In the southern Darfur in Sudan, in 1982, I lay for a week giggling with malaria. I had planned to travel north, through El Fasher and on to where the Kababish wandered; then perhaps on the old Forty Days Road to Egypt. Had I gone, which the total absence of petrol prevented, I might have met Michael Asher.

He would have looked at me with disdain, for I would have been in a Land Rover, with European friends, encapsulated to a great extent in my own culture. Mr Asher would have been on a camel, by himself or with a Nurabi, a Nas Wad Hayder or even a perfidious Sarajabi. He would have been right. The only way to really understand the challenge of the desert, and the austere dignity of the nomads who live in it, is to travel alone and to lead their life exactly as they lead it.

The desert has a fascination for the British. There is even a Desert Club, which meets once a year for dinner, at which we swap news of the way from Djanet to Bilma, what has happened to the Nabatean ruins at Maidan Salih, whether the Imraguen have had rain.

The writers