He is officially the most powerful person in British theatre and the man behind such smash hit productions as Grease, The King and I, Guys and Dolls, Saturday Night Fever and Chicago.

More recently, producer David Ian has given us the Fame-esque television series Britannia High and was the first to take the potentially risky step of hunting for West End stars via television talent shows. He appeared alongside his Sound of Music co-producer Andrew Lloyd Webber on the BBC’s How Do You Solve a Problem Like Maria? before controversially defecting to ITV for Grease is the Word.

In doing so, David left the relative anonymity of theatre production and emerged from the wings to find the spotlight firmly trained, not just upon the West End stars he was creating, but also upon himself.

So what effect has his newfound fame had on the 47- year-old?

With his sharp suit, winning smile and shock of silver hair he certainly looks the part.

“If people know you, your failure tends to be public,” says David who recently knocked Andrew Lloyd Webber from the top of The Stage 100 – the newspaper’s guide to the most influential people in UK theatre.

“People don’t normally remember a producer – they’ll remember the star or the writer. But when you have a public profile it’s harder to have a private disaster.”

Yet remarkably, David’s unconventional method of casting leading men and women – handing the job over to the voting public live on national television – hasn’t backfired.

Grease is the Word winner Danny Bayne is still wowing West End audiences in the classic musical while Connie Fisher attracted more than a million theatre-goers to the London Palladium to see her take on the role of Maria in The Sound of Music.

She has since won over the critics, made her television debut in ITV drama Caught in a Trap on Boxing Day and is about to embark on The Sound of Music Tour which comes to The Mayflower, Southampton, in September.

The idea for How do you Solve a Problem Like Maria?

arose from a BBC meeting, explains David, who, as chairman of Global Theatre oversees the programming of more than 58 theatres worldwide.

He had already jumped at Andrew Lloyd Webber’s invitation to co-produce a revived version of the classic Rodgers and Hammerstein musical, but letting the public choose their Maria was, he admits, a “massive gamble”.

“In the final ten there were only about three girls who I knew could have done it. If one of the others had got it we would have had a disaster of catastrophic proportions.

“I always thought it was more of a risk than other reality shows. There was a stage production at stake.

After Strictly Come Dancing the winner can go back to news reading or whatever they do, but this was eight shows a week in a live situation and with 2,000 people in the audience – there was nowhere to hide.

“I was fine until we started seeing everyone and lots of people were wrong for the role. What if we had a John Sergeant situation with people thinking ‘wouldn’t it be funny to vote for that one who can’t do it’. I had a fear about that. “But the public took it seriously. They knew they were voting for someone they would pay money to see. Even with Connie firmly ensconced at the London Palladium, David found himself having to defend his method of casting in the face of industry snobbery: how could a relative unknown rise to the challenge of a West End leading lady? What had happened to working your way up the ranks? “I understand why they were saying that,” says David. “But the girl who won is the one with the musical training. In all of these shows, the public have picked someone who is already a theatre performer. “There’s nothing remotely easy about the television show route. Other performers have an interview but we’re talking about being auditioned by six million people every week – that’s a huge test of resolve. “Also, to those in the industry who aren’t happy about it, market research shows that 70 per cent of the people who watch those shows have never been to the theatre so we know it is encouraging a new generation of theatre-goers. There’s no doubt that shows like this have transformed the West End business.” Soon Southampton will get a taste of the excitement when David Ian brings The Sound of Music, starring Connie Fisher, to The Mayflower. “All the shows I produce from Grease to Chicago we do in Southampton,” he says. “The Mayflower is truly the premiere theatre in the south and it’s always high up on a show tour.” Transporting a West End show – complete with spectacular moving mountain backdrop – is no easy task. “It’s got to be the London Palladium show but it also has to be moveable so we can break it down and transfer it between theatres,” explains David, who has enlisted the help of the original creative team, including choreographer Arlene Phillips (his fellow producer on ITV drama Britannia High). “People really are going to see the London Palladium show when they come to Southampton,” he says proudly.