British Transport Police has released CCTV images as part of an investigation into a violent assault on board a train from Waterloo Station earlier this year.
Officers are looking to identify a group of youths, pictured in the CCTV images, in connection with the incident which took place on Wednesday 25 March.
The victim, a 30-year-old woman, boarded the 11.57pm Waterloo to Shepperton train where she was approached by a group of youths.
"One of the female youths assaulted the victim, leaving her with cuts and severe bruising to her face," says PC Jason Weston-Collinson.
"This was a vicious attack that left the woman injured.
"No one should be subjected to an assault like this as they travel on the rail network and I would urge anyone who recognises the youths pictured in the CCTV images to contact us."
Anyone with any information about the incident or who recognises the youths pictured in the CCTV images is asked to contact BTP on 0800 40 50 40 or call Crimestoppers anonymously on 0800 555 111.