A 21-year-old man from the Scunthorpe area is recovering in hospital after he was struck on the head with a claw hammer in Lincoln.
A local man aged 21 has been arrested in connection with the incident and will be questioned at Lincoln Police Station.
The incident happened at around 12.50am on Sunday, September 1, on Hungate in Lincoln, in the area between Revolution bar, Home and Sugarcubes night clubs.
The injured man was taken to Lincoln County Hospital and later transferred to the Royal Hallamshire Hospital in Sheffield.
He has since undergone surgery and his condition is described as stable, Lincolnshire Police said in a statement.
The section of Park Street between Revolution bar and Sugarcubes night club on West Parade has been cordoned off by Lincolnshire Police, who are investigating the incident.
Detective Inspector Katrina Morton of Lincoln CID is leading the investigation. She is appealing for witnesses or anyone with any information about the incident to call the non-emergency 101 telephone number.