The United Kingdom’s decision to permit the United States to use British military bases in operations against Iran has placed Prime Minister Keir Starmer at the centre of a legal and constitutional dilemma over collective self-defence and complicity under international law.
A suspected Iranian drone struck the runway at RAF Akrotiri in Cyprus, causing limited damage and no casualties, according to British and Cypriot officials. Two further drones targeting the base were intercepted. The incident followed Starmer’s confirmation that Westminster had approved a US request to use British bases for the stated defensive purpose of destroying Iranian missiles at source, including storage depots and launch sites. In a joint statement with France and Germany, he referred to proportionate defensive action against threats.
Legal scrutiny has focused on whether US and Israeli strikes on Iran meet the threshold for self-defence under the United Nations Charter. Military analyst Sean Bell argued that international law makes no distinction between a state conducting an act of war and one supporting it, raising the prospect of equal complicity. According to Defence Eye editor Tim Ripley, British government lawyers had previously advised against participation when Washington sought access to bases including RAF Fairford and Diego Garcia, concluding that the campaign did not amount to self-defence. Iranian retaliatory attacks on Gulf states and the risk to British nationals and treaty partners are understood to have reframed the legal basis as collective self-defence.
Starmer has stated that the decision aligns with international law and is limited to protecting British lives and longstanding allies. However, operational realities complicate that boundary. US aircraft departing British territory would undertake extended missions, and any deviation from agreed defensive targets could implicate the UK. Domestic opposition adds further pressure, with a YouGov poll indicating that a majority of Britons oppose allowing US air strikes on Iran from UK bases.
