A Tube passenger was punched and left with a broken eye socket after telling off a thug who was vaping in a carriage.
British Transport Police said an argument erupted on an eastbound District line train from Sloane Square.
The victim, in his 40s, challenged a younger man who boarded the service and lit an e-cigarette at around 6.40pm on November 11.
The pair began rowing and as the train arrived at Westminster London Underground station, the dispute spilled over onto the platform.
A force spokesman said: “The younger man punched him in the face, fracturing his cheekbone and breaking his eye socket requiring surgery and causing damage to his vision.”
Detectives have released CCTV images of a man they would like to speak to believing he may have information that could help with their investigation.
Anyone who recognises him is asked to call BTP by texting 61016 or calling 0800 40 50 40, quoting reference 613 of 11 November.
Witnesses can also contact Crimestoppers anonymously on 0800 555 111.
