British Transport Police wish to speak to this man after a member of staff was assaulted at Sheffield train station.
A man pushed a staff member into a toilet after being refused travel on a train to London St Pancras, according to police.
The incident occurred at about 6.20am on Wednesday, May 13.
Investigating officer PC Stephen Slocombe said: “A man was refused travel on a train to London St Pancras as he did not have a valid ticket.
“When the same man then attempted to travel on another service without a ticket he was challenged by two revenue protection officers.
“He became violent and pushed one of the staff members into a toilet.”
Officers want to speak to the man in the CCTV and urge him or anyone who recognises him to get in touch.
PC Slocombe said: “We believe the man who assaulted the staff member may have been travelling to Leicester.
“Incidents like this are thankfully rare but are completely unacceptable. This member of staff was simply doing their job and we are working hard to find the man responsible.”
Call British Transport Police on 0800 40 50 40 or Crimestoppers on 0800 555 111.