Fire crews assisted police after a children's slide was set alight at park in Lewes on Friday.
East Sussex Fire and Rescue Service said it was called at 6.15pm to reports of a fire at Landport Park.
A spokesman said: "Police were in attendance when we arrived. A play frame in the park was alight.
"A user had set fire to a slide and crews extinguished it."
More information when we have it.