It happened at an odd moment. The world's press was congregating in South Africa, sniffing another catastrophe. The country's first all-race election was scheduled for the end of April. The prelude was peppered with massacres and violence was as intense as ever. The election was tense, and as the drama unfolded news editors could not cope with a bad-news story elsewhere in Africa. Not many journalists went. I was on the way to South Africa when I heard that the presidents of Rwanda and Burundi had been killed in a plane crash. I called my foreign editor, we discussed the possibility of massacres but agreed that I should not disrupt my plans.
Almost a month later I did go to Rwanda. I travelled the length of the country. I saw. I heard. When I sat down to write nothing came. I had a beer, and then another one, smoked a few cigarettes - but I could not write. The words seemed to shrivel on the screen when I called to mind what I had seen. Eventually, more as a note to the news editor, I wrote: "I do not want to tell you what I saw today" and then I went on writing. But it was a silly, feeble piece. I left and went on holiday. I feel guilty about Rwanda.
The genocide also began three months after the destruction of the American- led UN operation in Somalia. Criminal incompetence by the US military led to the slaughter of more than 1,000 Somalis by American firepower on the night of 3 October 1993. More importantly, 18 Americans died. Bill Clinton pulled the force out. The message was clear: no US troops were going to go to Africa again for a long time.
Rwanda and Burundi had been convulsed by mass ethnic killing in the past. Some 250,000 people had been killed the previous October in Burundi. The event had been barely covered - this was, in the minds of some, the sort of thing that went on in the Heart of Darkest Africa. And the world had not been terribly interested.
In Rwanda, at the time, there was a stalemated war. The Rwandese Patriotic Front, largely the children of the surviving Tutsis of the 1959 massacre who had grown up in Uganda, had invaded their homeland in 1990. They did not reach the capital and had negotiated a power-sharing peace agreement with the Hutu government. But their troops still occupied north-eastern Rwanda and went on the offensive as soon as the massacres started. Were the killings a spin-off of the fighting or something much bigger - and better organised?
The Rwandan genocide was the fastest in history. It was not an explosion of primitive tribalisim - Hutus and Tutsis share culture, language, religion and land. Nor was it overpopulation. The killing of some 1 million people in the space of about five weeks was organised and ordered.
These factors, the context of the genocide, obscured it. But some knew more and Panorama has been asking them questions. They were the diplomats and UN officials who represented the rest of humanity. At the time that massacres began there were 2,500 UN troops in Rwanda, monitoring the cease- fire. Panorama tells their tale both from the perspective of troops on the ground and from New York.
The Don Bosco school in Kigali, where the Belgian peacekeepers were based, became a refuge for thousands of Tutsis fleeing the Interahamwe, the Hutu militia. The Belgian government, having lost 10 of its own men murdered by the Interahamwe, lobbied the UN Security Council to have the entire force pulled out. It unilaterally withdrew its contingent. Lieutenant Lecomte describes how he had to shoot in the air, the only shooting he did in Rwanda, to clear a trail through Tutsi refugees who were begging the Belgians to stay, begging the soldiers to take them to safety, begging the UN troops to shoot them now rather than leave them to face the knives and machetes of the Interahamwe. The Belgians departed. Those left at the Don Bosco school were slaughtered.
The UN knew from an informer three months in advance that genocide was being planned. The Belgian Colonel Luc Marchal was also told where the arms caches of the Interahamwe were. He applied to UN headquarters in NY for permission to raid the stockpiles. Cut to Riza Iqbal, the UN official, who received the information. He did not pass on the information to the Security Council and refused permission for the raid. He said: "We said: 'Not Somalia again. It might lead to the use of force and unanticipated repercussions.'"
The Belgians and Americans lobbied members of the security council to pull out the whole force - there was, they argued with twisted logic, "no peace to keep".
The French, Italians and Belgians sent forces to Rwanda to get their own nationals out - the Belgians took the embassy dog but left the embassy Tutsis who were promptly slaughtered.
No one in the UN would call it genocide because it might mean they had to do something. (And one US official asked what, if it were genocide and the US was seen to do nothing, would be the effect on the upcoming congressional elections.)
The Security Council finally agreed to send 5,000 troops to Rwanda. The Pentagon, until then opposed to any intervention, offered 50 armoured personnel carriers but then spent months dickering over what colour they should be painted, where they should be painted and who should pay for the paint. They arrived after the Interahamwe had run out of victims.
And so on. Professor Michael Barratt, then the US desk officer at the UN, summed up the insouciance of the men who run the world. He stopped reading the telegrams, he said "because it was like a bad traffic accident. You look once but then you look away out of politeness."
There is one thing wrong with this film. Its title, taken from Burke's phrase, "All that is needed for evil to triumph is for good men to do nothing" misses its own point. Evil triumphed in Rwanda because weak men like Bill Clinton and Kofi Annan did things to ensure that nothing could be done.
Richard Dowden is Africa
correspondent of the 'Economist'