Two teenagers have been arrested after a video of a boy being punched in the face and then mocked was shared on social media.
The 30-second clip showing four youths in woodland was shared to Facebook group Pure Banter on Monday night and subsequently taken down.
In the video, a boy in a grey hoodie is punched in the head with such force that he slams to the ground, as he talks to someone on a mobile phone.
One of the boys is heard saying "Knocked him out bruv" as the victim struggles to get up before another youth in a black tracksuit hits him for a second time - this time in the face sending him hurtling to the floor.
Another voice is heard saying: "Leave him on the floor, leave him. Don't stamp on him."
The camera then moves closer to the victim as a voice is heard saying: "Why you crying on the floor bruv?" before he is kicked again.
The video was also shared on various other Facebook pages sparking several thousand comments from appalled viewers.
Tracy Lawrence wrote on Britain's F***ed: "OMG - I'm shocked and feel sick - I have a son the same age!! This is someone's son!!"
Anita Marriott added: "What's wrong with kids today? Something needs to be done before it goes too far!!"
Police confirmed two 17-year-olds were arrested on suspicion of assault, one on Sunday September 25 and another on Monday September 26, after an incident in Raphael Park, Romford, Essex, on July 21. They have been bailed until late November.
A Metropolitan Police spokesman said: "The victim was taken to hospital for treatment at the time of the incident and subsequently discharged."
Anyone with information can contact police via 101 or Crimestoppers anonymously on 0800 555 111.