The centre of the crisis is Niger, where seven million people, almost half the population do not have enough food. A further two million people in Chad, and hundreds of thousands more in Mali, Mauritania, parts of Burkina Faso and the extreme north of Nigeria are also suffering as a result of the crisis.

The agencies - including ACF, Care International, Oxfam, Save the Children and Tearfund said that new malnutrition figures underlined the need to act immediately. The latest statistics from Niger show that nearly 17 per cent of children under five are now suffering from acute malnutrition, over a third higher than the number last year.

A high level political response is needed to galvanise the effective and urgent delivery of aid as well as to ensure more funding. In particular, the agencies urged the UN to appoint a special representative for the crisis to help speed up the massive aid effort across several countries, and negotiate with governments both in the crisis-affected countries and the donor states.

Despite over six months of warnings, the funding for the crisis has been paltry and slow with the UN appeal for Niger still $107m short of its target. Some countries have increased their support, but others have been slower and less generous. The aid agencies called on rich countries to give generously and immediately fund the crisis in order to prevent a catastrophe, and to engage at highest political levels to overcome current delays in the delivery of aid.

Delays in funding have resulted in the late purchase and delivery of food to the affected areas. In Niger, for example, World Food Programme (WFP) distributions started too late and with a reduced number of people receiving food aid. On 2 July WFP announced it will increase the number of people it is helping in Niger from two to 4.5 million in the face of the appalling new malnutrition figures.
In Chad, where the WFP needs an extra $20 million, food distributions are only planned for only two months - yet as in Niger, it will take three or more months for the next harvest to be ready.

Kirsty Hughes, Oxfam said: "In parts of the Sahel, people are scavenging for wild leaves and seeds, and drinking dirty water. Whole villages are starving and desperate for food with children, nursing mothers, and the elderly particularly at risk”.

Drought, crop failure, pest infestations, increases in food prices and abject levels of poverty have triggered severe food shortages and poor grazing land, forcing people to leave their homes, and sell or kill their starving livestock and their meagre possessions. Such desperate measures not only indicate the depth of the crisis but also undermine investment in long-term development, the aid agencies warn.

Niger, the world's least developed country, is the worst hit with 7.1 million people in need of humanitarian aid. Nearly half a million children under the age of five are acutely malnourished, with a risk of permanent damage or death if they are not treated urgently. The cereal harvest has fallen by 30 per cent and pasture, essential for livestock herders, is 60 per cent below requirements.

In Chad, a country also affected by a long running conflict, some two million are affected by food shortages. There are reports of women resorting to eating seeds from anthills, with malnutrition rates of 27 per cent in some locations. Hundreds of thousands more are at risk in Mali, Burkina Faso and northern Nigeria.