A famine is defined as a shortage of food so serious that people are driven from their homes in a mass migration, as occurred in Ethiopia in 1984. Southern Sudan has suffered years of civil war and a current drought which has reduced people to scavenging for wild foods and leaves but it has not yet led them to leave their homes and support networks
A consortium of 15 aid agencies known as the Disasters Emergency Committee agreed at a meeting two weeks ago not to launch an appeal in Britain. There was enough food and resources available for transport into Sudan and the problem was one of access, not money, they said.
The committee, which includes Save the Children, Oxfam and the Red Cross, ratified the decision again on Monday but said they would keep it under review. However, Christian Aid has launched its own appeal for pounds 1m provoking dissent among the aid agencies.
The agencies have been caught unprepared because of the unexpected intensity of media interest in the situation. The BBC filed the first report seen in Britain early last month, but ITN later obtained more shocking pictures of emaciated children which were shown twice on News at Ten last week and again last night.
The BBC responded to what is now seen as a developing international story by dispatching extra teams to the area including the renowned reporter, Fergal Keane.
Mark Bowden, regional director of Save the Children for East Africa, said: "There are places of acute need all over southern Sudan but that doesn't mean the problems are all related. There is a lack of clarity. The media are getting into quite broad definitions of what is going on."
The worst affected area was El Ghazal, where 350,000 people were on the brink of starvation. However, thousands of tons of food and other aid had been promised by governments and donor agencies and the Sudanese government had increased the number of flights allowed into the area from one to four. "That is just about enough," he said.
Mr Bowden said it was essential members of the public were acutely informed so that they could be confident when an appeal came that they knew what it was for and how the money would be spent. "Personally I think it is irresponsible to appeal to the public at a time when we are still trying to define the problem."
A famine meant setting up feeding centres and relief shelters and could make a fragile situation worse by encouraging people to leave their homes and migrate to the feeding centres to obtain food. This was not appropriate in Sudan where the priority was to stabilise the situation which would take at least 10 months and require sustained support.
A spokeswoman for Christian Aid said its officials were working in a separate area, closer to the Ugandan border and accessible by road, where food could be trucked in. She said the charity had not used the term famine, but vulnerable people were dying. She dismissed suggestions that "famine fatigue" might set in if the situation worsened next year and another appeal had to be launched.
"That is something talked about ... But why wait till there is a famine? We want to do something now to prevent it happening. Do we want to see people dying? I don't think we do."