Once the only auditorium and later the larger of two spaces at South London Theatre, this 96-seat theatre was of a traditional design with fixed raked seating and view to stage through a proscenium. When Prompt Corner was completed in 1975, it was referred to as the Main Stage, only being named the "Bell Theatre" at a later date.
During the Old Fire Station's redevelopment in 2015-18, the ground floor was extensively remodelled to create a new foyer, demolishing Bell Theatre and Prompt Corner and constructing a new, larger studio theatre in their place.
The stage had a half-height Fly-Loft, with cyclorama that curved in at the stage left end. Behind this were the original fire doors, which were blocked off.
The entrance to Bell Theatre was via the old foyer and the auditorium provided the only audience entrance to Prompt Corner beyond. On stage there were entrances to both Prompt Corner upstage left and the Stage Manager's Room upstage and downstage right.