Rod Dickinson clearly remembers the night he made his first crop circle. It was the summer of 1991, just months before the famous crop-circle hoaxing duo, Doug Bower and Dave Chorley, came out about their nocturnal wheat-flattening activities; a time when the nation was still gripped by the idea that aliens might feasibly have been parking up in fields at night, all over the southern English countryside.

"No one had really mooted the idea these things might have been man-made," says Dickinson, an artist, "as far as people were concerned, me included, there were definitely other possibilities; at least some unexplained natural phenomena. I was fascinated." So when a friend challenged Dickinson to join him in an illicit attempt to create their own crop circle, the pair found themselves on their knees in the middle of the night, with a not very elegant, not very round mess on their hands.

Thirteen years later, Dickinson has just completed what he estimates to be his 500th foray into the art of what's come to be known as "circle-making". This time, things were a little different. The medium was sand, not crops, and the ambitious formation replicated a photographic image that Dickinson and his circle-making partner, John Lundberg, 35, had spent several weeks translating into a series of co-ordinates on a computer-design programme. From this, they'd created complex numerical spreadsheets, filled with measurements, from which his team of 13 assistants worked. He'd also secured advance permission from the landowner; there was a four-strong BBC film crew to capture the work in progress; a helicopter booked so a photographer could capture the end result, and a PR. Oh yes and, this time, he and Lundberg got paid several thousand pounds for their efforts by the satellite channel UK TV Gold, who commissioned the piece to launch their new comedy season.

But how does it feel to have a huge corporate logo slapped in the middle of your land? Very good, says a farmer paid £500 apiece for two fields to be used for Circlemakers' jobs. "If they'd been put in by an alien and I hadn't been paid, I'd have been hopping mad."

'It makes me chuckle sometimes," says John Lundberg, gazing across a wheat field in central England. "If somebody had said to me 10 years ago that today I'd be flying all over the world making crop circles for big companies and being paid for it, I'd have said they were mad."

The rewards for the crop circle entrepreneurs are high and growing. The AMD job was the group's most lucrative so far. Mr Lundberg is unwilling to give precise details, but says the contract was worth "tens of thousands of pounds". The budget for the Big Brother campaign was estimated to be £250,000, and for Orange's Wiltshire project about £100,000. "We are doing well," Mr Lundberg said. "We are all earning a very healthy living from crop circles."

Landowners are benefiting too, receiving payments - from the companies or circle-makers - for allowing their fields to be used for the work. The income easily covers the damage to crops, leaving farmers with a profit.

Richard Cowan, who farms 1,500 arable acres in Oxfordshire, has twice - last
year and in 2002 - allowed Mr Lundberg's company to make crop circles on his land for Orange. He was unwilling to say how much he was paid, but another farmer, in Wiltshire, said that the going rate was "at least £500 for each circle and sometimes much more". Mr Cowan said that the circles had caused him to him to lose about £200 worth of crop, giving him a "decent profit" from the deal.

He would be "unhappy" if people crept on to his land at night to make crop
circles - unless he was properly compensated. "Nobody wants damage to their crops, but the key thing is whether you are paid for it," he said. "I'm happy for my fields to be used as long as I know about it and I get compensation. I used to believe crop circles were made by aliens, but there's no money in aliens. It's much better this way."