Six fire engines and around 40 firefighters tackled a fire at a vehicle warehouse on Gascoigne Road in Barking.
Three cars were destroyed and part of the ground floor was damaged by the fire. There were no reports of any injuries.
Control Officers took the first of seven calls at 0051 and mobilised crews from East Ham, Plaistow, Poplar and surrounding fire stations to the scene.
The cause of the fire is under investigation.