Imagine you are at a study day being run by Friends of the Earth. They mount a play in which a group of angels who somehow got left out of the Book of Genesis fall to a completely barren earth, look around, and start reconstructing, re-enacting its life and death. They plant, grow, overgrow, eat, overeat; they tell themselves the earth will always be fruitful, but they’re mistaken. In the end two of the angels become Adam and Eve and walk off hand in hand into a ruined landscape lit by the rising sun. Then Luke Bedford sets it all to music.

After years of planning, Opera North's Ring cycle gets under way. The orchestra pit at the Leeds Grand Theatre is too small for Wagner's oversized orchestra. So this is a concert staging, to be repeated in the coming months at The Sage Gateshead, Birmingham's Symphony Hall and The Lowry in Salford. It's really a blessing, meaning that production staff don't have to grapple with Wagner's extravagant stage demands in order to make the impossible appear tangible. What Opera North have done is engage lighting designer Peter Mumford to create a concert staging.

The Barbican committed a grave sin last night. It forgot that people matter more than art. That their responsibility to the families of those who Jack Unterweger (the subject of John Malkovich's music drama, The Infernal Comedy) murdered trumps any interest in the dramatic potential of Unterweger's bizarre life. However constraining to the autonomy of creativity this may be, these are the rules of common decency. A portrait of Ratko Mladić that did little to show the horror of his crimes and much to convey what a loveable rogue he was would be a disgrace.

The extraordinary Longborough Opera Festival is with us again and for the next six weeks, in Martin and Lizzie Graham’s Palladian barn theatre near Stow-on-the-Wold. This year the world’s unlikeliest Ring cycle reaches Siegfried. But the improbability doesn’t end with Wagner; there is also Verdi (Falstaff) and Mozart – also, typically, a cyclic project, which has arrived at Così fan tutte. The whole set-up is so amazing that one longs to be enthusiastic about everything. But that can sometimes be difficult.

Its little-mermaid legend is enough to make the angels weep, given the bewitching gravity of Dvořák's masterpiece: a water nymph, caught between the human and supernatural worlds, condemns herself to eternal limbo for the sake of her erring princely lover.

It’s not often that a performance of Purcell’s King Arthur requires its entire cast of singers to strip down to very tight Union Jack boxer shorts. It’s not often either that the audience find themselves actively encouraged to talk over the music, yet both were unexpectedly and riotously true last night at the Spitalfields Festival. Pairing Baroque big-hitters The English Concert and I Fagiolini, there was nothing half-hearted about this semi-staging of Purcell’s semi-opera. It promised much and delivered more, and while those listening live on Radio 3 might have enjoyed better textural balance, they can’t have had nearly as much fun as the sell-out crowd sweltering away in Shoreditch Church.

Travelling by Eurostar, or plane, to the continent and buying a ticket, all for less than the cost of a Covent Garden stalls seat, might entice if you wanted to see a certain opera, singer or conductor. But to go so far for the look of a staging? Well, the Catalan company La Fura dels Baus’s phantasmagorical ENO production of Ligeti's Le grand macabre has left some of us hungry for more, which so far means going abroad to find it. Ultimately their latest Wagner doesn't always rise to the expected visionary heights, but it does boast world-class music-making and, wonder of wonders, real interaction between the singers on a human scale.

Mozart's Idomeneo is subjected to a famous bit of abuse in Milos Forman's Amadeus. "A most tiresome piece," a courtier critic sniffs. "Too much spice. Too many notes." As it happens, not a wholly inaccurate statement. The work is quite an exotic curry of an early Classical opera.

Donizetti's L'elisir d'amore must be the only opera from whose central lesson one can actually learn something. Its message - drink, chill out, back off and the girl will be yours - is as good a moral guide to life as any. But it was still surprising to leave Glyndebourne last night satisfied.

Public feuding, private sorrows: the elemental passions of Verdi's Ligurian power struggle haven't had a vivid London staging since the Alden-Fielding ENO classic gave it a guiding (or, according to taste, hindering) giant hand in the late 1980s. Dmitri Tcherniakov, the most disciplined opera director to have come out of Russia, was a clever choice for the company to invite to the Coliseum.