I thought I was going to die. An inflamed mob of about 50 desperate men had crowded round the car, trying to turn it over. They were staring at me and my companions with rage and hatred such as I haven't seen in a human face before.

Those companions, Barbara Jones and Richard van Ryneveld, were - like me - quite helpless in the back seats. If we got out, we would certainly be beaten to death. But our two African companions had indeed got out to try to reason with the crowd.

Finally one of them leapt back into the car and reversed wildly down the rocky path. By the grace of God we did not slither into the ditch, roll over or burst a tyre. He told us it was us they wanted. We ought to be dead.



Why did they want to kill us? What was the reason for their fury? They thought that if I reported on their way of life they might lose their jobs.

We were in Katanga province in the Democratic Republic of Congo, and had seen a Chinese supervisor cajoling local workers as they dug a trench.

The workers were grubbing for scraps of cobalt and copper ore in the dust of abandoned copper mines, sinking perilous 25m shafts by hand, washing their finds in cholera-infected streams full of human filth, then pushing enormous loads uphill on ancient bicycles to the nearby town of Likasi, where middlemen waited to sell the metals to Chinese businessmen.

To see the workers as they plodded miserably past was to be reminded of pictures of unemployed miners in Britain in the 1930s, stumbling home in the drizzle with sacks of coal scraps gleaned from spoil heaps. Except that, here, the unsparing heat made the labour five times as hard and the conditions were worse by far than any known in England since the 18th century.

Many of these workers perish as their primitive mines collapse on them, or are horribly injured without hope of medical treatment. Many are little more than children. On a good day they may earn $3.

We had been earlier to this awful pit, which looked like a penal colony in an ancient slave empire. We had been turned away by a fat, corrupt policeman who had pretended our papers weren't in order, but who was really taking instructions from a dead-eyed, one-eared gang-master who sat next to him.

By the time we returned with more official permits, the gang-masters had readied the ambush. The diggers feared - and their bosses had worked hard on that fear - that if people like me publicised their filthy way of life, then the mine might be closed and the $3 a day might be taken away.

China's cynical new version of imperialism in Africa is a wicked enterprise.

Much of the continent is selling itself into a new era of corruption and virtual slavery as China seeks to buy up all the metals, minerals and oil it can lay its hands on.

China offers both rulers and the ruled in Africa the simple, squalid advantages of shameless exploitation. For the governments, there are gargantuan loans, promises of new roads, railways, hospitals and schools - in return for giving Beijing a free run at Africa's rich resources.

For the people, there are these wretched leavings, which, miserable as they are, must be better than the near-starvation they otherwise face.

Persuasive academics advised me before I set off on this journey that China's scramble for Africa has much to be said for it. They pointed out that China needs African markets for its goods and has an interest in real economic advancement in that broken continent.

For once, they argued, foreign intervention in Africa might work, precisely because it is so cynical and self-interested. They said Western aid, with all its conditions, did little to create real advances in Africa.

Why get so het up about African corruption anyway? Is it really so much worse than corruption in Russia or India? Is it really our business to try to act as missionaries of purity? Isn't what we call "corruption" another name for what Africans view as looking after their families?

And what about China? Despite the country's convulsive growth and new wealth, it still suffers from poverty and backwardness. After the murderous disaster of Mao, and the long chaos that went before, China longs above all for prosperity.

And, as one genial and open-minded Chinese businessman said to me in the Congo as we sat over a beer in the decayed colonial majesty of Lubumbashi's Belgian-built Park Hotel: "Africa is China's last hope."

I find this argument quite appealing, in theory. Britain's own adventures in Africa were not especially benevolent, although many decent men did what they could to enforce fairness and justice amid the bigotry and exploitation.

It is noticeable that in much former British territory we have left behind plenty of good things and habits that are absent in the lands once ruled by rival empires.

Even so, with Zimbabwe, Nigeria and Uganda on our conscience, who are we to lecture others?

I chose to look at China's intervention in two countries, Zambia and the Congo, because they lie side by side, because one was once British and the other Belgian.

Also, in Zambia's imperfect but functioning democracy, there is opposition to the Chinese presence, while in the despotic Congo, opposition to President Joseph Kabila is unwise, to put it mildly. The Congo is barely a state at all, and still hosts plenty of fighting.

I have decided not to name most of the people who spoke to me, even though some of them gave me permission to do so, because I am not sure they know just how much of a risk they may be running by criticising the Chinese in Africa.

I know from personal experience with Chinese authority that Beijing regards anything short of deep respect as insulting and it does not forget a slight. I also know that this over-sensitive vigilance is present in Africa.

