Mittwoch aus Licht; BBC Proms 50 & 51 – review

A string quartet circling overhead in four separate helicopters, a dancing camel, a chorus spattered with paint, and two men with their top hats on fire – welcome to a wet Wednesday in Birmingham or, to be more precise, the world premiere of the complete Mittwoch aus Licht, Karlheinz Stockhausen's vast "opera in a greeting, four scenes and a farewell".

Birmingham Opera Company's production of Wednesday, the last instalment of Stockhausen's huge Light cycle (1997-2003) – an opera for every day of the week – was one of the most eagerly awaited events of the London 2012 festival. How would director Graham Vick handle this sprawling, enormously complicated score which demands not just the best musicians available but also large, flexible forces? Would it work, and would an audience stand six hours of it? And would Arts Council England regret spending a reported £920,000 on it?

Stockhausen disciples are a fervent bunch; some had even found their way from Japan to the former Argyle chemical works in Digbeth, a huge double hangar-like structure devoid of daylight – a suitably disorienting space for an avant-garde marathon. We sat in the dark on little camping stools for the Greeting: calming, ethereal electronics buzzed and whizzed around us as performers appeared out of the gloom: a kite-flyer ran past, a naked woman showered with a watering can; boys clambered up walls; upturned umbrellas became satellite dishes, receiving signals from outer space.

There was a feeling of flight, of slipping the bonds of gravity; all was wide-eyed, childlike wonder – a suitable introduction to the next scene, set above the clouds. We moved into the second performing space to hear the World Parliament debate the universal subject of love. Here, Stockhausen writes fiendishly difficult music for unaccompanied voices, and praise cannot be high enough for Jeffrey Skidmore's Ex Cathedra singers who displayed astonishing levels of virtuosity, their faces painted in the colours of national flags, as they extolled peace and love in languages real and imagined.

Next up (literally), 13 musicians were suspended from the ceiling, rising and falling and flying over a world of ships in harbours, a kindergarten of goats (naturally), wild geese and more, all represented by octophonic electronics and Vick's wonderful army of talented volunteers. It quickly descended into rather damp anarchy, with paper darts and ink pellets flying around and a trombonist splashing about in a paddling pool. My notebook's still wet.

Then it was time for the helicopter string quartet, and suddenly the mystery and the childlike wonder disappeared. Instead we had the crassness of the modern television age. The Elysian Quartet were introduced by Radio 1 DJ Nihal as we settled in front of four enormous screens to watch them clamber into a minibus and head for their waiting 'copters just a few streets away. As the rotors started to spin, the players, each listening to a coordinating clicktrack, began upward glissandi. We applauded as they rose over the rooftops, each screen displaying an individual player. Three mics were placed in each aircraft, one for the instrument, one for the player's voice and one for the machine itself, feeding back to a mixing desk.

It was a technological triumph but not a musical one. As a Birmingham sunset slid past the cockpit glass, the score barely got beyond those painfully banal glissandi. I'm sure it's a devil to play, like all Stockhausen – it's just a shame it's not more rewarding for the players and listeners, even when the tempi is governed by the beat of each helicopter's blades. Having come down to earth (descending glissandi this time), the quartet climbed back into the minibus and, toe-curlingly, we listened to their chatter en route to the venue before, horror of horrors, they and their pilots submitted to a finishing line interview, like Olympic gold medallists.

In the final scene we were transported to a galactic parliament. Delegates needed to elect a new president and naturally they chose a dancing camel with a penchant for champagne. (Don't look at me. This is avante-garde opera.) The camel sings of the colours and names of the weekdays, defecating seven different planet globes to represent them. Ben Parry's London Voices had mightily difficult choral lines to sing but triumphed as they worshipped their pantomime-camel president and sang of the starry firmament, hope, courage and peace in words Stockhausen had engraved on his tombstone, though he never heard them performed.

Was it worth the expense? Undoubtedly. This repertoire pushes the musicians to their absolute limits; the score may appear random but it's extraordinarily controlled and tightly organised, with passages of exquisite tranquillity. The message is resolutely warm, heartfelt and loving, moving in and out of language, space and time. It's a major achievement.

Emily Howard's Calculus of the Nervous System, however, is not. It received its UK premiere at Prom 51 last week. Using single chords and sometimes single unison notes, Howard tried to give us a sense of memories occurring and reoccurring – sometimes forcefully, sometimes only partially recalled. Strings shimmered, percussion and brass interrupted. Silence fell. Often. No melody emerged; no sense of tension and release.

These pianissimo parpings seemed a waste of the silkily talented City of Birmingham Symphony Orchestra, but the musicians were merely limbering up for the evening's main event, Shostakovich's often criticised but always powerful seventh symphony, "the Leningrad" (1941). The invasion theme of the first movement came towards us with a terrifying determination, batteries of percussion pushing ever onwards, driving the mindless war machine forward and repeating its brainless little tune over and over. The strutting bombast of the outer movements are thrilling in a cheaply instinctive way, but the symphony's enigma lies in its quieter central movements, suggestive of the composer's inner turmoil and, by extension, the plight of the besieged people of Leningrad. Here, conductor Andris Nelsons drew some outstanding playing from this glorious orchestra, bringing real depth and insight to these moments of intensity.

Warfare, this time the horror of 1914-18, also loomed over Prom 50 when, after the calm, clear skies of Mozart's Clarinet Concerto – played with consummate charm by the smiling Michael Collins on the beautifully creamy basset clarinet, as the composer intended – the horizon darkened for Nielsen's fifth symphony.

The BBC Symphony Orchestra was on brilliant form, their central adagio noble and broad, with strings and horns maintaining a heroic struggle against the mindless hate of the obstructive snare drum. Conductor Osmo Vänskä had clarinettist Richard Hosford turn his back on the audience for his extended, elegiac cadenza at the close of the first movement, an acoustic device that also suggested the quiet, private grieving of millions.

Nielsen composed his final works using an elegant golden pencil given to him by his daughter. This was passed to the English composer Robert Simpson and he, in turn, bestowed it on the fine symphonist Matthew Taylor. As the shouts of approval rose from the Prommers at the close of the Fifth, I noticed Taylor jammed in among the arena throng, applauding enthusiastically – a direct link from Nielsen to today.