A ticket inspector was caught on film exchanging blows with a passenger after allegedly suffering racist abuse.
Before the scrap broke out the train rider was lying completely flat along the seats with his feet on the upholstery, recorder of the footage Marian Hassan said.
The passenger ignored the conductor's requests to move his feet, leading the ticket inspector to push him off the seat, it is alleged.
The video appears to show the pair grabbing each other by the neck and exchanging punches and kicks while other passengers attempt to end the chaos.
A representative from the British Transport Police said the altercation began between the Poplar and Shadwell stations on London's DLR.
The representative said: “Officers from British Transport Police are currently investigating an allegation of assault and a racially aggravated public order offence on board a DLR service.
“The incident happened at approximately 8.45am on 24 November on board a train at Shadwell station.
“No arrests have been made and enquiries continue.
“Officers are aware of footage circulating on social media in relation to this incident, this footage is being reviewed as part of the investigation.
“The victim, a member of rail staff, was not seriously injured."
Anyone who saw what happened, or who has any information, is asked to contact BTP by sending a text to 61016 or by calling 0800 40 50 40 quoting reference 192 of 24/11/2019.
Crimestoppers can be contacted anonymously on 0800 555 111.
A TfL spokesperson said: “We are aware of this incident and are supporting the British Transport Police with their investigation.
"We are providing support for the staff member involved.”
