Masked thugs on a moped slashed a woman after ambushing a family in a car in south London.
The four relatives were targeted by two men as they were stopped in a vehicle in south London on Friday afternoon, police said.
They were threatened with a "large knife" and faced demands to hand over jewellery during the mugging in Coulsdon.
One of the occupants of the car, a 30-year-old woman, was slashed in the hand during an attempt to steal her bracelet, police said.
None of the other passengers - one 66-year-old man and two women in their 70s - were injured as the muggers made off with "a small quantity" of jewellery.
Police today launched an appeal for information after the incident in Keats Way at about 6.45pm on Friday.
A spokesman for the Met said: "The suspects are described as two white males, aged in their late teens or early 20s. Both were of slim build and wore dark coloured tracksuits, black crash helmets and facemasks."
Anyone with information should call Croydon CID via 101 quoting reference 6135/8jun, or contact Crimestoppers anonymously on 0800 555 111.
