The teacher-pupil relationship offers rich pickings for playwrights because of its peculiar imbalance of inequalities: age versus youth; innocence versus experience;. Russell and Mamet tackle these complex reciprocities in markedly different ways, and this is not just a matter of temperament but because English academe in the late Seventies is a different world from its American equivalent in the late Eighties.
Grown jaded and disillusioned in his safely tenured job, Russell's don can only see what is unspoilt and instinctive in Rita - the bright, motor- mouth hairdresser, not the woman who hungers to be able to make informed choices about her life. He questions the value of higher education for her essentially because he has lost belief in himself. Sweating on a tenure decision that a student, in an age of insane political correctness, can easily jeopardise, Mamet's academic functions in a society where higher education has become, in his phrase, the "virtual warehousing" of the young.
Both plays are about power but, as these finely focused productions illustrate, Oleanna is narrow and thrillingly single-minded, whereas Educating Rita is large-spirited and hearteningly supple. Mamet shows us how a student who is out of her depth uses a false charge of rape to shoot the swimming instructor (so to speak). The power relation, as she perceives it, is simply inverted: the humiliated becomes the humiliator. Russell's play, with more room for manoeuvre, is keenly alive to the sadness at the heart of teaching, a process that ideally involves empowering people not to need you any more.
Richard Lumley offers a compelling portrait in the Mamet of an almost neurotically ordered man fighting to retain self-control. There's not enough pain or warmth in his other performance, nor sufficient sense of an alcoholic's self-disgust. Carolyn Backhouse is splendid in both, whether projecting the humour and hunger of Rita or the burning-eyed dogmatism that becomes the American student's defence against failure.
Church's production of Oleanna is surely inflected and swifter than Harold Pinter's premiere staging of the piece. With the audience on either side of Ruari Murchison's triangular set, there's an almost claustrophobic feel. A shame that the don's bookshelves in Educating Rita look more Oxfam that Oxford. But that's a small quibble. Do go; it's an education.
n To 13 April. Booking: 01722 320333