A 31-year-old man suffered serious injuries after being attacked on the dance floor at Envi nightclub in Hopetoun Street, Bathgate around 2.40am on Sunday morning.
The man was on the dance floor when he was struck on the face and suffered a number of serious head and facial injuries.
He was taken to St John’s Hospital for treatment, where he remains.
Detective Constable Ross Collett from Livingston CID said: “Neither the victim nor those he was with saw who struck him and we are therefore keen to speak to any other patrons who were in the club and saw what happened. “Likewise if you have any other information that can assist with our inquiry then please contact police immediately.” Inquiries to identify those responsible for this attack are ongoing and anyone with information is asked to come forward.