Otis Ferry removed the car keys from two celebrity photographers to stop their "possessed" pursuit of Sienna Miller, a court has heard.
Otis Ferry said the photographers used 'aggressive' driving tactics
The son of Roxy Music singer Brian Ferry was leaving Boujis nightclub in South Kensington in February with the actress and his brother Isaac.
He told police it was a "sure-fire" way of preventing them following her.
The 25-year-old from Cross Houses in Shrewsbury denies two charges of criminal damage.
Ms Miller left the club in a silver Mercedes while Mr Ferry and his brother were in a black Freelander in which the defendant was a passenger.
He described Ms Miller to police as his brother's girlfriend and said he thought they had met in the New Year.
West London Magistrates' Court heard how he leant through the car windows of two photographers, Charles Pycraft, and Ben Brett, and grabbed their keys before discarding them.
In a police tape played to the court, Mr Ferry said the photographers were using "very aggressive" driving tactics and talked of "playing silly games".
The "last thing" he wanted was for them to go to Miller's address, the court heard.
Ferry said: "I just said, 'Look, please just leave us alone. Why don't you go home? Stop it, you're quite scary'."
They just "sneered", he said.
He continued: "I said, 'This is seriously not on.' It was unbelievable.
"I said, 'what the hell are you doing'?"
But he said a photographer had a "ridiculous grin".
Ferry said he took the keys straight out of the ignition.
"I thought it was a sure fire way for us to get away from them basically," he said.
"They were like, possessed."
The trial continues.