A 20-yr-old man has come forward to help officers with their enquiries in relation to a violent incident that occurred on board a tube where alleged racist language was used.
A video of the incident, where a young man punched a woman after being struck by a bottle, was uploaded on video sharing website YouTube on January 8.
The two passengers exchangers heated words, some of which were of a racial nature.
The confrontation then turned physical and passengers had to restrain the man after the woman allegedly hit him with a bottle.
Officers are appealing for witnesses to come forward to in a bid to finally identify the woman seen in the shock footage.
WARNING: Video contains offensive language and footage of a violent nature
A BTP spokeswoman said: "On Saturday, 12 January a 20-year-old man from Lewisham voluntarily attended a London police station in connection with the incident and is helping officers with their enquiries."
"We still need to speak to the woman pictured in the images so we can try to establish exactly what took place. We continue to urge her or anyone who knows her, as well as any passengers who were on the train at the time, to come forward."
Anyone with information should contact British Transport Police on 0800 40 50 40 quoting reference B7/LUA of 10/01/13. Alternatively contact the independent charity Crimestoppers anonymously on 0800 555 111.