Homeowners had to be evacuated after a huge blaze gutted a clothing factory and spread to a neighbouring building.
More than 120 firefighters battled to contain the fire and prevent it from spreading to two other warehouses.
Around 30 people were initially evacuated from their homes but have since been allowed to return as fire crews brought the blaze under control at around 2.20am.
Emergency crews were called at around 9.49pm on Friday to Tottenham, north London, where the fire had already spread through the single-storey building.
A smaller building next to the factory was also gutted and the cause of the fire is being investigated, London Fire Brigade (LFB) said.
The Metropolitan Police said there were no reports of anyone being injured and no arrests had been made.
LFB station manager Bill Dunn who was at the scene said: "When they arrived our crews faced a large, well-developed fire and they worked incredibly hard in what were extremely challenging conditions to successfully prevent it from spreading to two neighbouring warehouses. At its height we had over 100 firefighters at the scene.
"Around 30 people had to be evacuated from homes in the nearby area during the initial stages of the fire as a precaution but they have since been allowed to return."
Images from the scene showed flames emanating from the building in Pretoria Road, a short distance from White Hart Lane.
Eyewitness Mike Wood tweeted: "Pretty big fire just across the road from me in Tottenham. Probably a firework as it seemed to start from the roof."
Firefighters would remain at the scene into the morning to damp down, LFB said.
Road closures were expected to be in place for "some time" due to the scale of the blaze, the Met added.