The arrival of the tank gave rise to a wholly new technique of defence. Elaborate tank traps were a part of every fortified line, but the anti-tank gun was the most formidable of the tank's opponents. Here one of these guns is seen on the Western Front in a lorry in which it could be quickly transported to any point where it may be needed. Such guns were very effective, for the small shell they fired had considerable armour piercing capacity and had a delayed action fuse that did not explode until it was inside the tank.
