The Factory

The guard is only an actor, of course. But he's brandishing a metal bar so it makes sense to shut up, move, and face forward as per his barked command.

From behind us, two very loud bangs and a woman 's scream. People flinch, but before long we'll be accustomed to both sounds.

Badac Theatre Company's uncompromising production, staged in the underground caverns beneath the Pleasance, is not a ghost tour.

It's not about cheap scares, nor is it about whispered poetry or especially profound insights into human fear, panic and despair.

It is an invitation to re-trace the final steps of Holocaust victims and surrender to a sense of overwhelming sadness. Think carefully about whether you want to experience it, and don't even think of booking tickets for another show starting straight after it.

The dialogue is simple and repetitive, as are the meaningless physical tasks undertaken by a worker with a crumpled face and haunted eyes who is close to breaking point after sending hundreds to their deaths.

To call the production 'promenade' seems wholly inappropriate, evoking as it does a leisurely guided stroll. The audience is ordered from room to room, eventually filing into a confined space from which it is clear that three actors will not be walking.

They are only acting, of course. But they are also naked and covered in sweat, dirt and snot. Their loss of dignity does not feel artificial, and when they begin to sing the Israeli national anthem ' proudly, defiantly, urgently ' the scale of the suffering they represent becomes overwhelming.