Police officers have re-issued an image of a man they wish to speak to following a serious sexual assault at London Bridge Underground Station a year ago.
The incident happened at 9.30pm on Thursday 27 November 2014.
A man inappropriately touched a woman as she made her way through the station. He boarded a tube train and left the Underground at Waterloo.
Officers believe that at Waterloo he boarded a mainline train heading towards Alton.
DC Suleman Yazdani of the British Transport Police said: "I am extremely keen on speaking with this man as I believe he has vital information which could help with the investigation.
"Nobody should be made to feel intimidated or in fear.
"This was a serious sexual assault and I would encourage anyone who recognises the man in the CCTV image to come forward and help us."
Anyone with any information should contact British Transport Police on 0800 40 50 40 or text on 61016 quoting T-SUB/B4 of 30/11/15.