Ten fire engines and around 70 firefighters were called to reports of a fire and explosion at a block of flats in Fulbeck Way in Harrow.
A first floor flat and the roof of the affected flat were destroyed by fire. Sadly one woman was found dead at the scene.
Firefighters rescued a man, woman and baby from a second floor flat, which was not involved in the fire, using a 9 metre ladder. They were assessed at the scene before being taken to hospital as a precaution by London Ambulance Service crews.
A cordon was put in place and around 40 people from properties within the block were evacuated as a precaution.
The Brigade was called at 0057 and the fire was under control at 0333. Fire crews from Harrow, Northolt, Stanmore and other surrounding fire stations are at the scene. Firefighters are expected to remain at the scene throughout the day (October 21).
The cause of the fire is under investigation by the Brigade and Metropolitan Police Service.