Apollo theatre: The moment the ceiling collapsed
25 March 2014 Last updated at 19:37 GMT
Seventy-six people were injured when part of the roof came down during a performance of The Curious Incident of The Dog In The Night-Time at the Apollo theatre in December.
The local authority is still carrying out an investigation but has sent a letter to historic theatres in the West End saying the hessian wadding - a type of sackcloth - mixed into the plaster of Paris, had become progressively weak.
Chris Edwards was at the theatre the night it happened, he recalls the sequence of events.