The Mariinsky Opera’s Ring comes down to earth, from Valhalla to the sphere of the mortals, with Die Walküre. And there’s plenty that’s mundane about this production — not so much in visual terms but musically and dramatically.

For what should be the heartbreaking farewell scene of the disobedient but loving Brünnhilde and her well-meaning but morally flawed father, Wotan, the singers stand mostly rigid, facing the prompt box, communicating with each other only intermittently, when their lines of fire happen to intersect.

Other characters move their arms in a manner reminiscent of silent German cinema, circa 1932. And that’s the problem: the Mariinsky is still decades behind with its acting.

All three of the last Ring productions seen on this very stage — those of Keith Warner, Richard Jones and Götz Friedrich, dating to the late Eighties — demonstrated naturalistic acting vastly superior to this.

The tragedy is that one of the many directors lost during the genesis of this Ring was our own David Freeman, whose experience and stagecraft might have transformed the show.

In one respect, the Mariinsky has moved with the times. The sets are no longer old-fashioned realistic flats — though such horrors remain in their closet. In fact, the basic visual conception of monumental figures referencing other cultures than Wagner’s Nordic world is promising enough.

Blazing vermilion, crimson and cobalt blue are added to the less than subtle tonal palette of lighting designer Gleb Filshtinsky, though occasionally there are touches of inspiration — as when the hearts of those god-like figures glow in sympathy with the plight of the Volsung siblings, a moment of tenderness caught by Valery Gergiev too.

Gergiev’s conducting is erratic in the extreme, however. One minute he’s seizing on a purple passage, slowing it down to a crawl; the next he’s whipping up a storm. The orchestra doesn’t sound as if it has the music in its blood.

Certainly matters such as tonal blending, chord balancing and rhythmic ensemble leave a great deal to be desired.

As do the singers. Mikhail Kit lacks power and focus as Wotan, while his consort Fricka, Larisa Diadkova, adopting the traditional (and outmoded) persona of a termagant, produces a tone of such relentless harshness that a spouse could be forgiven for failing to see her point of view.

Avgust Amonov and Mlada Khudoley had their moments as Siegmund and Sieglinde but Olga Savova stretches credulity as the Valkyrie who sacrifices her divine status for the sake of love.

Tonight: Siegfried; cycle ends Saturday. Information: 020 7304 4000; www.roh.org.uk