A Tube station staff member was put in a headlock and punched and kicked after challenging a man for urinating at the station entrance.
Police today launched an appeal for information following the assault at Acton Town station.
Officers released an image containing six men they want to speak to in connection with the assault.
It happened at about 2.30am on September 14.
Anyone who knows the men in the image is asked to contact British Transport Police on 0800 40 50 40, quoting reference number 61 of September 14, 2019.