London fire live updates: Blaze engulfs apartment block

London (CNN)Hundreds of firefighters have been working through the night to put out a huge blaze that's engulfed a residential apartment block in West London. Follow here for live updates.

'Cause for optimism'

London Mayor Sadiq Khan has been speaking to Sky News about the number of fatalities and the number of people injured in the fire.

“We’ve got some figures," he said, "but obviously got to make sure we’re sensitive about the news we give out.

“Doing some basic crude maths which is all we can do...you’ll appreciate there are a number of people unaccounted for," he said.

“We’re still at the search and rescue stage, and that gives me some cause for optimism."

He was also asked if there was any update on the cause of the fire.

“At this stage, our focus has to be search and rescue," Mayor Khan said, "but there are very legitimate questions people are asking. I’ll do my best to make sure we get an answer to these questions because they are legitimate questions we all have."