Scottish Opera's new Die Fledermaus is the sort of show that never quite decides what to make of itself but survives the uncertainty. From its bright-red plastic front-drop, overprinted with Sixties BBC-style typography, it promises something like the post-modern debunk of the last ENO Fledermaus where Richard Jones took his revenge on Viennese Gemutlichkeit with home movies of cuddly kittens and Fenella Fielding making apfelstrudel. But no. When the curtain rose on Wednesday's first night in Glasgow it revealed a mischievously tasteless but essentially straightforward set, half-way between a Glasgow brothel and an Ideal Home exhibit. Act II had a gardening theme, and only Act III made reference to the bright-red plastic, which turned into Governor Frank's gaol. Not very obviously.

What the director Giles Havergal and his designer Kenny Miller are up to here I'm not sure. But one bravely unequivocal move they make is to dump Frosch, the drunken gaoler who normally appears at the start of Act III to bore the audience insensible with stand- up jokes. In the true spirit of comic relief all this is gone, and Acts II and III run seamlessly together - and very much the better for it.

Overall, I've seen more stylish Fledermause and more stylish casts; but Scottish Opera's has a West End swank that works perfectly well with the voices and personalities to hand. Lisa Milne is the star, with a tough, Glaswegian take on Adele that made riotous work of the dialogue and comes with enough coloratura to make the singing lively too. Peter Evans has a nice line in bounderish vulnerability as Eisenstein. And Janis Kelly plays Rosalinda like a suburban Marschallin, engagingly complete with feather. Nicholas Braithwaite, conducting at Scottish Opera for the first time, doesn't tease the rhythms enough - there could be more of that echt- Viennese holding back on the start of a phrase so that the release a few bars later comes with more of a surge - but if you don't mind your Strauss under-indulged it's a pleasurable performance with plenty to commend it.

The bad news currently at Covent Garden is that there is only one new production in its core season. The good news is that the near-unbroken run of revivals are in many cases cast at top strength; and the Lohengrin which opened last weekend is a prime example. Elijah Moshinsky's clean, unbusy but intense production, with its white-box set and fetishistic Christian totems gives you all the German Romantic context you need without smothering the singers - who accordingly get plenty of free space to fill with focused, well-projected characterisations.

And what singers they are. Dame Gwyneth Jones's yodelling Ortrud takes some tolerance, but it comes with terrifying power: nobody messes with this sorceress. Rene Papp's Heinrich is loaded with tone and dignity. Sergei Leiferkus puts his Russian snarl and dry, acerbic vocal elegance to admirable use as Telramund. Gosta Winbergh's Lohengrin is true and firm with barely a hint of tiring through the long span of the role.

Karita Mattila's Elsa shows her at a new, all-conquering stage of her career. Mattila has been prominent on the world opera circuit ever since she won the Cardiff Singer competition in 1983. But there's a sense in which she has been biding her time through a carefully paced progress from lighter to heavier lyric roles; and for all the pleasure they have brought, the real breakthrough came only last year when she scaled up to the challenge of Elisabeth in the Paris/Covent Garden Don Carlos and stole the show from Roberto Alagna. Wagner had to be the next step; and here she is, easing into the lyric borderland of that repertory fully equipped for all it asks. With Elsas in San Francisco and Paris behind her, she takes the role at Covent Garden in her stride: fresh-voiced but with full body in the tone, tender but strong. To hear her is to catch that radiant moment when an art comes suddenly alive; and it comes with loving encouragement from Valery Gergiev, a conductor who knows how to support younger voices and who really makes a difference when he's in the pit. He brings a rare sheen to the string sound, lustre to the woodwind, and a night of memorable musicianship to Covent Garden's easing-into- closure season. If you can't get to see it, there's a Radio 3 broadcast on 19 March.

That Carmen and Trial By Jury were written in the same year, 1875, is an accident of history no stage director would want to make anything of. You'd think. But the Carmen which has been playing at the Albert Hall this week is pure D'Oyly Carte: an English provincial romp done cheaply, badly, with a minimal design and less imagination. Perhaps it was naive to expect anything more from this latest Raymond Gubbay stab at stadium opera, but it did promise a credible director in Frank Dunlop, a heavyweight designer in Ralph Koltai, and a heartening dose of spectacle - the raison d'etre of these things and not hard to achieve in Carmen where parades, processions and big chorus numbers come as standard. I was also encouraged by a programme-book feature in which Mr Dunlop said that "people have often missed the point of Bizet's tragedy". Presumably he was about to put us right.

But having seen the show I'm none the wiser - unless the "point" is that Bizet really intended Carmen to be a lifeless piece of nothing with a comic cast whose hands seem to be soldered to their hips. At the very beginning there is the germ of an idea, as children gather on the bare, circular, bullring-reference stage and cheerfully abuse a female doll. But by the time the cigarette girls emerge in their underwear (a misreading of the text), looking like refugees from a Brian Rix farce and pouting till their faces break, the game is up. This is just tabloid camp; and I'm sorry to say it's done in English with amplification so that you hear every excruciating word of it. The spoken dialogue defies description.

In fairness, there are two casts running side by side: perhaps the other one is better. But I had Alan Woodrow struggling with the upper reaches of Don Jose, and a Dutch mezzo called Klara Uleman whose Carmen would have a nice career in English oratorio if she could sort out her intonation problems. Her attempts to sweep us to the hot and sultry south stopped short at Worthing. Pout and all.

Barry Wordsworth conducted the BBC Concert Orchestra with sprightly OK- ness, and if I had to give any laurels to anyone they'd go to Juliet Booth for a decent if robust Micaela. But otherwise this Carmen was a lost cause - about which I wouldn't complain so bitterly but for the way Mr Gubbay, self-appointed scourge of public funding for the arts, offers his projects as paragons of what can be done without subsidy, on a hard commercial basis. If our cultural needs could be satisfied by a conveyor-belt supply of standard repertory sub-standardly performed, he might be right. If, as I hope, we ask for more than that, he's not.

Finally, and far more positively, a note on the pianist Piers Lane whose Thursday-night recital at the Croydon Clocktower produced playing of real calibre: a tour de force of Chopin and Rachmaninov delivered with such substance, brilliance and imagination that you could only wonder why he still hasn't made the quantum leap forward into serious international stardom. Maybe it will come. And maybe the big-name record companies jostling to catch the fall-out from the film Shine will discover that David Helfgott isn't the only Australian who plays Rachmaninov. The Croydon Clocktower is a booming space but comfortable; and this concert was a part of a series in which Lane appears again on 13 March. Worth checking out.

'Die Fledermaus': Glasgow Theatre Royal (0141 332 9000), continues Tues & Thurs. 'Lohengrin': ROH, WC2 (0171 304 4000), continues Mon & Thurs. Piers Lane: Croydon Clocktower (0181 253 1030), 13 Mar.