OPERA / All on her own, the Widow without tears: Edward Seckerson on a speechless, setless, motionless Merry Widow from Glyndebourne

The phantom of the operetta is there inside our heads, and always will be. As Franz Welser-Most popped the cork on this particularly fine Glyndebourne vintage and Lehar's Merry Widow once more began to exude her charms, the whole glorious line of succession came back into focus - from Vienna all the way to Broadway, from Johann Strauss and Kalman, through to Herbert, Kern, Rodgers and Loewe. Where would the Gershwins have been without Gilbert and Sullivan; where would Lloyd Webber be without any of them? These days, of course, Sir Andrew's Phantom is more likely to wow them in Vienna than Lehar's Widow. But not that much has changed; their hearts are in the same place. So are their tunes.

At London's Royal Festival Hall you can enjoy Lehar's tunes without dialogue, without dancing, without sets. And it's bliss - the Widow without tears. Dirk Bogarde just happens to be on hand to keep us on track plot- wise ('How is your German, by the way? Never mind'). Tom Stoppard writes his material - very funny it is too. Actually, it's not really Dirk Bogarde at all. It's Njegus, Secretary at the Pontevedrian Embassy, and the operetta is not 'The Merry Widow' but something called 'The Confidential Secretary'. The Widow is incidental, you see, an irritation. Njegus saw it all: he was at the centre of it, it's his story. He tells us about the fan - 'remember the fan - it's rather like the handkerchief in Otello, except that Verdi makes everything sound much worse than it is . . .' He's wonderfully laconic and the timing is perfection. And he knows a thing or two about operetta: 'It's amazing what you can get away with if you put enough music round it.' Too right.

When it's not effervescing or high-stepping it, Lehar's music is written on a kind of illicit sigh. The spirit of the waltz is never very far away. But then the Merry Widow waltz is one of the world's great tunes and everything lyric in this lovely score has the same ache. Welser-Most and the LPO were well inside the style, leaping racily from the starting blocks in the prelude, immediately catching that heady amalgum of brashness and schmaltz, high living and sweet nostalgia. Welser-Most is not afraid of a little vulgarity in the mix, yet the fantasy of Lehar's scoring was touched in with white kid gloves.

'Vilja', another of the world's great tunes, comes caressed with whispering string glissandi and tinkling guitars. Our Widow, Felicity Lott - looking good for her money - sang it with luminous tone and melting portamento. Her Danilo, the impossibly good-looking Thomas Hampson, looked on, unable to conceal his adoration, though the plot had some way to run before he could reveal it. Hampson makes it all sound so easy: his perfect, idiomatic German, the way phrases pour off his vocal cords like honey. His big second-act 'Konigskinder' solo, chauvinism masquerading as fairy tale, was so strongly characterised, no translation was necessary. He and Lott looked as though they'd been treading the boards of the Theater an der Wien all their lives.