Thirsty tanks rely for success on fuel dumps already set up across Middle East

Modern armies don't march on their stomachs; they drive on their fuel tanks. That is a concern for the US Army, which has hundreds of Abrams M1 tanks in the field – each consuming about three gallons of diesel fuel per mile, and with a "cruising range" of up to 275 miles on a single 500-gallon (1,900-litre) fuelling. The 120 British Challenger tanks are less thirsty, consuming about one gallon a mile.

On their own, the tanks are burning nearly half a million gallons of fuel every day – equivalent to about 100 jumbo jets (the latter manage about 2 miles per gallon). Add in the needs of Humvee trucks and Bradley armoured vehicles (which get a few miles per gallon on good roads) and the Allied armies' needs are clear; fighting in the desert doesn't leave just the humans thirsty. This war may not be being fought over oil, but it is being fought on aircraft-grade kerosene: on the American side, a mixture known as "JP-8".

With roughly a million gallons of JP-8 needed every day, the logistics of a 300-mile "dash to Baghdad" come into sharp relief. The US has set up 23 fuel dumps in the Middle East with millions of gallons of JP-8. They have been stocked up in an exercise running alongside – and before – the more visible troop build-up. Every day thousands of gallons of JP-8 are flown to Iraq.

JP-8 was developed in the 1980s because the US military and Nato realised that having to provide different grades of fuel to different vehicles was a logistical nightmare, and potentially disastrous.

The historical lesson for this also comes from the desert, from Rommel's defeat in north Africa. On paper, the Afrika Korps was better led with more experienced fighters. But it lost to the British Eighth Army because the German and Italian vehicles needed different types of fuel, and they kept outrunning their supplies. They lost the fight behind their own lines.