Barbaric barber of Broadway

The ingredients were first class, the recipe a modern classic. The novelty came in the exotic cuisine: a Broadway musical in the opera house. Would it work?

The Royal Opera's first adventure into Stephen Sondheim - a co-production with the Lyric Opera of Chicago - was a triumph, with only the kind of quibbles that such a mixed marriage across musical and theatrical boundaries is certain to produce.

Sweeney Todd, a black hymn to London, proved a clever choice. Premiered in New York in 1979, this gory tale of the Demon Barber of Fleet Street who slits the throats of his victims and puts them in Mrs Lovett's meat pies, is by most reckonings Sondheim's finest.

The music, a mincemeat of Seventies smoothness - think Tubular Bells and sweet violins - with chewy, teeth-breaking nuggets from Shostakovich and Stravinsky, stands up to the scrutiny of operatic performance.

This is not a musical of stand-alone hits like the Royal Opera's only other foray into the form, Gershwin's Porgy and Bess. With Sondheim, familiar themes return but with nervy rhythms shattered like shards of glass, jaggedly transformed.

It makes for a tense, enthralling evening, incisively conducted by American Paul Gemignani, a doyen of Broadway and a Sondheim specialist. If the orchestra can't yet boast that authentic pit band crispness, they are smart enough players to learn. The chorus, too, needs to match soloists in edge and clarity.

In Thomas Allen (Sweeney Todd) and Felicity Palmer (Mrs Lovett), this production had stars of unrivalled quality. Finding new form late in his career, Allen brings terrifying stillness to the role of Todd. His hunched figure holds all humanity's ugly curse.

Only twice does he let his feelings go: in his mad Epiphany and when he discovers his latest victim is his beloved wife. His voice (acceptably amplified) sits easily within the part, each word audible. Allen's genius is to make us weep with this bloody-handed murderer.

Palmer is a definitive Mrs Lovett: hilarious, rude, tender, desperate, bloody and, finally, pathetic. She negotiated the fiendish knotty rhymes of A Little Priest with comic panache. Neil Armfield's production, with sets by Brian Thomson, tended towards the fussy but had its strengths: the abstract cage-within-a-cage set was effective in the asylum scene, though the shadow play and constant pulling back and forth of curtains grew wearying elsewhere.

Act One is long and always prone to feel episodic. But Act Two held all in taut suspense. The strong, mainly English cast elicited touching cameos from ROH veterans: Robert Tear's Welsh valley Beadle, Rosalind Plowright's Beggar Woman, Bonaventura Bottone's cod-Italian Pirelli and Jonathan Veira's orotund Judge.