An old age pensioner was punched in the face by a much younger man for "staring" at him on a train.
The 81-year-old was on his way to visit his grandchildren when the "frightening assault" happened on a service in south London.
A young man accused the senior citizen of staring at him soon after boarding the London Victoria to Orpington train with his girlfriend at Penge East.
This was followed by what police called "heated words" between the pair. The assailant then leapt from his seat and hit the OAP with a heavy punch to the face. He also aimed a kick at the victim's head.
The attacker and his girlfriend got off and left the scene when the train pulled in to Bromley South station.
Now police have issued an appeal to hunt down the man responsible for the assault, which took place on Monday at 6.30pm.
PC Clive Thomas is investigating. He said: "The elderly man had been travelling onboard a London Victoria to Orpington service when the incident happened.
"A short while into the journey this man accused the 81-year-old victim of staring at him.
"Heated words were exchanged before the man jumped from his seat and delivered a fierce punch to the victim's head. He then went on to kick him in the head before leaving the train at Bromley South station with his girlfriend.
"It is vitally important that we speak to the man pictured to find out what happened and I would urge him or anyone who recognises him to contact police immediately."
Anyone with information is urged to call British Transport Police with information on 0800 40 50 40 or Crimestoppers on 0800 555 111.