A suspicious fire has destroyed a derelict former Melbourne primary school turned squatters' den.
The blaze engulfed the old Clayton Primary School on Browns Road on Saturday afternoon, collapsing the central structure of the building, and forcing firefighters to approach the fire from the outside only.
Crews also had to take extra precautions because the primary school contained old asbestos.
Flames spread to the old oval, putting several houses in Moriah Street under threat.
Extra MFB crews were called in, stopping any damage to homes.
The school has been empty since being sold be the Education Department and is a known spot for squatters, the MFB says in a statement.
A search by firefighters of the school did not find anyone inside.
The cause of the fire has been deemed suspicious and Victoria Police have been notified.
CLAYTON SCHOOL FIRE:
Rescue units: 1
Aerial units: 1
Breathing apparatus support: 1