Even by the standards of decadent Roman emperors, the career of Marcus Aurelius Antoninus – known to history, through his worship of the Sun, as Heliogabalus – is an especially shocking one. Edward Gibbon describes how he “abandoned himself to the grossest pleasures with ungoverned fury”. What they? Gibbon declines to sully Decline and Fall...by telling, only saying “their inexpressible infamy surpasses that of any age or country”.

A depiction of the life of this libertine, then, is likely to prove hot stuff – which, indeed, Francesco Cavalli’s Eliogabalo did and does (well, in a sense).

Composed for Venice and published in 1668, it is not thought to have been performed until ten years ago. Its initial neglect clearly arose less from its salacious content for its own sake as from the comparison that might have been drawn between the antics on stage and those of the corrupt state of La Serenissima.

The production at Grange Park is the UK premiere of the work and of obvious interest for this reason alone. Whether it will go on to enjoy revivals in the future seems unlikely in the light of its unthrilling musical content and a plot of labyrinthine complexity.

True, there are passages of great beauty, particularly those involving Julia Riley, in the ‘breeches role’ of Alessandro Cesare, who is destined to be the next emperor. There is excellent work, too, from a trio of leading ladies (Claire Booth, Yvette Bonner and Sinead Campbell-Wallace) as, respectively, Eliogabalo’s girlfriend, and two of Alessandro’s admirers.

Unfortunately, it all too often seems that as soon as a good tune gets going, complete with plangent accompaniment on gamba, sackbut and other period instruments (conductor Christian Curnyn), the music is cut short in its tracks.

As for the story, I read director/designer David Fielding’s programme synopsis three times without fully absorbing it. Without surtitles we’d be utterly lost in an opera where the title role is played by a woman (Renata Pokupic) dressed as a man but (given Eliogabalo’s kink) sometimes as a woman, his blowsy female nurse is a deep-voiced man in drag (Tom Walker) who has a moustachied ‘gay clone’ biker boyfriend (Joao Fernandes) and spends much of the time camping it up with the emperor’s male squeeze Zotico (Ashley Catling), and the butchest bloke on stage – apart from the gladiator Tiferne (Francisco Javier Borda, pictured above) – is a combat-jacketed soldier sung by a counter-tenor (James Laing).

There are further performances of Eliogabalo on June 21 and 26 and July 2 and 5. Box office: 01962 73 73 66 (www.grangeparkopera.co.uk).