Troops to brave Afghan winter in Bin Laden hunt

British and American ground forces may soon land in Afghanistan, according to hints in Western capitals last week, not only in pursuit of Osama bin Laden and his al-Qa'ida associates, but to save more than seven million Afghans from starvation. But such an operation is fraught with military risk and political uncertainty.

Western troops may find themselves in the midst of a winter war, in the same season and on the same terrain as a British army that was annihilated 159 years ago. Only one survived from the 20,000 sent in the East India Company's Army of the Indus. The troops of Operation Enduring Freedom will not share that fate, but military planners in London and Washington are not underestimating the difficulties of the task ahead.

While fending off the Taliban, al-Qa'ida and possibly an increasingly discontented Northern Alliance, the troops will have to contend with General Winter, who will bring temperatures of -21C and snowbound roads, while waging a humanitarian war which will be as important as the shooting one.

The aid agencies have warned of a catastrophe of breathtaking scale, with 7.5 million people at risk. If these Afghans, mainly the old, the young and women, were to die from the cold, disease and starvation in the coming months, the already fragile "global coalition against terror'' will wither.

US aeroplanes have been dropping food along with the bombs, but this is not a viable long-term solution, even if there is a huge rise in the volume of this from the 37,500 "packets'' already dropped. Clare Short, the Secretary of State for International Development, announced that "aid was getting through", but this amounts to just 500 metric tonnes a week, much of it commandeered by the Taliban.

The UN predicts that around 6.1 million people will be left in Afghanistan through the winter, and the bare requirement for their survival is 600,000 tonnes of food, as well as shelter, clothing, medicine, water and sanitation.

With the roads impassable in a few weeks' time, a stockpile of 250,000 tonnes will have to be built up. The UN World Food Programme has just 9,228 tonnes inside Afghanistan. One of its largest warehouses, in the northern city of Mazar-i-Sharif, is now empty. Ruud Lubbers, the United Nations High Commissioner for Refugees, said: "We are in a real race against time and right now we are losing. Unfortunately, we are not receiving the support in the region or internationally that we need.''

To supply just the food needed for the winter would take 21,000 journeys by truck or 19,000 by Hercules transport aircraft. At the best of times that would be highly difficult for aid agencies to organise in a short period, and with a war on the ground it is impossible. So there is little doubt that allied forces will have to be involved on a very large scale to attempt to prevent the humanitarian disaster. And this will impinge on military tactics.

Military planners in the Pentagon and the Ministry of Defence had countenanced a war of short skirmishes. That would not help the free distribution of aid. Thus there is an alternative scenario being painted. In this one, the Taliban regime will begin to disintegrate through air strikes and commando operations, and its forces will no longer be willing to remain in exposed, targetable areas.

They will then be driven from the fertile plans and valleys to the mountains, where they could be bottled up. Specialist allied troops, with air support, could tackle the Afghan fighters away from the civilian population. Neutralising the Taliban and al-Qa'ida will take time in the mountains, which is one of the reasons for the repeated warnings from American and British leaders that the campaign may take months, or even a couple of years.