The Royal National Theatre has scored its biggest hit to date with Trevor Nunn's new production of Rodgers and Hammerstein's Oklahoma!. In the week after opening on Wednesday, 15 July 1998, it has repeatedly broken the RNT's box office records. Discussions are now under way for the future of the production once it finishes its present run on 3 October. A cast album, West End and Broadway transfers and/or a return to the National's repertory next spring are all distinct possibilities.

The previous RNT record for a one day's worth of ticket sales on a single show was set in 1992 with Nicholas Hytner's production of Carousel, the last RNT Rodgers and Hammerstein outing. That racked up £50,000 in sales the day after opening. Last Thursday after its opening, Oklahoma! topped £60,000. It subsequently broke its own record on Friday with £76,000 in sales. This week it broke the overall box office record for total ticket sales in a day. The previous record, set last year, was £91,000 in ticket sales for three shows combined running in the RNT's Olivier, Lyttelton and Cottesloe theatres. On Monday, Oklahoma! alone took in £104,000 in ticket sales. The show is now sold out into next month.

Set in the American West at the turn of the century, Oklahoma! tells the story of young Laurey and the two rivals for her affections: Curly, a cowboy, and Jud, the hired farmhand. The classic score includes 'Oh, What a Beautiful Mornin', 'Surrey with the Fringe on Top', and 'People Will Say We're in Love' as well as the rousing title song.

The Rodgers and Hammerstein Organisation, rightsholders of the musical, are thrilled with what it calls 'a radiant and exhilarating production'. Mary Rodgers (daughter of Richard) and James Hammerstein (son of Oscar) along with R&H president Ted Chapin and other R&H representatives flew over to London for the opening.

Bert Fink, vice-president of public relations at R&H told What's On Stage, that they 'are all madly in love with this production. It feels like a new, freshly minted show and yet every word is Oscar Hammerstein and every note is Richard Rodgers. Nunn has really burrowed into the sub-text, he has listened to the script, he has looked at it with new eyes and is bringing out things that were always there but that no one else had discovered.'

In an interview with the New York Daily News, Mary Rodgers added: 'It sounds like dopey hyperbole, but this is better than the original. I want the entire world to see it.'

R&H were also excited about Anthony Ward's design and Susan Stroman's 'incredible array of choreography', considered a brave departure from the Agnes De Mille original. Fink says there has never been a production on this scale that has not used the De Mille choreography.

Director Nunn's decision to cast the company with, aside from British comedienne Maureen Lipman, relative unknowns has also paid off. Fiona Walsh, spokesperson for the RNT, says this was a deliberate decision, in keeping with Nunn's determination to achieve a fresh new look. He didn't want to use any established stars 'on which the production would hang.' Nevertheless, she says, the show is 'going to make stars out of people'. The principals Josefina Gabrielle, Hugh Jackman and Shuler Hensley - Laurey, Curly and Jud, respectively - have all been approached for other major projects.

The future of the production itself is still uncertain. Oklahoma! has a straight run in the RNT's Olivier Theatre until 3 October, but then it must clear out to make way for a production of Antony and Cleopatra, starring Helen Mirren and Alan Bates. Transfers and recordings have all been mooted, and Fiona Walsh says she would be 'extremely surprised if nothing else happens'. At the moment, however, nothing has been agreed. Trevor Nunn has been on holiday since the opening and will not return for another week.

Bert Fink is confident, however, of Oklahoma!'s Broadway future. 'It's not an exaggeration to say that every major Broadway producer in the past ten days has called this office or called the National or hopped on a plane and flown over to London,' he says. 'They're all interested in having Oklahoma!. I think there's a very, very good chance we'll see it on Broadway within the next two years or so.'

Oklahoma! was the first collaboration between Richard Rodgers and Oscar Hammerstein II. It broke all box-office records when it first opened on Broadway in 1943. The legendary duo went on to create Carousel, South Pacific, The King and I and The Sound of Music. Based on the Lynn Riggs' play Green Grow the Lilacs, Oklahoma! ran for more than 2,000 performances and marked a significant development in the history of musical theatre, with the songs becoming integral to the libretto, furthering the plot and character development. The last major London revival was the Cameron Mackintosh's production in 1980.

For more background on Trevor Nunn's gamble, see the What's On Stage feature on Is it OK? The Modernising of Oklahoma.