The pursuit of "excellence" is a preoccupation for leaders and change agents who wish their organisations to be the best that they can be. "How do we achieve excellence?", they ask. "Is there a formula, a roadmap?" There is no shortage of offerings: total quality management, business excellence, process redesign, lean thinking... the list seems endless. Advocates of the latest offering trumpet its efficacious properties, sceptics see reinvented wheels, scholars bemoan hype that threatens to discredit worthy methodologies. Diagnostic benchmarking attempts to bottle organisational excellence and make it accessible and usable for change agents and their colleagues. It presents in various forms, from Ishikawa's quality diagnostic to the Baldrige Framework, the EFQM Excellence Model, the PROBE tools and many others. It offers a means of checking the organisation's health and identifying actions that will help it to progress on its journey towards excellence. This study has subjected diagnostic benchmarking to intensive scrutiny to better understand its role as an enabler of organisational improvement, thus addressing an important gap in the body of knowledge. It has deployed an inductive methodology in the case study setting of an English local authority, which has committed energy and resources to diagnostic benchmarking and has been officially designated as an "Excellent Council". Through the eyes and interpretations of those who are engaged in its deployment, the role of diagnostic benchmarking is revealed to be less formula or roadmap, more stimulus and aid to reflection and learning. Its meaning for participants ranges from "a gold bar that others won't share" to "a waste of time when I might have been doing my job". The study concludes that diagnostic benchmarking has played a role as an enabler in this particular setting, and suggests contingent factors that may have worked for and against its effectiveness in that role.