St Albans railway station worker 'head-butted' over no smoking request
A railway worker was "head-butted" after asking his attacker to stop smoking on the platform.
British Transport Police has released an image of a man it wants to speak with about the incident at St Albans station.
Officers said when the man was confronted about his smoking he became "aggressive".
When the worker phoned the police he was head-butted in the side of the face, they added.
PC Jackie Gray said: "This victim was violently assaulted simply for trying to do his job.
"Luckily the victim managed to steady himself, or else he would have fallen backwards on to the tracks where he could have been seriously injured.
"Offences like this on the rail network are rare and so we are working to establish who the offender is and bring them to justice."
The attack happened at about 17:35 BST on 11 September, but information about it has only just been made public by police.