A 16-year-old boy was punched in the face during an attempted robbery in South Nutfield.
The incident took place in Bower Hill Lane at around 1am on Saturday.
The boy, who had attended a private party at a nearby property, was confronted by the offender who demanded his phone.
When the victim refused to hand over his phone, he was twice punched to the face.
Investigating officer Det Con Karen Scholey, said: "It is believed the offender was with a group of friends who were turned away from the private party which the victim was attending"
The offender was a slim white youth, aged about 17, with short blond hair which was combed to one side.
He was wearing a grey Adidas hooded top and blue jeans
