British counter-terrorism police on Thursday arrested a 27-year-old dual U.K.-Iranian national in Westminster, London, on suspicion of preparation of terrorist acts, and searched two properties in the capital. A 26-year-old British national was separately questioned under caution — an interview recorded for potential use in future prosecutions. He is the sixth person arrested in the investigation into a security incident at RAF Fairford, a U.S.-run air base in England.
Prime Minister Andy Burnham said Wednesday that the U.K. sees "strong indications" that Iran played a part in the incident. Vicki Evans, the senior national coordinator for Counter Terrorism Policing, called the investigation "hugely complex" and said specialist teams are "interrogating multiple lines of inquiry" and "looking at all possible angles — including possible foreign state involvement." Iran's embassy in London denied any role, calling the speculation "unfounded and malicious," and on Thursday summoned the British ambassador in Tehran.
RAF Fairford has been used in recent months by American bombers to strike Iran, after former Prime Minister Keir Starmer granted the U.S. permission to use British bases for "defensive" strikes against Tehran during the Middle East war. In the early hours of Sunday, police mounted a major operation after receiving what they described as a range of information — including an alert from a local farmer who grew suspicious seeing men with three vans near the airbase. Five British men in their 20s, all from London, were arrested on suspicion of explosives and terror offenses. Officers found a quantity of gasoline in the vans but no explosives. The five were released on bail Monday under strict conditions as the investigation continues.
President Donald Trump publicly criticized the decision to release the first five suspects. Burnham insisted the U.K. is working closely with the U.S. and that authorities have the situation under "the strongest grip." Iran, meanwhile, has hit back diplomatically by summoning Britain's ambassador. The case puts the spillover risk of the U.S.–Iran war squarely on British soil.
Evans thanked the public for its "continued support and patience" while specialist teams work through the investigation. With the sixth arrest, the focus has shifted from the original five British suspects to whether a foreign state orchestrated the plot. If the "strong indications" are confirmed, it would be the most serious conspiracy against a Western military base since the Middle East war began.