Since the beginning of time, humans have imagined themselves visited by strange beings - spirits, ghosts, angels, gods and now aliens. For believers, the timeless universality of these other worldly experiences throughout history is proof that God exists. They say it shows beyond a doubt that we are born naturally religious, born with an instinct to worship a supreme being and filled with intimations of heaven glimpsed by a few specially sensitive people. So it must be true.

Everyman (BBC1) this Sunday risks putting itself out of business once and for all as a religious based programme. It solves the mystery of such experiences, and, potentially, finds the root of all world religions at one remarkable and controversial stroke. What if all mystical experiences could be explained by a particular malfunction of an identifiable part of the brain? What if these same experiences can be reproduced in ordinary people by stimulating that part of the brain? Its a programme to set atheists punching the air.

Yes! Proof at last God does not exist! Dr Michael Persinger, Professor of Neuroscience at the Laurentian University in Canada believes he has found God-and its a brain disorder. He takes an ordinary woman, who has never had any odd experiences, and puts her through his brain test. With electrodes stimulating one part of her brain, she too reports seeing grey beings, a face speeding towards her, a sense of extraordinary well being and a vaguely sexual sensation. It mirrors so many of the descriptions we hear from those who believe they have been visited by other spirits. The results match those in oxygen deprivation tests which reproduce, under laboratory conditions, those out-of-body and near death experiences where the dying think they have glimpsed heaven. It is always a long dark tunnel, ending in a bright light, with angel-like creatures accompanied by a reassuring euphoria. It is, I'm afraid, the same pleasurable experience summoned up by those who indulge in sexual perversions with near-hanging and asphyxia.

We shouldn't be surprised. After all ,many epileptics, who have clearly diagnosed brain lesions, report many of the same visions and hallucinations during a fit as mystics. The programme includes speakers who suggest that biblical miracles, such as Jacob's ladder of angels or Paul's conversion, reflect some of these explainable brain functions precisely. If the three wise men were to be alive now and saw the Star of Bethlehem, they would doubtless interpret it as a UFO.

Alien abduction experiences are now remarkably common - and painfully convincing to those otherwise normal people who have experienced them. Two sane and sensible ordinary women talk in this programme about their regular alien abduction experiences and how difficult it is to live with them. How can they make others believe what is so real to them? In a sense, the experience is real. They have seen and heard these things so often, always at night, always carried out by shadowy aliens. Vaguely sexual sensations are an important part of it with both women believing they have had eggs taken from them to create a hybrid new race.

Dr Persinger points out that women and men have had these visions for centuries, describing them in the Middle Ages as incubi or succubi-devils who perform unwanted sexual acts on people in their sleep. In the Middle Ages, the alien abductees would have been burned as witches. Now I suppose, we should be sending them to a psychiatrist. Even if their brain malfunction cannot be corrected, they might be more at peace with their visions if they could realise what they are- phantoms of the mind. It is clearly distressing for these people to feel they have been selected as messengers by space godfathers - especially when the nature of the message is so vague.

It leaves them with a sense of urgency that the world needs saving  [Just like the religious evangelists-LB] -but quite how or from what remains incohate. Orthodox religions have always found ways to accommodate new scientific discoveries. So what will they do with God as a brain malfunction? I suppose they will relocate God in the brain and say he was always in our heads, scientists have merely proved his existence, or something of the sort.

Meanwhile, atheists will smile and wait for the day when religious apocalyptic visions, which have given rise to so much dangerous fanaticism, are put to rest with a medical cure.