This paper describes the development and application of an innovative problem structuring method to guide interventions in the way in which the UK Ministry of Defence delivers infrastructure projects and services. This method uses an adaptation of the Viable System Model to structure a set of stakeholder assessments that leads to the building of a Hierarchical Process Model. The resultant model, which appears readily transferrable to other multi-organisational contexts, comprehensively represents the functions required for a specified system to be effective in its environment and affords insight into the processes and capabilities that require intervention -either to increase performance (addressing weaknesses) or to increase understanding (addressing uncertainty). The paper also describes a number of methodological learning points identified through the use of a structured approach to evaluation which again appear to be readily transferrable to other multi-organisational contexts.