A female commuter chased a thug down a Tube platform after he allegedly threatened and assaulted an unsuspecting passenger.

Footage shared online shows a bald man punching an Asian man in the face on a train at Upton Park in an apparent random attack.

As the attacker flees, a woman sitting next to the victim leaps from her seat and gives chase down the length of the platform.

The video, which has been shared on social media, was brought to the attention of police who confirmed they are investigating.

The incident took place at around 3:40pm on Monday, 17 October.

The British Transport Police said the footage was being studied as part of “an ongoing investigation" and that it could not comment further.

Outraged social media users condemned the attack but questioned what prompted the altercation in the firts place, and why it was being filmed.

One tweeter wrote: “Despicable but seems more to the story. No one films videos of other people randomly.” Another described the attacker’s behaviour as “disgusting”.

Police later said a 33-year-old man has been arrested in connection with the incident after officers were made aware of the video.

The man was arrested on suspicion of "assault occasioning actual bodily harm and using threatening or abusive words/behaviour or disorderly behaviour likely to cause harrassment, alarm or distress".

He has been bailed until November 14.

Do you know the woman in the footage? Contact our news desk on 0203 6152500 or news@standard.co.uk