Footage of English football fans abusing a black man and proudly declaring their racism has gone viral around the world, sparking condemnation and a police search for the perpetrators.
It has also provoked debate about the nature of racism in modern Britain, in both football and politics.
Images caught on a mobile phone in Paris appear to show Chelsea fans preventing a young black man from boarding a train, repeatedly shoving him back on to the platform as he attempts to board, one fan yelling "Chelsea" at his face.
A video grab shows Chelsea football fans packed on to a Paris Metro train pushing a black man to prevent him from boarding. Photo: AFP
The group of white men can then be heard chanting, "We're racist, we're racist and that's the way we like it" in the footage filmed by British expat Paul Nolan and obtained by The Guardian in Britain.
Nolan, a video journalist living in Paris, said he noticed the fans were behaving in an agressive way when he arrived at the station, not allowing people on the train.
"There were threats of beatings. They said they're going to knife someone … and people were clearly very intimidated," Nolan said in an interview with The Washington Post.
The Chelsea v Paris Saint-Germain Champions League match in Paris ended in a draw. Photo: AFP
"We will support any criminal action against those involved in such behaviour, and should evidence point to the involvement of Chelsea season ticket holders or members, the club will take the strongest possible action against them including banning orders."
A Chelsea fan has since claimed the song was actually about current Chelsea captain John Terry, who was once charged by the Football Association for calling a player a "f---ing black c---" and said the fans were pushing the man off the train because it was crowded.
The incident is the latest high profile example of racist harassment by football fans.
A Chelsea fan was banned for life in 2012 for racist slurs at player Didier Drogba. According to the BCC, a Millwall fan was banned for life in 2013 for hurling racist abuse from the stands. In Europe, Spanish football club Villarreal was fined in 2014 after a fan threw bananas at Barcelona player Dani Alves.
Former England footballer Ian Wright challenged Chelsea to take action over the incident and said it reminded him of his own childhood.