by 1953, there were 685 police boxes on the streets of greater london, with an additional 72 smaller police posts, also designed by trench, used in the inner divisions where there was no space for the larger kiosks. between 1923 and 1960 the police box and/or post system had been adopted by most of the provincial police forces throughout great britain. the design and construction of the police boxes used in each system were at the discretion of each individual force, and consequently varied a great deal from location to location, but the police pillars/posts were usually one of three successive models provided by the general post office (gpo).