted the attention of the international med