Police are searching for a group of men who attacked a passenger and left him with a broken nose after he stepped in to stop them harassing a woman on a train.
CCTV images of five men have been released after the assault, which took place around 1am on Thursday 19 December.
The 44-year-old victim from Hornchurch reportedly boarded the 12.32am Liverpool Street to Shenfield station, when he noticed the five men harassing a woman.
Detective Constable Paul Attwell, the investigating officer, said: "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."
After later attending hospital, the victim discovered that he had broken his nose during the attack.
DC Attwell added: "This was a nasty attack on a man returning from a Christmas evening out with friends, and who stepped in to stop a woman who was alone from being harassed."
Anyone with information is asked to contact British Transport Police on 0800 40 50 40 quoting background reference LNA/B5 of 24/12/2013. Information can also be passed to the independent charity Crimestoppers, anonymously, on 0800 555 111.
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