Saddam Hussein could poison water supplies to kill his own people before he is driven from power, military sources said today.
British and US troops will also carry 3.5 million emergency food packs to avert a potential humanitarian disaster following the invasion of Iraq.
Strategists are planning for a “worst case scenario” of two million civilians being displaced in the war and dozens of safe areas will be set up for them.
In the biggest operation of its kind since the Second World War the armed forces expect to deal with humanitarian problems for several days before the UN and other aid agencies arrive.
A total of 30,000 food packs have already been loaded on to British trucks and 200,000 on to US vehicles in Kuwait.
They will be taken in to Iraq by road behind front line troops – if dropped from the air they could land in minefields.
A military source at Central Command in the Qatar desert said the huge food stores would be enough to feed the Iraqi people but a bigger fear was that Saddam would poison the water.
He could spread disease through the water supply or order loyal troops to drop lethal chemicals into it.
A military source said engineers were working on ways to stop Saddam poisoning his own people.
“There is no telling what this man might do and our engineers are looking at that, it’s a problem we are planning for,” he said.
“If it is contaminated it’s already pretty bad so the situation would be made worse.
“Most of the desalination plants are already working at 50% effectiveness.
“Half a million tonnes of raw sewage a day is dropped into the Tigris and Euphrates and that washes down to Basra.
“Only half the population has access to pure drinking water as it is.” In the immediate aftermath of a successful invasion of Iraq the military will have responsibility for feeding some 25 million people.
They believe some may have stockpiled supplies from oil for food programmes but some of that may have been withheld from them by Saddam’s regime.
A source said: “We are not sure where a lot of this food is stored.
“There is a bit of a black hole – 500,000 metric tonnes of food a month is shipped around Iraq and 60% of the population are completely dependent on that.
“We have put short term humanitarian aid into Kuwait and they are loaded on to vehicles to be brought forward if required.”
Likely areas for distribution of food have already been identified.
They will mainly be in urban areas as up to 75% of the population lives in cities and towns.
Dozens of potential sites for civilians displaced by fighting have also been pinpointed and will be close to road and rail networks.
Two or three of the “displaced citizens assembly areas” will be in the British area.
Planners are reluctant to turn the assembly points into camps which could become permanent but a military source said: “We have got provisions for stores to construct camps if we have to.”
Commanders coming across groups of wandering Iraqi civilians will direct them to the assembly points.
A source said: “We will get people off the main routes for their own safety.
“The safest thing they can do is stay at home – we are not going to flatten the country and bomb everything in our path.
“We accept people will move and we will take them to somewhere safe.”
Hundreds of thousands of people have already crossed borders into Syria and Jordan.
A source said: “Hopefully all this won’t be necessary but we have to plan for the worst case scenario.
“We will treat these people like decent human beings, unlike their own government.”
The British operation to feed civilians is being handled by a civil contingencies team of 10 regular military officers and 60 Territorial Army reservists.
USAID, the American equivalent, has more than 1500 people involved in the humanitarian effort.
Analysts suggest between 1% and 10% – up to two million – of people across Iraq could be displaced in the war.
“What we will do is provide a stopgap between any humanitarian matter being identified and the UN and NGOs getting involved,” said one.
“They are better equipped to deal with it but we take our responsibilities very seriously.”