Ed Miliband summoned Iran's ambassador to the United Kingdom on Monday and said Britain would not tolerate threats on its soil, in response to an incident involving RAF Fairford that has prompted sharp government concern.
The prime minister told Parliament that Iran's Islamic Revolutionary Guard was "almost certainly" responsible for the RAF Fairford incident, an assessment that has heightened diplomatic tensions between London and Tehran. Officials said inquiries into the episode are continuing as ministers consider how to respond.
Summoning an ambassador is a formal diplomatic protest that signals the seriousness with which the UK is treating the matter. Miliband said the move underlined a demand for explanation and accountability, and reiterated that the UK will protect its territory and personnel.
Government sources said investigators are still gathering evidence and that further statements could follow when more information is available. For now, ministers have emphasised the need for a measured response while preserving national security interests and diplomatic options.
The development comes amid already fraught relations between the UK and Iran. British officials said they would continue to consult with partners and use diplomatic channels to press for clarification, even as they reserve the right to take additional steps depending on the outcome of the ongoing investigation.