Police have made a third arrest after shocking footage emerged online of a boy being attacked by a gang in an east London park.

Video footage shows the alleged victim, 15, being surrounded by a group of boys before he is floored twice by blows to the head in Raphael Park, Romford.

Two boys, aged 17, were arrested on Sunday and Monday in connection with the assault.

Police said a third teenage boy, also 17, was arrested on Wednesday and taken into custody at an east London police station.

At the beginning of the video, the alleged victim can be seen talking on a mobile phone as the other boys listen and one mentions “getting money tonight”.

He is then punched and knocked to the ground before one of the group can be heard saying: “You knocked him out bruv.”

Another boy tells the group not to kick him and to leave him lying on the ground.

The alleged victim then staggers to his feet before he is flattened by another punch.

He lies on the floor sobbing, while one of the boys says: “Why are you crying on the floor bruv?”

The boy is then kicked in the side before the video ends.

He was taken to hospital for treatment after the attack but has since been discharged, police said.

The two teenagers arrested on Sunday and Monday have been bailed to attend an east London police station in late November, while the third boy remains in custody.

Officers are appealing for anyone who has information about the attack on July 21 to come forward.

Anyone with information can contact police via 101 or Crimestoppers anonymously on 0800 555111.