The curtain lifts, what must be a train rolls on to the stage, and they're singing Chhaiya-chhaiya. So begins a Bombay cinema story onstage in London. And the West End at that, under Andrew Lloyd Webber, the man behind London's most famous musicals for decades.

Chhaiya-chhaiya from Dil Se.. inspired Webber into doing a musical on Bombay films. With Shekhar Kapur at his side, it happened. That scene sets the musical rolling. And it starts history unfolding in London's famed theatreland.

Bombay Dreams is coming true this June at the Apollo Victoria theatre. Quite a change for Webber, even from that varied journey from Jesus Christ Superstar to Cats, Evita and The Phantom of the Opera. Webber is producing this one, with his Really Useful Theatre Company, and music of course is by A.R. Rahman.

Some of that music has been heard before, some is new. After Chhaiya-chhaiya comes a version in English of a duet from Taal, then another with the line yaai re, yaai re (echo from Rangeela) before it takes off into English lyrics and another tune. There's about 20 songs, many of them to all-new music. In Bombay style, they're there as songs to be listened to, and to push the story along.

As for the story, don't worry about guessing the end. Rich film producer Madan Kumar accidentally spots Akash (Raza Jaffrey), a poor slum dweller, and picks him for a role in his films. But Kumar is killed when he takes on the Bombay mafia who want to control his company. Madan's daughter Priya then takes up her father's business. The poor Akash falls in love with rich Priya, but not with sweet Sweetie who loves him. Priya too loves Akash secretly but she is engaged to Vikram. On the day of her wedding, she learns that Vikram was behind her father's killing. She turns to a happy destiny with Akash. And so the subtitle of the musical comes true: Two Hearts, Two Worlds, One Dream.

Two worlds came together when Andrew Lloyd Webber met Shekhar Kapur in 1999. The two hit it off immediately. "I have waited for years for the culture of the Bombay film industry to be presented professionally to international audiences," says Kapur. Meera Syal, who gave British audiences Goodness Gracious Me, a take-off on South Asian life in Britain, was called in to do the script. Oscar winner Don Black, famous for his Bond songs and for The Phantom of the Opera, has penned the lyrics.

Worlds came together also for Preeya Kalidas, who auditioned four times in 2000 and again last year before she landed the star role. She was told of her Bombay Dreams the day she finished shooting for the film Bollywood Queen where she plays an Indian girl from East End in London who nurtures dreams of Bollywood.

Bombay Dreams is about Bombay, a good deal in it is from Bombay, but it is very much a West End musical. Preeya Kalidas who plays Priya sings most of the songs, with Raza who plays Akash. The father sings a song, so does Sweetie. But not in the Bombay style of singing. A little more of the opera here than Lata Mangeshkar. The dances are being choreographed by Farah Khan along with West End veteran Anthony Van Laast. The musical has a cast of 42, and is being produced at a cost of £4.5 million (Rs 31 crore).

In the hard world of West End, Bombay Dreams is a big gamble for a producer to take. Audiences for West End theatre have fal-len 15 per cent over the past few months, largely because American tourists have kept away. None have lost more audiences than the musicals. London might just have had too many of them; a critic remarked that their presence is giving the West End "a dismally constipated look". The cynics among the critics are asking how many takers there will be for a musical of another culture that has the sights and sounds of the Indian entertainment business, but perhaps lacks substance.

Bombay Dreams is being targeted with hostile criticism even before it's happened. Not for English audiences, said one critic, those "Amazons on roller skates, pretending to be singing trains". London now knows of Bollywood, but not everyone is a Bollywood fan. A critic in The Guardian spoke of the "unfeasibly garish world of Bollywood and all its attendant laughter, tears, trilling, twirling and navel-wobbling".

Webber's last play at the Apollo Victoria, Starlight Express, ran to 7,406 performances over 18 years. Bombay Dreams has been booked for a year. The box office is open but theatregoers haven't exactly been rushing in for reservations yet. The Really Useful Theatre Company will be looking at plenty of the "brown pound". Indians in Britain, and visitors from the US, rarely go to the West End. Now is the time for them to show money and, it is hoped, taste.

"It's the first ever West End show produced by Webber that has a predominantly Asian cast," says Preeya Kalidas. "And I am the first Asian female in the world to be playing the lead in a Webber musical. It's phenomenal, and that in itself will make history." But to pay for itself and more, that history will have to run and run.