A 14-year-old boy was struck in an unprovoked attack, police said.
At around 9.30pm on Saturday, December 13, the victim was walking home over Millennium Bridge, Lancaster when he was chatted to by two youths of a similar age.
One of them is believed to have then struck him from behind causing him to fall forwards and sustain injuries to his face, as well as breaking and chipping his front teeth.
DC Sue Palmer from Lancaster CID said: “This was a completely unprovoked, nasty attack on a young man who has understandably been left shaken by this incident.
“I am asking anyone who may have witnessed this or has any information about it to get in touch with us.”
The first youth was white, approximately 5ft 7in, slim build, aged around 14 to 15 years old, with black, shiny hair to one side.
He was wearing a darkish-grey fleecy hoody and dark tracksuit bottoms.
The second youth was white, approximately 5ft 7in, medium build with a rounded face, aged around 14 to 15 years with light brown/blonde hair.
He possibly had his hood up and was wearing a darkish top.
Anyone with information can call Lancaster CID on 101 quoting incident number 463 of 14 December 2014.
Alternatively, they can contact Crimestoppers anonymously on 0800 555 111 or online at Crimestoppers-uk.org.
No personal details are taken, information is not traced or recorded and you will not go to court.