The Royal Opera’s new Ring cycle con- tinues its perplexing journey. We have reached Siegfried, the second stage of the main action — Wagner designated Das Rheingold as the Ring’s “pre-evening”, or prologue — and the ideas invoked in Keith Warner’s staging continue to be overshadowed by the feebleness of their realisation. Stefanos Lazaridis, the set designer, has opened out the decaying marbled hall of the first two instalments, so that the action of Mime’s machinations to acquire the Ring is framed by an enlarged version of the fireplace that dominated his Rheingold and Walküre. The curtain rises on a striking stage picture: through a charred hole in the ceiling, a plane has crashed, its chassis a skeleton, its propeller and a wing detached (the latter peeps through the curtain to hint at the twisted girders of the “helix” that is this Ring ’s defining, even straitjacketing, visual image).

The Wanderer emerges from this wreckage, and Siegfried uses one of the propeller blades to forge his father’s sword anew. So far, not so bad. The stage is marginally less cluttered than before, but, for much of the evening, this Siegfried still looks less a piece of theatre than a group of opera singers awkwardly negotiating a design concept. Warner’s ideas, allegedly based on Wagner’s reading of the German philosophers Feuerbach and Schopenhauer, and a tendentious linking of the composer’s racial theories with the Nazis’, have little room for manoeuvre in Lazaridis’s stage-hogging visualisation.

In Das Rheingold and Die Walküre, Warner’s shortcomings as a director of actors were glaringly exposed, and his lame attempts at comedy in Acts I and II of this Siegfried fall hopelessly flat. With Gerhard Siegel and John Tomlinson, consummate performers of Mime and the Wanderer in other productions, this is surprising, but they get little help from the Siegfried of John Treleaven, whose histrionic skills amount to little more than desperate mugging and hammy gesticulating.

Treleaven’s performance grows in dramatic stature after he has slain the dragon Fafner and first experienced fear in his emotional encounter with the sleeping Brünnhilde. Warner botches the ex-Valkyrie’s glorious reawakening by “imagining” it out of sight of the audience. Brünnhilde makes her appearance through a doorway in the spinning white wall from the closing act of the Walküre. When she eventually arrives, the director handles the angst of Siegfried’s first encounter with a woman, and her first experience of burgeoning love, with intelligence and intensity, but it’s too little, a bit too late.

Nonetheless, this climactic act is perhaps the most distinguished of the cycle so far: it begins with Tomlinson’s Wanderer bestriding the white wall, laterally tilted and spinning like the hydraulic platform of Götz Friedrich’s never-to-be-forgotten staging of this scene at Covent Garden in the 1970s and 1980s.

The state-of-the-art Royal Opera House stage machinery isn’t quite up to the technical wonders that were evidently achievable in the old Victorian theatre, however: the platform wobbles; Erda’s entrance, wheeled in like a giant Dalek sitting in her Rheingold armchair, is similarly jittery, and you don’t get the vertiginous impression of the Wanderer teetering on the brink, close to the world’s end, that his desperate encounter with the all-knowing earth mother (Jane Henschel) should convey.

If this act is the Warner/Lazaridis Ring’s theatrical high, then Act II is its risible nadir. Initially, it looks promising: the dragon’s lair is the same hole, seen from above, that the Act I plane has crashed through. Then the Forest Murmurs sequence is staged as a tableau of sentimental kitsch: Siegfried sings his reverie against a star-spangled backdrop on a grassy knoll, while assistant stage managers dressed as wood pixies wheel in stuffed male and female reindeers on hospital trolleys. The soprano playing the part of the Woodbird (Sarah Fox) clumsily “flies” a replica avian on a fishing rod — the whole scene looks jejune and ridiculous.

Feuerbach and Schopenhauer may be Warner’s guiding lights, but Mervyn Peake, Tolkien, Harry and even Beatrix Potter — the lying Mime “exposed” by Fafner’s truth-revealing blood puts on a giant mouse mask — seem the most obvious visual references. The dragon looks like something from a bad ghost-train ride, and Siegfried dispatches him by picking his nose with his sword.

Musically, too, this is an evening of ups and downs. Tomlinson sounds a bit worn, but sings with authority, and Lisa Gasteen’s appealingly sung Brünnhilde is painfully short of a climactic high C at the end. Treleaven lasts the course, but he’s an unmusical, inaccurate singer. True, the casting alternatives aren’t limitless, but ENO’s Richard Berkeley-Steele was easier on both ear and eye. The out- standing performers are Siegel and Peter Sidhom (Alberich) as the squabbling Nibelung brothers.

Antonio Pappano’s grasp of the long musical paragraphs continues to grow in power, and his command of the excellent ROH orchestra is enhanced at every stage. If his musical conception remains episodic, any Ring-in-the-making is a work in progress, so one hopes there is still time for revisions to the staging and a more architectural approach to the music.

The return to the opera stage, after an absence of more than five years, of the popular English soprano Lesley Garrett should be cause for rejoicing. She is the diamond in the dunghill that is Welsh National Opera’s dreary new staging of Lehar’s The Merry Widow. Looking gorgeous in Agostino Cavalca’s My Fair Ladyesque frocks, she works her famous bottom off to inject some life into Patrice Caurier and Moshe Leiser’s leadenly spoken, unfunny and drab-looking production. Garrett, Donald Maxwell (Baron Zeta) and Linda Ormiston (Praskowia) deliver hints of champagne operetta effervescence in an evening of purgatorial tedium, but the real flattener is the pedestrian conductor, Michal Klauza. Pappano’s Siegfried is a toe-tapper by comparison.