A few questions: can an unknown new musical with no big stars be a hit? Can an unknown new musical with no big stars be a hit as the West End in London copes with the recession? And, perhaps most importantly, can an unknown new musical – set in the Warsaw ghetto in 1942 – with no big stars be a hit as the West End copes with the recession?

This is the challenge that the team behind Imagine This has embraced. In a small Southwark rehearsal studio the ensemble is going through an intense sequence set near the ghetto walls. Old furniture is piled up at the side of the room. About 20 blue plastic pistols litter the floor. The smell of sweat fills the air. If perspiration sold tickets Imagine This would be booking beyond the next Olympics. But, all things considered, they have a mountain to climb.

For the people behind the show this is clearly a labour of love. The director, Tim Sheader, is currently the artistic director of Regent’s Park Open Air Theatre. After helming Gigi this is anything but a walk in the park, but he does not feel that the subject is particularly controversial.

“In terms of subject matter it starts from where Cabaret left off. We don’t go into Auschwitz, but we start with the incarceration. Cabaret was provocative and new when it opened, but since then there have been plenty of movies that have covered this area – Schindler’s List, The Pianist, Life is Beautiful – so we are following in the footsteps of commercial work.”

Stage, however, is very different from screen, as Liam Steel, the choreographer, acknowledges: “Theatre doesn’t have the luxury of film. We have to work really hard covering a very long time-span very quickly and still hit the gut. The very first song, The Last Day of Summer, starts with freedom in 1939 and ends in imprisonment in 1942.”

The action draws on Jewish history with the bulk of it taking place in a play-within-the-play. The ghetto inmates decide to act out the 2,000-year-old story of the siege of Masada, when 936 rebels committed mass suicide rather than be captured by the Romans. The resonances do not need to be spelt out. Meanwhile, a resistance fighter is hiding from the Nazis and a young woman falls for him. Can love bloom with tragedy looming?

Imagine This was due to be staged on Broadway in 2005 but a financial hiccup intervened. It had a brief run in Plymouth last year, when backers were impressed enough to finance this West End opening. Sheader is excited at the prospect of a meaty show. “I’m sick to death of seeing another rehash: Take That, Rod Stewart. Hen night theatre has its purpose but there is more to musicals than having a laugh.”

The team all cite Sweeney Todd and Les Misérables to argue that dark subject matter and massive success are not mutually exclusive. They may have a point. In Spain earlier this year an Anne Frank musical was a hit, while American Psycho: The Musical is Broadway-bound. But regardless of subject matter, Imagine This has its work cut out. When cash is tight theatregoers may opt for escapism. And there is no real bill-topper. The biggest name is Peter Polycarpou, who starred in Phantom of the Opera and can certainly belt out a tune, but who lacks a Michael Ball/Crawford fanbase.

Sheader is determined: “It’s a gamble, but it has to work on the strength and integrity of the piece. It is a celebration of the human spirit. I’d find it far more difficult to sit here and convince you that The Producers would be a hit,” he argues. “That kind of pastiche and irony is tougher, this is honest and on the nose.” But can being on the nose put bums on seats?

The team bringing the project to the UK understanda-bly shares Sheader’s passion. The LA-based lyricist David Goldsmith jumped at the chance to be involved. “It is rare to get the chance to do serious theatre material as a lyricist,” he says. “You invest your heart and soul in it.”

Glenn Berenbeim, a neat, talkative American who wrote the story, recalls being approached by the composer Shuki Levy. “Shuki had a lifelong dream of telling the Masada story. When I met him I said, ‘There are 35 subjects that would interest me more if you want an audience to watch a bunch of people killing themselves.’ Then I listened to his music and was frustrated to find it so appealing – because I really wanted to walk away.

“Who wants to pay $100 to see characters kill themselves unless it’s opera? But then I had a flash, the idea of ghetto actors putting on a play about Masada, and I was suddenly interested in the story for its metaphorical value, not its robes and sandals.”

The trio have solid show-business pasts. Goldsmith is a successful television writer, Berenbeim most notably co-wrote the pseudo-religious drama Touched by an Angel, while Levy penned music for He-Man and the Masters of the Universe and the TV version of Inspector Gadget. Excerpts from Imagine This on the show’s website vary from the cheesily soaring to the cornily sentimental. It might be more meaty than We Will Rock You, but Primo Levi it ain’t.

Berenbeim talks a good fight: “Every time something comes along and helps redefine what a musical is about, whether it is Showboat or Jesus Christ Superstar, something opens up and theatre adjusts.

Who would have thought anyone would want to see singing cowboys in Oklahoma or a bunch of people talking about their careers in A Chorus Line?”

Goldsmith and Berenbeim are both Jewish but do not see Imagine This as a Jewish project. Neither does the producer Beth Trachtenberg, who points out that more than half the backers are not Jewish. “It is very important that this is not a story told by the Barmitzvah Club,” laughs Berenbeim. “One of the cast has spoken movingly about losing family in the Holocaust, but most are not Jewish. My father was the product of a long line of rabbis, but he converted to Christianity when I was 30. Theatre is my church, if not my religion.” He puts his hands together. “It is not a coincidence that praying and clapping seem the same.”

In the back of my mind I keep hearing the Spamalotsong, You won’t succeed on Broadway if you don’t have any Jews. If only theatre was that simple. Imagine This is a story of striving against incredible odds. I wish it well. And if Imagine This survives in the West End it will be a story of triumphing against incredible odds.

UNLIKELY SUBJECTS

Cabaret Swastikas-and-suspenders mix has made this a perennial hit (1966)

The Producers Mel Brooks’s all-singing, all-dancing Nazis put on stage (2001, above)

Jerry Springer: The Opera Trailer trash telly critique that wound up Christian groups (2003)

Thalidomide!! A Musical A love story that also tells the story of the notorious drug (2005)

I, Keano Tribute to soccer hardman Roy Keane relocated to Ancient Rome (2005)

Thatcher The Musical! The nine ages of Maggie from grocer’s daughter to diva (2006)

— Imagine This previews at the New London Theatre, London WC2 from Nov 4 and opens on Nov 19 (www.imaginethisthemusical.com 0844 4124654)

Editor's choice

• Vote for the Breakthrough Award winner
• David Tennant back as Hamlet after back surgery
• Matt Smith is the new Dr Who