Emblazoned on a drop-curtain in front of a mirror-image of the auditorium, the three great tenets of the French revolution seem to be mocking us right at the start, above all the second of them: equality, really, given the make-up of the Royal Opera stalls?

Cosi fan tutte is, as the opera’s subtitle clearly tells us, “A School for Lovers”. But too often these days it can feel like a school for the audience. Joyless productions lecture us sternly on the battle of the sexes – on chauvinism, feminism, cynicism and sex – until we’re battered into fashionable discomfort. A happy ending? For Mozart’s most complicated comedy? Don’t be naïve.

Scotland was at the cutting edge of culture in 1988, when the Edinburgh International Festival hosted the UK premiere of Nixon in China in the Houston Grand Opera production at the cavernous Playhouse.

Once upon a time writing an opera was first and foremost a question of choosing a good story. But times move on, and today – as Nicholas Till reminds us in a fascinating programme note for Philip Venables’s and Ted Huffman’s new chamber opera – the medium is the message, and the how has become at least as important as the what. 

Those who booed the production team last night - there was nothing but generous cheering for singers, conductor and orchestra - might reflect that this was at least regietheater, that singular brand of not-all-bad director's opera in Germany, with discipline and purpose close enough to its subject. There were some cliches and the occasional question-mark - who's the trembling, plastic-wrapped youth in underpants and why the nearby oil drum?

It’s not hard to see why The Sicilian Vespers has struggled since its surprisingly successful opening run at the Paris Opéra in 1855. Verdi had composed it reluctantly, despised the librettist, Eugène Scribe, who he regarded as a well-named cynical scribbler, and tried unsuccessfully to get a release from his contract. The result is undeniably patchy, narratively implausible to the point of silliness, and though tight by the standards of French grand opera, nevertheless at least one scene too long.

"About as much fun as you can have with your clothes on," promised a member of the two Royal Opera casts teamworking their way through multiple roles and costume changes for what in effect is Alice's Adventures Under Ground and Through the Looking Glass in under an hour.

Wigmore Hall audiences don’t usually roar. But when a star soprano who has already made her mark at the world’s major opera houses pays a visit, they do.

Of Wagner's four Ring operas, Siegfried poses the biggest casting problem. Most heroic tenors with the lungs to last the evening are not going to be ideal incarnations of the stroppy adolescent who learns and fights his way through an often nightmarish fairy-tale landscape. Torsten Kerl, not an agile mover to say the least, certainly wasn't.

Kurt Weill’s “Broadway opera” – his own preferred description – is an extraordinary and brilliant piece of work. Its music ranges from the seriously dramatic to fun numbers like the "Ice Cream Sextet" and the jitterbug dance song “Moon Faced, Starry Eyed”; there’s a lot of spoken-dialogue-with-music, as well as solos, duets and all manner of ensembles; and the story is both comic and tragic.