British aid agencies have come together to launch a joint fund-raising appeal to help more than 10 million people affected in the Horn of Africa.

The current drought is the worst in the Horn of Africa for 60 years and thousands of families, desperate for food and water have trekked for days from Somalia to the Dadaab refugee camp in Kenya. The Kenyan government has periodically tried to close its border, although it is now open with 1,200-1,550 refugees a day crossing, according to some reports. They are heading in droves to the refugee camp complex at Dadaab, built in 1991 at the beginning of Somalia's civil war. It has a maximum capacity of 90,000 but is now overwhelmed by in excess of 370,000 people. Desperate people stumbling into camps to find help are so malnourished that statistics reported in Nairobi were at first not believed. "We sent them back because we thought they were wrong," says one senior aid official in Kenya's capital, the de facto centre of the current drought response.

The severe food crisis already affecting people in parts of Kenya, Ethiopia, Djibouti and Somalia. Rains have failed over two seasons. Now wet season has ended, there is little prospect of rain before September.

The UN reports that:
'at least one in three children is malnourished in parts of southern Somalia and some who have fled the country are dying in refugee camps. Localised starvation may exist in areas we are not able to get to. If we don't intervene immediately, hundreds of thousands more Somalis will be affected'.

Weather in the region has become increasingly unpredictable erratic and its troubles deepened in 2007, when the US launched air strikes against suspected al-Qaeda cells in Somalia. The US's fear that funds could be diverted to terrorist hands meant they cut food aid to the area. The protracted war in Somalia has driven over 20,000 Somalis into Kenya in the past two weeks, says the UNHCR.

The World Food Programme has been feeding 4.3million people in Ethiopia, but had to reduce rations in March as funding ran out. The UN described it as a "humanitarian emergency", classified as one step down from "catastrophe".