Just before 2pm on January 4, a man sexually assaulted a woman as the pair passed one another at Sloane Square Underground station on the stairway.
The British Transport Police has released an image of a man whom they wish to speak to as they believe he may have information which could help their investigation.
Anyone who recognises him is asked to contact British Transport Police by texting 61016 or by calling 0800 40 50 40, quoting reference 600 of 5 January.
People can also contact Crimestoppers anonymously on 0800 555 111.
