on Monday evening.

He was riding a bike along Middle Road in Southampton at about 5.30p.m. when he was stopped by another teenager, also thought to be 16.

After demanding cash from the terrified youngster the thief removed the bike keys from the ignition and stole a quantity of cash after forcing open the seat.

The thief then warned his victim not to go to the police and reinforced his threat by lifting his shirt to reveal an unknown weapon. The culprit is described as dark brown skinned with a distinctive goatee beard. He was wearing a beige coloured baseball cap, short sleeved shirt and dark blue jeans.