It began when the lovelorn lady sang. 40 years on, the curtain falls on Tosca

It was production that became an operatic legend. From the ashes of her career, Maria Callas triumphed as Tosca in an opening-night performance that won 27 curtain calls and a 40-minute standing ovation. The show became The Mousetrap of opera, a staple of the Covent Garden programme and the oldest production in the regular repertoire of any company in the world.

It was production that became an operatic legend.

From the ashes of her career, Maria Callas triumphed as Tosca in an opening-night performance that won 27 curtain calls and a 40-minute standing ovation. The show became The Mousetrap of opera, a staple of the Covent Garden programme and the oldest production in the regular repertoire of any company in the world.

But this week it will take its final bow. After more than 230 performances, the Tosca first mounted by the director Franco Zeffirelli in 1964 will grace the stage of London's Royal Opera House no more.

When Maria Guleghina, one of a string of successors in the title role, throws herself from the theatrical battlements on Saturday, the curtain will come down for good on a slice of British operatic history.

Yet when, at the end of 1963, Zeffirelli asked Callas whether she would take on the role of Tosca, the success of the project was far from certain.

The 40-year-old diva had not sung on stage for two years. She agreed to return partly because her affair with the shipping tycoon Aristotle Onassis was turning sour and partly for a fee rumoured to be an unheard-of fortune of £10,000 for half a dozen performances.

The whole show was mounted in six weeks, instead of the usual years, at a record cost of £32,000. That investment has been recouped in spades.

On its first night 40 years ago, queues began five days before curtain-up. More than 120,000 people applied for 12,000 tickets with top-price tickets set at six guineas but changing hands on the black market for £100.

The Financial Times said the end of Act I was "possibly the most splendid sight Covent Garden has ever seen." Zeffirelli said of his captivating heroine: "She was everything I ever hoped my Tosca would be."

Later, an ITV broadcast of Act II of the production on The Golden Hour was watched by twice as many as those who tuned in for Dr Finlay's Casebook or the Winter Olympics.

Zeffirelli's Tosca (re-directed by John Cox in 1991) has been revived almost every season since. While costumes and set have been repaired and patched up, the look remains demonstrably that of 1964. And the cast over the years has proved as glittering as the first pairing of Callas as Tosca and Tito Gobbi as Scarpia, the police chief she kills when trying to save her lover, Cavaradossi.

Everyone from Placido Domingo and the Argentinian José Cura to Montserrat Caballé and Maria Ewing has appeared in it. Luciano Pavarotti chose it as the vehicle for his final full-scale performance in London two years ago.

The decision to call it a day has been made as a new version is finally under discussion in London for 2006. It is expected to reunite Antonio Pappano, Covent Garden's musical director, with Angela Gheorgiou, whom he directed in a film version of Tosca three years ago.

It means that the battered sets and costumes that have enchanted four decades of audiences are being sold on to the Chicago Lyric Opera. Elaine Padmore, the ROH's director of opera, said: "We are selling it on in fantastically good shape to a place where it will have a very happy life. I'm sure lots of Americans are going to adore it."

But it leaves few chances for British music-lovers to catch the original production. All bookable seats are sold out for this week's performances, although it is being relayed live from the Opera House tomorrow night. At least 15,000 people, from the Botanical Gardens in Belfast to Center Parcs in Sherwood Forest, Nottingham, are expected to seize the big-screen opportunity. In London, crowds will gather at Canary Wharf as well as Covent Garden Piazza.

The Opera House is hoping for better weather than the storms that washed out the English National Opera's attempt at live opera in Trafalgar Square last Wednesday.

Ms Padmore said every company found that productions of Tosca and La Bohème proved the most popular. "They're always the one that last longest and traditions grow up around them," she said. "They are wonderful star vehicles for generations of singers. But there comes a point when you want to create a new tradition, create a new excitement, and reach a new generation."

Small print in the contract for the sale gives the Royal Opera House the right to reclaim the show when Chicago tires of it - or if the new version fails to match the star quality of the old.

But this production is not expected back in London again. "We're going to make something new," Ms Padmore said. "You've got to move on. We'll get over the sadness."