Every project should have a business justification, in most cases demonstrating a favourable balance between investment of resources and the anticipated (or at least expected) returns.
It is a principle of a PRINCE2 project that this justification remains valid throughout the life of the project, not simply used to trigger the project and then forgotten about. The progress of a project will therefore be heavily dependent upon the continuing maintenance of the business case and its continuing demonstration of a worthwhile project. This is explored in the Business Case theme.
In PRINCE2, the business case can be documented in the Business Case document, and supported by a Benefits Review Plan.
In PRINCE2, no business case = no justification = no project.
