Britain’s domestic intelligence chief has warned that Iran is intensifying efforts to strike sensitive military sites, even as Tehran rejects any role in a series of incidents at British airbases. MI5 Director-General Ken McCallum made the claim in his annual speech on Tuesday.
McCallum told his audience that Tehran’s thinking had shifted significantly this year, with Iranian ambitions now aimed at better-defended targets such as military facilities.
Suspected plot against RAF Fairford and related arrests
Prime Minister Andy Burnham said the Islamic Revolutionary Guard Corps (IRGC) was almost certainly behind a suspected plot against RAF Fairford in Gloucestershire, an airbase that US bombers use for strikes on Iran. The concern led Washington to pull its military jets from the site earlier this month over security worries.
Police declared a major incident after three suspicious vans drove close to the base on September 27. Five British men in their twenties were arrested under the Explosives Act and later released on bail. Officers found petrol in vans linked to the suspects but no explosives, and the men were freed without charge under strict conditions.
Two more people, including a British-Iranian national, were arrested later and subsequently released. None of the men has been charged. Separately, two Latvian men were arrested on Friday for trespassing at RAF Molesworth, a site used by the US military and NATO for intelligence operations. They were also released on bail.

Two Iranians sanctioned over hostile activity
Foreign Secretary Ed Miliband said on Monday that the government was imposing sanctions on two Iranians accused of helping or taking part in hostile activity on behalf of the Iranian regime. One is Ruhollah Bazghandi, who heads IRGC counterespionage operations.
The other, Shahram Ali Reza Tamarzadeh Jakki, was described by British officials as a facilitator for the Zindashti criminal network.
Spy chief doubts Iran can mount complex attacks
McCallum declined to discuss the Fairford case, citing an ongoing investigation, but said it was “not unique” and that similar cases had occurred elsewhere. He added that UK authorities had carried out 50 arrests over the past year to disrupt Iran-linked operations.
Despite the warnings, he said he doubted Tehran could carry out sophisticated attacks, possibly using explosive drones, because of the limited skill of the operatives it has used in Britain. He noted, however, that the IRGC has considerably more experience with conventional and hybrid technology in countries closer to Iran.
Tehran has rejected accusations that it was involved in the Fairford incident or in any other harmful activity in Britain.