A gang of up to 20 youths reportedly followed a teenager through a town centre before filming him being attacked.

Police are investigating the assault, which is said to have happened outside Morrisons in Mill Way, Sittingbourne, at around 4.30pm yesterday (Monday).

One man, who witnessed the violence from his car, shamed the group of "13 to 20" youngsters online who were apparently recording the boy before he was punched in the head twice.

He said "There was a group of kids aged 13 to 16 following him from the Sittingbourne railway station side and they were all recording to obviously post on social media.

"They were tripping him and pushing him until eventually he got pushed over by one of the children and fell to the ground before being punched in the head twice by the same boy."

The witness explained he was unable to get out quick enough as he had his seatbelt on and shopping on his lap, but praised those who came to the boy's aid.

"People acted very swiftly to grab the boy who was assaulted," he said.

"But unfortunately not the boy who assaulted the victim."

He went on to say two women at the scene rang police and asked the victim for his name and address.

He said: "Before anyone says 'this is just kids', I don’t care what anyone says, regardless of age.

"It’s absolutely evil to see what I just saw and I've just got home now and it’s still playing on my mind.

"The boy was absolutely distraught as you can imagine, but I would just like to mention well done to everyone who was involved to act and help the young lad."

A police spokesman said: "Kent Police is investigating a report of an assault which is alleged to have happened at around 4.30pm on Monday, August 8 in Mill Way, Sittingbourne.

"Inquiries are ongoing."