The five British men who were arrested over a suspected terror plot near a UK airbase may have been unknowingly working for Iran, experts say.

The suspects, who have been released on bail, were arrested close to RAF Fairford in Gloucestershire on Sunday after one of the group called 999, reported.

The development has left some experts suspecting the group, who are all British nationals from London, may have been unwittingly coerced into the alleged plot without fully understanding its scale or severity.

On Wednesday, Andy Burnham said there are “strong indications that Iran played a part” in the plot although an investigation is still under way.

Iran’s history with criminal proxies

On Monday, Assistant Commissioner Laurence Taylor, head of Counter Terrorism Policing (CTP), said officers investigating the case were considering all angles, including that “this may be activity committed by proxies, or individuals either knowingly or unknowingly, working on behalf of a foreign state”.

Tehran has strongly denied any involvement in the alleged plot, with Iranian foreign minister Abbas Araghchi insisting Downing Street is “barking up the wrong tree”.

However, Dominic Murphy, former commander of Counter Terrorism Command for the Metropolitan Police, has said the use of criminal proxies is a common practise for both Iran and Russia.

“Russia and Iran have been using criminal proxies for a very prolonged period of time to great effect to commit incidents and attacks and sabotage here in the UK,” Murphy told The i Paper.

“My own experience with Iran is that this is exactly the sort of thing they would do.”

Murphy, who was involved in counterterrorism operations for 22 years, said the proxy groups are often made up of “people that might be considered vulnerable or are involved in criminality already”.

He said the fact one of the group tipped off the police could indicate that they may not have fully understood the scale of what they were being asked to do.

“They may have realised what they were doing and potentially got concerned and scared about that and called the police,” he said.

“We have seen a lot of people being duped into doing something. They might even think it’s set up as some kind of big prank or as something else. And it turns out to be a very serious activity that you’re conducting on behalf of a foreign state,” he added.

Andrew Barnes, former head of intelligence at the Met Police, has also suggested the call may have been made due to one of the suspects getting cold feet.

He said: “In many forms of crime and this kind of stuff, where people decide that it’s not what they want to do, it’s not what they thought, they back out.”

Sophisticated target

Other experts have speculated that the incident, including the call to the police, may have been a deliberate attempt by Iran to signal its capability to co-ordinate a potential attack.

Roger Macmillan, a counter-terror expert and former security director at the London-based independent broadcaster Iran International, told The i Paper: “It could simply be that they have done this deliberately [made the call] to signal some sort of intent, some capability… to instil fear in people.”

He added that the 999 call could be to “actually draw out the response… They might have been told, ‘Well, [if] nothing happens by this time, call 999, you’re going to get arrested, but we’re going to pay you [this much] .’”

While the suspects’ intentions have not yet been confirmed, some counterterrorism experts have pointed out that the alleged plan to target the base, which is used by US and British air forces, included “a level of sophistication that isn’t common in terrorism”.

Nick Aldworth, an ex-detective chief superintendent in CTP, told The i Paper the fact that the vans featured in the suspected plot used fake company branding as a disguise suggested detailed planning likely to be beyond self-radicalised terrorists.

The target is also an unlikely one for common criminals without support from a malign state, especially given the security measures in the surrounding area, he added.

Fairford’s runway is almost two miles long and is reinforced to support heavy American bombers such as the B-1 Lancer and B-52 Stratofortress, and also hosts a detachment of U-2 high-altitude reconnaissance aircraft, said Christoph Bergs, an air power analyst at the think-tank Rusi.

The theory that the alleged plot was co-ordinated by Tehran-backed proxies is also supported by Iranian dissidents who say the Islamic Revolutionary Guard Corps (IRGC) – Iran’s elite military forces – frequently hires gang members who may not know that a foreign state is involved.

In March 2022, a journalist from Iran International was attacked, with MI5 director-general Ken McCallum saying the Persian-language channel was the target of  20 “potentially lethal Iran-backed plots”.

In 2024, Reporters Without Borders published a report detailing a series of incidents in the UK allegedly linked to Iran.

Volant Media, the parent company of Iran International, was also targeted in an arson attack in London earlier this year.

Shiva Mahbobi, who fled Iran after being tortured, said: “It doesn’t matter where you are from if you need money. It could be a middleman approaching them, saying: ‘We’ll give you £1m to go and do this.’”

Mahbobi, a psychotherapist who works with the Campaign to Free Political Prisoners in Iran, said she believes the UK’s banning of the IRGC this summer has angered Tehran.

“The regime is really trying to intimidate not just people but governments,” she said. 

“They’re trying to say: ‘We have people everywhere, we can activate our cells in different countries, we can plot terrorist attacks anytime we want.’”

A second dissident, who asked to remain anonymous, said Tehran believes its tactics – to use Iranian-backed proxies – have been successful in deterring European nations from supporting the US war on Iran.