Sleep pointing south, read facing east, stay south of water ... the ancient practice of vastu is India's answer to feng shui. Its foremost practitioner is Mr Reddy, so revered that even the prime minister asks his advice. Peter Popham reports from Delhi
Going by his own apartment, Mr MVR Reddy is not the most obvious person to approach for advice on interior design. The flat he shares with his wife in a tower block in east Delhi has sulphur-yellow walls bare of any picture or ornament, a nondescript suite, a table, a day bed, a few books dumped in a corner. There is a strip light on the wall. The Reddys might have moved in yesterday.

But none of this matters: the essentials are right. Mr Reddy's favoured seat, on the sofa, faces east: the optimal direction for concentrating. The couple's bed is arranged so that their heads point south: both sleep soundly and awake refreshed. The kitchen, however, was a problem. Originally it was in the north-eastern corner of the flat, what is called the "God corner". To cook at this spot, or to put the lavatory there, or the matrimonial bed, is to ask for trouble. So although the cupboards and work surfaces remain where they were installed, Mr Reddy has shifted the stove to a spare room in the south-west. And now all goes well.

Mr Reddy, who must be 6ft 3in, a burly, gravel-voiced bear of a man, is a practitioner of "vastu". Vastu is to India, broadly speaking, what feng shui is to China: it is the ancient code of beliefs, rules and practices that for many centuries, even millennia, has governed the way that Indians build. In a pre-scientific world, it was a means of regulating architecture and town planning. Rooted in ancient texts handed down through generations of engineers and builders, it prescribes a proper place and direction for everything. "For everything," Mr Reddy intones impressively, "there is a place."

Major roads must run due north and south and east and west. (The only piece of equipment a vastu practitioner needs is a compass.) Water - pond, river, lake - should be located in the north. It is best if any mountains are in the south. The house itself and its ground should be a square or a rectangle. If possible the house's central space should be a courtyard, open to the sky - and so on. The ancient prescriptions apply equally to the problems of entire countries and to the organisation of a tiny apartment.

Just as much as ayurvedic medicine or the holy text Bhagavad Gita, Vastu is a product of India's native Hindu genius. But although, as Mr Reddy remarks, India's Hindus and Muslims are constantly ulta pulta (literally "upside down") in relation to each other, the one community doing practically everything in a completely different way to the other, vastu is one thing that brings them together.

Roads in Muslim-built cities of ancient India such as Hyderabad, Mr Reddy's home town, run north and south and east and west. Whole cities were laid out in accordance with vastu's precepts. "In the old days," Mr Reddy remarks, "when India was governed by kings, they used to follow the rules of vastu because they were interested in the welfare of their people." India's most famous building, the Taj Mahal, is a splendid embodiment of vastu: a perfect square, aligned to the compass points, with a river in the north that flows east, a high entrance to the south, a lower one to the north, all structures symmetrical.

For all its venerable age, vastu occupies an odd sort of intellectual no-man's-land in modern-day India. Mr Reddy calls it a "science", but it cannot be studied as such at India's universities; nor, according to Mr Reddy, is there real agreement on what the science would consist of even if it were. But neither is it fully part of the traditional religious scene - its practitioners do not wear orange robes or smear their brows with tilak and holy ash.

Jugal Kishor, another prominent Delhi-based practitioner who writes a weekly vastu column in the Times of India, became an expert through his studies in ancient Indian history and architecture. Mr Reddy, on the other hand, claims to have blundered into the profession by accident. "I am the most failed man on earth!" he declares dramatically. He has a law degree but has never practised. He was (and would like one to believe that he still is) a modernist and rationalist. "I was an ardent critic of the science," he says. "I used to say, if good food is coming out of the kitchen, why bother about going through this door or that door? But then a friend said, `If you want to criticise a subject you must know it profoundly. You are making unwise comment.' I took up his challenge.

"At that time I was unhappy. I had to face a lot of problems for which I was not responsible. So, as I was an only son with land and property of my own, I rectified it according to the rules of vastu: removing septic tanks which were not in the proper place, changing the location of the kitchen, moving some entrances."

The beneficial effects of this, he insists, were both rapid and permanent. "Before, I was very intolerant and impatient. Once the changes were made, I had mental peace."

"I also was not believing it," adds his wife. "But after the rectification, I found some improvements in our life - for example, financial growth." "House and spouse," says Mr Reddy. "These things only bring mental peace."

They were so impressed by the change in their lives that Mr Reddy immersed himself in the subject for the next five years: not following a master (there are none), nor even steeping himself in the books ("All the books contradict one another"), but learning by trial and error.

I pressed Mr Reddy to explain in a nutshell the scientific basis of this "science". He would not be drawn. In a recent book called The Secret World of Vaasthu (sic), Gouru Tirupati Reddy, no relation, waffles portentously about how "billions of years ago the atmosphere comprising dust particles began to converge into a globe due to the reciprocal gravitational pull among the particles," and so on. But MVR Reddy does not attempt to pull the wool over my eyes with such stuff. All he will say is, "It is a science. So scholars should get together to find the scientific basis of it."

Perhaps, I suggested, it works like a placebo. "A placebo can give a brief improvement," he sniffs, "but the effect of vastu is permanent. I have been practising now for 25 years, and I could fool one or two people but not hundreds. People come to me by word of mouth - if one person in a family uses me, soon I am working for all the other members of the family, too." His work involves advice on the construction or rectification of everything from flats to factories - "But if a businessman comes to me and says he has a problem in his office," says Reddy, "first I ask to see his house."

As India grows more affluent, more and more people in the middle classes are building themselves large houses. This trend, apparently, has had two results. "Previously," says Mr Reddy, "people thought, if we have money we will have everything. Now some people have more money than they ever dreamed, but no mental peace." These are the people who stream through his door.

Second, some of the grand houses constructed with this new money break all tenets of vastu. Mr Kishor has recently been advising the owners of a palatial new house in one of Delhi's best "colonies", who found the house to be practically uninhabitable, with bitter disputes breaking out between members of the family. Mr Kishor pronounced that the problem was the house's most imposing feature, a huge central staircase. He advised that it should be destroyed and replaced by staircases in different parts. "If something is wrong in the centre," he says, "it is the death of the house." His recommendations are now being implemented - at mind-boggling expense.

Mr Reddy's most eminent client is the prime minister, Atal Behari Vajpayee, whom he has advised both when he was leader of the opposition and since he became PM. But there, he confesses, he has failed. "I recently visited 7 Race Course Road [the PM's official residence], and it is the worst possible house," he says gloomily. "Everything is very, very bad - the kitchen is in the north-east, the entrances are wrong. I gave Mr Vajpayee advice, but I was told they cannot make the changes for security reasons. But India's last two prime ministers had very short terms in office. And if the vastu there is not rectified, no prime minister will last more than a year and a half. In that house, heroes are becoming zeroes."

Vastu, if you choose to believe Mr Reddy, accounts for everything. India itself is unhappily placed, having sea to the south and the Himalayas in the north, comparing badly with Switzerland, for example, whose vastu is perfect, which accounts for its prosperity and peace. "India's position is a problem," Mr Reddy says. "At times it grows and at times it falls. Uncertainty is there."

But there is a simple vastu solution even to this gigantic problem of a whole nation, though one which Mr Reddy hesitates to propose - "they would stone me to death!" It is the mountains in the far north which are the headache. The answer? "Let Pakistan have Kashmir and all will be well. Up to Jammu - the foothills below Kashmir - we are all right".