Four fire engines and around 25 firefighters were called to a flat fire on Cambridge Gate, near Regent’s Park, in Camden.
Part of a split-level maisonette on the fifth floor of a mid-terraced residential block of flats was damaged by fire. There were no reports of any injuries.
Firefighter Mark Spall, who was at the scene, said: “As we arrived, there were no signs of smoke but there was a strong smell of burning.
“Crews quickly went in and searched the floors of the building and discovered light smoke coming from the top floor.
“We then pulled back a bed in a bedroom of the flat and thick, black smoke came out of an access panel.
“Crews used specialist cutting equipment to gain access behind the wall and part of the ceiling and swiftly brought the fire under control.”
The Brigade was called at 1838 and the fire was under control by 1952. Fire crews from Euston, Soho and Islington fire stations attended the scene.
The cause of the fire is under investigation.