In this harrowing special report from the Democratic Republic of Congo, film-maker Sam Kiley accuses Britain of turning its back on a human tragedy that has already claimed more lives than any conflict since the Second World War

They knew it could happen. The two middle-ranking officers, observers with the United Nations mission in Congo, had already warned their headquarters. They called again saying: 'Get us out of here - we're going to get killed.'
Drunken, red-eyed youths and heavily armed children high on marijuana fingered their weapons, flashed their knives. They hungrily peered in on the two unarmed volunteers in a remote outpost of the $2 million-a-day mission to Congo.

Major Safwat al Oran, 37, from Jordan, and Captain Siddon Davis Banda, 29, from Malawi, waited patiently. For six days they strained their hearing and searched the skies for a UN helicopter. It was only a 35-minute ride from its heavily guarded base. They locked themselves in their little compound knowing there was no way they could drive to safety in Bunia about 30 miles away, through the militia.

Their pleas for rescue increased in urgency. They began to fear the incredible - that the UN would not get to them in time. The Lendu militia, like their enemies the Hema, have a well-earned reputation for cannibalism. They began to inch closer.

The helicopter did eventually turn up. It picked up the major and the young captain - but by then they were rotting in a ditch.

Someone had burnt them with cigarettes, and cut out their brains, hearts, livers and testicles. 'Our assumption is that at least parts of these men were indeed eaten,' said a senior UN source involved in the internal inquiry into why the unarmed officers were left to die.

No inquiry has been conducted into why the Democratic Republic of Congo, a country the size of Western Europe, has been abandoned like those two UN officers.

The catastrophe was foretold. Experts on the region, human-rights groups, UN officials, priests and the occasional journalist have regularly warned of an impending apocalypse since serious fighting broke out there in 1997.

The causes of conflict have been carefully catalogued, the criminals in charge of the militia carefully identified, their backers exposed. What has the response been to a six-year-old conflict that has now claimed more lives than any since the Second World War?

Two years ago Tony Blair told a wet-eyed Labour Party conference: 'I tell you if Rwanda happened again today as it did in 1993, when a million people were slaughtered in cold blood, we would have a moral duty to act there.'

Human rights groups estimate around four million have died in Congo over the past five years. Since Blair told his Brighton audience the international community 'could, with our help, sort out the blight that is the continuing conflict in the Democratic Republic of Congo, where three million people have died through war or famine in the last decade', at least another million have perished.

Blair went on: 'The state of Africa is a scar on the conscience of the world. But if the world as a community focused on it, we could heal it. And if we don't, it will become deeper and angrier.'

The 'scar' is now a volcanic tropical ulcer. Last month the UN Security Council finally voted to impose an arms embargo on Congo. But Britain and the US stood in the way of extending an embargo to include Rwanda and Uganda, which back the militias slaughtering civilians in eastern Congo.

Bunia, the 'capital' of the unrecognised Congolese province of Ituri, has been at the centre of the best-publicised bloodletting. Since 1999, 50,000 people have died around this north-eastern town set in a fertile landscape. Sadly for its surviving inhabitants, Ituri sits on top of what are thought to be vast oil reserves near Lake Albert.

Thomas Lubanga runs Bunia. He is the leader of the Union of Congolese Patriots. His tribal army of about 12,000 men is made up almost entirely of members of the Hema group. Although about 1,500 French-led European Union soldiers are now in Bunia to back the 700 Uruguayans from the UN, Lubanga still rules.

A recently declassified UN investigation into massacres not far from Bunia reveals the extent of Lubanga's capacity for horror. The report said a 14-year-old-boy was fleeing from the gold-rich town of Mungwalu - a gold-mining centre where the UN observers were murdered. The youngster, his family, a Protestant priest and other civilians were stopped at a junction. Hema gunmen accused the priest of mocking them because he was wearing his ceremonial robes.

'The soldiers had red eyes, and they were singing and dancing. They slaughtered the priest, cut him to pieces, removed his heart and liver and cooked them. The rest of the group had to pay money or eat the human flesh to be allowed to leave. Another four men, three women and three children were killed.' Among the dead was a pregnant woman who was gutted.

In Congo for the past 50 years tales of cannibalism have been apocryphal. Today they are a norm - what better way to sow terror into the hearts of your enemies than to instil the fear that they could be eaten?

