Four Bristol City football fans are wanted by police in connection with a brawl on a London train taking them to an away match earlier this season.

The group of men were travelling to watch their team play Charlton in an evening match in October when they became involved in a fracas with other passengers.

One of the people who stepped in to try to split up the argument was a senior police officer with the City of London police. He was off-duty at the time.

The incident happened on a Charing Cross to Charlton train shortly after 6.30pm on October 21.

Two other men, both Bristol City fans, have already been arrested, British Transport Police said.

Officers investigating the incident have released CCTV images of the men they want to speak to. They were caught on camera as they left Charlton station. Police have urged anyone who recognises them to contact the investigation team in London.

Detective Constable Colin Saysell, based at Temple Meads railway station, said: "A group of at least six Bristol City fans boarded the crowded 6.34pm Charing Cross to Charlton train on Tuesday, October 21.

"During the journey the group of Bristol City football fans became involved in a public disorder incident.

"We'd like to appeal to members of the public to contact us if they were on that train and witnessed anything, or if they know the identity of those men shown in the photographs."

The game, which kicked off at 7.45pm, ended with Bristol City FC beating Charlton Athletic two-nil.

Bristol City FC is supporting the campaign to identify the fans. A club spokesman said: "We don't condone violence in anyway, whether it be on or off the field, at home or away."

Witnesses, or anyone who recognises the men, should contact British Transport Police by calling 0207 391 5275 and quoting reference number B6/23102008.