A total of 20 fire engines and some 125 firefighters were at the scene to tackle the flames of the building in Worcester Park
A major blaze broke out at a four-story block of flats in south-west London in the early hours of Monday.
A total of 20 fire engines and some 125 firefighters were at the scene to tackle the flames of the building in Worcester Park, reports BBC.
The fire brigade's 999 control officers had taken 29 calls about the fire and engines were sent out around 1.30am.
The cause of the fire is not yet known and no injuries have been reported.
"The whole of the four storey building is alight," the London Fire Brigade said in a tweet.
Graham Adams, from London Fire Brigade, said: "This is a challenging fire and firefighters are working hard to bring the blaze under control.
"Firefighters will remain on scene for a number of hours and we would urge people to avoid the area if possible."
London Ambulance Service said: "We sent an incident response officer, an ambulance crew, two medics in cars and our hazardous area response team.
"We have not treated any patients; however we remain on the scene as a precaution."