"OH, THE FLOGGING and the misery," sings the flogged and miserable Novice in Act I of Billy Budd. "I can't stand any more." There have always been critics of Britten's opera who would say the same: who find its sadomasochistic subtext of desire distorted into malice all too much, its pretext of a head-on conflict between good and evil all too thin.

For me, though, Budd is one of the great works of lyric theatre. Its torrential confluence of beauty, power and anguish leaves me on my knees. And after the first night of Welsh National Opera's lacerating new production last weekend, I wasn't the only member of the audience to feel like crawling out into the streets of Cardiff. It was that good.

Directed by an Australian, Neil Armfield, the production owes something to Francesca Zambello's Covent Garden Budd. The design is abstract, everything stripped bare (including the flogged Novice), with a central platform on hydraulics that moves to the motion of imaginary waves, cantilevering up to create above- and below-decks tableaux for the big chorus numbers. Armfield's theatre aims directly for the gut. But with a sensitivity too, that is less absorbed than some productions by the idea of Vere and Claggart struggling to possess the boy: a tug-of-love that certainly exists, but can distract from other issues.

In this Budd, the Billy isn't such an obvious object of desire. So the focus shifts toward power, justice and conscience, with Captain Vere as the central character. And what a stunning Vere Nigel Robson is, on outstanding dramatic and vocal form. WNO do the revised two-act version of the opera so you don't get the muster scene that establishes Vere's credentials as a leader of men. But Robson unequivocally delivers the authority as well as the humanity of the role.

And he comes as close as anyone I've known to absolute conviction in the final scene. Billy has "saved" him, sings the Captain. From what? It doesn't bear the scrutiny of logic. But with Robson, I really could believe he had been saved from something, if only self-contempt. Here was a man of honour, crushed by conscience but restored by love.

Vocally, the find of this Budd is Phillip Ens, the young Canadian bass of chilling presence who sings Claggart. Against such competition, Christopher Maltmann's Billy (winner of the Lieder prize in last Year's Cardiff Singer competition) doesn't quite claim the centrality he should. But it's a fine voice, if a touch tight. And he moves well: agile and alive on stage.

As for the conducting, Andrew Litton is a star. He goes for big sound, with the brass perhaps too in-your-face for comfort. But the raw, brute dynamism of this reading is electro-chemical. And when was comfort ever relevant to Billy Budd?

There was more Britten in London, with a new, student-cast Albert Herring directed by Mike Ashman at the Royal College of Music. It was modest and a mite slow, and its young artists flapped around rather - a common temptation in comic opera. But I enjoyed the singing from the (second) cast I heard: Damien Thantry a model of Anglican ineffectualness as the vicar, Miranda Keys a fiercely well-articulated Lady Billows, and Alfred Boe (who didn't flap) a touching Albert.

Maurizio Pollini is a living lesson in how not to flap. His playing has unwavering focus - to the point, exact - and his Chopin/Debussy recital at the RFH last week raised the usual question of whether he doesn't draw the emotional parameters of his art too narrowly. But there's no keener mind, no finer technique to be heard among the world's great pianists; and it's heartening that so cerebral an artist pulls so big an audience. The hall was full for this recital, the response ecstatic.

The supreme event in London, though, has been the settling of an old score. So to speak. Sixty-five years ago, the BBC commissioned a symphony from Edward Elgar - to be his third - and never got it. Death intervened, and the fragmentary sketches for the piece became museum objects, protected from any attempt at completion by the composer's family and by a general belief that they were, in any case, unperformable.

But as mounties get their man in the end, so the BBC, ever mindful of its duty to the licence-payer, gets its music. And last Sunday at the RFH, the BBC Symphony Orchestra gave the 60-years-late world premiere of the sketches, "elaborated" (such is the agreed term) into a complete work by the latter-day composer Anthony Payne.

As high-profile a project as I can remember in the world of British music, this "elaboration" raises three important questions. Is it right to complete the work of a dead composer against what seem to have been his wishes? Is the result authentic? And, quite separately, is it any good?

The moral question is debatable. But the fact remains that there are plenty of precedents for a post-mortem completion (Mahler's 10th, Berg's Lulu, Puccini's Turandot), and the test has to be whether the end result is worthy of the composer's name. In this case, the result is a handsome and substantial score (in every sense, at nearly 60 minutes' length) and a magnificent achievement for Anthony Payne which, ironically, will bring him fame beyond the possibility of anything he's ever written in his own right.

As for authenticity, it sounds convincing, even though the material has largely been assembled, Frankenstein-like, from discarded flesh. Elgar left some 130 pages of manuscript. But in many cases, the ideas are little more than chord progressions, with no marking as to where (in which movement, even) they belong. So Payne was reduced to guesswork, and a fair amount of from-scratch composition. Paradoxically, the only music that sounds out of character is straight from Elgar's pen: the opening of the first- movement exposition, of which Elgar completed some 17 bars in full orchestral score. It's how we know the kind of sound he wanted - big and spare. But the musical material is odd: raw fifths and fourths in brazen parallel. Your ear says: how can this be Elgar? But it is, and pretty startling too.

The scherzo isn't as impressive: lightweight, Spanish Lady stuff. But the adagio is darkly powerful, with a haunting solo-viola close. And the finale is where Payne's invention gets truly tested. After a pomp-and- circumstantial start and a handsome tune, Elgar's manuscript jottings stop, leaving no idea of how the piece is to finish.

Payne's solution is masterful, resolving on a definitive C-minor pedal that leaves no doubt of the symphony's tonal centre. As Andrew Davis brought his baton down on those concluding bars, there was an sense not just of having heard a fine performance - the BBCSO in muscular good form - but of having opened up a time capsule. This has to be the last Romantic symphony to reach an audience: there won't be any more. It is the freakish coda to a finished culture: grandly melancholic, and a fond farewell.

'Budd': Cardiff New (01222 878889), Tues, & touring.