In Simon Gray's 1981 play, set in the staff room of a Cambridge language school in the early 1960s, the troubled 14-year-old daughter of a member of staff is disturbed by the appalling notion that you can't prove that other people exist. "Perhaps when we thought about them or remembered them, or saw and heard them even, we were actually just making them up."
Out of the mouths of babes. The terrible point of Gray's play is that the surface bonhomie of staff-room life only thinly disguises the fact that none of the people give a toss about each other; they have no emotional reality for each other. None of them can get the name of the new teacher right, even after he has been there a year.
The disintegrating St John Quartermaine, suffering increasingly from short-term memory loss, is the potent symbol of all that is rotten in this staff room. Not only does he fail to register the answers to his inane pleasantries, but he becomes more ghost-like himself as the play continues. At one point, it appears that he may have spent the entire half-term holiday sitting in a staff-room chair. When he is finally banished from the room, it is clear his absence will barely be noticed. Cruelty is easy if you don't think people really exist.
Gray's play is not quite a tragedy, more a clear-eyed and rather demoralising account of the failings of the human heart. It has an almost Chekhovian delicacy that is occasionally realised in this production, although perhaps its troubled characters are too repulsively self-obsessed to trouble us very much. The play evokes a melancholy at the failure of human relationships and our inability to really communicate with each other, rather than real pain at that most terrible of human states: an inability to love or be loved.
It doesn't help that the well-acted production sometimes conspires to make the play seem old-fashioned rather than in period. None the less, this is an honourable and compulsively fascinating evening that disproves the notion that Gray is merely a witty chronicler of mid-century, middle-class life.
· Until Saturday. Box office: 01604 624811. Then touring.