At least 40 firefighters fight a fire in an apartment above a shop on a busy main street.
Videos and photos taken by witnesses show a room full of flames as smoke streams through an open window into the air.
Six fire trucks and dozens of firefighters were called to fight the inferno on Camden High Street in northern London.
The entire apartment on the first floor was on fire.
There were more than two dozen calls at 999 at the height of the fire, which broke just before 1pm.
Did you experience the fire? E-mail to firstname.lastname@example.org.
It was not known if anyone was in the building when the fire broke out.
The cause of the fire is unknown.
Witness John Burr said he saw the fire when the first firefighters arrived at the scene.
He said to Mirror Online: "The smoke was rising, the fire department had just left, they took out their hoses and did their thing.
"It seemed to spread [into the next room], "
An ambulance crew was on site.
Mr Burr said the builders worked on the ground floor and removed the roof on Wednesday.
There was no indication that the fire was related to the work.
A spokesman for the London Fire Department said, "Six fire trucks and about 40 firefighters were called to fire in an apartment above a shop on Camden High Street.
"The entire first-floor apartment is on fire, and the Brigade's 999 control officers have answered 26 calls to report the fire.
"The brigade was called at 12:56.
"Firefighters from Euston, Kentish Town, Soho and Holloway are on site.
"The cause of the fire is currently unknown."