The horror started just before midnight on Wednesday this week. After listening to the latest television news about the health of Nelson Mandela, a South African family living not far from the former President’s hospital unit turned in for the night.

But Roelof and Laura du Plessis, a married couple with four children who live on a heavily fortified farm outside Pretoria, did not have a peaceful night’s rest.

In fact they were about to become the latest victims of what is nothing less than a savage race war against whites. Hearing noises outside their home, Mr du Plessis, 46, got out of bed and ran outside.

To his horror, he found his 19-year-old son being held with a gun to his head by a gang of five armed black attackers. Father and son were ordered to lie on the ground. The invaders did not ask for money or the keys to the expensive vehicles in the drive. They were there only to terrorise and kill.

Hearing voices outside, Laura, 44, came out of her bedroom to investigate — and her torch illuminated an awful scene as the gang pointed guns at her husband.

Her son managed to get up and sprint off into the darkness when the men were confused by the flashlight. But Du Plessis was not so lucky.

The intruders opened fire at once, shooting him six times through the throat, lungs and abdomen.

As he writhed on the ground in agony, the men ran off into the night leaving empty bullet cartridges littering the yard.

In the darkness, Laura attempted heart massage on her husband, who could still talk despite his appalling injuries, but to no avail.

“He was shot through the lungs and I was doing CPR,” she told the Daily Mail, between huge sobs. “He said ‘please go and fetch the car and take me to hospital’. But he was too badly hurt and he died in my arms.”

In the morning, when white friends from neighbouring farms followed the trail of the raiders, they discovered the men had carefully cut through fences and skirted areas with security patrols — suggesting how closely they had planned their route of attack.

“It is definitely coming down to a race thing,” Laura du Plessis said as she was comforted by her family. “They hate white people. We have never had a fight with any black people. I always stop and give others a lift. We employ black people.

“My husband fought for me. I am grateful that he wasn’t tied up and forced to watch me being raped before he was killed. He was an amazing man. He was my life.”

A friend of the family, who asked not to be named, told me he was certain that the killings are part of a sinister, systematic bid to drive white people — and, in particular, farmers — out of South Africa.

“If this was happening in any other country, the military would be deployed to protect us,” said the friend. “There are gangs moving around the country targeting white people.”

The statistics — and the savagery of the killings — appear to support claims by these residents that white people, and farmers in particular, are being targeted by black criminals.

Little wonder that what unfolded on the Du Plessis homestead has sent tremors of fear through the three-million-strong white community.

Last month alone there were 25 murders of white landowners, and more than 100 attacks, while Afrikaner protest groups claim that more than 4,000 have been killed since Mandela came to power — twice as many as the number of policemen who have died.

It is not just the death toll, but the extreme violence that is often brought to bear, that causes the greatest fear in the white community.

Documented cases of farm killings make for gruesome reading, with children murdered along with their parents, one family suffocated with plastic bags and countless brutal rapes of elderly women and young children.

These horrors have prompted Genocide Watch — a respected American organisation which monitors violence around the world — to claim that the murders of ‘Afrikaner farmers and other whites is organised by racist communists determined to drive whites out of South Africa, nationalise farms and mines, and bring on all the horrors of a communist state’.