The system of numbering pendants was adopted prior to the First World War to distinguish between ships with the same or similar names, to reduce the size and improve the security of communications, and to assist recognition when ships of the same class are together. Traditionally, a pendant number was reported with a full stop "." between the flag superior or inferior and the number, although this practice has gradually been dropped, and inter-war photos after about 1924 tend not to have the full stop painted on the hull. The system was used throughout the navies of the British Empire so that a ship could be transferred from one navy to another without changing its pendant number.