A £2,000 reward is being offered as police search for a man who head butted a train driver, leaving him with a black eye and cut to the head.

The vicious and unprovoked assault meant the driver needed stitches in his head and he was shaken and upset by the attack.

Police have released an image of a man they want to talk to after the driver was attacked when assisting the train’s conductor remove a man, who appeared to be drunk, from the 7.04pm Horsham to Victoria train last month.

As they moved onto the platform, the man became aggressive, head butting the driver, British Transport Police (BTP) said.

The attacker fled the station leaving the driver with a black eye and a nasty cut on his head which needed medical attention.

The reward has been put up by train operator, Southern, following the incident at Cheam station at around 8pm on Tuesday, March 24.

Police have issued an image of a man who they think can help with their enquiries.

Detective Sergeant Sarah Garden said: “This attack left the victim feeling shaken and upset. He required stitches to his head wound.

“Staff have the right to go about their duties without the fear of violence, and we will do everything we can to find the person responsible.

“I think the man in the picture has important information about what took place. Who is he?”

Southern’s head of trains, Martin Grier said: “This was a vicious and totally unprovoked attack on our driver who was simply trying to help another staff member with a difficult situation.

"We urge anyone who recognises this man to contact BTP.”

Anyone with information is asked to contact BTP on 0800 40 50 40, or text 61016, quoting reference SSUB/B11 of 07/04/2015.

Information can also be passed anonymously to the independent charity Crimestoppers on 0800 555 111.