By Hilary Andersson BBC Correspondent in Tzaneen, South Africa

On the side of a motorway in northern South Africa, white couples held hands with their heads bowed, as a quiet prayer was uttered for 1,500 white farmers who have been murdered since apartheid ended in 1992.

About 1,500 whites have been murdered since the end of apartheid

The murders, often horrific in their brutality, are on the increase, according to a report by South Africa's Human Rights Commission.

Aatie Vermaak, a third generation white farmer, drove down a long dirt road on his farm showing us where he had been attacked in January.

Black assailants had followed him, and when he stopped his car they shot him the stomach.

Mr Vermaak was intensive care for a month, his gall bladder had to be removed, his liver was in pieces, and he nearly died.

"They stole nothing. They just shouted kill the dog, kill the dog," he said.

'Kill the farmer'

Like many white farmers who have suffered similar attacks Mr Vermaak thinks the attack was racist.

His farm is near the town of Polokwane, where just a year ago thousands of black South Africans gathered for the funeral of a prominent ANC activist.

If you tell me I like a black man or that a black man likes a white man, you are lying White farmer

"Kill the Boer! Kill the Farmer," they chanted in unison to the beat of a warlike dance.

That day Nelson Mandela stood by and watched, looking troubled.

Old racial tensions in South Africa still run deep, and yet the country's future relies on multi-racial unity.

That war cry has still not been fully outlawed, although South Africa's Human Rights Commission did recently declare it unconstitutional, and a form of hate speech.

Black frustration

An hour's-drive away, amidst steep green ravines and lush farmland lies the town of Tzaneen.

Mr Vermaak thinks violence against white farmers is racially motivated

There at dusk, we entered a farm, accompanied by a black unionist Robert Mukabela, who wanted to show us the roots of black frustration.

On that farm we found 90 black farm workers living crammed into a few squalid rooms.

Sleeping spaces were divided with plastic bags strung from branches of a tree that had been dragged into the room, in a pitiful attempt to create divide up the living space.

There were no beds, not one toilet, and no electricity.

The labourers said they were being paid a wage of 12 rands ($1.6) a day. That is barely enough to eat on.

Few of the children there could afford the transport to go to school.

One 19-year-old black labourer told us the white farmer there had just beaten him.

"Yesterday, I was working and I made a mistake. So the farmer hit me on the back of my head.

"And while I was falling down he jumped on my back. It's not the first time," the teenager said.

Deep racism

We went to find the white farmer in question. At the gate of his town house, he at first denied the allegation of assault - then he admitted it.

"He didn't want to listen, so I gave him a good slap.

"That's how we work with them," he said.

Farmers either leave the land or improve security

"Do you realised people will accuse you of racism?" I said.

"You can do that," the farmer said.

"Is that a fair accusation?" I asked.

"Yeah, in America, in England, there, in all places there is racism - it's the order of the day.

"If you tell me I like a black man or that a black man likes a white man, you are lying," he said.

The deep racism of a few farmers like him fuels the violence that is driving other moderate white farmers off the land.

"I just cannot see my children or my grandchildren taking up farming. There is an uncertainty prevailing", said Mr Vermaak.

There is no land grab in South Africa like there is in Zimbabwe, but white farmers in South Africa fear their days of farming here, are numbered.