During World War II, Royal Observer Corps members stationed in about 1000 posts across the country reported the position, height and numbers of aircraft flying overhead to one of about 40 control centres in contact with fighter operations rooms, anti-aircraft units and the police. Aircraft identification was a highly valued skill.

After the War, members were also trained to detect and report nuclear blasts and fall-out. Some of the instruments used by the Corps are featured in the display. With the end of the Cold War, the Corps was finally disbanded in 1995.