An air ambulance, road ambulance, three paramedics’ cars and a fire engine were called to Ashenground Park after a girl fell from a tree at about 7.30pm on Tuesday (August 18).
A South East Coast Ambulance spokesman said an 11-year-old girl fell from a height of about 20ft and fractured both her wrists.
She was treated at the scene before being taken, by road, to the Royal Sussex County Hospital, in Brighton.
An eye witness said many residents went to see what the commotion was all about.
He said: “I’ve never seen anything like it in all the years I’ve been here.”