'From where I'm sitting," splutters Jeremy Sams, "I can't think of anything less safe in the world." The director seems flabbergasted, wounded even, by my suggestion that his new West End production of The Wizard of Oz seems a surefire hit. After all, it reproduces much of the formula that made Sams's 2006 staging of The Sound of Music such a triumph: it's a musical better known as a film; it's an Andrew Lloyd Webber collaboration; choreographer Arlene Phillips and set designer Robert Jones are back on board; the lead, Danielle Hope, is an unknown who won the part in a reality TV show, Over the Rainbow.
"Nothing's safe," continues Sams. "Nothing's safe, and to say safe almost sounds pejorative and derogatory. There are good titles – but if you don't respect a title, the audience throw shoes at you very quickly."
If contemplating the audience makes Sams nervous, he has no fears about his creative team. "These are all people who have done big shows, so when things get hairy and scary and look massive, they can say we've got through this before, we'll get through it again." It also helps, says Arlene Phillips, that "we can pick at each other's work. None of us are precious about anything if, in the bigger scheme of things, it isn't going to work."
Nor does Sams feel any trepidation about working with a young actor whose only qualifications are a drama A-level and three months of training. "We always wanted a young girl, aged 17 or 18, so whoever we cast, it would have been the same issue," he says. As far as he is concerned, Hope's appearance on reality TV has been nothing but advantageous – not, oh cynical reader, because of the attendant publicity, but because "someone who's got the fearlessness to get through a TV job like that arrives with a certain amount of chutzpah. It's an audition process and an unbelievably stressful and public one."
Hope is perfect casting, he thinks, because she embodies "the most key thing for Dorothy – not ever to be defeated or downhearted. Even when things are going against her, she has to believe it's going to be OK." A few minutes in Hope's company is enough to see what Sams means: she is radiant with optimism. She is so down-to-earth, you wonder what possessed her to enter Over the Rainbow.
"I'd never watched a reality TV programme," she laughs. "I didn't know what I was in for." She only applied because she didn't think she would be able to afford to go to drama school. Despite her inexperience, Hope talks like a seasoned actor. Asked if she feels burdened by the responsibility of comparing favourably with Judy Garland, she admits that she did initially, but then says firmly: "I'm not going to imitate Judy because no one could and no one should. I made a conscious decision to find out who [Dorothy] was – if you make that as real as possible, an audience should forget about what they've seen."
Nonetheless, it's clear that the fame of the film is as much a curse as a blessing. "There's no way of replicating it, because how do you put a movie on stage?" asks Sams. "Movies have different logic, different structures, different feel, different tempo." Yet there is a sense in which it is the movie that audiences come to see – and the creative team respect that. "I'd be mad to reinvent it completely," says Robert Jones. "Everyone's got images in their head of what The Wizard of Oz is, and to an extent you've got to give them that. But it's got to be my take."
With another Oz story, Wicked, already attracting huge West End crowds (last year it broke box-office records, earning over £1m in a single week), Sams and Jones know that, to compete, this has to be a lavish show. But it isn't just that, says Sams: the story demands visual extravagance. "It's a picaresque with scene after scene after scene in different places, so the show has to be perpetually delivering more things," he says. The stage for Oz has a triple revolve, with a system of hydraulics that can raise or tilt each section. The models for the design alone took five months to make; and, with 25 scene changes, the building of the set has been "a nightmare".
It has also made the transfer from the rehearsal room – a bog-standard space with a resolutely flat, still floor – problematic. "So much of the movement becomes hit and miss," says Phillips. "A stage section you thought was going to be smooth has a gap and you can't ask people in high heels to tread on it. It's a complicated process."
And then there's the last-minute work required to tailor the show's lighting and sound. I spend an afternoon watching rehearsals, and progress is agonisingly slow. I start watching at 2pm, as the projections team screen a just-finished animation of the haunted forest. There is a long lull, then the Wicked Witch's wrought-iron castle revolves into position, presided over by Hannah Waddingham's imperious witch and two terrifying monkeys. It looks glorious – but it has taken an hour and 20 minutes to run through barely two minutes of show.
The danger, Sams recognises, is that this intense focus on getting the technology working, testing lighting and sound effects, tailoring the choreography to the stage, might swamp the story at the heart of the show. "The trick," he says, "is to take what we had in the rehearsal room, which is a heartfelt, touching, small thing, and make it small but big." But despite all his jitters, he's clearly having the time of his life. "It's The Wizard of Oz," he says cheerfully, "and who wouldn't want to work on The Wizard of Oz?"
