By Peter Biles
BBC News, South Africa
The economic crisis in Zimbabwe is having a severe impact on its neighbour, South Africa. An estimated three million Zimbabweans are thought to have fled to South Africa to escape the chaos and they continue to flood across the border at Beit Bridge.
The original Beit Bridge was erected in 1929 and a new one built in 1995
The Limpopo River, famously described by Kipling as "great, grey-green and greasy", forms the border between Zimbabwe and South Africa - two close neighbours, but now a world apart.
Zimbabwe is on its knees. Its people are starving and desperate.
South Africa is seen as the land of opportunity. And the bright lights of this economic giant beckon.
It is winter here now and this is the dry season. That is good news for the thousands of mainly young Zimbabwean men prepared to take the risk of crossing the Limpopo.
They come down to the river bank on the Zimbabwean side, sometimes in large groups. Then they disperse.
They are able to wade across, but they need to keep a look-out for crocodiles in the shallow water.
When they reach the South African side, they dry themselves down and edge nervously towards South Africa's triple-layer border fence.
This is a barrier that was put up in the days of apartheid - when the country's white rulers tried to stop the guerrillas of Umkhonto we Sizwe, the armed wing of the ANC, from infiltrating from Zimbabwe.
But these days, the security is not as formidable as it looks.
Peter Biles examines the gaps and holes in the wire mesh
The illegal migrants from Zimbabwe approach the first fence and cut the wire mesh or burrow in the sandy soil to open a gap underneath.
Then, using their bolt-cutters, they make their way through rolls of razor wire. And finally, they penetrate another layer of fencing.
By this stage, one of the Zimbabweans is probably leading the way as a scout.
But the "border jumpers" are rarely deterred.
In daylight, with my car parked on a quiet narrow road that runs along the border, a man suddenly appears. He leaps over the nearest fence with unexpected agility and vanishes into the South African bush.
All this happens within a few hundred metres of the Beit Bridge border post, the only official crossing point between Zimbabwe and South Africa.
Under the noses of the South African police and soldiers, this is as brazen as it gets.
I carry on watching with fascination.
Donald, a workman, says he repairs about 100 holes a day
A few minutes later, a group of six men come surging over the security fence.
They look left and right to see if there is any approaching traffic, cross the road and dart out of sight.
A little further along the border, I meet a workman in red overalls. Donald's job is to repair the holes cut in the fence by the Zimbabweans.
"Sometimes, I have to fix 100 a day," he says. "The situation is getting worse and worse. Our army isn't patrolling enough."
"Perhaps what we need," suggests Donald, "is for Robert Mugabe to put up a fence on his side of the border."
Looking for work
Zimbabwean motorists who cross the border legally are short of petrol
I make my way back to the petrol station at Beit Bridge. This is the first stop for Zimbabwean motorists who have crossed the border legally and need to fill up their empty tanks.
There is precious little fuel in Zimbabwe these days.
But in the car park, it is not long before I run across some of those who have come across the border by less orthodox means.
"Yes," says 23 year old Tony, "I swam the Limpopo. We have no food, no money and no jobs in Zimbabwe."
Promise is also 23. He is from Harare and has come to South Africa to look for a job in an attempt to support his family.
He thinks he might find some work on a local farm, but many have made the same journey ahead of him and a record number of Zimbabweans are now being picked up by the South African police and deported.
Determined young men
It is thought that about 1,000 Zimbabweans are being arrested in South Africa every day and sent home, but as many as 3,000 a day may be coming into the country.
So that means plenty appear to be slipping through the net.
Some of the more circumspect Zimbabwean migrants enter South Africa under the cover of darkness.
Most want to head south to the big cities of Johannesburg and Pretoria.
All this is the consequence of what is happening in Robert Mugabe's Zimbabwe
As the early morning mist begins to burn off, a teenager approaches me and asks for a lift.
Others are hitching on the main road, the N1 highway.
The local farmers are getting more than a little jittery about this influx.
They are hardly enamoured with large groups of poor, hungry and determined young men, traipsing across their land.
Game farmer Gideon Meiring sees himself living on a frontline.
He says the police can not cope, so with military precision, Gideon now runs his own patrols and tells me he comes across Zimbabweans on his property almost every day.
All this is the consequence of what is happening in Robert Mugabe's Zimbabwe, a country that was once a jewel of Africa.
And from all the Zimbabweans I meet at the border, there is just one simple refrain: "We are suffering."
From Our Own Correspondent was broadcast on Saturday, 21 July, 2007 at 1130 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.