Graham Vick is not a scorched-earth director - the kind who napalms a piece with ideology, leaving nothing behind but the debris of the assault - but he is a reductivist, with a reputation for stagings that clear away the marginalia of convention and return to first principles. Above all, he's a master of straightforward story-telling; and the good thing about his new Fidelio at ENO is that it's a paragon of clarity. The set may be conceptual, the costumes 20th-century, but the presentation is so beautifully transparent that you'd have to be one of the intellectual walking-wounded not to follow it.

The not-so-good thing, though, is that the first principle to which this Fidelio returns is, I think, the wrong one. It plays on a stage completely bare but for a massive wooden cross - initially laid flat, then tilted up toward the audience to reveal the prisoners' chorus lying, like bodies in a mass grave, underneath. The message, unequivocally, is that this is an opera about death and resurrection. But it isn't. Salvation, certainly, comes into it: Fidelio, after all, is a rescue opera modelled on the many French Revolutionary stage-works inspired by the storming of the Bastille. It celebrates the triumph of conscience over tyranny, the heroism in the souls of ordinary men and women; and its themes are brotherhood, hope, struggle - especially struggle, which breaks out in a sweat from so much of the music.

But salvation by the cross? I think not. The final chorus may address God, but no serious reading of the text could take that as more than embellishment. Salvation here comes from a human hand; and the problem with Vick's Fidelio is that, under the persistent shadow of that cross, the humanistic focus of the opera is eclipsed. For all the determined vernacular of David Pountney's new English translation, the characters are pallid, dead (so much for resurrection), and succumb to the all-too-accessible vice of Fidelio: dullness. It's not that things move slowly - far from it: the pace is fast, with pared-down dialogue - but that they feel so thin. You never feel the weight, the struggle, the encompassing of the heroic. Even the spectacle of the tilting cross is tame by comparison with the similar effect in Francesca Zambello's Billy Budd last year at Covent Garden.

The compensation is that Richard Hickox's conducting is not dull, and apart from some first-night lapses of ensemble it was an exhilarating, vital and effective reading: proof that Hickox's considerable abilities don't just suit English repertory. There's also forceful chorus singing and fine if not ideally cast principals in Mary Plazas, Gwynne Howell, Anthony Rolfe Johnson and Kathryn Harries. But overall this new Fidelio feels lightweight, too simplistically committed to the wrong goal. Expectations for it ran high: Vick and Hickox seemed a strong team. In the event, only Hickox really delivers.

Conductors have been to the fore at all levels this week, starting with the very modest Opera Inside Out: a little company based in Newbury whose work - strong on design and casting - I've admired before. It does things conservatively but well, and its latest offering is a Don Giovanni with two sopranos - Sharon Fleetwood-Law and Sidonie Winter - who would be a credit to any national company. On the opening night, though, there were problems - caused partly by the decision to poke an interval into the second act, with some attendant juggling of the standard aria placement, partly by some unfortunate wigs (Ottavio's looked like a dead sheep) and partly by general First Night gremlins. It could have gone horribly wrong but didn't - thanks largely to the calm, unruffled and extremely musical sang-froid of the conductor Gerry Cornelius, who strikes me as a newcomer of promise. A good bet for something like Wexford and, in the future, for the Donatella Flick Conducting Competition, whose fourth season culminated on Thursday with a glittering finals concert at the Barbican. None of the three finalists - all in their 30s - struck me a major star, and there are undoubtedly better, younger talents around. The problem is that the Daniel Hardings of this world have little to gain and much to lose by entering a venture like the Flick; and what hope is there of coaxing a good performance from an orchestra which, in fairness to the competitors, is going to do as they direct and no more? The band in question here, the LSO, wasn't allowing itself the licence to play well, to fall back on its own experience. But that said, the winner, Tommaso Placidi, deserved his prize. He was the only finalist who seemed to be making something happen on the platform, and the only one with a real sense of line.

Meanwhile, in the upper reaches of the profession, Michael Tilson Thomas returned to the LSO last Sunday with a relishable programme of Stravinsky and Ravel at the Barbican, and a slight shock to the ears. Six months into its new relationship with Colin Davies, the LSO has naturally been adjusting itself to his personality and tastes which come steeped - as anyone who has followed the recent LSO Bruckner cycle will know - in European classical tradition: placid, reasoned, eloquently questing for the grail of an upholstered string sound. But for MTT the orchestra switched back into its former mode of dazzling, upfront, transatlantic virtuosity: especially in the Ravel, where Jean-Yves Thibaudet made a camp but brilliant soloist in the Left Hand Piano Concerto - all fire and steel and technical agility - and the second Daphnis and Chloe suite came so saturated in glamour you could smell it.

Broomhill, the avowedly unglamorous country-house opera establishment in Kent, has been touring on both sides of the Channel a community music- theatre adaptation of the Chester Mystery Plays with a massive, amateur cast of Belgians, French and English. I saw it in a sports hall in a village outside Lille and was astonished by how good the makeshift music was (MD Charles Hazelwood), how the direction (by Mark Dornford-May, who, like the Newbury Ottavio, has a winning way with dead sheep), and how powerful the performances. The text was polyglot, each player using his own language, but seamlessly delivered; Lucifer was a woman, Jesus a Belgian Arab, God a small French boy of mesmerising presence (a perfect Puck for Britten's Midsummer Night's Dream); and the sheer perversity of it all was pleasure enough. But it was also deeply touching. Humbling too, in that the French and Belgians were so much better actor/singers than the Brits.

'Fidelio': ENO (0181 632 8300), Wed & Fri.