Three men had a knife fight on a Tube platform as shocked passengers watched on in horror.
One of them was seen lying on the ground.
A youth – in a black hoodie – then kicked him four times in the head.
The third – in a grey tracksuit – was seen standing over him.
Cops – who are investigating – said the shocking brawl involved knives.
It happened at Colliers Wood Underground station, in south London.

One passenger on a Tube filmed the brutal scenes on their mobile phone.
A man can be heard saying: “Oi oi.”
A woman added: “That is unacceptable.”
Londoners reacted in horror at the violence , as reported on Need To Know
Jemima Lavender said: “This actually made me sad.
Donna Trainor added: “Someone’s son lying there and no one helped.”
Another said: “I lived in Colliers Wood in 2004.
“It was such a nice area.”

One fumed: “Animals.”

A British Transport Police spokesperson said: “Officers attended Colliers Wood Underground station following reports at 10.30am on 17 December of a fight between three young men involving knives.
“A man in his 20s was arrested at the station on suspicion of possessing an offensive weapon.
“He has been taken to hospital with injuries that are not thought to be life-threatening or life-changing.
“Enquiries are ongoing, and anyone who has information or witnessed the incident is asked to contact BTP by texting 61016 or by calling 0800 40 50 40, quoting reference 211 of 17 December.”