The Westminster City Council's 12-month investigation revealed that Nimax was not in a breach of current laws and that the collapse was a result of the "age of the structure."

London theatre owners have, however, been called upon to instate more rigorous inspections of their buildings. All of the West End theatres have undergone detailed inspections since the incident at the Apollo.

"This has been one of the most thorough investigations of its type, and our main aim now is to ensure that an accident like the one at the Apollo never happens again. Simply put, the onus needs to change – experts and owners need to prove that structures are safe, rather than not prove they are unsafe. We have worked with all the theatres over the last 12 months and have been encouraged by the way they have proactively engaged with us following the shocking events of last year," Westminster City Council member Nickie Aiken said in a statement.

Some 88 people were injured Dec. 19, 2013, when a part of the theatre's ceiling collapsed during the middle of a near-sell-out performance of The Curious Incident of the Dog in the Night-time.

Witnesses reported hearing a "strange crackling" noise prior to the "entire dome roof" of the Apollo Theatre collapsing onto patrons below. Many in the audience initially believed the noise was part of the performance. The Apollo Theatre, which opened in 1901, is located on Shaftesbury Avenue in London's West End. The theatre is owned and operated by Nimax Theatres and has 775 seats over four levels. Nimax also owns and operates London's Lyric, Garrick, Duchess and Vaudeville theatres.

"I welcome the conclusion of the Westminster investigation, which confirms it was a terrible accident. Not a day has passed where I do not think about every single audience member, the cast and staff present on that December evening," said Nimax executive Nica Burns.

It is reported that 132 people have reported compensation claims following the incident.