London Mayor Sadiq Khan has declared a "major incident" as a massive fire gutted an entire West London tower block.  Grenfell Tower is reported to be 24 to 27 storeys tall.

London Fire Brigade

"I could hear the people screaming 'help me', and nothing could be done.  The building was too big," said a man who identified himself as an Australian in London named Jodie in an interview with the BBC.  Other residents told the broadcaster that there were no fire alarms, and they were only alerted to the emergency by the screams of neighbors.

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London Fire Brigade

Police said that residents were being evacuated, but it's unclear how many were able to get out.  Some residents gathered in a nearby church community center, as others wandered in shock wearing their nightclothes. 

Flames roared through the tower block in the early morning hours, visible for miles around.  When the sun came up, a column of block smoke rose from the North Kensington community near Notting Hill. 

North Kensington

Disturbing to many witnesses is the speed at which the fire spread.  The first calls came in to the fire department at shortly before 1:00 AM local time.  By the time news crews arrived at 1:30 - 1:45 the building was fully involved.  Smoke continue to pour out as of 6:00 AM.

Late last year, a neighborhood activist organization called the Grenfell Action Group wrote a blog post complaining of what it claims is lax fire safety conditions at the tower:

"There are not and never have been any instructions posted in the Grenfell Tower noticeboard or on individual floor as to how residents should act in event of a fire."

The cause of this fire is unknown and so far there is no indication that the fire is related to the Grenfell Action Group's complaint.