The bus which was parked in Duke’s Mound, Brighton, caught fire at 8.30pm due to an electrical fault. It took an hour for the fire brigade to put out the fire.
One of the homeless men, Wayne Holmes, was the one to sound the alarm after trying to put out the fire with a fire extinguisher.
He said: “I smelled the smoke, ran upstairs, grabbed a fire extinguisher, and squirted it. I realised it was an impossible job so ran back down and called the fire brigade.”
The bus was damaged considerably by the accidental fire and Sussex Homeless Support have said it will take many months to repair.