To the power of three

Stephen Oliver defied tradition and set his opera trilogy in the London Transport Museum.

Site specific works are the ne plus ultra of contemporary art. The Covent Garden Festival has long been interested in moving beyond the confines of traditional venues so it came as no surprise on Friday to begin an evening of work by Stephen Oliver at one of the country's lesser- known opera houses, the London Transport Museum. Why? Because Commuting, receiving its posthumous world premiere, is set in a railway carriage.

Sitting between trams bound for Greenwich, Stratford and New Cross Gate, the first thing you notice is that there is no orchestra. It's hardly cause for raised eyebrows in a choral work, but opera? Not content with abandoning accompaniment, Oliver also did away with conventional text. Yet Commuting, the comic tale of a meeting between a thief and a fence on a crowded train, is as fully characterised and dramatic as the wordiest settings.

The four members of the hugely versatile Cantabile double and cross-dress as 12 characters ranging from medallion man to vicar to horsewoman using Christopher Woods's costumes and a vast palette of vocal mannerisms and melismas. Oliver writes repeated, idiosyncratic patterns of sound, which are highly suggestive of character through rhythm or shape. When the vicar passes round a collecting box with a rising, upward inflexion, you don't know precisely what he's saying, but you understand. Likewise the expressive, inquisitive yodelling of a Swiss tourist. At its height, he wittily blends the voices into a thoroughly Brittenesque threnody, complete with wailing child.

As they say on all good cookery programmes, it's something he had prepared earlier. The Waiter's Revenge - an absurd fable for six voices and director - dates from 1976 and packs food, sex, hierarchy, hangovers and customer hell into half an hour. Set in a ritzy restaurant, which ends up with rat poison on the menu, the opera was served up in this instance in a plush, marble-pillared room beneath the Theatre Museum.

Once again, Oliver disproves the notion that the 20th-century musical idiom is limited to expressions of angst and dislocation. Simon Callow's zinger of a production found every last laugh in this perfectly constructed mini-opera, aided and abetted by his cast's acting as well as their virtuoso technique. Cantabile were joined by Katherine Steffan and Sophie Grimmer but the show was well and truly stolen by Paul Hull's hilariously arch head-waiter getting more than is humanly possible from the seemingly banal phrase "Pe-de-de-de-de-deh".

Ricercare Number 4, an elaborate four-voice setting in the form of theme, chorale and variations, to a text by the emperor Hadrian, was commissioned by Callow on the death of his lover. Individual voices - notably Morgan Crowley's floating counter-tenor - pull against the texture, resolving into rich, unsuspected cadences. Hisses and dying falls punctuate flowing sustained passages, interleaved with writing of eloquent simplicity reminiscent of Maxwell Davies's richly expressive O Magnum Mysterium. Sung by candlelight, the performance was a moving valediction to a talent lost to Aids, years before his time.