A man had his leg broken after he was assaulted in the street.
It is thought that following an altercation at the Joiners Arms pub on Queen Street, the victim, a 30-year-old man from Heysham, was approached from behind by a man as he walked along Pedder Street.
The man jumped on his back, forcing him to the floor striking his left knee on the ground.
As a result the victim was treated for a broken tibia which will require surgery.
DC Tris Hardwick of Lancaster CID said: “We have released a CCTV image of a man who we would like to trace as part of our ongoing enquiries and I would urge anyone with information about his identity to get in touch with us.
“Similarly we would like to speak to anyone who witnessed the incident who hasn’t come forward already.”
The incident happened at 8.30pm on Sunday August 30.
Anyone with information should contact us on 101 quoting log number 1565 of August 30.
Alternatively Crimestoppers can be called anonymously on 0800 555 111 or on-line at Crimestoppers-uk.org.