Her Majesty’s Inspectorate (HMI Probation) is charged with inspecting adult probation and youth offending services in England and Wales. The Inspectorate has existed since 1936 and, since 1991, has played a significant role in the development of effective practice. In this chapter, we combine analysis of inspection reports, inspection standards and research into the impact of inspection in probation conducted by one of the authors to argue that the Inspectorate can contribute to reimagined probation practice. In our analysis, we focus on three of the four forms of rehabilitation laid out in the introduction to this book. Specifically, we argue that the standards support personal rehabilitation; that the way in which the Inspectorate engages with staff and – increasingly people on probation – can be understood through the lens of moral rehabilitation; and that thematic reviews and inspections can have a significant impact on policy that can support social rehabilitation. We conclude with a discussion of the difficulties in attributing cause and effect to inspection work and consider how the Inspectorate can work towards a more productive, parsimonious and proportionate system for delivering probation.