IN 1987, five days after getting married, Kate and I flew to Sudan to begin work as English teachers in the small desert township of Babanusa. Bored with England and disillusioned with Thatcherism, we had answered an advertisement which stated that "enthusiasm is more important than experience". An interview at the Sudanese Embassy, with talk of the harsh climate, the lack of alcohol and the monotonous diet, had only increased our excitement. Our honeymoon was going to be the biggest adventure of our lives.

Eight years earlier, Michael Asher had been working as an undercover security officer in Belfast when he had seen that same advertisement. Once in Sudan, teaching beside the Nile, he had found himself drawn to the mysterious desert tribes of semi-nomadic Arabs whom he saw riding their camels to market. As soon as he got the chance, he bought a camel and set off into the desert, in search of a legendary trading and slave route known as the Forty Days Road.

He never found the Forty Days Road but he did discover his destiny in this beautiful, unforgiving landscape littered with bones. Travelling with the Arabs and speaking their language, Asher brilliantly chronicled a timeless way of life, under threat, as he saw it, from the twin evils of drought and development. His was a world of camel-rustlers and charcoal- burners, living by an ancient code of honour which combined a casual attitude to violence with a surprising and touching gentleness.

The Arabs of the desert would offer their last cup of water to a stranger but would kill you without a qualm if you laid hands on their camels or their women. Asher envied their simple existence; these were men who still believed that the world was flat and "whose alphabet lay in the tracks left by camels in the sand". As one nomad, Mohammed Belal, told him, cradling a baby son in his lap: "What good is school? Look around you. Green bushes. Tall grass. Water. Fat camels which eat well. What more do we need? His school is here in the wadis."

I read Asher's book over and over, attracted by the romance of the nomadic life which was happening just outside my town. I, too, saw these people coming to market with their buttermilk and their goatskins, their faces covered by headcloths to shield them from the desert wind. I knew that I could never be like Asher; without his skills, honed in the SAS, I would not survive two nights in the desert.

His was a Boy's Own Adventure story, a tale of Kalashnikovs and cattle- thieves, of dehydration and danger and strange encounters with officials, policemen and bandits. It was not for me, yet still I longed to get beneath the skin of the Sudanese people in the way that Asher had managed to do. After three years of juggling work and desert treks, Asher resigned his teaching post to live with the Kababish nomads. I never rode a camel or joined a nomadic tribe, but I like to think I found something of the same spirit and values among the people of Babanusa.

Like Asher, I was overwhelmed by the generosity of people who had almost nothing to give; like him, I was inspired by their simple, unquestioning Islamic faith. When the time came to leave Sudan, as a final act of solidarity we decided to share in the Ramadan fast, going without food and water during daylight hours for a month. It was then that I came to understand the hunger and thirst which had accompanied Michael Asher and his companions across the desert, and the communal nature of a society in which strangers share all that they have in order to survive.

In Search of the Forty Days Road was published by Penguin in 1986, but is now out of print