Taxis are a law unto themselves in the desert. When and if one appears depends on the heat and whether a driver is prepared to make the trip. The money they earn is always secondary.

We trundled across the rocky plain, jammed together and united by our discomfort. There was no road, just a clearing of undergrowth discernible only to the driver. A sign warned of sand drifts and, as if on cue, suddenly sand was everywhere, eddying from the crests, slipping across the track, settling over the windscreen. Swathes of it spun across the landscape like sugar. Dunes mounted up along the side of the road, their errant particles threatening to engulf us.

‘It’s a lucky day today,’ said the driver. I wondered what he meant by that. More to the point, what exactly constituted an unlucky day?

Drifts building around the wheels are only to be expected when driving across the Sahara. Sometimes the grains are so fine they cause deeper slippage. Ramps have to be put down and vehicles are often coaxed out like frightened animals.

Perhaps those who hate the Sahara have a point when they argue that it is not about space, freedom, solitude or escape, but getting stuck, not to mention the poison from exhaust fumes, heat exhaustion and cigarette smoke.

The real desert is none of these things, of course. It is the planet in the raw, the earth’s skin mashed to a pulp, burnt and scabbed. In its vastness human beings look like ants. Buildings are etched into the earth’s surface as if part of it. Roadblocks melt into its haze like coagulating lava.

Alongside the misty peaks of the Tassili the taxi swung left. Gold canyons emerged dotted with palm trees and acacias. Specks of Barbary sheep balanced like acrobats on crags. For miles beyond just the sweeping line of crisp dunes and low hollows fell upon a horizon the shade of ox blood.

Dusk fell, and with it the temperature. I huddled, dry-throated, in my inadequate cotton clothes, thinking of the bag containing the solitary sweater I had brought, which was beyond reach in the luggage rack on the roof.

It was dark when to everyone’s relief we rattled into Tamanrasset. A little later, I peered tentatively into the void, and strode into it.