Yet again, we choose to ignore butchery in Africa

'I remember visiting a hospital in Sierra Leone and being sick at the sight of the wounds'

We were standing in a laneway near the Kissey Mosque. The Imam had just shown us the place where the rebels had shot his son and several other members of the congregation.

The dead had been buried on a patch of waste ground at the back. Scraps of clothes and the smell of dead bodies, it was the aftermath of a small massacre. As we stood talking, a woman approached carrying something round, wrapped in a towel. She was heading in the direction of the cemetery further up the road. I asked her what she was doing and she pointed to the bundle. It was her husband's head and she was taking it for burial. He had been shot by the rebels and by the time the dogs had finished with the body there was just the head and some bones left.

That is just one image from several weeks of horror brought to the people of Freetown, Sierra Leone, by the killers of the Revolutionary United Front (RUF). It is as murderous an army as has ever disgraced the name of Africa.

In January 1999, the rebels attacked Freetown to try and overthrow the democratically elected (and hopelessly inept) government of President Ahmed Kabbah. They came very close to doing so before they were beaten back by Nigerian troops of the West African international ECOMOG intervention force. In the process more than three thousand civilians were killed, most of them victims of the rebels' butchery.

And it was quite literally butchery. Hands and legs were chopped off as punishments, people were beheaded and burned in their own houses. As human rights abuses go, the sacking of Freetown by the RUF was one of the worst atrocities in recent history. These were not the actions of over-zealous troops acting on their own, but part of a strategy to terrorise the population into accepting rebel control. I remember visiting the main hospital in Freetown and being sick after looking at some of the wounds inflicted on innocent men, women and children.

And then what happened? After months of pressure and negotiation involving the government, the rebels, the UN and Britain, there was a peace plan which brought the butchers into government - the equivalent of bringing Idi Amin back to Uganda to help rule the people he terrorised for years.

But no one believed the war could be won, or rather no one was willing to spend what it would take in lives and money to defeat the rebels. President Kabbah had no choice but to accept killers in his cabinet. The Nigerians who propped up the government wanted to go home, and a bad peace was made.

The UN and the people of Sierra Leone are paying for that now. Peacekeepers killed and abducted, a siege at the house of the main rebel leader, and the rebels killing any civilian they dislike. A huge African crisis is building and the blue helmets of the UN are caught in the middle again. Or rather, until they exchanged fire with the rebels they were caught in the middle. I suspect it's now truer to say the UN is seen by the rebels as an ally of President Kabbah and a participant in the conflict.

The rebels left the UN little choice after the persistent targeting of its troops, but the justification for opening fire doesn't alter the material reality which now confronts the security council. Is the world willing to go to war in Sierra Leone? Because that is surely where we seem to be heading.

And if we do, it might be worth remembering what happened the last time UN troops become embroiled in a shooting war in Africa. That was back in Somalia in 1993 when the American-led multinational force had to retreat after being humiliated by the clan forces of Mohammed Aideed.

The Americans (and the Pakistanis) caused the deaths of huge numbers of Somalis when they escalated the war in response to Aideed's aggression. American and Pakistani UN soldiers were brutally killed and those who were sent to keep the peace responded with massive violence. In the flash of a missile, peacekeepers became just another feuding clan on the streets of Mogadishu. The longer term consequence of that disaster was the drawing of what became known in Congress as the Mogadishu line - the point beyond which America would never again involve itself in other people's conflicts.

We saw the result of this tragically in Rwanda a year later when the UN allowed up to a million people to be killed in a genocide, and Clinton's State Department officials refused to publicly use the word "genocide" for fear of being legally obliged to intervene under the UN Charter. We saw it again in Bosnia and in Kosovo where America refused to fight a ground war that might involve substantial casualties. The UN secretary general, Kofi Annan, must feel like he is reliving a nightmare. After all, he was head of peacekeeping during the Somalia debacle and when the UN abandoned Rwanda to its fate.

Mr Annan is an African who succeeded an African to the post of secretary general. I am sure he would point out - rightly - that the secretary general is the servant of the security council which is in turn subject to the competing interests of its members. But the manner in which he and his department handled Rwanda was dismally poor. He was lucky to escape from the Rwanda disaster with any reputation: a bloodbath in Sierra Leone would leave him vulnerable to serious pressure. Or maybe I would be better off saying that it should leave him open to serious pressure - if it were anywhere else in the world but Africa, it would.

The majority of troops involved in the UN operation in Sierra Leone are African. They include, astonishingly, a Nigerian contingent (the Nigerians are the rebels' most hated enemies - so much for introducing troops who'll be seen as impartial).

The problem for the UN security council is that it has lent its weight to a fatally flawed peace agreement. It is the guarantor of a deal between a hopelessly weak government and a rapacious rebel army; the peace agreement was a product of exhaustion and wishful thinking. The UN wanted Sierra Leone sorted out quickly and in the process became the administrator of a corrupt and corrupting process.

The rebels are a divided and paranoid lot. They want to continue to control Sierra Leone's lucrative diamond industry and to do this, they need to keep their troops and weapons. That is why the UN is finding it so hard to disarm these troops. When the rebels made peace they were under pressure militarily but by no means defeated, and they were acutely aware that if ECOMOG pulled out the government would collapse. And after the Sandline affair Britain had no intention of committing itself to the defence of the democratic state. There would be no mercenary army coming to the rescue, much less a gunboat full of Royal Marines.

What is the world to do? Either get out fast and look the other way while the rebels take power and slaughter all around them, or change the nature of the international force and deploy a large army of disciplined multinational troops with a robust mandate. The ECOMOG force was renowned for its abuses of human rights; any new force will have to be led by countries with no previous record in the conflict. Somewhere not very far down the road a catastrophe is waiting to happen.

The writer is a BBC Special Correspondent