A woman has been filmed chasing a man who brutally attacked an Asian passenger on the London tube in what is being described as a racist attack.
The mobile phone footage shows a white male approach a young man and punching him in the face.
A woman sitting beside the young man immediately jumps up and chases the man out of the train.
She can be heard yelling for someone to call the police.
British Transport Police say a suspect has been arrested following the incident, which occurred at the Upton Park station on Tuesday.
"A 33-year-old man has been arrested on suspicion of assault occasioning ABH and using threatening, abusive words, behaviour or disorderly behaviour likely to cause harassment, alarm or distress," police say.
The footage was uploaded to Twitter by the Muslim Council.