Keir Starmer authorised US forces to use two British military facilities — Diego Garcia in the Indian Ocean and RAF Fairford in Gloucestershire — for strikes on Iranian missile batteries and launch sites on 1 March, according to Al Jazeera and Stars and Stripes. Downing Street described the operations as defensive in scope.
The distinction is doing considerable legal and political work. Diego Garcia has hosted US long-range bomber operations since the Cold War; B-2 Spirit aircraft flew from the atoll during the 2001 Afghanistan campaign and the 2003 Iraq invasion. RAF Fairford is the US Air Force's primary European staging base for strategic bombers, including B-52H aircraft deployed during Operation Iraqi Freedom. Strikes launched from these facilities against targets inside a sovereign state are, by conventional military taxonomy, offensive operations. The UK government's position — that destroying Iran's retaliatory capacity constitutes defence of allied forces — reprises the framework Britain applied during Operation Shader against the Islamic State, where London distinguished between RAF combat sorties and enabling operations from sovereign bases, both justified under Article 51 collective self-defence.
Starmer referenced the 2003 Iraq vote in Parliament. Tony Blair's decision to join the Iraq invasion cost Labour its foreign policy credibility for a generation and contributed to a leadership crisis that took over a decade to resolve. 139 Labour MPs rebelled against Blair on 18 March 2003 — the largest governing-party revolt in modern British parliamentary history. Starmer is attempting to preserve the US-UK security relationship, Britain's primary alliance commitment, without absorbing the domestic cost Blair paid. When he told Parliament that Britain had "learned those lessons," he was speaking to Labour's backbenches as much as to Washington.
The distinction between lending airfields and joining a war has a limit, and within sixty minutes of the authorisation, that limit was tested: a drone struck RAF Akrotiri in Cyprus, British sovereign territory. In 72 hours, London moved from enabling the campaign to absorbing a strike on its own soil to publicly refusing further involvement — a sequence that exposed how quickly the "defensive" framing erodes when the infrastructure you provide makes you a target.
