Residents at a block of flats in Ruislip were evacuated in the early hours after a fire broke out at around 4:20am.
London Fire Brigade sent eight fire engines and around sixty firefighters to a fire at a block of flats on Pembroke Road in Ruislip.
Part of a balcony at a seventh floor flat was destroyed by fire, the brigade confirmed.
Fire crews were was called at 4:26am and the fire was under control by 6:16am.
Fire crews from Ruislip, Hillingdon, Harrow, Northolt, Wembley, Southall and surrounding fire stations were in attendance.
The cause of the fire is under investigation.