Nick Harding from London Fire Brigade said the audience at the Apollo Theatre were walking around in a dazed condition after the ceiling collapsed.
The Kingsland Fire Station manager said, "People were in a lot of shock ... a lot of them had head injuries and other injuries so it was quite a confused scene."
More top news
A painting by artist LS Lowry is to go on show to the public for the first time.
Migrants trying to get to Britain made a mass attempt to break into entrance to the Channel Tunnel near Calais in France late Saturday.