Sweeney Todd, Royal Opera House, London

Was it opera? Is the Royal Opera House dumbing down? Does it merit public money? Not mic-ing; not surtitles in English - surely.

Forget the groans. Tonsorial parlours are in. This is a terrific show. OK, so there were a few first-night rough edges. It needs to pack more of a punch. It could be darker, viler, more savage. But Stephen Sondheim's Sweeney Todd is a work that can hold its own in any opera house. For a start, like Bernstein's Candide, it has a humdinger of a book and lyrics - better than a hundred operas I could name - by Hugh Wheeler and Sondheim himself. With its grim take on Dickensian London, at times it's a bit like hitting Bart's Oliver! for the first time. But this has a (slightly ageing) cast to kill for, and, my, the poor old dears sing their socks off.

Sweeney has seen the world, and he doesn't like it. Like countless murderers, he has an Eiger-sized death wish. Sir Thomas Allen delivers a kind of baritone take on Canio in Pagliacci, battered by the myriad conflicting emotions that make Peter Grimes and even Lulu great operas. True, our leading operatic knight gets a bit gruff in the lower ranges these days, but the stage command is unabated, the Norse-Celtic singsong of his spoken voice superb, and he attempts the subtle transitions into Sondheim's arias like an old hand at the musical.

It's black stuff: for all the wit of the libretto - mostly from Mrs Lovett (Felicity Palmer), the henpecked Sweeney's gruesome aide-de-camp, whose pie-making parlour has needed a lift ever since "[her] Albert's legs give out with the dropsy". By the end, when Todd bumps off his wife-turned-beggar and caged bird of a daughter in quick succession, it turns into a Titus Andronicus or even King Lear finale, with the tenor Doug Jones's sympathetic Tobias serving up more than a dose of Lear's Fool and Poor Tom.

But that's the point: Sondheim is shrewd; he's complex; he's bitter. Pace Broadway, no mere candyfloss musical here. The Australian Neil Armfield's production has transferred fantastically well from Chicago (where Bryn Terfel sang the role) to the capacious stage of the Royal Opera House; even its bare side-walls were drummed into use. The sets by Brian Thomson are perfect: terrifying giant silhouettes and grim cages, evoking the claustrophobia of Copperfield London, from which the lovers - Anthony Hope (Thomas Dazeley), as he is called with a John Bunyan/Iris Murdoch twist, and Johanna (Rebecca Evans) - alone finally escape, and around which prison guards (Sweeney's Botany Bay past) and undertaker-like figures amble.

Coping with the mic-ing (more amplifiers, please; not fewer) in one joyously horrible, gargling duet after another come Felicity Palmer, a tour de force as Mrs Lovett, baker of "the worst pies in London", who has almost all the best puns, delivered in a horrifying drawl - you'd think she was Dot Cotton of EastEnders' cousin. All the tongue-twisting duets and several of the mass numbers (not quite all) work well. Jonathan Veira and Robert Tear (playing bluff Dickensian cameos - both, of course, bumped off) and even - in the hopelessly underdirected key role of Todd's lost wife, the Beggar Woman - Rosalind Plowright, of whose voice (she was the Royal Opera's Medea) we would like more, please.

Wonderful stuff - gory, and more sickening than plum pudding. Just what Christmas needs.

To 14 January (020-7304 4000)