Everything about this production is superb. The music, as always with Wagner, is magnificently powerful; the singing, especially that of Austrian tenor Andreas Schager in the title role, is superb, the orchestra, conducted with glorious musical understanding by Antonio Pappano, is meticulous; but the most memorable impression was made by the inspired direction of Barrie Kosky.

Kosky is perhaps the most creative of all contemporary opera directors. His productions are always buzzing with ideas, sometimes excellent, occasionally outrageous, but always interesting and provocative. This version of Siegfried begins with the sight of a pair of feet moving back and forth on a swing, then slowly the curtain rises to reveal a naked octogenarian. This is the ancient earth goddess Erda who, despite having only a small part in Wagner’s original epic, is onstage for much of Kosky’s cycle, having already been seen in the previous part, Die Walkure. Wagner may have hinted that Erda oversees and perhaps partly controls events, but Kosky emphasises it by giving the part greater prominence.

A naked 83-year-old on a swing, however, was the least of his innovations in the first Act of Siegfried. This consists mainly of exploring the relationship between the thuggish anti-hero Siegfried and Mime, the dwarf who brought him up from infancy. Both are revealed as rather unscrupulous characters and Kosky exploits this by treating the scenes between them as a sort of mythological sit-com. Both Schager as Siegfried and British tenor Peter Hoare as Mime take to this distinctly un-Wagnerian approach with aplomb and the humour reaches its peak when Siegfried takes on the task of re-forging the powerful sword Nothung which was shattered in Die Walkure.

This is accomplished in wondrous style when Siegfried drags a whirring, steaming, rotating Heath-Robinson contraption to the centre of the stage on which he re-makes the sword, celebrating by clutching it across his body and playing air-guitar on it. This is gloriously effective and would, I feel sure, have been hated by Wagner, mainly because he did not think of it first.

Siegfried later uses Nothung to slay the dragon Fafner, who is dressed in a splendidly glittery pantomime-like suit, and to gain revenge on Wotan’s spear by shattering it. As the main character in the opera, Siegfried’s role is hugely demanding, but Schager’s voice remained impressively powerful throughout, professionally moderated for the duets he sang with Sarah Dufresne and Elisabet Strid, playing the Woodbird and Brünnhilde respectively.

The Royal Opera House must have felt they were taking a bit of a risk in entrusting Wagner’s Ring Cycle to as unpredictable director as Barrie Kosky, but the result has been an outstanding success. We can look forward to its completion next year with the final opera, Götterdämmerung, for which we can be sure Kosky has been saving some of his most striking ideas.

Siegfried will be performed at the Royal Opera House on various dates until April 6. Box Office and details visa rbo.org.uk or 020 7304 4000. This production can also be seen live in various cinemas on March 31, with encores from 5 April. For details, see rbo.org.uk/about/cinema-25-26