The Wyvern Theatre was evacuated earlier tonight causing confusion among theatregoers.
It is reported that an alarm went off in the building after 9pm this evening while the audience were watching comedian Ross Noble in a stand-up show.
It turns out the break glass was accidentally activated.
A witness said there was first an invacuation as staff locked audience members inside. He said: "They put a block of wood through the handles to stop anyone from outside the auditorium being able to open them.
"Then we were asked to leave after a while."
The building was evacuated and the crowd stood outside for 10 minutes before being let back in just before 10pm.
A Wyvern Theatre spokeswoman said that the evacuation was quick and that the show continued after.