The ceiling of a packed London theatre has collapsed on the audience during a performance, wounding more than 88 people including children and leaving terrified theatregoers covered in blood and dust.

The incident happened at the Apollo Theatre during the West End show The Curious Incident of the Dog in the Night-time and comes the week before Christmas when London’s theatres are traditionally busy.

Witnesses heard creaking noises in the 112-year-old theatre before the collapse but thought it was part of the show, before a section of the ceiling collapsed and brought down parts of the balconies.

Rescuers commandeered a red London double decker bus to transport some of the wounded to hospital.

Emergency services said that they did not believe there were any fatalities and that all those trapped after the incident had now been freed.

“We have treated 81 walking wounded and seven more seriously injured patients at the Apollo Theatre incident,” London Ambulance Service said in a statement.

There were around 720 people in the audience at the time, the London Fire Brigade said.

“A section of the theatre’s ceiling collapsed onto the audience who were watching the show. The ceiling took parts of the balconies down with it,” senior firefighter Nick Harding said.

“In my time as a fire officer I’ve never seen an incident like this. I imagine lots of people were out enjoying the show in the run-up to Christmas.”

The London Fire Brigades Union said that an “ornate ceiling of plaster and wooden supports collapsed”.

Several people were stretchered away from the scene.

Others including some with bandages on their heads were being treated in the lobby of the nearby Queen’s Theatre, where the musical Les Miserables was showing, which had been turned into a triage centre.

Desmond Thomas, 18, part of a school party watching the show, said they heard noises before the accident.

“Maybe 10 minutes into the performance we heard a tap-tap noise, we thought it was rain,” he said.

“There was a crack and then it suddenly seemed to get bigger and suddenly it collapsed. The next thing we knew the whole theatre filled with dust and smoke.”

A thunderstorm had hit London in the hour before the incident.

A red London bus took several casualties including a child to hospital afterwards.

London hospitals said they were on major incident footing.

Pictures on social media showed people fleeing the theatre with head injuries and covered in dust.

Simon Usborne, a writer for the Independent newspaper, said there was a “cloud” of dust obscuring the stage after parts of masonry appeared to fall away.

“There was panic, there was screaming,” he said.

Martin Bostock said he suffered a head injury after he was hit by falling debris.

“It was complete chaos in the theatre. Absolutely terrifying and awful,” he told Britain’s Sky News.

“I was in the lower stalls with my family in the early stages of the show.

“I think the front part of the balcony fell down. At first we thought it was part of the show.

“Then I got hit on the head.

“We got out with cuts and bruises. I think most people did.”