Battle surplus

A Battle surplus is when officers and men of a unit or Brigade are left out of action and retained to replace casualties incurred. Before an attack Operation Orders provided that a certain proportion of officers and other ranks in every unit to be engaged was not to accompany the unit into action. It was styled "first reinforcements" and was retained to form the nucleus for reconstructing the unit should the worst happen. They were also employed on special work of various kinds close behind the fire zone.