Die Meistersinger von Nürnberg, Hamburg State Opera, Germany

It's not only in Israel that people have problems with Wagner. Many Germans today are also uncomfortable with his legacy, not least with Die Meistersinger von Nürnberg. This rosy romantic comedy was originally conceived as a popular pot-boiler, but Hitler – latching onto the pageantry, patriotic paeans to "holy German art" and paranoid warnings against "false foreign rule" – posthumously co-opted it as the official opera of the Nazi regime.

How, many Germans ask, is it possible to stage this work today, with 20th-century rather than 16th-century echoes of Nuremberg resounding in our ears? And, indeed, how far should Wagner and his music-dramas be held to blame for creating the cultural and moral climate that led to Nazism and the devastation of the last world war? The war's fall-out is still everywhere to be seen or felt in re-united Germany – and, pace Basil Fawlty, it's impossible for anyone ("us" or "them") not to mention it: just this week the German papers were full of a new book that effectively accuses Churchill of war-crimes in his indiscriminate bombing campaigns. And certainly, in a city such as Hamburg – the historic Hanseatic port that was razed to the ground by the RAF in a single night's air raid with the loss of more than 40,000 civilian lives – it's hard, as a visiting "Brit", not to share with Harry Enfield's Jürgen the German an overwhelming urge to go up to strangers and try to "apologise for the conduct of my nation in the war" (even if, as the son of a Jewish refugee who fled the city in 1935, I also feel "they" had it coming).

The war breaks in, too, on Peter Konwitschny's provocative new staging of Die Meistersinger at the Hamburg State Opera – towards the end of Act Two, to be exact, when, in the midsummer mayhem that follows Beckmesser's sleep-disrupting serenade, the enraged citizens of Nuremberg turn on the 16th-century Dürer panorama of their city that has formed the stage's backcloth and rip it apart to reveal a bombed-out, fire-scorched shell beneath.

To complete the time-shift, the returning Nightwatchman, who first appeared as a doddery old man in a nightshirt, now reappears, nearer active-service age, in a 1940s army greatcoat, while a booming off-stage horn-call sounds more like the all clear from a nearby docks than an "all's well" from a medieval neighbourhood watch. As the curtain falls, the Nightwatchman shakes an impotent fist at the skies. When it rises again for Act Three, it reveals a ghostly black-and-white bomber's-eye view of the blitzed city of 1943. It is thus before this apocalyptic vision that Hans Sachs, the cobbler-poet, sings his great "Wahn" monologue, despairing of the self-destructive madness that besets mankind, and towards it that Beckmesser stares in shocked disbelief, as if to say "Did I really cause all this?", before turning away in gruff denial.

The contrast between the two Mastersingers' reactions – the one reflecting philosophically upon the violence of the night before, the other refusing to accept any responsibility for the actions that provoked it – is here put into high relief by the director's decision to dress both Sachs and Beckmesser, and indeed all 12 members of the Mastersingers Guild, as identical Wagner-lookalikes, in the composer's trademark green velvet jacket, flowing silk cravat and floppy artist's beret. It's a decision that had at first seemed merely contrary – since we all know that Wagner identified himself with Walther, the iconoclastic young rebel, not with the Mastersingers he rebels against - but now begins to make sense.

It only really becomes clear what Konwitschny is up to, however, during the climactic song-contest, when the director has each Mastersinger, to increasingly amused cheers of recognition from the audience, bring on a character from one of Wagner's other operas as guests of honour. The result, as we come to realise that it's not just Walther's fate that hangs in the balance but the whole heritage of the Mastersingers' art as well, is to transform the scene from a potentially pompous medieval prototype of a Nuremberg rally into a burlesque parody of a Nuremberg trial, with Wagner himself in the dock and Wotan, Siegfried, Tristan et al acting as chief witnesses for the defence.

The verdict here is, of course, something of a foregone conclusion, since Sachs's successful plea to the victorious Walther to overcome his instinctive reluctance and join the guild becomes, in this staging, a winning defence not only of Germany's ancient song tradition but of Wagner himself and all his works. But it's when Sachs starts out on his dark warnings against "false foreign rule" corrupting honest German ways that this subversively iconoclastic staging springs its last and most outrageous surprise, prompting uproar among some parts of the audience. For, as Sachs embarks on what British Wagnerites tend to call "the nasty German Nationalist bit", and many German Wagnerites see as the composer's single most cringe-making passage, a couple of his fellow Mastersingers suddenly step out of character and begin to barrack him, man to man. "But, Oscar, you can't say that! No, really, you just can't say that!"

And, as the debate quickly spreads from stage to stalls, the seamless flow of Wagner's music actually stops with the result that a riot of booing and heckling, both for and against (including cries of "Honecker's man" in reference to the director's East German birth) inevitably ensues. At last, a loudspeaker voice announces that the performance will now continue to the end. Though, even so, the director begins to dim the lights before the company has even finished its final hymn to "holy German art".

Konwitschny's approach is clearly not the only way to stage this piece – if you want to see a more timelessly untroubled reading, Graham Vick's warmly human version is at Covent Garden – but it's certainly a brilliant way of staging the debate over whether the work can be staged at all, even if the result is perhaps so exclusively and introspectively German in its exposure of raw post-war nerves that any foreigner present must feel like a gate-crasher at a family wake.

But it's also very funny for most of the time, with much broad comic business, and, in the final Festival Meadow scene – staged against an Antz-style blow-up of vastly magnified meadow flora, with the apprentices carrying in their guild symbols atop giant blades of grass and a ballet of lederhosen-clad girls in multicoloured butterfly wings – moves into a realm of inspired, and magically un-Germanic, fantasy that nicely cuts both Wagner's and Konwitschny's pretensions down to size.

Musically, it's strong, too. As is clear from the start of the swiftly sonorous overture, Ingo Metzmacher, the latest conductor to fill Mahler's old job as Hamburg's general music director, is out to breathe fresh air and light back into this often over-weighted score. He largely succeeds, keeping everything spry and nimble, though with no want of spiritual undertow when required. At the performance I attended, both Sachs (Oscar Hillebrandt) and Eva (Camilla Nylund) were late substitutes: though I gather much of the detail of dramatic interpretation was lost, their vocal strengths paid tribute to Hamburg's solid repertory-ensemble.

As Walther, though, the Cornish-born tenor John Treleaven, here sporting the golden curls of the young Albrecht Dürer, Nuremberg's very own Renaissance Man, looked every inch the impassioned young romantic knight, and sang with a winning and untiring freshness and apparent spontaneity to match Walther's burgeoning poetic power. A once-familiar voice with ENO and our regional companies, Treleaven has recently been carving out a Continental career for himself as one of our leading Heldentenors abroad; his series of Tristans in concert with the BBCSO in December and February should be well worth catching live (at the Barbican) or on Radio 3.

Hamburg State Opera (00 49 4035 6868; www.hamburgische-staatsoper.de), 27 Nov, 1 Dec; Royal Opera House, Covent Garden, London WC2 (020-7304 4000; www.royaloperahouse.org), 23 & 28 Nov, 2 Dec