The incident happened in an alleyway between Houghton Road and The Crescent at about 6pm. The boy, who is in his late teens, was assaulted by four men with their faces covered. He received minor injuries as a result of the incident. DC Eliot Ducket said: This was an unprovoked attack and Id urge anyone with information or who saw anything suspicious to contact us. Officers believe this to be an isolated incident. Anyone with information should call 101 quoting CF0040060117. Alternatively contact Crimestoppers, anonymously, on 0800 555111 or online at www.crimestoppers-uk.org.