VIDEO footage has emerged of a teenager being punched 20 times in the head on a bus.

In the attack, which lasts about 25 seconds, a teenager launches a vicious assault on another boy on a Brighton bus.

A teenage girl can be heard screaming “get off him, get off him now” as the attacker grabs the victim’s hair and lands blow after the blow in the victim’s face.

The video has been widely shared on social media.

The man, who posted it online, said: “That’s me daughter and her boyfriend being attacked on the number 1 bus.”

The mobile phone footage, which was filmed by a woman, starts with the attacker, who was wearing an adidas bag, walking over to the victim.

The attacker leans over a girl, who was sitting with the victim, before starting to throw punches.

After hitting the victim about 12 times in the head, the victim lands punch back before receiving a number of blows to the face.

The circumstances surrounding the video are not known and Sussex Police said it had not been reported to them.

But the incident is believed to have happened on October 2.

Marie Sansom, from Brighton and Hove Bus Company, said: “We have not been contacted by Sussex Police or by anybody involved, nor has anyone else brought it to our attention.

“As always, we will liaise with the police and offer any help they require.

"I'd encourage the victim or his family to come forward and report this assault to us so we can investigate it"

A leading anti-bullying charity has issued a warning following the video.

A spokeswoman for anti-bullying charity Ditch The Label said: “If you are experiencing bullying, it is never your fault.

“If you need free and confidential advice and support from experienced mentors who know and understand what you are going through, we’re here for you at www.ditchthelabel.org/community.”