One outstanding performance made this new staging of Monteverdi's 1643 opera, The Coronation of Poppea, just about worthwhile: the veteran bass Robert Lloyd, who has not sung with English National Opera for 30 years, gave a first class account of Seneca, the philosopher, who slits his wrists and dies in a bath at Emperor Nero's bidding.

Never mind that Lloyd had to wear green wellies and push a lawnmower in true Roman Stoic fashion. It was that kind of an event.

The Chinese director and choreographer Chen Shi-Zheng, who staged Monteverdi's Orfeo for the company last year, has returned with another baffling enterprise in which the Indonesian Orange Blossom Dance Company shimmy and jive at any opportunity, appearing when you don't need them like the Policeman's Chorus or the Spanish Inquisition. At times they turn into benthic beauties, scampering across the sea floor.

Unaccountably, in Walt Spangler's design, the action takes place underwater, which may be deeply Freudian for Monteverdi's sexiest opera but this is open to debate. At the end they become dragonflies.

A snorkeller flip-flops across the stage on a harness. Liquid video imagery attracts attention when you long for stillness. Ottavia (Doreen Curran) travels everywhere by white pumpkin, a seasonal gesture perhaps.

Elizabeth Caitlin Ward's costumes, witty, opalescent and translucent up-to-the-minute creations, are one of the evening's strong points.

Cheerful to report, ENO has pulled together a strong cast of highly promising young British singers, including Lucy Crowe and Tim Mead, elegantly conducted from the harpsichord by Laurence Cummings.

The problem was that they all seemed to be in the wrong roles, with none really bringing Monteverdi's spellbinding, and outrageously immoral last opera alive. All were made to strip off (most of) their kit, which they did nicely if repetitively.

As Poppea, Kate Royal has a pretty voice and managed to look hazily and enviably like Liz Hurley modelling her latest line of beachwear. But the full depravity and allure of Nero's mistress - described by Tacitus as having "every asset except goodness" - as yet eludes her.

As a gamine Nerone, Anna Grevelius showed huge talent, even though the casting was not ideal, and works better sung by a man. A five-strong continuo, lucky to be on dry land, made some of the loveliest, most sensuous sounds of the evening.

Until 6 November. Information: 0870 145 0200. (BBC Radio 3, 10 November).