Nobody knows Simon Cowell like rival The X Factor judge Louis Walsh. As a new series of TV’s biggest show begins on ITV1 this Saturday, Louis told TV & Satellite Week magazine about the man behind the myth…

Simon Cowell is the saviour of Saturday-night TV… The secret of his success is really quite simple: he makes the kind of TV that he’d like to watch himself. He’s one of the few people who truly understands television. He knows what people like. He has an instinct for popular taste like nobody else in the industry.

There’s nobody else who could have done what he has done with The X Factor… Nobody knows as much as he does about music and, perhaps more importantly, nobody knows as much about people.

Simon has got phenomenal instincts… He’ll say: ‘That’s got to go in the show, it will make people laugh.’ Or he’ll say: ‘People are going to go “Oh my God, what a voice, what a song” when they hear this.’ Sometimes you want to argue with him when he says it, but he has never been wrong.

Simon and I are both ultra-competitive… We’re not just competitive within the show, we’re even more competitive about making the show top of the ratings. He always wants us to be the number one show – and he always wants every show to be better than the last one.

There’s a lot more to Simon Cowell than the man you see on screen… He’s far more intelligent, far more articulate. He doesn’t just show up on a Saturday night thinking up smart comments. There are always 10 things going on in his head. As the brains behind the show, he’s always pushing the producers, the choreographers, the people who pick the songs, to get more out of them. He hates people getting complacent.

Of course, that means he’s tough to work with… But that’s what makes him good. You never see him lose his temper. He doesn’t swear at anyone. He never raises his voice. He just says: ‘I think it would be better like this’.

Simon and I go back a long way and he has always been the same… We first worked together around 1998 at the time of the launch of Westlife. Even then, he was always insisting we needed better songs, better videos, better styling. That’s just the way he is.

I know he has his critics, but those people don’t really know him… They say he’s smug. That’s not smugness, that’s just his Englishness. Andrew Lloyd Webber has it, Richard Branson has it. He’s really very down to earth. He may have the big cars and the big houses, but he’s actually very ordinary. It’s important to him that he stays in touch with ordinary people and what they like.

The music industry doesn’t understand him because he’s never interested in credibility… He always goes for sales. You’re never going to see one of his acts winning the Mercury Prize and he’s never going to be critically acclaimed. But he’ll always be in the bestsellers.

He’s the Rupert Murdoch of the music business… People are sniffy about Murdoch’s newspapers, but they still sell more than anyone else’s.

Of course, I still get annoyed with Simon sometimes… He knows how to prod and press the buttons to annoy you – and he knows he’s doing it. If during the auditions, for instance, I say something really good, he’ll turn to the cameras and say exactly the same thing. Then he’ll look over at me and say: ‘Guess which one of us you’ll see saying that in the finished programme?’ But he does it in a really funny way. I really believe the man’s a genius.