“In sooth I know not why I am so sad” is one of the best opening lines of all drama, let alone Shakespeare, but director Edward Hall replaces it with a transposition of a later line, “Which is the Christian, and which the Jew?” to make a point about racial tension: the antagonists, merchant Antonio and moneylender Shylock, step forward to the front of the stage.

Hall’s all-male Propeller company is in Kingston this week with a revival of their delightful A Midsummer Night’s Dream and this powerful new production of The Merchant, moving on to Rome and a two-month residency at the Watermill, Newbury; in May they decamp to New York and Milan before returning to Cheltenham, Salford and Oxford in June.

Why is The Merchant, designed by Michael Pavelka, set in a prison of clanking bars and grey-suited inmates, functional chairs and tables and two mobile cages? Portia is imprisoned by her dead father’s insistence on a trial by suitors choosing between gold, silver and lead. And Shylock’s daughter, Jessica, will escape her domestic life by deceit and disguising her sex; just as Portia and Nerissa help out Bassanio (Antonio’s friend, Portia’s lover) by going to Venice disguised as lawyers.

By not wasting time on creating a silly fictional world for the play, Hall and his company get right down to brass tacks: there’s a wonderful simplicity about the prison inmates adopting their roles within the disciplines of slopping out and doing press-ups and the pervasive masculinity of the environment highlights the romantic developments, too.

Richard Clothier’s Shylock may not hit the heights as a stage villain, but he certainly defines the quality of mercy around him, bearded and vindictive, just as Bob Barrett’s flagrantly decent Antonio, squeezing out his lines between bars, is a feather blown by misfortune. Jon Trenchard’s splendid Jessica is a gaol bird jail bait who motors the plot in a way I’d not experienced before: Richard Dempsey’s Lorenzo is not only a lynchpin lover but a key witness to the Belmont beatitudes.

The prison of the play condemns the characters to making their escape, and that’s the beauty of the metaphor, the search for justice in love and commerce held in the uneasy equilibrium of revelatory gender-bending role-playing. Kelsey Brookfield and Chris Myles are excellent as Portia and Nerissa in high heels, camp corsets and butch braces, while Jack Tarlton’s well-felt Bassanio and Richard Frame’s butch but subtle Gratiano make free within the constrictions of civil liberty – and prison regulations.

-Michael Coveney