Four fire engines and around 25 firefighters tackled a fire at a block of offices with dwellings above on Cheshire Street in Shoreditch.
A small part of the basement was damaged by the fire. Three people were rescued by firefighters wearing breathing apparatus. There were no reports of any injuries.
The fire is believed to have been accidental and caused by an electrical fault.
The Brigade was called at 0708 and the incident was over for firefighters at 0922. Firefighters from Bethnal Green, Shoreditch, Shadwell and Dowgate fire stations attended the scene.