The English National Opera should have someone at the door on Ernani nights to ask people whether they have seen an opera before and, if they say no, to suggest politely that they come back another day. This is not one for first-timers.
Though based on a Victor Hugo play, the semi-historical plot is very clunky. Emotions succeed each other in compartmentalised fashion, unlikely twists are accepted with not an eyebrow raised - and, more usefully, there are obvious devices to speed our knowledge of the action. In part three, the henchman Don Riccardo takes pains to explain the process of voting in a new Holy Roman Emperor to the Spanish king Don Carlo, a hopeful candidate. "I know," comes the response. Of course, Verdi couldn't be expected to revolutionise opera straight away, but Rigoletto was a long way off.
Ernani is not, then, the kind of work ENO is known for. Yet the company goes at it wholeheartedly, filling the stage with an enlarged chorus in a rainbow of Velasquez-inspired costumes by the late Maria Bjornson. Mysterious hooded figures move reflective black panels around the set, creating spacious rooms or menacing walls. Elijah Moshinsky has returned to revive a staging he created here 25 years ago, last seen in 2000, though there's little evidence of a strong directorial hand; only Alastair Miles fulfils his role's dramatic potential, as a deliciously villainous Silva.
It's the orchestra who can claim much of this opera's best music, and here Mark Shanahan brings a spring to their playing. Apart from Miles, though, the best reason to catch this revival is Cara O'Sullivan, who sings beautifully as the heroine Elvira, every note clear, poised and carefully placed, each word audible. Rhys Meirion in the title role and Ashley Holland as Don Carlo are slightly less polished, but still strong. Oh, to hear them in a better opera.
· In rep until July 2. Box office: 020-7632 8300.
