Operatic villains come in many guises, but Joseph de Rocher, Jake Heggie and Terence McNally’s “dead man walking”, is surely in a league of his own: a convicted rapist and murderer, a coarse, swaggering brute of a man. Even on Death Row, Joe clings to the one thing he can control: refusing to admit his guilt, denying the justice system and his victims’ parents the satisfaction of knowing for sure that they have got their man.

Michael Mayes (Joseph de Rocher)
© Mark Allan | Barbican

In last night’s performance of Dead Man Walking at the Barbican, Michael Mayes was nothing short of sensational. Physically, he looked the part – a big man, the precise image of the casual murderer of your nightmares. The voice matches the size of the man, with giant reserves of power in a baritone of exceptional versatility: Mayes can be gruff, he can be velvet smooth, he can hold a note perfectly in tune when breaking into falsetto. And he produced one of the most credible acting performances you will ever see in opera. You don’t sympathise with Joe – he is far too vile a character for that – but you enter completely into his head. It takes a lot to upstage Joyce DiDonato in full flood, and Mayes did just that.

Not, to be clear, that DiDonato was anything short of her best. She sings Sister Helen Prejean, a nun whose experiences visiting Death Row inmates form the basis of this opera (and the preceding book and film). The pre-concert talk contained a video contribution from Sister Helen, which made it clear that DiDonato has her mannerisms and character traits off pat. We expect little short of vocal perfection from DiDonato and we got that with her usual purity of voice and perfectly weighted phrasing. But we also got character development that made sense, as the young, idealistic nun struggles to make sense of the dark brutishness of the people she is confronted with and to reconcile this both with her faith and with the limits of her own ability to cope.

Joyce DiDonato (Sister Helen), Maria Zifchak (Mrs de Rocher)
© Mark Allan | Barbican

There are strong contributions from everyone in a big cast. Two of the supporting roles stand out: James Creswell is strong and nuanced as the prison warden, Maria Zifchak is heartbreaking as Joe’s mother. All are helped by the quality of Heggie’s vocal writing: his music fits each voice like a finely tailored glove. There are vocal challenges, for sure – you couldn’t sing this without having a full range of operatic skills – but his vocal lines use those skills to achieve emotional effect without ever trying to impress you with the degree of difficulty. Every line flows naturally from the type of voice and the characterisation.

I’m less taken by Heggie’s writing for the orchestra, largely because I prefer sparser orchestrations where I can better hear the colour of individual instruments. The score of Dead Man Walking has an awful lot of tutti and an awful lot of big string writing, augmented by brass en masse rather than as individuals. It’s lovely to listen to a score which is inventive and full or interest while being tonal, at the same time as being modern in its ability to draw from many musical idioms (gospel being the one that’s obviously appropriate to the story, with vintage rock’n’roll putting in the occasional appearance). But although Mark Wigglesworth and the BBC Symphony Orchestra conjured plenty of power and impact from the louder passages, the subtlety of the piece – of which there was a great deal – was coming from the voices, not the orchestra. And that includes both choruses: the BBC Singers were chilling in their impersonation of the jeering prisoners; the Finchley Children’s Music Group providing the contrasting sweetness and light of the convent’s young charges. Leonard Foglia’s adaptation of his full staging for the concert platform was highly effective, with costumes and a few props perfectly able to place you in the action.

Michael Mayes (Joe), James Creswell (George Benton), Joyce DiDonato (Sister Helen)
© Mark Allan | Barbican

But the main point of this opera is to make you think – about crime, punishment, forgiveness, redemption. McNally’s libretto is perfectly paced, and the opera asks more questions than it answers: can we really forgive such appalling crimes? Does it matter if the criminal repents? Even if that repentance only happens in the face of death? What part should vengeance play? The opera forces you to consider your own feelings: it nudges you in the direction of the Christian view that true repentance is the only thing that matters for salvation, but that’s not shoved down your throat.

Given that Dead Man Walking is 18 years old and has met with huge success elsewhere, it’s astonishing that this was its UK première, and it’s a pity that there was only this one performance. Let’s hope there are more soon: it’s a work of intense music drama that deserves to be heard.