Here, a darker Africa begins: Robert Mugabe’s ruined Zimbabwe, the towns squalid and shattered, the countryside desolate and overgrown. Many of its famished and tattered blacks seek to escape at Beitbridge, swimming the river, or paying the waiting omalume, “uncles”, the people traffickers, to smuggle them past the border patrols to a new life in South Africa.

For almost all of its 1,200 miles of polished tarmac and plump service stations, the N1 offers evidence that post-apartheid South Africa has avoided the bloodshed and collapse that have haunted its neighbours. In a continent awash with troubles, its prosperity and stability draw not just illegals from across the Limpopo, but even French-speakers from Niger and the distant Sahara.

A tiny half-mile section of the N1, though, past Mokopane in Limpopo Province, chills the heart. It is overlooked by a large white cross that lies on a green hillside. Look closer, and the cross is seen to be made up of scores of small white crosses planted in neat lines. And then the eye is drawn to what seem to be bursts of snowdrops on the kopjes, the two small hills that lie on each side of the cross. These, too, are little white crosses, swirling on the slope.

The Afrikaners, the native whites of South Africa, have a flair for setting monuments to their rugged history in such sweeps of landscape. The crosses are their handiwork – or, more specifically, that of the “Boers”, or “farmers”. They seem to commemorate some distant epic, a trek with ox wagons, a battle with Zulus or the British.

But Mokopane is not to do with the past. The word “Plaasmoorde” is hand-lettered on the slope. It means “farm murders”. Over 1,700 of South Africa’s commercial farmers and their families, mostly white and Afrikaans, but including a substantial number of English speakers, have been killed since the end of apartheid in 1994.

The ages of the victims vary – from infants to people in their eighties. The attackers usually operate in gangs of three to eight. Extreme violence, including rape, torture and physical mutilation, is often involved. Sometimes nothing is stolen, leading to claims that the attackers are motivated by racism and a desire for revenge.

Mokopane, then, deals with the present, and, in the most brutal way, with a future in which the rural Boers, for more than 300 years the white tribe of Africa, fear they face extinction.

The world has more than an inkling of what has happened in Zimbabwe. Over the past six years, to the accompaniment of farm invasions, beatings, livestock maiming and now mass hunger, Mugabe has seized more than nine-tenths of his country’s white-owned commercial farms. He is about to complete the ethnic cleansing of rural Zimbabwe.

What is happening in South Africa is less known and is, in most respects, different. In Zimbabwe it is government policy, instigated by the president, and seen through by party thugs. South Africa, in which the bulk of commercial farmland remains in white hands, has model policies of land restitution and reform – validation by land claims courts, compensation at market value, incentives for black empowerment and land ownership – whose principles are accepted by most landowners.

The process of restitution is intended to be scrupulously fair, untouched by the rancour that built up over the long years of baaskap, white supremacy. Whites moved from areas designated as black “homelands” by the apartheid regime are entitled to claim on the same basis as displaced blacks, though the latter- are far more numerous. Valuations are by independent assessors. Progress has been slow, though the white farmers have little reason to complain. A decade after apartheid, less than 5% of commercial farmland is in black hands, though the government has set a target of redistributing 30% of white-owned land to blacks by 2014.

For all the legislation and goodwill, there is horror. Zimbabwe’s white farmers were expelled, and uncompensated. Very few were murdered.
It is true, sadly, that South Africa suffers from a general epidemic of violence, and farmers cannot expect to be immune in a country where 18,793 people were murdered in the year to March 2005, the great majority of them urban blacks.

But the farmers’ numbers are small, and their vulnerability high: 10 times higher than for the population at large, or so it is claimed, making them the most at-risk profession in the non-military world. Go to the farmlands, and it shows.