According to multiple reports, police rescue workers are responding to a partial balcony or ceiling collapse at the Apollo Theater in the West End of London. According to eyewitnesses, an undetermined number of people were trapped inside and there numerous injuries. London Ambulance said that it treated 88 patients following the collapse, seven of them serious enough to require hospitalization. There are no reports of fatalities, and the cause of the collapse is unclear.

According to the London Fire Brigade, all the trapped audience members at the theater have since been freed. 

According to the BBC, audience members heard a "crackling" noise before the collapse in the crowded theater, during a performance of "A Curious Incident Of The Dog in the Night-time," at about 8:15 p.m. London time. 

Jess Bowie, an editor at House Magazine, was in he audience. Shortly after the collapse Bowie tweeted, "Was just seeing 'The Curious Incident' in the West End when the roof of the Apollo Theatre caved in. Absolutely petrifying. Don't know if anyone is trapped in there but people outside are covered in dust and some in blood. Utterly horrible." 

The Apollo theatre first opened its doors in 1901, and has a capacity of 775 people. According to a London-based reporter for NBC News, tonight's performance was sold out

We'll have more on this developing story as it becomes available.