A huge fire has engulfed a tower block in Latimer Road, west London, with eyewitnesses claiming people are trapped in their homes.
The fire at Grenfell Tower on the Lancaster West Estate was reported at 01:16 BST and about 200 firefighters are tackling the blaze.
The Metropolitan Police said “an evacuation process is under way”.
The BBC’s Andy Moore said the whole tower block was alight and there are fears the building might collapse.
London Fire Brigade sent 40 fire engines to the tower.
Eyewitnesses said they could see lights – thought to be torches – flashing at the top of the block of flats, which people say is “close to burning through”.
Image caption Forty fire engines and 200 firefighters are tackling the blaze
George Clarke, the presenter of Channel 4 TV programme Amazing Spaces, told Radio 5 Live: “I’m getting covered in ash, that’s how bad it is.
“I’m 100 metres away and I’m absolutely covered in ash.
“It’s so heartbreaking, I’ve seen someone flashing their torches at the top level and they obviously can’t get out.”
Tim Downey, another eyewitness, told the BBC part of the building was “completely burned away”.
“It has burned through to its very core,” he said.
“It looks very bad, very very bad. I’ve never seen anything like this. It’s just such a big fire.
“The whole building is just crumbling. It’s just billowing black smoke.”