Invasion by a colonising power has convulsed a country, dividing families – even individuals – between the rival claims of resistance and collaboration. A captured freedom-fighter from the indigenous elite faces execution; an imperial general hopes to wed his widow and bring a kind of peace to the conquered land.

To create a sensitive and original music-drama around the subject of a school killing is a colossal achievement. Director Simon Stone, set designer Chloe Lamford and novelist Sofi Oksanen’s cutting libretto make Innocence seem like a masterpiece. I wish I were less ambivalent about Kaija Saariaho’s score.

Nearly 40 years old, Andrei Serban’s Royal Opera Turandot feels like a gilded relic (I felt like a relic myself on learning that my writer neighbour wasn’t born when I saw Gwyneth Jones as the ice princess in 1984). Yet so too, outwardly, did Puccini’s only really grand opera when it premiered in the 1920s, exoticism being mostly confined to operettas and musicals. What keeps it modern is the score, which made it vital to hear what Antonio Pappano had to say with it.

Psychological depths in the myth of the water nymph who yearns for the human world, with disastrous results, have led to some unusual settings for Dvořák’s operatic masterpiece on the theme: a nursery, a hotel room (both successful), a brothel (not so much). What, though, when a production returns to the fairy-tale, developing at the same time the ecological devastation implied in the opera?

It’s always a disappointment when the Venusberg orgy Wagner added in 1861 to his original, 1845 Tannhäuser to suit Parisian tastes gives way to foursquare operatic conventions. Especially so in this revival of Tim Albery’s 2010 production, where Jasmin Vardimon’s choreography (pictured below) seems executed with more brilliance than ever and post-viral vocal problems loomed large last night for this hero.

This multimedia horror revue gave me heart trouble, which is an odd kind of compliment. Not at first: the assault of abrasive music, the one singer having to leap all over the place vocally, competing with spoken word and information overload, can seem self-defeating. And that vile word “lobotomy” is enough in itself to trigger a panic attack. But ultimately the impact is powerful, unforgettable, in tune with great artistic statements about the human condition.

“The great thing about this production,” Colin Davis observed in 2003, during rehearsals for its very first run, “is that the director [David McVicar] hasn’t attempted to shock anybody. He has tried to tell the story of The Magic Flute. And thank God for that.”

Handel’s audiences must have taken a very long time to settle – at least an act, to judge from the mostly inconsequential music of Alcina’s first hour. Lovely: we’re on an enchanted isle where puritanical people have been transformed into animal-headed courtiers, and a love-imbroglio merits only a “so what?” Richard Jones and his singers keep it lively and focused, but the bounce needed from Christian Curnyn and the Royal Opera House Orchestra doesn’t come.

In usual circumstances, a fully staged opera and every voice-and-piano song-cycle by a single genius in one weekend would be an embarrassment of riches. The only problem about Britten hitting the heights, above all in setting toweringly great poetry by Auden, Blake, Donne and Hölderlin, at the top of a long list, meant one sitting and squirming at most of Ronald Duncan’s wretched lines for an opera which even in its very subject is problematic, The Rape of Lucretia.

No gods, ancient Egyptian or otherwise; no sinister priest along the lines of Russia’s antichrist Patriarch Kiriil, sending soldiers to their deaths with the promise of heaven. Military ritual under what looks like a Russian/Chinese flag prevails in Robert Carsen’s severe take on Aida, more rigid than Verdi’s surprisingly unified late score - a musical masterpiece if not a dramatic one.