A 21-year-old man was left with a bleeding nose, split lip and badly damaged front teeth after a man punched him at Leeds train station car park.
The incident took place just after 12am on October 26.
Police constable Gavin Keenan said: “The victim, a 21-year-old man from Bradford, was with a group of friends walking through the car park at the back of the station, when he became involved in a verbal altercation with a man.
“The man, who was with his partner, then launched an unprovoked and violent attack on the victim, punching him in the face.
“He was left with a bleeding nose and split lip. His two front teeth were also badly damaged and will require extensive dental work.
“This type of behaviour is completely unacceptable. We believe the man pictured may be able to assist with our enquiries into this incident. If you recognise him please contact us.”
Anyone with information can call British Transport Police on 0800 40 50 40, or Crimestoppers anonymously on 0800 555 111.