Five fire engines and around 30 firefighters tackled a fire on Portland Place in Marylebone.
Half of a ground floor flat in a six-storey residential block was damaged by fire. Four adults wearing smoke hoods were led to safety from the first and second floors by firefighters wearing breathing apparatus. They were all taken to hospital by London Ambulance Service suffering from smoke inhalation. A further 10 adults and one child left the building before firefighters arrived.
Fire escape hoods provide members of the public with up to 15 minutes protection from four of the main fire gases (carbon monoxide, hydrogen cyanide, hydrogen chloride and acrolein) and can be worn by conscious or unconscious people. If more than 15 minutes protection is required then another hood can be given to each wearer. They do not provide oxygen but temporarily filter toxic smoke to make breathing easier.
The Brigade's 999 Control Officers received five calls about the fire.
The Brigade was called at 0010 and the fire was extinguished by 0152. Crews from Soho, Paddington, Kentish Town and Lambeth fire stations attended the scene.
The fire is being treated as accidental and the most probable cause is a textile that was too close to a lightbulb.
A London Fire Brigade spokesperson said: "Firefighters recommend that you have a look at our online Home Fire Safety Checker to make sure there are no hidden hazards in your home.
“The online tool will ask you a series of questions that will help us work out the level of risk in your home, or the home of someone you care for. It only takes a few minutes to get tailored advice to keep yourself and loved ones safe from fire.”