In many respects I would describe Mustafa as a thriller, a whodunit, for it’s a play in which the fate of a prisoner rests on whether key characters are able to come to a conclusion which means, like a Holmesian deduction, the impossible is possible.

Naylah Ahmed's play questions our belief systems of the known and the unknown, the seen and the unseen, and whether powers and forces beyond our understanding and experiences exist. For Len (a superbly naturalistic Paul McClearly), the older warder, it is something he cannot accept or come to terms with; he refuses to step outside the security of “what I know. What I can see hear, witness ... All the other stuff, it’s just smoke and mirrors.” But is it?

Mustafa is in prison following the death of a boy during an exorcism, and in an isolation cell because of an incident in the dining hall in which another prisoner was injured. Munir Khairdin’s calm, controlled performance contrasts well with that of Ryan Early’s brilliant, brash young goading prison officer Dan, who is forced to face his own inadequacies and insecurities.

The solicitor, putting together the case for an appeal, turns out to be Mustafa’s estranged older brother, and we get insights into their upbringing and separation, where one has disowned his heritage “to fit in” whilst the other has kept faith.

Colin Falconer’s simple caged set and Tim Mitchell’s low level lighting, in the confines of the upper space at the Soho, serve to increase the intensity of the piece, creating a claustrophobic atmosphere in which both actors and audience are participatory players.

This is a compelling and engaging production, delicately directed by Janet Steel, of Ahmed’s poignantly profound and insightful piece for the Kali theatre company, which champions female Asian writers.

- Dave Jordan