– Detective Constable Paul Attwell, the investigating officer
In order to stop the ordeal, the victim walked over and challenged the men's behaviour, as the woman was alone at the time.
As a result he was attacked by the group, who all left the train as it arrived into Seven Kings station.
The victim, stayed on the train and left at Romford, where he reported the incident to police.
A passenger who tried to stop 5 men harassing a woman who was travelling alone on a train has been attacked and left with a broken nose.
Police have released CCTV images of five men they are trying to find.