Ten fire engines and around 70 firefighters were called to a fire at a block of flats on Bath Street in Islington.
Part of a split-level flat on the 16th and 17th floor of a 20-storey block was damaged by the fire. One woman was treated at the scene for smoke inhalation by London Ambulance Service crews. A further 50 people left the block before the Brigade arrived.
Station Commander Keith Carmichael, who was at the scene, said: "There was a lot of thick smoke issuing from the building when crews arrived, which prompted a high number of calls to our 999 Control Officers.
"Our aerial ladder from Soho Fire Station was used initially to tackle the blaze from the outside as crews made their way up to the fire floor inside."
The Brigade's 999 Control Officers took 15 calls to the fire.
The Brigade was called at 1739 and the fire was under control by 1906. Fire crews from Shoreditch, Whitechapel, Dowgate, Islington, Bethnal Green, Soho and surrounding fire stations were at the scene.
The Brigade's fire investigators believe the fire was accidental but the exact cause has been recorded as undetermined.