 The Taliban withstood barrages of air strikes from AH-64 Apache helicopters, 500 pound bombs dropped by B-1 bombers and withering cannon fire from A-10 ground attack jets before the British finally withdrew after a 10-hour battle.The Taliban fighters, who say they have the expertise to defeat the strongest army, had dug sophisticated networks of trenches often leading from compound to compound.The assault was the latest in a series of battles by British forces around the bridgehead and the short road at the north end of the valley, criss-crossed by networks of ancient canals that make Helmand fertile enough to produce a third of the world's opium crop.