British Prime Minister Andy Burnham said on Monday that a suspected plot targeting the RAF Fairford air base in Britain was "highly likely" to have been coordinated in Iran, and almost certainly directed by the Islamic Revolutionary Guard Corps.
The incident near RAF Fairford began in the early hours of September 27 when five British men in their 20s were arrested near the base on suspected terrorism and explosive offences.
They were later released without charge on police bail "under stringent conditions", and police said they were considering whether a foreign state had been involved.
Last week, US President Donald Trump said a threat linked to Iran had prompted the removal of American B-1 bombers from the air base and U.S. officials have told Reuters that there had been a suspected plot involving Iran to launch a drone attack.
"We will not tolerate these threats on our soil," Burnham told parliament. "We will crack down on Iran's use of criminal networks, using our full range of powers to target them and their funding streams, and we will bring further sanctions to restrict the capacity of Iran and the IRGC to do us harm."