BTP officers are today releasing a CCTV image after a man was attacked for challenging sexual harassment on a London Overground train.
The incident happened between 5am and 6.30am on Sunday 16 June between Whitechapel and Hoxton stations.
Two men are reported to have harassed and sexually touched two women. When a passenger challenged their behaviour he was assaulted.
The victim, aged in his 30s, was taken to a local hospital. He has since been released.
The suspects left the train at Hoxton station.
Officers believe the men in the images may have information that could help their investigation.
Anyone with information is asked to contact BTP by texting 61016 or by calling 0800 40 50 40 and quoting reference 82 of 16/06/19.
Alternatively call Crimestoppers anonymously on 0800 555 111.