What are we on now, the 14th defence review since 1945? The 3rd since 2020?
That's far more than any other NATO country. There is an obsession with policy and paperwork and policy wonks and none of those defence reviews has arguably had a positive impact (unless its a managed decline). We're always the wrong shape, wrong tech, wrong strategy, outdated, obsolete, too cutting edge, not enough manpower, not enough cash.
It's not doing us any favours.
They generally are done by fresh governments or after major geostrategic changes.
1957: To reflect the profound change in military aviation due to widespread adoption of air-to-air missiles and the nuclear ballistic missile, change in the army from Regiments to Cold War Brigade structure.
1966: Integration with NATO command structures and withdrawal of forces from East of Suez and Labour spending cuts due to financial constraints.
1975: To reflect détente and Cold War stalemate, established the Army of the Rhine and other standing European forces, focus on anti-submarine operations in the Atlantic and the creation of the British nuclear doctrine that stands to this day
1981: Thatcher naval cuts which led directly to the Falklands war
1990: Reduction in the army headcount of 20% by removing large standing forces across Europe because of the end of the Cold War, removal of frontline deployed fighter squadrons in Germany.
1994: Conservative military spending cuts due to the end of the Cold War, 'peace dividend'
1998: Incoming Labour government review deciding to increase military spending and create rapidly deployable intervention forces whist maintaining Trident. New investments in Special Forces and intelligence.
2003: Post 9/11 review continuing the trend to invest in rapidly deployable forces and reduce large slow moving force elements. Set the requirement to be able to participate in three simultaneous small-medium sized conflicts or one major conflict and one minor conflict simultaneously alongside allies.
2005: In light of the Iraq war; Recapitalisation of British defence manufacturing after it had been hollowed out by the Conservatives and ending legacy Conservative Cost Plus equipment supply contracts.
2010: Incoming Conservative-Liberal coalition made largest financial defence cuts since WW2, 2.5% of GDP to be reduced to 2.0%
2015: Conservative spending increase to 2.0% of GDP after they realised they had cut too much leaving massive unfunded defence procurement and the world was getting less stable again. Refocus on creating standing Middle East forces.
2021 (delayed from 2020): Slight increase in defence spending to 2.2% of GDP and need to create new allied command structures and deployments to replace ones lost due to Brexit.
2025: Incoming Labour, set spending at 2.5% of GDP to rise to 3.0% by 2030 and NATO commitment of 3.5% at some point during the 2030's.