Police have arrested a 25-year-old dual UK-Iranian national in central London on suspicion of plotting a terrorist attack, following a security incident at a US-run military air base in England that British authorities have linked to Tehran.
The man was arrested on Thursday as Counter Terrorism Policing searched two properties in the UK capital as part of the investigation, reports AP.
The arrest follows the detention of five British nationals in their 20s from London in the early hours of Sunday. They were arrested near RAF Fairford on suspicion of explosives and terror offences and have since been released on bail.
Scores of residents were evacuated from their homes near the rural air base as armed police and army bomb-disposal experts moved into the area.
Police found no explosives but recovered a quantity of gasoline, an accelerant, from three vans linked to the five suspects.
Vicki Evans, senior national coordinator for counter-terrorism policing, described the investigation as “hugely complex”, saying specialist teams were pursuing multiple lines of inquiry.
She said authorities were “looking at all possible angles — including possible foreign state involvement”.
British Prime Minister Andy Burnham said the UK had “strong indications” that Iran played a part in the incident. However, he provided no specific details about what was allegedly being planned or why British intelligence had linked Tehran to the case.
Iran has denied involvement. Tehran has previously said it considers any base used to launch attacks on its territory a legitimate target.
RAF Fairford, located 100 miles (160 kilometres) west of London, has been used by American bombers during decades of conflicts in the Middle East, including this year’s war with Iran.
The decision to release the five suspects on bail has drawn criticism from senior US officials.
US President Donald Trump said, “I was surprised they were released on bail,” adding, “I wouldn’t have done that,” while expressing respect for Scotland Yard.
US Secretary of State Marco Rubio said many people were “disturbed” by the decision.
In response, Prime Minister Burnham said British authorities had the investigation under “the strongest grip and the closest control”. He also confirmed that discussions were continuing with US counterparts to explain UK legal procedures and developments in the case.
The security incident comes amid heightened concern over hostile state threats. British security services have warned that both Russia and Iran have used proxies to carry out crimes on UK soil.
Official figures show that national security cases involving hostile state activity, including activity linked to Iran, rose by 50 per cent in the six months to December 2025.
UK officials have also said Iranian-linked proxies have been behind a series of arson attacks and other strikes in Britain and other countries. Many of the attacks have targeted the Jewish community in an effort to sow fear.
Officials have warned that Tehran could widen its range of targets in the UK if conflicts in the Middle East continue.
