Duke Vincentio of Vienna, as presented in Measure for Measure, has to be the least appealing hero in any of Shakespeare's plays. Off he goes on his travels (supposed), leaving the city to be governed by his coldly efficient deputy Angelo (Adam Newsome). This prudish popinjay decides to revive long-dormant laws against sexual licence, and promptly sentences Claudio (Richard Neale) to death for having made his fiancée pregnant out of wedlock. Urged to plead for the life of her brother, the novice nun Isabella (Amy Stacy) discovers that he can be saved - but only if she submits to Angelo's sexual demands.

So how is the duke at fault in all this? Well, he hasn't actually left Vienna at all, but is creeping around disguised as a friar - well does the waggish Lucio (Alexander Caine) call him "the old fantastical Duke of dark corners" - and observing all this corruption at close hand. Though it is obviously in his power to stop it, he allows the dreadful drama to proceed, even to the extent of letting Isabella to believe her poor brother dead. And when the whole thing eventually pans out happily, 'happiness' in Isabella's case is understood by him to be achievable only by her disregarding the religious vows she has held firm to throughout - and consenting to marry him.

A very odd attitude to marriage is a feature of this play. Punishment, for Angelo, comes in the form of his being forced to the altar with the fiancée (Caroline Devlin) he shamefully dumped after her dowry disappeared at sea. And Lucio is ordered to wed a prostitute as his penalty for the aforementioned (and other) disobliging remarks about the duke that had been delivered - in a hugely enjoyable scene - to the mighty man himself during his monkish masquerade.

Hugely enjoyable, in fact, is the whole of this latest production by Creation Theatre Company, which sees them for the first time in the atmospheric setting of Summertown's North Wall theatre. This converted Victorian swimming pool, part of St Edward's School, proves an ideal venue for this dark-hued drama, with its bare redbrick walls, subtly and deftly lit by Ashley Bale. The prison scenes are exceptionally well-managed, with gloomy recesses and sliding constructions of metal bars that suggest - somewhat Fidelio-like - the evil of wrongful imprisonment. The cold efficiency of the chief turnkey (Lucy-Anne Holmes) adds to this effect.

The play's main message - that our self-proclaimed moral guardians are often the biggest lechers - emerges loud and clear, with all the lucidity we have come to expect from Creation. It is a message, of course, that hardly needs underlining in the month of the Eliot Spitzer prostitution scandal in the US, and any number of similar indulgences by members of our ruling class.

This gripping and excellently acted production continues until April 12. I recommend it highly.