The paper reviews the principal elements and functions of an experimental electronic data processing system for the Oceanic Area Control Centre, and indicates their relation to existing methods of control at the Centre, which are briefly outlined. A stored-programme transistor computer maintains an electronic file of flight progress data on up to 100 aircraft, and is connected to a number of keyboard and teleprinter units for input or output of data and interrogation by controllers. In the interest of flexibility, all functions of the system are specified in detail, and may be changed at will by conventional computer programming techniques. These functions include automatic print-out of flight progress strips and automatic identification of overdue position reports and potentially conflicting flight paths.