NSW boy's leg broken in muck-up day prank

A 13-year-old boy has had his leg broken on Sydney's northern beaches, reportedly in a muck-up day prank, with an 18-year-old man being charged over the incident.

On Tuesday afternoon a 13-year-old was allegedly tackled to the ground at a Freshwater park by a group of Year 12 students.

The young student was helped by witnesses at the park and taken by paramedics to hospital with a broken leg, police said.

A day later an 18-year-old man handed himself into the local police station where he was charged with reckless wounding causing grievous bodily harm. He will face Manly Local Court next month.

The principal of St Luke's Grammar School, where the 13-year-old is a student, sent an email to parents about the incident and said the school's thoughts were with the seriously injured boy and his family, according to the Manly Daily.