A set of objectives and policies have been established to guide the design and development of a multi-centre processing network architecture to meet the Bank's requirements well into the 1980's. Based on these objectives and the initial conceptual model of the architecture, a functional architecture has been developed. This is a plan for mapping the component subsystems onto hardware, software and communication networks. The overall communication network architecture comprises networks for real-time transactions and for bulk file transmission between processing centres. The real-time communication netwroks are application-independent, common systems through which terminal workstations can access any Service Processing System for which they are authorized. The real-time processing systems architecture supports independent Service Processing Systems on physically modular processing facilities which are minicomputer-based; each processing facility is dedicated to a given Service Processing System. A pilot project had demonstrated the basic viability of this approach, which will provide a means of implementing Service processing systems at lower cost, with higher reliability and with better accomodation of differing scales of operation than a large mainframe approach.