Factbox-What is known about arrests at US airbase in Britain

The decision by the UK government to permit the United States to utilize British airbases, including RAF Fairford in Gloucestershire, for airstrikes against Iran has sparked controversy since the conflict began in February 2022. Initially, then-Prime Minister Sir Keir Starmer resisted the request, motivated by his opposition to involving the UK in the conflict, which he deemed a "war of choice" initiated by then-US President Donald Trump.

His refusal led to a significant rift with Washington, as American warplanes had to undertake longer routes to reach their targets. Following mounting US pressure, Starmer eventually acquiesced, allowing the US to employ British bases for defensive operations.

Since then, the US has consistently sent B-1 bombers from RAF Fairford to strike Iran. This has irked Tehran, with Iran's Islamic Revolutionary Guard Corps (IRGC) threatening to attack the base, stating that any facility used for aggression against Iranian territory would be a legitimate target. The IRGC also denounced Britain for exacerbating regional misfortunes and causing the "disaster of Israel."

In response to the heightened tensions, the UK's counter-terrorism operation has intensified. Five men have been arrested on suspicion of terrorism and explosives offenses, following the discovery of three suspicious vans near RAF Fairford. Police suspect Iran as the most likely state actor behind the alleged plot, with the possibility of direct involvement being ruled out in favor of more direct engagement.

The incident has prompted the RAF base to be placed on its highest state of alert, while RAF Lakenheath in Suffolk, another US base, has its threat level raised to Charlie, the second-highest.

The incident has prompted British authorities to scrutinize potential involvement by other actors, including Russia, which has recently threatened to launch direct attacks against the UK for its continued support of Ukraine. A local farmer reported encountering the suspected plotters while driving home, raising questions about the effectiveness of security measures. US President Donald Trump claimed that US intelligence agencies were aware of the plot and collaborated with British counterparts to prevent it.