The charred remains of in the staff car park at prison have been towed away as police hunt the arsonists.
The two vehicles, a white Audi and a red Volvo, were engulfed in flames at the high security prison in Glasgow at around 6pm on Wednesday night.
The melted cars were removed from the scene by a recovery vehicle just hours later.
Both motors were completely gutted by the flames, with the Audi's front wing melting away under the intense heat.
Police and officers cordoned off the car park last night.
Footage obtained by the Daily Record shows multiple cars on fire as thick smoke billows across the car park.
Cheers and screaming can be heard from inmates inside of the prison building.
A source said: “I’m at Barlinnie car park and somebody has set fire to some cars.
“Both cars on fire, and all the cons are watching out the window cheering. All the spectators."
Fire crews were dispatched to the scene to extinguish the flames.
Police Scotland confirmed they are investigating the blaze.
A spokesperson for the force said: "We were called to Barlinnie prison around 6pm on Wednesday evening, where two cars were found to be on fire.
"This incident is being treated as wilful fire-raising.
"Enquiries are ongoing."
A Scottish Prison Service spokesperson confirmed no one had been injured in the incident.
The Scottish Fire and Rescue Service has been contacted for comment.
