The execution and delivery of corporate strategy is critical to the growth and survival of organisations. Programme management is seen as the vehicle to deliver ever changing strategic direction of organisations. With the importance of programme management one would think the level of research conducted in this area would be high, however the opposite is true. The author saw an opportunity for research in this area, and through a detailed review of the literature, unearthed the need for a maturity assessment of current programme management practice, developing twelve maturity guiding principles to direct the research. An institutional theory lens was used to explain characteristics of project and programme management, plus the business sectors in the research. This study is unique in that no maturity assessment of programme management in practical or theoretical settings is evident, nor the use of an institutional lens to describe practice and business sectors, one can infer a low level of maturity from a theoretical perspective. A qualitative assessment using a multi-case study tradition was employed across ten business sectors, using survey type qualitative interviews, and a custom analysis model to interrogate data and provide research findings. Results from the research show a contrast in maturity from the theoretical perspective, where a medium level of maturity exists in the empirical setting across the business sectors involved in the research. Furthermore, analysis carried out during this research yielded a generic programme management lifecycle, and a generic definition of a programme. These outputs from the research can be a considered significant contribution to the current theory. Future research opportunities are outlined which include quantitative investigations into each of the twelve maturity guiding principles developed, the testing of the generic programme lifecycle and definition developed, and the use of learning cycles to enhance benefits realisation and programme success.