A young boy was pulled to safety from the rubble after the upstairs floor of a bar collapsed on punters.
The mezzanine at Two More Years came crashing down at 4.45pm on Saturday, injuring 13 people.
Customers were sent into chaos with some of those who narrowly escaped the collapse desperately searching through the debris to rescue those who did not.
Footage filmed seconds after the floor caved in shows staff running around in their efforts to manage the situation, while punters are heard screaming and crying in panic.
Dozens of people are seen trying to heave giant pieces of wood off from others lying on the floor - while others cling onto any surface they can find.
One man appears to pull a child from the rubble of the collapsed ceiling.
Meanwhile, a witness recalled seeing a man carried out of the building on a stretcher and put into an ambulance.
A major incident was declared by the London Ambulance Service who were in attendance along with the London Fire Brigade and the Met Police.
A total 13 people were hurt in the tragedy, with three said to have "potentially serious" injuries.
Four were rushed to hospital.
One customer told how he and his friend ran to the side as the floor "came down in seconds".
"There was just this sort of cracking sort of noise and dust started coming down,'" he added.
"Me and my friend just ran to the side and the whole thing just came down in a matter of seconds."
He added it was lucky that there were not more people sitting directly under the mezzanine floor that came down.
Emergency services were called to the pub at 4.44pm on Saturday.
Another witness who was in the pub at the time told MyLondon : "I was sitting at the table for one to two hours drinking beer for myself only then suddenly the platform collapsed.
"I saw every second of that. It happened so fast, maximum five to six seconds the venue collapsed, everyone screaming and yelling
"I was just looking to that side and I saw everything clearly"
