But then comes an extraordinary moment. Behind the iron grills, and bathed in the warm rosy glow of history, advancing pilgrims bear candles, a glimpse, a flashback of Russia's past. And a foretaste of the coronation, where the stage opens up to its full depth like an empty gallery space whose main installation is a burnished gold wall upon which hang icon-like portraits of political leaders peering out through a mess of wiring. A video monitor hangs incongruously to one side. Boris is wheeled in on a moveable dais, his portrait emblazoned behind him. He wears the formal three-piece suit of today, an ornate crucifix his only concession to the past. Family and officials around him are dressed in the gold-embossed splendour of traditional 16th-century vestments. Past and present collide, but nothing changes. And throughout this teeming chronicle that is Mussorgsky's great opera - given here (with one significant addition) in its stark and uncompromising original version - there is but one witness, that enduring symbol of Russian folklore: the Simpleton, the wise-fool. Zambello gives him rare prominence; she gives him an umpire's chair from which he is all-seeing, all-knowing.
Zambello is an exciting director. She has a natural feel for the epic sprawl. She loves the open stage. This show is literally manhandled from one scene to the next, token scenery unceremoniously pushed and dragged in and out of the action. Her crowd-control is outstanding: she can turn the operatic cliche - the cowering chorus with outstretched hands - into a thrilling frozen tableau; she can have Boris disappearing into a sea of those same hands like a drowning man; she can take your breath away with the seemingly obvious. Like Boris delivering his great monologue, "I stand supreme in power", astride the map of his domains. Like the unsettling scene between Boris and the odious Prince Shuisky (an oily Robert Tear) played out here like a burlesque between two madmen keeping up appearances. It is Shuisky who literally opens the door to Boris's nightmare at the close of that scene. It is the Simpleton - Boris's conscience - who comes through it, an apparition of the murdered Dmitry. Why has no one thought of that before?
John Tomlinson plays Boris with all the authority and operatic extravagance of a bygone age. But his whole demeanour suggests a thoroughly modern madness - like Yeltsin on a bad day. Call it melodrama, if you like, but it rings horribly true. There are stand-out performances all around him: John Connell's Pimen, Jeremy White's Valaam, John Daszak's Grigory, Susan Gritton's Xenia, Timothy Robinson's Simpleton, Della Jones, no less, overripe in every respect as the Inkeeper. But collective spirit counts for more than individual worth in a piece like this, and ENO's music director Paul Daniel, responding in kind to the sheer weight of history conveyed in Mussorgsky's grave and ruthlessly economical score, displayed compelling leadership. This is an opera about a people. And the people - as portrayed in all their complexions by the seething ranks of the ENO chorus - were magnificent. Small wonder Daniel and Zambello chose to add the Kromy Revolution scene - one of the great virtuoso choral scenes of all time - to Mussorgsky's 1869 version.
No sooner is Boris dead and his heir despatched than angry mobs haemorrhage on to the stage. The arrival of Dmitry, the Pretender, in a mirror image of Boris's coronation, signals yet another brave new dawn. Except it isn't, is it? Only the Simpleton knows better. Iron grills descend, imprisoning the people once more. The Simpleton puts his head in a noose. Fade to black.
Coliseum, London, tomorrow and Wed (booking: 0171-632 8300)