From the opening bars of David Price’s urgent rock score to the full cast’s capering at the play’s end (in what now appears to have become a firm Stratford tradition), the Swan’s new production of Measure for Measure is a constant delight. A Shakespeare play often thought difficult to stage proves a winner this time under director Roxana Silbert, with a rich vein of dark humour and, indeed, plenty more of the knockabout variety.

The production’s tone is set chiefly in the performance — part as comedian, part conjuror — of Raymond Coulthard as that very peculiar gentleman, Duke Vincentio. He it is who departs (allegedly) from his Viennese fiefdom leaving power in the hands of his agent Angelo (Jamie Ballard). This humourless martinet decides to revive laws against pre-marital sex and sentences to death young Claudio (Mark Quartley) who has got his fiancée Juliet (Sarah Ovens) with child.

But the Duke hasn’t gone away at all. He is creeping around disguised as a friar proving himself to be truly the “old fantastical duke of dark corners” that the wonderful comic character Lucio (Paul Chahidi) calls him. From the shadows he observes as the hypocrite Angelo responds to the pleas for mercy from the condemned man’s sister, soon-to-be-nun Isabella (Jodie McNee), by offering a reprieve if she will sleep with him.

Having escaped that fate through a subtle plan cooked up by the duke, the postulant embraces one perhaps worse by agreeing to marry her saviour. Clearly much into sado-masochism to judge by his leathers and the like, he might be supposed, too, to be more interested in boys than girls. What delicious archness Mr Coulthard injects into the utterance as Lucio is told: “I never heard the absent duke much detected for women; he was not inclined that way.”

By then, of course, Vincentio is firmly in his disguise and obliged to endure a character assassination on himself gleefully supplied by Lucio. The comic device proves so funny that Shakespeare treats us to it for a second time.

Scarcely less amusing are the antics of Elbow (Ian Midlane), another of the Bard’s word-mangling constables, and the low-life characters Pompey (Joseph Kloska) and Mistress Overdone (Annette McLaughlin).

Measure for Measure continues until March 10, 2012. Box office 0844 800 1114 (www.rsc.org.uk)