Prime Minister Keir Starmer announced on March 1 that the United Kingdom has agreed to allow the United States to use British military bases for “specific and limited” defensive purposes, a marked reversal from earlier British objections to American strikes from UK soil. Starmer said Gulf states had asked the UK to strengthen their defences, that British jets had been deployed to the region and had intercepted an Iranian attack, and he insisted the UK had not taken part in any strike on Iran.
That same evening London, Paris and Berlin issued a joint statement saying they might take “necessary and proportionate” defensive action to degrade Iran’s capacity to launch missiles and drones. The language is carefully calibrated: it signals solidarity with regional partners and with Washington while attempting to preserve a veneer of legal and diplomatic restraint.
The shift reflects a pragmatic calculation. Until now Britain had publicly worried that US strikes conducted from UK territory could violate international law and undercut the principles of the UN Charter. Faced with recent hostile Iranian activity in the Gulf and direct requests from Gulf states, however, London has deprioritised those legal qualms in favour of immediate security concerns — a trade-off that European capitals are echoing.
For France and Germany, the calculus is similar. European leaders remain uneasy about lowering the threshold for force, but they also judge that Iran’s recent actions present a direct risk to allies, to commercial navigation in the Gulf and to European interests in the region. Militarily, however, Europe’s room for manoeuvre is limited: the continent’s defence attention and resources remain concentrated on Russia and Ukraine, making substantial boots‑on‑the‑ground intervention in the Middle East unlikely.
The immediate consequence is a transatlantic alignment of intent if not of scale. Allowing US access to British bases strengthens the operational toolkit available to Washington and its partners, but it also raises the prospect of incremental erosion of legal norms governing interstate use of force and complicates Europe’s claim to be a guardian of the rules‑based order. Policymakers should expect further pressure on legal red lines, risks of escalation with Iran, and a deeper questioning of whether Europe can reconcile its principles with short‑term security demands.