Thames Valley Police is appealing for witnesses after a robbery in the early hours of Monday morning.
At about 4.30am, two 19-year-old men were walking along Orpington Grove, in Shenley Brook End, when a dark blue vehicle pulled up alongside them.
An Asian man got out of the passenger side of the vehicle, holding a knife in his right hand and told the victims to hand over their phones. The victims said they did not have phones but the man stole a black Slipknot satchel containing a black iPhone 4 in a camouflage carry case from one victim and a HTC mobile phone from the pocket of the other victim.
The man then got back into the car and they drove away.
The main offender is Asian, around 5ft 6ins, and was wearing a grey hooded top with a navy blue body warmer over the top.
The driver of the car is white, about 17-years-old, chubby build and face, with short hair. He was wearing a navy jacket. There was one passenger in the rear of the vehicle, who was a white boy aged about 13-years-old.
Any witnesses can call police on 0845 8 505 505. If you don’t want to speak to police or leave your name, call the charity Crimestoppers on 0800 555 111.