Last week, Britain's Disasters and Emergency Committee, which brings together 15 national aid agencies such as Oxfam, Christian Aid and Save the Children, decided against launching an emergency appeal. It argued that the problem was not the availability of supplies, but gaining access to the starving in the midst of Sudan's civil war, and called on the international community to put pressure on the combatants to allow aid to reach the people who needed it.
Christian Aid has launched an appeal on its own, however, and other agencies, including UN bodies such as Unicef and the World Food Programme, say they are critically short of funds.
The WFP has asked governments for $65.8m to finance emergency air-drops of food. But even if it gets the money, it needs permission from the Khartoum government to make more flights from Lokichokio in north-western Kenya, and so far it is still waiting. In February and March the government banned all relief flights.
Clare Short, the International Development Secretary, is among those who believe Sudan's Islamic government is not interested in preventing famine in the south, where it is fighting the Christian rebel movement, the Sudan People's Liberation Army (SPLA). Last week she accused Khartoum of deliberately causing starvation by blocking aid, but others say the SPLA also fails to show concern for civilians caught up in the war.
While the rains have failed for two years, apparently due to El Nino, what has put at least 350,000 people on the brink of starvation is the continual fighting, which prevents harvests being planted or harvested and disrupts aid efforts. Marie Staunton, deputy director of Unicef in Britain, who has just returned from southern Sudan, said that during one week of her visit, Unicef had been unable to land its aircraft at half of the 10 locations to which it is delivering supplies for malnourished children.
The worst-affected area is Bahr al Ghazal province, where an SPLA warlord who defected to the government some years ago switched sides again in January, attacking Wau, the provincial capital, and displacing thousands of people. "They have already survived a great deal of hardship, " said Ms Staunton, "but now the most vulnerable people - babies, the elderly and children who have lost their parents - are beginning to die." Unicef is feeding orphaned children such as eight-year-old Adel Tong, who has been looking after her brother Ding, 4, and sister Achat, 3, after their parents died.
"A great deal depends on the next two weeks," said Ms Staunton. "Crops must be planted now in time for the summer rains, if they come. Other agencies have brought in seeds and tools, but unless other food supplies arrive in time, starving people will eat the seeds rather than planting them. If that happens, all 350,000 people in Bahr al Ghazal will be starving by October."
Tomorrow, the Sudanese government and the SPLA are due to begin peace talks in Nairobi, but for hundreds of thousands, if not millions, of people in southern Sudan what matters is a bureaucratic decision in Khartoum. Unless permission is given within days for more flights, another famine will set in - and man rather than nature will be to blame.