An electrical fault is believed to have sparked a fire which turned an ambulance on a 999 call into a fireball.
It is the initial finding of investigators who are trying to work out what caused the vehicle to burst into flames yesterday morning.
The alarm was raised in Flash Lane, Trent Vale, at 3.40am on Monday, April 6.
A Staffordshire Fire and Rescue Service spokesman said: “Crews discovered the front cab of the ambulance alight. Two firefighters wearing breathing apparatus used a hose-reel jet to extinguish the blaze.
“An investigation is underway. At this time we believe the blaze may have been caused by an electrical fault.”
Paramedics had been treating a patient inside a property on Flash Lane when the ambulance caught fire. West Midlands Ambulance Service says all of its 999 vehicles are less than five years old.
An ambulance service spokesman said: “We are continuing to carry out an internal investigation into the root cause of the fire. We can confirm that the ambulance was destroyed in the fire.”