Black/White, The Basement at Bristol Old Vic, Bristol

At first glance, Black/White looks unpromising. Irish priests, paedophilia and whiskey – the unholy trinity that seem to sum up the Catholic Church as it enters its second millennium – can be an awful subject matter if it gets into the wrong hands. The end product can all too easily be sententious, sensationalist or sentimental: cheap tabloid theatre with cardboard cut-outs played for tears or kicks.

So what's a promising young writer like Sharon Clark doing with a topic which threatens to throw her straight into the dumpster of history with all the other mediocre wannabe playwrights who can't get beyond today's headlines? Well actually, she's showing exactly what it is that sets her apart from the pack of also-rans. She takes these themes and delivers a piece which brims with humanity, reality and wit. Which turns its title around to show that the Catholic Church's attempts to cover up the wrongdoings of "its own" are far from the black and white issue which they may first appear. And which demonstrates that even the classic whiskey-sodden priest can be depicted as far more than a coagulation of Bushmillls and Hail Marys.

The strength of Black/White lies in the fact that Clark has created fully-rounded characters who live in a morally ambivalent universe. The rebel priest whose approach to Catholicism appears to owe more to liberation theology than strict Papal obedience, the good Catholic boy with a vocation and the corporatist bishop striving to cover up the paedophilic tendencies of a recently deceased priest could so easily be ciphers marched around on stage like puppets to deliver the playwright's message. Instead, Clark manages to paint each of them in multifarious shades of grey, a mottled collage of good and bad, just like people in the real world.

Like its characters, Black/White is not perfect. It takes a few minutes to shake off its self-consciousness and settle into its narrative groove, but that does little to detract from its ultimate strength and engaging sense of realism. The writing is complemented by acting of a standard which goes far beyond what one would usually expect of cheap and cheerful lunchtime theatre. The director Joyce Branagh and the actors John Telfer, Dan Winter and Cornelius Garrett, have worked hard to ensure that these characters are believable and true to life.

There are times when a play is totally unsuited to its venue. Black/White is such a play. This production should not be confined to a converted cellar in the bowels of the Bristol Old Vic, with a tiny lunchtime and early evening audience forgoing a quick drink for a bit of bite-sized culture. It should be on a proper stage, attracting real audiences and rave reviews. It should be making Top Five lists. One can only hope that a far-sighted producer will have seen the gem hidden in the Old Vic's Basement, and will bring it out into the light for everyone to enjoy.

Ends tonight (0117-987 7877)