Love them or loathe them, TV casting shows have proved to be a legitimate way of launching a career in musical theatre. Agents, producers and casting directors may once have sneered at the idea of turning the audition process into a voyeuristic light entertainment show viewed by millions, but these days a lot of the auditionees are experienced professionals proposed by their agents.

“It’s just another form of open casting,” says Donna Soto-Morettini, who has worked as a casting director and performance coach on all the TV casting shows. “If anything they are more humane than the traditional open call auditions. The BBC in particular is very careful to make sure that everyone coming to an open call is treated well and has a positive experience. Since the trend for celebrity casting became the norm, they are now the only way of getting an unknown cast in a leading role in the West End.”

Soto-Morettini will be drawing on two decades of teaching, training and auditioning musical wannabes when she presents TV Talent Show Audition Secrets, in The Stage events series, at the Prince of Wales Theatre on October 31. She has also just brought out an invaluable book about auditioning, Mastering the Audition – How To Perform Under Pressure, in which she suggests various strategies for dealing with one of the most brutal tests of character, guts and nerve, not to mention talent, known to man.

I look out at this sea of people and ask myself, ‘Why are we getting it so wrong?’

In the book she describes auditions as “flawed, nerve-racking, panic-inducing and wholly unpleasant”. They are, however, a necessary evil and, according to the author, one which is best addressed by understanding the nature of the beast.

Having worked in both traditional audition situations, as well as the TV kind, for many years, she firmly believes that the latter is every bit as valid and worthwhile as the former. She disagrees vehemently with those who feel that TV casting show victors lack the stamina or the long-term training to sustain a career on the stage.

“If you survive what gets thrown at you in a TV casting show, you have already proved you have stamina and flexibility, that you can learn quickly, and that you can connect with an audience. That’s exactly what the conservatoires are trying to achieve – stamina, courage, flexibility.

“The quality of what comes out of the conservatoires is incredibly varied. There is not a casting director in London who would disagree with that. I’ve spent as much time trying to undo what training has done as I have trying to help people who’ve not been trained. The whole training thing doesn’t always work for kids with raw talent.

“There was one very talented kid I recall who, after three years, felt his training hadn’t helped him at all. It had made him over-analytical, he doubted his talent, and he felt he didn’t want to do it any more. What he had once felt passionate about was turned into something functional and regimented.”

That said, Soto-Morettini believes preparation, guts and self-knowledge are the keys to success in auditions, over and above raw talent.

“If you do a lot of prep, even without being enormously talented, it can get you through. Often it is all about the aura of mastery and confidence you bring to the table, what you might call presence. The auditioners need to feel they are in safe hands. It often helps to have an inflated sense of self-belief.”

In musical auditions, how important is it to choose the right songs?

“It is the critical thing. I’ve been doing auditions for the new series of The Voice since August and I can’t tell you the number of times my note has been ‘What a poor choice of song’. The reason it is so critical is that you have to choose something that really suits your voice. The producers of The Voice, more than any other show I’ve worked on, are looking for people who know their own talent. What kind of artist are you? What’s the kind of music you do best?

“Our ability to assess ourselves is poor. One of the reasons I wrote the book was to examine how it is we can be so self-deluded. With the ‘bedroom singers’, the rank beginners who have only sung in front of their bedroom mirror, they really don’t know what the standard is, which means they can’t judge the sound of their own voice. The longer you stay singing in your bedroom, telling yourself how good you are, the worse it gets.”

Is there a type of performer who should steer clear of TV talent shows?

“I’ve watched some seasoned professionals make big mistakes on these shows, so you need to ask yourself, ‘Could I damage my career by doing this?’ In a couple of cases last year, I’d say the answer to that was a resounding yes. But if I were a talented youngster now, trying to launch my career, I’d have a go, even if I’d done my three years’ training.”

How have the TV casting shows changed the way the theatre views the audition process?

“What’s happened is that a lot more people know how the audition process works, from watching it unfold on TV. Friends tell me auditionees are a lot more gobby now. They’ll say, ‘Hang on, I don’t think you really understood what I was trying to do’, whereas in the old days they would just leave quietly after they’d done their audition. Casting is quite a small world, so it is not a good idea to antagonise those behind the desk.

“One of the reasons I wrote the book is that I see so many performers driving themselves crazy, and sometimes giving up on themselves, because they are having to sell themselves under conditions of horrendous pressure. I have watched mediocre people swear they’re brilliant, I’ve watched baritones who said they were tenors. I look out at this sea of people and ask myself, ‘Why are we getting it so wrong?’

“I don’t think we prepare young people well for auditions at the training level. I genuinely think there is a gap there that needs to be filled. So my book is aimed as much at the schools and the teachers as it is at all the people who went through training.”

The Stage Events – TV Talent Show Audition Secrets is at the Prince of Wales Theatre on October 31. Mastering the Audition – How to Perform Under Pressure by Donna Soto-Morettini is published by Methuen Drama, priced £14.99. Methuen Drama are offering a 20% discount and free postage and packaging (£12) when you order direct by calling 01256 302699 or emailing direct@macmillan.co.uk and quoting offer code GLR 8AF.