What is it like to drive a Challenger tank over desert terrain for six days in a row? Or hover an Apache AH1 attack helicopter a hundred metres above enemy ground? How quickly can a Sapper clear a field of unexploded devices, or build a bridge - or blow one up? What is it like to fix bayonets, and engage in hand to hand combat, or train a 5.56 mm SA80 sniper sight on an enemy soldier, and pull the trigger? How do you find out what a soldier must learn...