Armed police fired weapons during a dramatic arrest of a suspect on the A27 yesterday.
Witnesses said that police in unmarked cars forced a Mercedes to stop by targeting its tyres with 'Hatton' rounds, designed to destroy what they hit then disperse into a powder.
A man was then arrested on suspicion of possessing a firearm, and led away in handcuffs by officers.
The operation, which took place at around 4:30pm, was led by the Trident Gang Crime Command, a division of the Metropolitan Police tasked with gang violence and shooting incidents.
"MPS detectives and armed officers from the MPS Specialist Firearms Command stopped the car at around 15:30hrs in relation to firearms," a police spokesperson said.
"The operation was led by officers from the Metropolitan police, based in New Scotland Yard, London.
"There were no reports of any injuries. A suspected firearm was recovered.
"A man was arrested on suspicion of possession of a firearm and has been taken into custody at a local police station."
Traffic on the main south coast road had to be halted while the operation was carried out, and one lane of the dual carriageway remained closed for an extended period afterwards.
One commuter told the Brighton Argus that they had passed through just after the incident had taken place, and that there was a large police presence. The eyewitness added that police had handcuffed a "very large" gentleman at the side of the road.