Two men have appeared in court charged under the UK's National Security Act following an incident at the RAF Fairford military base.
Mohmed Abdulkarim, 24, has been charged with assisting a foreign intelligence service, while Nouman Essghir, 24, was charged with one offence of entering a prohibited place for a purpose prejudicial to the UK.
The US removed its bombers from the base in Gloucestershire, south-west England on security grounds shortly after five British men were arrested nearby in the early hours of September 27. A major incident had been declared after three suspicious vehicles were seen near the airbase.
Assistant Commissioner Laurence Taylor, the head of national counter-terrorism policing, said police believed Mr Abdulkarim was assisting Iran.
Mr Abdulkarim and Mr Essghir, a dual British-Iranian national, appeared at Westminster Magistrates' Court.
Prosecutors said Mr Abdulkarim, who was in a wheelchair in court, arranged for five men to take three vans and drive to RAF Fairford at the behest of a man called “Ali”.
The five men bought about $400 worth of petrol, which was stored in drums, prosecutor Louise Gray said.
“One of them was told there was a bomb in the van … (and) one of them called 999,” Ms Gray added, with police arriving shortly after.
Ms Gray said Mr Essghir had conducted reconnaissance of the base on instructions from “Ali” in August, adding that he was also in one of the vans which drove to RAF Fairford the following month.
Mr Abdulkarim was granted bail ahead of his next court appearance in November. Mr Essghir has been remanded in custody.
A total of eight men have been arrested in the investigation. Six of them remain on police bail.
Mr Taylor said that for the public the Fairford incident “was defined by images of three vans being stopped and searched by armed police officers, and the arrest of five men at the scene”.
“The subsequent release of those five men on police bail sparked significant questions and speculation about the investigation and why that was the case,” said the officer, speaking outside the Scotland Yard police headquarters in London.
“We know that decisions made during our investigations can sometimes appear illogical to those on the outside, but I want to make it very clear that there will always be good reason or rationale behind them.
“We will always ensure that, should we identify any ongoing threat, we will manage that as part of the investigation. Like our adversaries, our tactics vary – and may not always be obvious.
“In this case, this decision-making has led to swifter progress, better evidence and ultimately us securing the charges I have announced today.”
Mr Taylor said the investigation had involved reviewing “extensive” CCTV footage and the contents of dozens of digital devices.
“While some of the circumstances remain unclear, we are confident that this activity was conducted on behalf of a foreign intelligence service,” he said.
He said that proxies were increasingly being used by those who wished to destabilise the UK, but investigations “take time to establish what those individuals knew about the ambition behind the tasking”.
“Sometimes individuals can have no knowledge or even partial knowledge of what they are being asked to do, on behalf of foreign states. Sometimes they have full knowledge.
“This is not a theoretical threat, this is something we are responding to every day at counter-terrorism policing, particularly in the case of Iran.
“We have seen a range of incidents in recent months, that we believe have been directed by the Iranian state, and as the Director General of MI5 said recently, we are working together to intervene, identify and respond to that threat.”
British Prime Minister Andy Burnham said at the end of last month that the activity at Fairford was likely to have been co-ordinated in Iran.
