Doing up Gilbert and Sullivan can be a perilous occupation, as the recent over-pleased-with-itself camp rendition of The Gondoliers proved at the ENO (losing all the freshness and primary-coloured vitality of Martin Duncan’s original production at Chichester in 2003). But if any serious “rot” set in, it was with the rocked-up overhaul of The Pirates of Penzance at the Public Theater in New York a quarter of a century ago.

That delightful version, starring Kevin Kline as the pirate king, became a West End hit and a fairly good film. Now the Orange Tree has given house room to Chris Monks’s modern re-setting, where supposedly Baywatch meets Reservoir Dogs, first seen at the New Victoria, Newcastle-under-Lyme, ten years ago. It is an almost wholly successful transposition and in these intimate surroundings one has the rare pleasure of hearing the voices “un-miked” and accompanied by just a keyboard and a violin (expert work by Simon Pickering and Rachel Steadman).

Frederic (beautifully played and sung by the light tenor-voiced Stephen Carlile), the pirate apprentice in a pink tutu, has only known one woman, his nursemaid Ruth (Julie Jupp in middle-aged Barbara Windsor mode, tight miniskirt and leopardskin boots). The Major-General’s daughters abseil down the cardboard rocks in sports gear and leotards to do their callisthenics and aerobics. The pirates in black suits and shades pounce on their prey. Frederic is enchanted by the odd fish Mabel (Philippa Stanton in dowdy tweeds and serious spectacles) and the action prosecuted by the Major General (Alan McMahon) who emerges from the sea in a diving suit and flippers and is camping out on the beach in a tiny tent.

No Gilbert and Sullivan is funnier, nor more melodically fecund, than Pirates, and Monks’s production does it proud, with some witty updates for the Major General’s big patter number (he was a quarter-finalist on Mastermind and a script writer on Coronation Street) and maximum mileage on the central pronunciation mix up over “orphan” and “often.” Frederic, the leap year baby, will not reach maturity in 1940 but in 2060. And the cadre of night police, doubled by the girls and the pirates (“Tarantara, tarantara”), wear green security boiler suits, posing a triple threat of truncheons, torches and mobile phones.

Frederic’s spurning of Ruth is turned into a nasty manoeuvre by the desperate pathos of Julie Jupp’s performance and the satire on “duty” easily assimilated in the cod Mafiosi context, with Craig Purnell as an athletic pirate king with a fine sense of absurdity. Mabel’s sisters are a sexy little trio of Louisa McCarthy, Catherine Le Brun and Elen Rhys, and the pirates and policemen feature notable contributions from the nifty Nick Haverson and the looming bass Ben Crowe. Musical comedy, operatic bravura, lyrical extravagance, sustained and interweaving choral lines: the score has the lot, and Monks’s production, instead of being over-cosy or annoyingly twee, which it could easily have been, is in fact a small-scale triumph.

- Michael Coveney