Two men were arrested and are in police custody in Oxford tonight after police shot out the tyre of a car near the busy Green Road roundabout in Headington.

Metropolitan Police firearms officers fired two "hatton rounds" - a weapon designed to disable a car's tyres - at an Audi in London Road, close to the roundabout.

The vehicle was stopped shortly after 3.20pm and a search later recovered a handgun.

Two men, aged 29 and 38, were arrested on suspicion of possessing a firearm.

A force spokesman told the Oxford Mail the "pre-planned intelligence-led investigation" was not terrorist-related and the men were not believed to be from Oxford.

He added: "Two men have been arrested in a pre-planned Metropolitan Police intelligence-led investigation.

"Officers from the central task force have been working closely with colleagues from Thames Valley Police.

"The specialist firearms units were supporting the central task force and Thames Valley Police officers in order to stop the vehicle and preserve the safety of the public, officers and the targets of the operation.

"Two hatton rounds were discharged into the tyre of an Audi on the A4142 junction with London Road.

"This was done to prevent the car driving away from police. A search has recovered a firearm."

The incident caused traffic chaos on the A40 in both directions and adjoining roads while police dealt with the incident. London Road was reopened to traffic about 4.30pm.

A 25-year-old man from London Road said: "I saw one police officer with a shotgun and I think the rest had pistols.

"A number of unmarked vehicles surrounded this Audi and then officers pulled the driver out and put him on the floor.

"Then they opened the boot of the car and started filming inside with a camera."