Police are hunting a man after a 62-year-old woman was allegedly knocked unconscious in a "callous and unprovoked" attack at a Tube station.
Officers have released CCTV images of a man they want to speak to after a woman was apparently punched in the face and kicked as she lay helpless on the floor at Green Park station.
The victim was walking towards the Victoria line platform when she was accused of staring at a man, who is then alleged to have knocked her out, police said.
The alleged attacker is then said to have walked away towards the Victoria line as the woman remained on the floor at around 6.40am on December 23, police said.
Investigating officer Det Con Dick Mortimer, of the British Transport Police, added: "This was a shocking, callous and unprovoked assault.
"Violence on the London Underground network is completely unacceptable and we will do everything we can to bring offenders to justice."
The alleged victim, from Brixton, was taken to hospital with a cut to her head and bruising to her face and leg.
Anyone with information should contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference LUA/B4 of 09/01/14, or call the independent charity Crimestoppers anonymously on 0800 555 111.
