I'm not rude - I'm realistic

It turns out that Walsh has always been in the centre of some feud or other. Primarily, there is his endless criticism of Robbie Williams. "I don't care if people don't like me for telling it like it is about Robbie," says Walsh, drinking three cups of coffee and eating a huge hamburger and chips ("I haven't had any food since yesterday!" he says a touch defensively). "Robbie has no talent," he says.

He's also fallen out with former protégé Ronan Keating and with Pete Waterman. "Ronan sacked me as his manager two years ago," he says. "He wanted to write his own songs and go in his own direction, and I told him he was no George Michael but he was a great Cliff Richard, and he took offence.

"I was pissed off at the time but now I don't care that much." And Waterman? "Oh, that was ego," says Walsh. "It was because my group, Girls Aloud, got the Christmas number one and his didn't."

He is also renowned for being very controlling with everything about his protégés. I have friends in Dublin who paint a picture of him as a coldhearted, money-obsessed egotist. "Look," he says, "I know how people can be successful. If they want to be a pop star and make money and last on the music scene, they should do as I tell them."

But if Louis Walsh is truly unpleasant, he doesn't reveal that side to me. I'm sure all the Oirish gossipy stuff is part of his shtick, but everyone loves a gossip and he's so good at it. He tells me all sorts of things, most of which are, unfortunately, libellous.

What I really want to know is whether he gets on with his fellow judges. Do they hate one another and argue all the time?

"Not true!" he says, holding his hands up in the air. "I mean, they've both got pretty big egos but I get on with them both. I really do. Sharon's a star. Everyone loves her.

"When we are at auditions, and someone dreadful is singing, she keeps a straight face but she's kicking me under the table which makes me start laughing. I see her all the time."

What about Simon Cowell? Are they friends? "Simon's Simon. He thinks the show is all about him really. He's so self-centred, you know, he got cross with me when I referred to him, on the show, as having had his teeth done but, you see, I've come out of my shell since last year."

He certainly has, but why? "Last year I hadn't done much television. This year, though, I feel I'm being more like myself. I don't think I'm being rude to people, not at all, but I think I'm being realistic. These people want to be pop stars! They're going to have to work hard and get used to criticism."

Louis Walsh knows all about success and failure. At the age of 49, he's been a pop promoter for more than two decades. "I'm one of nine kids in my family," he says.

"When I was growing up in Kiltimagh, County Mayo, all my friends and siblings were playing football but I wasn't. I was in my room listening to pop music. I bought that Antony and the Johnsons CD before it won the Mercury Prize. Then I'll go and get something completely different the next week. I love the old favourites, the Spinners, the Platters."

But it's this love of the old favourites that has got him into trouble with the other two judges on The X Factor. "Sharon and Simon keep moaning that I have chosen the wrong songs for my acts but I've told them to bog off.

"Simon chose me to be on the programme with him because I love music, so it would be ridiculous of him to complain about my choices. Simon doesn't like music! He doesn't even buy CDs."

His career took off after talent-spotting Johnny Logan of Eurovision fame. "I was sitting in a town hall somewhere in the middle of Ireland when I heard Johnny Logan sing. I saw something then. We did What's Another Year and he won Eurovision."

Since then he's managed Samantha Mumba - "now in the States," he says - and, more famously, Boyzone. "They had two good singers in Stephen Gately and Ronan [Keating], and the other three were just token Ringo Starrs."

Walsh is notorious for keeping tight control of his protégés and, for a while, Boyzone were squeaky-clean pretty Irish boys with a hugh following of pre-teen girls. And then Stephen Gately came out as being gay.

"I thought it would cause a terrible rumpus and it did," says Walsh. "Everyone went wild over it and it was a hard time for Stephen, but he weathered the storm. Coming out now doesn't cause the controversy it used to then."

Walsh, however, is quite used to controversy. His own sexuality is often gossiped about, but not by him. He is unmarried and lives half his life in Dublin and half over here. He has a flat in the Philippe Starckdesigned Yoo Building in Maida Vale, as well as homes in Dublin and Miami, plus a collection of cars and modern art.

"I lead a quiet life," says Walsh. "I don't do anything to excess. I'm against drugs really, especially for pop stars. I manage boy bands. They have to be clean. When I'm at home I see my friends." Any special friends? I ask him. "I have lots of good friends," he says evenly.

What's next then? "I'm looking for a new Irish boy band," he says, "and I'm having a break."

If his future looks good, what about the future of those seven remaining contestants on the show?

Walsh believes that Journey South, Shayne and Andy could well get record deals. "We have better people on the show this year." And who is going to win? "I couldn't possibly say," he answers coquettishly but then looks around secretively and mouths a name at me.

On the pain of death, I cannot reveal it as I promised him I wouldn't. "Simon would kill me!" he says.

But then Walsh looks reflective. "Mind you," he says, "you Brits are weird. Steve Brookstein won last year and he was terrible, so who on earth knows really?"