Our team was reported to the authorities in Zambia's copper belt by Chinese managers who had seen us taking photographs of a graveyard at Chambishi, where 54 victims of a disaster in a Chinese-owned explosives factory are buried. Within an hour, local "security" officials were buzzing around us trying to find out what we were up to.

Beijing regards Zambia as a great prize, alongside its other favoured nations of Sudan (oil), Angola (oil) and Congo (metals).

It has cancelled Zambia's debts, established a "special economic zone" in the Copper Belt, offered to build a sports stadium, schools, a hospital and a malaria treatment centre as well as providing scholarships and sending experts to help with agriculture. Trade is growing rapidly.

All this has aroused the suspicions of Michael Sata, a populist Zambian opposition politician famous for his combative manner and his biting attacks on opponents. He was once a porter who swept the platforms at Victoria Station in London. Now he's the leader of the Patriotic Front, with a respectable chance of winning a presidential election set for the end of this month.

"The Chinese are not here as investors; they are here as invaders," he says. "They bring Chinese to come and push wheelbarrows, they bring Chinese bricklayers, they bring Chinese carpenters, Chinese plumbers. We have plenty of those in Zambia."

This is true. In Lusaka and in the Copper Belt, Chinese workers are a common sight at mines and on building sites, as are Chinese supervisors and technicians. There are Chinese restaurants, Chinese clinics and Chinese housing compounds - and a growing number of Chinese flags flapping over factories and smelters.

"We don't need to import labourers from China," Sata says. "We need to import people with skills we don't have in Zambia. The Chinese are not going to train our people how to push wheelbarrows.

"Wherever our Chinese 'brothers' are, they don't care about the local workers. They employ people in slave conditions."

He accuses Chinese overseers of frequently beating up Zambians. His claim is given force by a story in that morning's Lusaka newspapers about how a Zambian building worker in Ndola, in the Copper Belt, was allegedly beaten unconscious by four Chinese co-workers angry that he had gone to sleep on the job.

I later checked this account with the victim's relatives in an Ndola shanty town and found it to be true.

Denis Lukwesa, the deputy general secretary of the Zambian Mineworkers' Union, backed Sata's view, saying: "[The Chinese] just don't understand about safety. They are more interested in profit. They are harsh to Zambians and they don't get on well with them."

Sata warns against the enormous loans and offers of help with transport, schools and health care with which Beijing sweetens its attempts to buy up Africa's mineral reserves.

"China's deal with the Democratic Republic of Congo is, in my opinion, corruption," he says, comparing it to Western loans, which require strong measures against corruption.

Everyone in Africa knows that China's Congo deal - worth almost £5 billion (R77,3 billion) in loans, roads, railways, hospitals and schools - was offered after Western experts demanded tougher anti-corruption measures in return for increased aid.

Sata knows the Chinese are unpopular in his country. Zambians use a mocking word - choncholi - to describe the way the Chinese speak. Zambian businessmen gossip about the way the Chinese live in separate compounds, where - they claim - dogs are kept for food.

Some Africa experts tend to portray Sata as a troublemaker. But his claims were confirmed by a senior worker in Chambishi, the scene of an accident in 2005 at the Beijing General Research Institute of Mining and Metallurgy explosives plant, in which 54 people died.

The worker recalls the aftermath of the blast: "Zambia, a country of 11 million people, went into official mourning for this disaster. A Chinese supervisor said to me in broken English: 'In China, 5 000 people die, and there is nothing. In Zambia, 50 people die and everyone is weeping.' To them, 50 people are nothing."

Many in Africa also accuse the Chinese of unconcealed corruption. A North American businessman who runs a copper-smelting business in Congo's Katanga province explained that his company is constantly targeted by official safety inspectors because it refuses to bribe them. Meanwhile, Chinese enterprises get away with huge breaches of the law because they pay bribes.

There is a lesson for colonial pride and ambition in the streets of Lubumbashi - 80 years ago an orderly Art Deco city full of French influence and supervised by crisply starched gendarmes, now a genial but volatile chaos of scruffy, bribe-hunting traffic cops where it is not wise to venture out at night.

Outsiders come and go in Africa, some greedy, some idealistic, some halfway between. Time after time, they fail or are defeated, leaving behind scars, slag heaps, ruins and graveyards, disillusion and disappointment.

We have come a long way from Cecil John Rhodes to Bob Geldof, but we still have not brought much happiness with us. Even Nelson Mandela's vaunted "Rainbow Nation" in South Africa is careering rapidly towards banana republic status.

Now a new great power, China is scrambling for wealth and influence in this sad continent, without a single illusion or pretence.

Perhaps, after two centuries of humbug, this method will work where all other interventions have failed. But after seeing the bitter, violent desperation unleashed in the mines of Likasi, I find it hard to believe any good will come of it.