Iolanta, Opera Holland Park London<br />La Gioconda, Opera Holland Park, London<br />BBC Proms (1,6 and 14), Albert Hall/Cadogan Hall, London

It was an afterthought for Tchaikovsky, but his 'Iolanta' has been reworked as a gripping sexual psychodrama

Commissioned as a companion piece to The Nutcracker and saddled with a lopsided libretto, Tchaikovsky's Iolanta was premiered in the same year as Maeterlinck's Pelléas et Mélisande. History has judged the opera with pettish condescension; applauding its bewitching orchestration while dismissing the vocal writing as uneven. Ostensibly a fanciful, even fey work, a thing of its own century and not the next, it is, in Annilese Miskimmon's unrelentingly taut production for Opera Holland Park, an electrifying drama of sexual repression, guilt and release.

Set in a dreamlike walled garden of sharply angled, skyward-thrusting stems, and dressed with the pacifiers of the nursery (a rag-doll), drawing-room (a gramophone) and madhouse (a straitjacket), Miskimmon's production implies that the heroine's blindness is as hysterical as her father's insistence that she be kept unaware of her condition. Surrounded by cooing nurses (Carole Wilson, Sarah Redgwick, Patricia Orr), kept under lock and key, shushed and soothed, suffocated and subdued, Iolanta (Orla Boylan) is insane. Fumbling through real or imagined darkness, an outsized child, she is the only resident of the castle to move naturally. Around her, everyone else is holding their breath, as though on the point of screaming.

To establish and maintain such appalling neurotic tension, balance it with the sweetness of the score, allow lullabies, laments and love duets to unfold luxuriously, suggest a syphilitic subtext to King René's guilt, and introduce and explore the characters of Iolanta's swaggering betrothed, Robert (Mark Stone), and the stranger who liberates her, Vaudemont (Peter Auty), is an extraordinary achievement for Miskimmon, designer Nicky Shaw, conductor Stuart Stratford, the City of London Sinfonia, and the cast. Auty, Boylan and Mikhail Svetlov (King René) are magnificent, the supporting cast incisively characterised and sung, the climax radical and wholly credible.

Does Iolanta need a companion piece? No. But the slipshod Pulcinella that precedes it at least fills the time until darkness falls. Some operas need darkness, and La Gioconda, which is too long to allow for an apéritif, is one of them. Famous for its much-parodied Dance of the Hours, Ponchielli's love-pentangle has some exquisite passages but suffers from a surfeit of poisonings and plot-twists that are made more ludicrous by natural light.

Designed by Jamie Vartan, Martin Lloyd-Evans's spartan production is one where the big ideas – freeze-frame orgies and slow-motion violence – are lavished on the chorus, leaving the leads free to hurl high notes at each other like so many custard pies. In the title role, Gweneth-Ann Jeffers smoulders, shudders and shimmers with a gleaming timbre and rock-solid technique. Olafur Sigurdarson and David Soar snarl heroically as Barnaba and Alvise, and Yvonne Howard sings the role of Laura with sensitivity and intelligence. Some great singing and some great set-pieces, then, and a stylish performance from the orchestra under Peter Robinson. But there's something wrong when an audience titters indulgently at what the composer imagined to be his most affecting moments.

Ignoring everything else except Doctor Who (Prom 13), I used the first two weeks of the BBC Proms to try to identify what makes a good performance of Messiaen. By good, I mean transcendent, for Messiaen is a composer who either leaves you feeling dazzled with wonder or dreadfully puzzled and tired. The answer, I think, is a kind of radiant, animated calm. This was absent in Wayne Marshall's panicky Dieu parmi nous (Prom 1) and the Orchestre Philharmonique de Radio France's uninspired Et expecto (Prom 6), but gloriously evident in Pierre-Laurent Aim-ard's L'alouette lulu (PCM 1), the First Septenary of the BBC National Orchestra of Wales's La Transfiguration (Prom 14), and, most particularly, in Olivier Latry's L'Ascension (Prom 6). The Royal Albert Hall militates against such purity of focus. It's a building meant for alien extravaganzas, dry ice and childish squeals. Yet the silence during Latry's performance was almost as breathtaking as the music itself.

'Iolanta'/'La Gioconda' (0845 230 9769) to 8/9 Aug