Lubanga said he had a disciplined force. He proudly told me his top officers had been trained in Uganda - which gets around £60m a year in British taxpayers' money. 'The top level of our commanders were trained in neighbouring countries, especially Uganda,' he said.

Dieudonné Uringi, the priest in charge of the Catholic cathedral in Bunia, sat on a wall next to the graves of two of his fellow fathers who had been killed by Lendu along with 14 other Hema civilians. They were massacred in the cathedral's seminary - their bloody fingerprints were still visible where they had tried to hide under the stage of the seminary's cultural centre.

'Uganda,' he said, 'has armed both sides - all the groups in Congo - so that it can maintain a state of chaos and its officers can come here and plunder in the name of peacekeeping.'

The UN agrees. In 2000 a panel of experts named a close relative of Uganda's President, Yoweri Museveni, as a leading exploiter of Congo's wealth. Uganda has little gold and no diamonds. But its official gold and diamond exports soared when it sent troops into Congo in 1997 as a 'pacification' operation against rebel groups.

The UN said Salim Saleh, Museveni's relative, should be banned from travelling. He has not been; instead he enjoys close relations with Britain, employing British managers in his Ugandan companies.

The murders in the cathedral followed the Ugandan army's withdrawal from Bunia. The Lendu, with Ugandan help, swept into town to annihilate their rivals - using Ugandan-supplied weapons. 'If you want to understand what is happening here and stop it, you have to cut off the supply of weapons, and that means deal with Uganda and Rwanda,' Father Uringi said.

Ituri province has been a low priority for Rwanda. But to keep its rivalry with Uganda alive - the two countries came to blows over Congo's diamonds in Kisangani on the Congo river three years ago - Rwanda has been looking for clients in the north-east. It found one in the murderous Thomas Lubanga who ditched his Ugandan friends last December.

Human Rights Watch has interviewed numerous witnesses who have seen Rwandan officers training his men and flying weapons to him at secret jungle airstrips.

'I was with Lubanga when he flew to Kigali [Rwanda's capital] on 31 December last year,' alleged a local investigator who had fled Bunia to escape Lubanga's thugs. 'He met top government officials and signed a co-operation deal. There was a lot of drinking and celebrating, and when he flew back into Congo he took six tonnes of weapons with him. The weapons were loaded in Kigali by Rwandan soldiers.

'His chief of security is Rwandan, his name is Rafiki.'

Rafiki Saba Amiable, a member of the Tutsi tribe, has become infamous in the region and has been implicated in dozens of massacres of the kind not seen since the genocide of a million of his own tribesmen in Rwanda. Last week British Foreign Office officials launched an investigation into 'Rafiki' - who almost certainly uses a nom de guerre, after seeing a preview of the Channel 4 film Congo's Killing Fields .

Rwanda gets £37m a year in British aid. It is most heavily involved in Congo's North Kivu and South Kivu provinces closer to its own borders. Here Rwandan officers have plundered vast amounts of gold, diamonds and coltan - a mineral which is used in the manufacture of capacitors for mobile phones - while claiming to be fighting against the extremists who carried out the 1994 genocide.

'Rwanda has been hiding behind the guilt the outside world has for having failed to stop the genocide. It has been able to do what it likes in Congo without fear of real criticism - and now four million, maybe more, have died in a conflict fuelled by Rwanda,' said a senior UN source based in Goma, the Congolese town used as Rwanda's main entry route.

The UN and British intelligence have known this for years - among their many sources would have been dozens of British media reports going back five years. In 2000 the UN said James Kabarebe, the head of Rwanda's military intelligence, should be subjected to the sort of international travel ban imposed of Zimbabwe's Robert Mugabe.

But Britain has done less than nothing to ensure such a ban. Shortly before Easter this year Kabarebe, Rwanda's spy chief, was a guest of the Foreign Office and MI6 on a semi-official visit to London.

Anneke Van Woudenberg, Human Rights Watch researcher, is the author of the definitive study of the horrors in the region around Bunia, Ituri Covered in Blood . She said: 'The British Government must use its influence in Uganda and Rwanda to stop the arming of these militia groups which is still going on. Any peace efforts by the UN will be hopeless unless Britain steps in.'

· Sam Kiley's film 'Congo's Killing Fields' will be shown in 'Dispatches' on Channel 4, at 9pm tonight.