Five men were arrested in the early hours of September 27 after a farmer spotted balaclava-clad men near RAF Fairford and called police, according to The Times. Armed officers intercepted three vans near the village of Whelford, about two miles from the airbase, at around 00:45 BST.

The men were first arrested on suspicion of offences under the Explosives Act, then further arrested on suspicion of preparing a terrorist act. Police evacuated 85 homes in Whelford while Army bomb disposal experts examined the vehicles, and set up a 400-metre cordon.

Counter Terrorism Policing is leading the investigation, which senior coordinator Vicki Evans described as being at an early stage. Gloucestershire Police said they believed the incident was contained. Prime Minister Andy Burnham was being kept updated, according to The Times.

The Times reported that detectives are investigating whether Iran is linked to a possible plot, after Tehran made threats against the base. RAF Fairford hosts US Air Force bombers. With no charges announced yet, the inquiry is expected to continue for some time.