Four fire engines and around 25 firefighters tackled a flat fire on Oldfield Road in Willesden.
Half of a first-floor flat in a converted terraced house was damaged by fire. Part of the loft space was also damaged by the blaze. Four people left the building before the Brigade arrived.
A London Fire Brigade spokesperson said: “This incident is a reminder of just how important it is to have working smoke alarms in your home. There were no smoke alarms fitted in the property. Instead, the fire was discovered when a neighbour was woken by a crackling sound. Upon investigation they saw smoke and flames coming from the first-floor window. They then made the first of six calls to the Brigade.
“Smoke alarms give the earliest possible warning when a fire starts. We encourage everyone to have smoke alarms fitted in every room where a fire could start, plus a heat alarm in the kitchen. It’s important to test them regularly.”
The Brigade was called at 0612 and the fire was under control by 0829. Fire crews from Park Royal, Willesden, North Kensington and Wembley fire stations attended the scene.
The cause of the fire is under investigation by the Brigade and the Metropolitan Police Service.