The paper describes the application of integrated production control using three computers to the Rotherham works of the Park Gate Iron and Steel Co. Ltd. The system, installed to meet the needs of a considerably expanded steelworks, will come into service early in 1964.Offline production-planning facilities cover operations from the steelmaking plant to the finishing mills, but online production co-ordination is restricted to the primary-mill area through which all products must pass. Process controls are applied as automatic programming of the bloom mill and computer control of the billet flying shear.The production-planning computer receives incoming orders and feedback data from the works. It updates the appropriate magnetic-tape files and issues working schedules to the various departments.Primary-mill instructions are issued as paper-tape input to the co-ordination computer. Here ingots are identified with orders, and processing instructions are relayed to operators on a tabular display system and by direct links to the automatic mill programmer and the shearing computer.The shear-computer system measures ingoing length, predicts outgoing length and directs billet cutting for minimum waste. It also tracks and identifies the cut billets on the cooling bank.