Arsonists set a bonfire alight last night (Sunday) in Syston a week before it was due to be lit for a public event.
Firefighters from Birstall tackled the blaze, which was started on Fosse Way, at 9.48pm.
Leicestershire Fire and Rescue Service said it was believed the fire was started deliberately.
A spokesperson said: “The initial caller stated that someone had lit a bonfire mound prepared for an organised event.
“Fire crews advised that one large bonfire, measuring 20 metres by 20 metres, was involved in fire.
“One compressed air foam system branch was in use to protect the surrounding area and a large amount of tyres had been found within the bonfire and were removed.
“Our crews attempted to salvage unburnt wood for the planned bonfire on November 5.”
The bonfire was allowed to burn out overnight and the fire service carried out an inspection this morning to ensure it was no longer smoking.