Police are looking for a group of West Ham fans who allegedly started singing “vile” anti-Semitic songs on a first class train carriage.

The men refused to stop their offensive chanting after being challenged by a fellow passenger on the service from Watford Junction to Birmingham New Street, police said.

Detectives today released CCTV images of five men they want to speak to about the incident on August 15.

The chanting allegedly started at about 7pm as the train pulled out of the station and continued until Milton Keynes.

West Ham had played and lost a Premier League match against Leicester City at Upton Park earlier in the day.

Pc Michael Botterill of British Transport Police said: “A man who boarded the train at Watford Junction took his seat in the first class carriage.

“A group of West Ham fans were already seated and, as the train pulled away, they began to sing anti-Semitic songs.

“The man, quite rightly, took offence to these vile songs and challenged the group over their language. However, they refused to stop and continued with their chanting.”

Police received reports from several other witnesses about the behaviour of the men, who are believed to have left the train at Northampton.

Pc Botterill added: “This sort of casual racism has gone unchallenged for too long.

“We know the vast majority of football fans are decent people, but for those who continue to make life unpleasant for the travelling public, our message is clear: we will not tolerate your yobbish behaviour.

“I think the men in the pictures we are issuing today, have information about this incident. Please let us know who they are.”

Anyone with information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference MSUB/B4 of October 12, or phone Crimestoppers anonymously on 0800 555 111.