On the battlefields of the First World War, initially successful attacks all too often ended in failure because artillery weapons could not be moved up quickly enough to support assault infantry at the sharp end of the fight. As the first tanks appeared on the battlefields in late 1916, British designers tabled ideas for self-propelled gun carriages capable of negotiating difficult terrain, carrying their own loads of ammunition and providing some degree of protection for their crews. One design that never made it off the drawing board was the ED3 Emplacement Destroyer, a 27,000-pound vehicle mounting a 4.5-inch howitzer.1 Surviving sketches of this unrealized concept bear a striking similarity to a series of self-propelled guns employed during the Second World War. One of these was the Canadian-designed and manufactured Sexton 25-pounder.