The stair is the company's oldest employee: genuine 1908 fabric, walked at full weight by policy, creaking in F sharp. It has appeared in more Nightjar dramas than any performer and holds a contract clause to that effect.
Care rules, in order of importance: never oil it, never rehearse a careful footstep, and never ask it to creak on cue. It responds to weather, dread, and the kettle.
When it was threatened with replacement in 1974, the board received four hundred letters and one live goat. The stair stayed. The goat stayed too; see Voices.