With a strategic defence review expected to begin in 2010, this article reflects upon the history of the review in British defence policy and planning. The authors argue that for decades successive defence reviews have followed a process in which policy development moves through four phases: failure, inertia, formulation and misimplementation. This has resulted in a cycle of defence reviews that have proved to be incomplete and unsustainable: a cycle in which each review leaves so much unfinished business that another radical reappraisal of defence policy is soon thought necessary, and a cycle from which a succession of governments have so far proved unable or unwilling to escape. The article suggests that the strategic defence (and security) review promised for the next parliament is in danger of continuing this pattern of policy deficiency. The authors contest that this need not be the case. With a close understanding of the pattern of past reviews it should be possible for the 2010 review finally to break the mould and produce a coherent and above all sustainable defence policy and strategy.