Police officers, the London Fire Brigade and the London Ambulance Service are now at the scene. More than 200 people live in the block.
At least two people have been injured and flats at the 24-storey Grenfell Tower evacuated.
Police and Fire Brigade personell rushed to the scene as dramatic pictures emerged on social media showing the flames licking up the side of the block.
Metropolitan Police report evacuations are now underway. We await an update as to whether there are any further injuries.More news: MP CM Shivraj Singh Chouhan Ends 'Fast For Peace' After 28 Hours
More news: No longer out of bounds: Trump allies question Mueller probe
More news: Rafael Nadal : Player eyes 10th French Open with injury misery in mind
It said cordons were in place and advised that the estate and surrounding area were to be avoided.
More than 200 firefighters are battling a giant blaze in a high-rise tower block in West London.
"The fire is getting a lot worse, there is a lot of smoke, it is out of control".
Reo, who lives about 300 metres away from the building, was in his kitchen when the fire erupted.