I reckon that deep down international theatre producer David King cares about his art. He may seem more interested in box office receipts than whether his shows move his audience's emotions or stimulate their intelligence, but twist the arm of the man who in the 1990s made a mint on a song-and-dance show called Spirit of the Dance, and there is a detectable pride - not just in the millions it made him, but that it eventually became "first-class quality".

This was the show inspired by Michael Flaherty's hit Irish music and dancing extravaganza Lord of the Dance. It had similar music, similar dance moves - the poster even had the strap line "In the footsteps of Lord of the Dance". This was the first of many productions that King cheerfully calls his "knock-off" shows. Mind you, you really have to twist that arm. For the most part King is very candid about why he is in show business, and it has got little to do with art.

"I'm a huge success," says King, who is the latest tycoon to spread his largess on Channel 4's The Secret Millionaire. He is sitting in the bar of a smart West End hotel, his camel coat draped over the back of his chair. A fast talker, he ignores the cappuccino in front of him. "I'm probably the most successful international producer in the UK," he shrugs. "I sell more tickets than Lloyd Webber and Mackintosh."

Although we are sitting in the heart of London's theatreland, this is not home territory for King. No matter how successful, a David King show rarely ends up in the West End or on Broadway, a track record which clearly pleases him no end.

"I go to the parts that other West End producers don't reach," he says. "I play venues in American towns that you've never heard of - that I've never heard of. Instead of playing Chicago, I'll be 5,000 miles away in a town of 30,000 people that is starved of any kind of entertainment. So when one of my shows come into town, it's as if the West End has arrived. They're like: 'Oh my God, I can't believe it'. I'm bringing 24 dancing singers, lights and props and sound to a nowhere town in the middle of America."

'I'm a huge success. I sell more tickets than Lloyd Webber and Cameron Mackintosh

For theatre cognoscenti, it is probably fair to say that a David King show is probably nowhere near as entertaining as a conversation with the impresario himself. The productions run to a strict formula. He takes an idea - often one that is well proven in the West End, such as the Abba musical Mamma Mia! - strips out anything that resembles a story, keeps the music, adds his own choreography and tours the result around provincial theatres all over the country, and the world.

"I'm not going to win any Olivier awards. I'm not going to get an Oscar for my work. But I can tell you this, I'm the bank manager's best friend," he says.

I am beginning to worry for the Leeds-born multi-millionaire-several-times over. He has a tendency to be completely honest when talking about his shows. "If you're someone who just wants to go out and have a great time, and watch a no-brains-required show, then I'm your man." I worry that when he speaks about how uncultured his American audiences are, and how little intelligence his shows need to watch them, that we may be approaching a Gerald Ratner moment.

But then buying a ticket for a good night out is not the same as buying an engagement ring. Cheap - whether in price or in taste - is not something that people worry about being associated with when going out on a Saturday night. King, a former market trader whose previous businesses do actually include a string of jewellery shops, clearly knows his audience. Perhaps he should. He is the son of a ukulele-playing music hall comedian whose act was very similar to George Formby's. Except while George topped the bill in the big theatres, Stanley King toured his act around the smaller venues.

It is only obvious now, but King's shows do much the same thing by touring the provinces while the more famous original versions do business in the big venues.

"But I have to say that the quality I now produce is first class. It's probably 90 per cent of a Broadway or a West End show," he says. And then he adds with perhaps a little more self-deprecation than is good for him: "You wouldn't quite put them in the London Palladium but you could easily put them in Woking or Milton Keynes".

The King empire was created out of an act of purest chutzpah. His businesses were doing badly when a friend dragged him to see Flaherty's show. He left the theatre thinking: "I could do that" and spent his "last 100 quid" on a poster advertising Spirit of the Dance. The show did not exist and when Flaherty's producers at the Apollo chain of theatres hauled him in for a meeting and presented him with a copy of his poster, he fully expected to be sued. Instead, he was asked how soon he could open in Apollo's other venues.

That was in 1996. These days King shows number in the 20s. He can be employing 500 dancers at anyone time. He is coy about how much he is worth, but admits to at least £40 million.

"It's been a bloody miracle," he says. And then, ever with an eye on the bottom line adds: "It's like I've done a bank raid and not gone to prison."

'The Secret Millionaire' is on Channel 4 on Monday May 14 at 9pm