Michael Quinlan (1992, p 160) recognized that focusing on the specific content of the UK’s defence programme following a defence review is of far less value than studying the reasons why the related decisions were made in the first place. In line with his thinking, this chapter concentrates less on the ‘what’ and more on the ‘why’ of defence review decision making. In doing so, it balances academic commentary on the process of defence reviews from the last 75 years with the views and observations from recent practitioners. These inputs from senior officials within the MoD are, understandably, almost exclusively focused on the Quinquennial Review period.

Individual defence reviews methods regularly attract scrutiny from the defence academic community, sometimes to the point where process has overshadowed outcome. For instance, Andrew Dorman (2001a, p 24) suggested that ‘many of the novel features of the [1998] SDR surround its conduct rather than its findings’. Nevertheless, there has been little academic analysis of pan-defence review processes and whether they all have a cyclical connection, or common attributes. One exception is research undertaken by Paul Cornish and Andrew Dorman (2010, pp 395–6), which concluded that UK defence reviews throughout the Cold War and Early Expeditionary period followed a flawed, four-phase, policy development process. Cornish and Dorman argued that policy failure was followed by policy inertia, which led to policy formulation, and, finally, policy misimplementation. Furthermore, they contended that this resulted in an as-yet inescapable cycle of incomplete and unsustainable defence reviews. More recently, they developed this thinking to identify ten unwritten rules that influence the character and quality of defence reviews, which can be summarized as follows:

• • Reviews are quickly overtaken by events.

• • Governments find it difficult to sustain the logic of their own strategy review.

• • Reviews are inevitably underfunded.

• • Reviews are constrained by the capability decisions by which they are immediately preceded.

• • In any review, certain areas will be considered ‘off-limits’ for party political, domestic or international reasons.

• • The unanimity of service chiefs cannot be maintained, as their allegiance to their respective service takes precedence over their commitment to Defence overall.