Three mysteries of the 80s remain: Eddie The Eagle, Limahl's haircut, and crop circles. But the greatest of the three is crop circles.

For a while, many people thought strange forces could be at play. Circles were popping up across the south of England like huge patches of alopecia. And on the edge of the circles, people looked on in wonder.

Aliens, some thought. Freak weather conditions, said others. Weird electromagnetic forces, still more claimed. Even magic was mentioned.

Or could it be mischievous pranksters, pulling the wool over the eyes of a gullible public?

Most people seemed to shrug their shoulders and conclude it was probably the latter. But a hardened group of devotees still maintains there is more going on the fields of Wiltshire, Hampshire and elsewhere than one could imagine.

Wiltshire circles

The debate even survived the admission by Doug Bower and Dave Chorley, two retired artists, that they had been responsible. Doug Bower even demonstrated on television earlier this year how to make your own crop circle with a plank and length of rope.

Yet for the legions of crop circle believers that is not enough. At least half a dozen organisations operate in England which can count their members in the hundreds. And they all think something is going on.

Crop circle researcher Colin Andrews discusses his plans

It is a view which has been given a shot in the arm by the announcement that US billionaire Laurance Rockefeller, 88, is to fund research into whether they are genuine.

Photographer Lucy Pringle is just one of the many in no doubt that hoaxers cannot be responsible.

Having researched crop circles for the last 10 years, she has written books on the subject and is a firm believer. Just because some circles have been claimed by hoaxers, she says, it does not mean "the genuine thing" does not exist.

George Bishop of the Centre for Crop Circle Studies points to a figure of only 3.5% of circles being fakes. And at the same time he estimates that only 40% of circles are noticed.

Stonehenge, with the Hale Bopp comet. The site of early crop circle?

While they agree that hoaxers are not responsible, opinions still vary on what is responsible.

Mrs Pringle, who lives in Hampshire, believes the circles (or "formations", as she calls them) are caused by low frequency microwave radiation, and that they occur on the earth's "energy lines".

As for what causes the radiation, she says she cannot answer. But one possibility is that other worlds are trying to contact us.

"Are they a means of communication? We don't know, but we have tried to communicate with others. We've sent up messages in universal languages to Mars and so on, so it stands to reason that perhaps others are trying to communicate with us."

In any case, there is a different atmosphere inside "genuine" formations than in hoax ones, she said. One woman told her it was a personal experience that words could not describe.

"A lot of people are perfectly chatty before they go into the formation, then when they are inside it's like a cathedral. You feel terribly small and insignificant in the vast majesty of a sacred place."

A different feeling

It's not just the feeling that's different inside hoaxed circles, she said. The stems of the crop show when they have been pressed down by hoaxers. But the microwave radiation instead makes the stems bend under their own weight. Hoaxed circles had flaws in their geometry but genuine ones were mathematically accurate, even when they had hugely complicated designs.

Others in the crop circle community refuse to believe that such intricate patterns can be replicated at night-time by people with planks.

Mr Bishop, a former journalist, first got involved in the crop circle scene when he went to report on a sighting. He agrees with Mrs Pringle that there is a special atmosphere.

"I stood looking into this crop circle, thinking: 'Wow! What next?' It completely turns your life upside down. Some people throw away careers, and exhaust their family and finances in chasing circles," he said. And since then, his life has never been the same.

Phil Mackie reports from Wiltshire for Radio 5Live

Based in Devon, he said he thought crop circles happened all over the country, but said only those in the south of England were reported. In the north, he said, he thought there was more of a reluctance to talk about things that people did not understand.

He added that ancient stone circles - which include Stonehenge and Avebury - could have been built on the sites of early crop circles. But in any case there were 450 reported sightings before 1980 and any media interest. There was even a report of one in 900AD in Lyon, he said.

Mrs Pringle said many people would not admit their suspicion that circles were genuine because of the fear of mockery. "England can be cruel," she said.

Part of the Circlemaker Website, illustrating a plan for a Wiltshire 'hoax'

But the crop circle community continues to flourish, nowhere more so than on the Internet (see Internet Links on the left).

Michael Hutchinson, author of a book called Bizarre Beliefs, and a member of the UK Sceptics organisation, said a lot of people now thought there was something genuine about crop circles.

"And it's too many," he said. "There's no good evidence to show crop circles are anything else than man-made."

The spread of stories about paranormal happenings posed difficult problems for people who campaigned for scepticism, he said.

"It's much easier to tell a story and misinform people than it is to tell them the harmless, boring, truth."

Nevertheless he did see a beauty in crop circles. "Some of them have been fantastic. I know people who have made them and they consider it an art form, which is what it is."

Proof positive

Earlier this year, the BBC programme Country File filmed crop circle hoaxers - including Doug Bower - at work. Lindsey Morris, one of the production team, said the programme was not intended to show that crop circles were hoaxes, but that circles could be fabricated.

"They did create a complex circle," she said, "and did it in about two hours."

But it did not happen without a certain amount of resistance from some crop circle believers, which included chasing the hoaxers.

So far this year about a dozen have been reported. Whether they are true or not, many people would be sorry if the circles stopped appearing in the countryside. Farmers excluded.

Tom Bewley, spokesman for the National Farmers' Union, said crop circles were "frankly, a bloody nuisance", with the damage to plants, and the risk of tourists coming to see the circles.

But this had not stopped one farmer, who had land near Stonehenge, from making the most of his bad fortune, said Mr Bewley. When his field was overrun with tourists, he set up an entry gate, charged £2 entry, and started selling colour aerial photographs.