Police said they were called to Bailey Road, near the M60, shortly before 12:40 a.m. when this was reported by an officer on patrol.
A spokesperson for GMP said: “Following initial investigations, detectives are treating the incident as arson.
“A joint investigation with the Greater Manchester Fire and Rescue Service is underway.
“No arrests were made. “
Police believe there were no occupants at the site at the time of the fire and no injuries were reported.
Dramatic footage and video footage showed the forecourt on fire as the flames spread between the cars and the building.
Smoke could be seen billowing through Stockport from a distance as the blaze took hold.
Strange images taken in the aftermath of the fire showed that a number of luxury cars had been completely destroyed.
The side of the building behind was charred with smoke.
The Greater Manchester Fire and Rescue Service tweeted about the blaze in the early hours of the morning, saying: ‘Our crews are currently facing a fire in an industrial area on Bailey Road, Stockport.
“Local residents are advised to keep doors and windows closed.
“Please avoid the area while our crews respond to this incident. ”
They then tweeted an update saying, “Our crews have worked hard to bring this fire under control.
“At its peak, seven fire trucks and a number of support vehicles were present.
“Please continue to avoid the area while crews do damping work.” “