A nine-year-old boy has been airlifted to hospital after a piece of playground equipment reportedly collapsed on him.
Police taped off the recreation ground in Cherry Lane, Crawley, following the incident at 1pm today.
Witnesses described four police cars at the scene.
An air ambulance also attended the scene.
A Sussex Police spokesman said: "Emergency services were called at just before 1pm Tuesday to a play area on Cherry Lane, Crawley to a child who had been injured.
"A nine-year-old boy from Crawley had been struck by a pole, part of the playground equipment, and suffered a head injury.
"He has been airlifted to St George's Hospital to be treated. He is in a stable condition. The Health and Safety Executive has been informed."