But while the killing in Darfur continues, and the Sudanese government prepares for a deadly 'final solution', the international community has looked on, seemingly impotent to act.

For the past three years the Sudanese military, along with the feared Arab militia on horseback, known as the Janjaweed, have attempted to crush a rebellion in the Darfur region by systematically wiping out village after village. Men, women and children have been massacred; rape has been employed as the most brutal of weapons.

Some 13 United Nations resolutions have been passed condemning the killing, but none have so far stopped it. The most recent, calling for the deployment of 20,000 UN troops to protect Darfur's citizens, has been hampered by Sudan's refusal to allow 'blue helmets' in. Although some UN member states have labelled Khartoum's actions genocide, the world body is requesting permission from the alleged 'genocidaires' to take action to prevent it.

Sudan's president, Omar al-Bashir, has likened a UN peacekeeping force to "western colonisation" and has vowed to personally lead the "jihad" against it.

President Bush, who has used the word genocide to describe the slaughter in Darfur, yesterday admitted his "frustration" with the UN and raised the possibility of ignoring Sudan's refusal to allow UN peacekeepers in and simply send in troops "in order to save lives".

As politicians and diplomats try to find a way to put pressure on Sudan, hundreds of thousands of people around the world will today make their voices heard, demanding action to end the slaughter in Darfur. In London, survivors of the Holocaust and the Rwandan genocide will join protesters outside the Sudanese embassy, while faith leaders will deliver prayers to Downing Street. In New York, former secretary of state Madeleine Albright will address the crowd in Central Park.

And in perhaps the most stark reminder of the world's inability to intervene in slaughter on a mass scale, a rally will take place in the centre of Kigali, Rwanda, followed by a march to Ecole Technique Officiele . . . the site of the UN base during the Rwandan genocide.

President al-Bashir's attempts to characterise the push for a UN force as an issue only for the west have been helped by Russia and China's refusal to vote for peacekeepers. But today there will be more demonstrations in Africa than in Europe.

From the Gambia on the west coast to Dar-esSalaam on the east, events have been planned to bring attention to the crisis. Even Sudan's Arab neighbours will make their voice heard. A candlelit vigil will take place in Cairo; a petition will be signed in Bahrain.

No campaign for Africa is complete, it seems, without a smattering of celebrity endorsements.

Elton John, Bob Geldof and Emma Thompson all signed an open letter to British prime minister Tony Blair yesterday calling for action. Earlier this week, Hollywood actor George Clooney addressed an informal session of the UN Security Council.

"This genocide will be on your watch. How you deal with it will be your legacy, " Clooney told the assembled ambassadors. "Your Rwanda, your Cambodia, your Auschwitz."

There are currently 7,000 understaffed and under-resourced African Union peacekeepers patrolling Darfur. Since a fudged peace deal was signed in May by only one of the three rebel groups the violence has increased and the AU troops have been unable to do anything to prevent it.

They have been holding on until a UN force is able to replace it. But the AU's mandate ends on 30 September and Sudan has insisted that the force leaves. Instead, more than 10,000 Sudanese troops will be sent to Darfur to "protect" the Fur, Massaleit and Zaghawa tribes. These are the same Sudanese troops who, along with the Janjaweed, forced Darfuris to flee in the first place