Britain has formally accused Iran of orchestrating a security incident near RAF Fairford, a strategically critical airbase in southern England used by American heavy bombers.

Five British nationals were arrested on September 27 near the Gloucestershire base on suspicion of terrorism and explosives offenses, later released on bail under strict conditions.

A sixth arrest followed in the days after the initial incident, as police continued to assess the possibility of foreign state actor involvement.

Prime Minister Andy Burnham told lawmakers in the House of Commons that the plot was almost certainly directed at the highest levels of Iran’s security apparatus.

“I can confirm our assessment that it is highly likely to have been coordinated in Iran, almost certainly directed by Iran’s Islamic Revolutionary Guard Corps,” Burnham said.

“We will not tolerate these threats on our soil,” Burnham added, warning that further sanctions against Iran remained firmly on the table.

Despite the scale of the security response, which included bomb squad deployment, investigators did not find viable explosives in the vans, though accelerants including petroleum were discovered.

Foreign Secretary Ed Miliband confirmed that Iran’s ambassador had been summoned to receive the direct message that Britain “will not tolerate attacks on our soil.”

Iran’s state news agency IRNA reported Ambassador Ali Moussavi as “categorically rejecting the accusations” and calling on the British government “to present evidence supporting its allegations if it possesses any.”

Miliband announced immediate asset freezes, travel bans, and director disqualifications against two named individuals linked to the alleged plot.

Those sanctioned are Ruhollah Bazghandi, identified as head of counterespionage operations in the IRGC, and Shahram Ali Reza Tamarzadeh Jakki, described as an alleged facilitator for the Zindashti criminal network.

Miliband said both were being targeted for “their role in facilitating or engaging in hostile activity on behalf of the Iranian regime, with the clear intent of threatening, planning or conducting attacks overseas.”

A joint statement signed by 29 countries condemned “in the strongest terms Iran’s use of violent attacks,” including acts of lethal plotting, arson, sabotage, and cyber-attacks.

All five members of the so-called Five Eyes intelligence alliance signed the statement, alongside most European NATO members, including the US, Australia, Canada, France, Germany, Spain, and Ireland.

RAF Fairford holds particular strategic significance as one of the few European bases capable of hosting US Air Force heavy bombers, including B-1s and B-52s, aircraft with the range to reach Iran.

Following the September 27 incident, the high-tech B-1 bombers departed the airbase, while the larger contingent of B-52s remained stationed there.

The base is located roughly two hours’ drive west of London in a rural area north of Swindon, and traces its operational history back to Allied air campaigns during the Second World War.

Burnham closed his parliamentary address with a direct warning to Tehran, stating that Britain would “crack down on Iran’s use of criminal networks, using our full range of powers to target them and their funding streams.”