This miserable road to freedom is lined with the carcases of dead donkeys. For about 100km before the Beitbridge border post, there are scores of them, smashed by the roaring 40-ton juggernauts that thunder up and down the road from South Africa in the night. Donkeys never move out the way. All that is left is a hide stretched over a skeleton, cleaned within a day by dogs and maggots in the 40 degree sun.

Scrawny, ragged children at the side of the road gesture with their hands, putting fictional food in their mouths. In the shade of a thorn tree a woman sits in the shade of a thorn tree next, with a naked infant in her lap, limp and motionless. They undress them when they are sick, to cool their fevered bodies.

I stop at a garage on the outskirts of the town. Into Beitbridge each day several thousand pour for the chance of escape from despair, starvation, cholera, chaos and brutality. Yesterday in Harare I saw young men sprinting in panic from a pick-up full of police, for the crime of hawking fluffy red and white Father Christmas caps at the traffic lights.

It is Christmastime and people with a little hard currency are heading for the paradise of South Africa's gleaming, abundant supermarkets to bring back food, maybe some cheap clothing.

None of the dozen fuel pumps has fuel. The garage is more like a refugee camp. Haggard-looking men lie against the wall, grimy from the sweaty backs of thousands of others before them. The cement forecourt is smooth and stained from the feet of moving, hungry multitudes.

They are waiting for a lift, for money, for a tout to help them through the electrified fence after they were refused entry into South Africa.

There are rocks all over the forecourt that battered southbound pick-ups have used for jacks. Broken glass, fast food trays, torn tyres, broken vehicle parts everywhere.

A high toll

I have to change money here. The bridge toll is in Zimbabwe dollars.

The US dollar has become the unofficial national currency, but state offices are forced to charge in Zimdollars. When I eventually get to the toll window at the customs and immigration building I present a freshly printed five hundred million dollar note I have just exchanged. The official laughs and waves me on. The charge is 13 million Zims. No change, there never is now.

Through a maelstrom of vehicles, five vehicles thick from one side of the narrow road to the bridge. A lone woman police officer is uselessly on duty. Miraculously, the crush thins and we squeeze on to the two-lane bridge, built at the turn of the last century. It trembles alarmingly as the big rigs rumble across. Up to his waist in the river below, a young man casts a net for fish. This is the crocodile-infested Limpopo river?

The South African side is a revelation. Traffic monitors with two-way radios, policemen and immigration officers bringing order to a meandering queue of several hundred, mostly seated, so slow is the process. It takes up to six hours to be cleared.

At the immigration section, a woman officer gently chides: “Come on you guys, stay in the line.” The police are friendly, helpful. I am astounded. Confronted every day with this river of misery, much of it suffering from cholera, the hearts of the authorities are softened.

Tears of rage

Even here the infection of fear stays with the Zimbabweans. I attempt conversation with a young man next to me with new white Nikes and the penetrating eyes of a street thief. He mumbles and turns away. You never know who's listening.

Finally, out of the border complex and on to a big, new, pothole-less road. On the other side of the road there is a queue of vehicles 5km long, waiting to enter Zimbabwe. Most of them are pick-ups, each one with an industrial trailer, stuffed tight, piled up to three metres high, listing awkwardly with mattresses, bicycles, wheelbarrows and the big checked plastic bags that are the mark of the Zimbabwean diaspora.

But more than anything else they are stuffed with food: big bags of maizemeal, sugar, flour, five-litre bottles of cooking oil. And there are 18in bars of carbolic soap - and shiny new 20-litre plastic canisters for carrying and storing water in the country's cholera-infested towns.

Nearly all the vehicles have South African vehicle registration plates. Zimbabweans with jobs and money in South Africa, bringing salvation to starving, thirsty mothers, fathers, spouses and children.

On the road to Johannesburg this relief convoy dominates the northbound traffic. Some of them are so overloaded the trailer axles have snapped. The contents are strewn at the side of the road: broken water canisters, buckled galvanised iron baths, spilled maizemeal.

After about 200km of road without dead donkeys, of sanity and order, I was overcome with rage and sorrow and wept.

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