Six fire engines and around 40 firefighters were called to a flat fire on Harrow Road in Westminster.
Firefighters tackled a fire on the third floor of a terraced building with a shop on the ground floor. One person was rescued by firefighters wearing breathing apparatus, and treated at the scene by London Ambulance Service crews.
The Brigade was called at 1110, and crews from North Kensington, Paddington, West Hampstead and other surrounding fire stations attended the scene. Firefighters had the incident under control by 1137.
The cause of the fire is not known at this stage.