This is the shocking moment when a fist fight broke out on a busy commuter train in an alleged row over face masks.
The confrontation happened in front of terrified passengers as the train approached Streatham Common station in south London.
Witnesses say the pair came to blows after the man in the yellow jacket was challenged over his lack of a face covering.
Face coverings are now mandatory on public transport across England and those who refuse to wear them face an on-the-spot fine of up to £100.
The clip shows the pair squaring up to each other with the man in the yellow jacket telling him to "get off at Streatham Common".
As they separate, the other man says: "You've got a problem with me, you are looking at me, I asked you the question."
During the confrontation, the man in the yellow jacket is seen to point to a woman who he tells to "shut the f*** up as well".
The exchange appears to simmer down as the man in the blue jacket sits down but continue to trade insults.
But the fist fight breaks out when the man in the blue jacket is kicked in the hands.
He stands up while the man in the yellow jacket says "go on, go on".
Horrified train passengers beg the men to break up the confrontation to no avail.
The pair are then seen wrestling to the ground as one passenger vainly attempts to separate them.
Police have confirmed they are investigating the incident but say no arrests have yet been made.
A BTP spokesperson said: "British Transport Police is aware of a video circulating on social media of a fight which occurred on a train near Streatham Common railway station.
"The incident was reported to the police at 5.53pm on 27/07."
Anyone who recognises the men in the video can contact BTP by texting 61016 and quoting reference 395 of 27/07/20.
