Detectives investigating a sexual assault on board a Jubilee Line train from London Bridge to West Hampstead have released this image in connection.
At around 1.40pm on Thursday 28 May, a woman was sat on the train when a man who boarded either at Bond Street or Green park approached and sat next to her.
He then sexually assaulted her, using a newspaper to conceal his actions.
The woman confronted him, and he moved away down the train before getting off at West Hampstead Underground station.
Detectives would like to speak to the man pictured, as they believe he may have information that 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 334 of 8 June.