Police have released images of a man they want to speak to following a sexual assault on a train between Stratford and Ilford.
The victim, a 34-year-old woman, boarded the 5.04pm train at Stratford on June 9.
A man then attempted to grab her arm and began touching her inappropriately.
He also made lewd comments and when challenged by the victim became verbally abusive, before getting off at Ilford station at 5.15pm.
DC Hatcher said: “We will not tolerate any form of unwanted sexual behaviour on the rail network and are determined to find the man who carried out this assault.
“This incident occurred on a busy train, and I would be interested in speaking to anyone who witnessed what took place.”
Anyone with information is asked to contact British Transport Police on 0800 40 50 40.
Information can be passed anonymously to Crimestoppers on 0800 555 111.