The Spy Who Hoodwinked Hitler - Dummy tanks at El Alamein. Bogus generals in Algiers. Sham armies on D-Day. All were ruses masterminded by Dudley Clarke. Robert Hutton tells the story of the British soldier who made an art form of duping the Nazis

Examining the reconnaissance photos, Behrendt was convinced that the Allies weren’t in any hurry. They were constructing some kind of pipeline towards the southern end of their line, probably to carry water, which was barely halfway completed. There were supply dumps appearing in the south as well – always a telltale clue about where an attack would come. True, a large number of trucks were parked at the northern end of the line, about 25 miles back from the front, but they hadn’t moved for weeks.

- By Dudley Clarke

Hans-Otto Behrendt stared at the map in front of him and tried to think, despite the fierce Egyptian heat. A few miles to the east, 100,000 of his fellow German and Italian soldiers were waiting in the desert, facing almost twice as many Allied troops. The opposing armies were stretched out in parallel lines about 40 miles long, running from the Mediterranean coast in the north down to the Qattara Depression in the south, impassable to vehicles.

It was only a matter of time, Behrendt knew, before those Allied troops launched their attack. As intelligence officer to the German commander, Erwin Rommel, it was his job to work out when it would come – and where.

The date was 23 October 1942. For the previous two years, Axis and Allied forces had pursued each other back and forth across north Africa. At one time or another, each side had thought it was on the point of victory – only for the tide to turn. A few months earlier, Behrendt had believed he might be about to witness the capture of Egypt. Axis forces had been barely a day away from Cairo, where panicking British soldiers and officials had been preparing to fight to the death or flee, piling civilians onto trains and burning vast tranches of secret documents. But, after months of retreats, the Allied armies had somehow held out. And Axis forces, short of fuel and ammunition – short of everything, in fact – had been unable to strike the decisive blow.

Now it was the turn of the enemy to push for victory. Troops from across the British empire had dug into the sand, waiting for their new commander, Bernard Montgomery, to give the word.