Fire investigators are confident the cause of the blaze at a block of apartments near Leamington last week was an electrical fault.
The fire ripped through Blackdown Hall in Sandy Lane last Wednesday afternoon causing extensive damage to the former stately home.
Many of the flats were affected with residents having to evacuate to a shelter set up at North Leamington School nearby.
A Warwickshire Fire and Rescue Service spokesman said: “Following the investigation we have determined the most probable cause for the Blackdown Hall fire as an electrical fault in one of the flats.
“The reason we are using the word ‘probable’ is because given the severity of the damage in the area where we have determined the fire started there is little residue left and we cannot be 100 per cent certain of the exact origin but fire investigators are confident it was electrical.”
Gary Phillips, deputy chief fire officer for the fire and rescue service said the damage would have been reduced had sprinklers been fitted in the building.
He said: “I continue to be dismayed that government, planners and developers do not see the benefit of fire sprinkler systems which if installed in the flats would have prevented significant damage and turmoil for the residents
“I have spoken many times of the benefit of sprinklers in residential properties and I sincerely hope that during the repairs the building owner considers their installation so this doesn’t happen again. “
More than 50 firefighters tackled the blaze.