This project shows how an interactive object based graphical user interface for a plant supervision or control application may be implemented using state-of-the-art software languages and tools. In many current plant supervisory, control and data acquisition systems (SCADA) data presentation is limited to archaic character based graphics and text based prompts with little or no use of pointing devices. With the emergence of object-oriented programming languages and graphics function libraries this project shows how a decisive upgrade in the graphics for these systems may be achieved, thereby bringing realism into plant mimic diagrams. The mimic diagrams created in this project consist of a static background, acquired by the use of scanning devices or paint packages, and a dynamic background of icons, generated using object-oriented C++ classes. The project is an object-oriented application and hence illustrates the object-oriented paradigm. The thesis introduces the area of supervisory, control and data acquisition systems. It examines graphic standards and operating system options, and highlights the need for a user friendly extensible graphic interface to telemetry systems. It also shows how object-orientation should provide for systems that are not only easier to extend and maintain but may also spawn parts which may be used for future projects. The thesis, based on experience gained throughout the project, examines C++, classes, inheritance, problems associated with C++ environments and the dangers of product incompatibility. It discusses graphic elements, such as bitmaps, icons and menus, and shows how object-orientation may be applied to them. It expounds on real-time considerations and icon animation and details the full project implementation including compilation and memory management systems used. Finally it points to the future, to the impact of object-oriented programming on technical management, to object-oriented databases and the object-oriented SCADA workstation of the future, and to changes imminent in C++ itself.