First, the numbers. In his career to date, Simon Cowell’s acts have sold 100m albums and achieved 75 No 1 singles. In the last round of this year’s American Idol series, 63.2m viewers voted – more Americans than voted for George Bush. His latest show, America’s Got Talent, was NBC’s No 1 for the whole of last summer. This is a colossus bestriding our pop culture, who knows how to hold it down and slap it until it cries. On air, he’s careless with the dreams of young hopefuls: “If you sang like this 2,000 years ago, people would have stoned you”; “If your lifeguard duties were as good as your singing, a lot of people would be drowning.” Off air, he’s brutally ambitious: he set up The X Factor as a rival to Pop Idol, on which he appeared, but which was owned by his 1990s chart rival Simon Fuller, the man behind the Spice Girls. Cowell is branching out into drama and has been working on an updated movie version of Fame for the past couple of years. His combination of drive and sarcasm clearly pays: his company, Syco, employs a mere 11 people but was responsible for 40% of the profits of its parent, Sony BMG UK, in 2006, and this year’s Rich List values him at £100m.

Walking up the stone steps to his large Holland Park house, therefore, is slightly intimidating. There’s a chauffeur outside and a security camera that lights up when you press the bell at the gate. The James Bond part of me is hoping for the front door to open onto a sprawling laboratory of popular culture, with vast super-mega-computers calculating the perfect cheekbones for a male singer, and a secret room of songwriting elves bashing away at fairy pianos, writing hits for The X Factor. When Cowell comes to the door, however, he’s all bounce and smiles. He’s wearing jeans and a dark, crew-neck jumper, his hair tousled. He carries a small, unmarked brown bottle in the same hand as his cigarettes and lighter, and dumps them before perching on a vast modern armchair in an immaculate, tasteful room decorated in muted autumn colours, a bit like a hotel. (He lived in one once, until he got bored with the room-service menu.) He – or, rather, his housekeeper – makes me tea, biscuits and hot cross buns, and he chats away, hesitant and cheerful rather than dry and snappy. I make some obvious goofs that television’s Mr Nasty would have leapt on, but he’s warm and friendly, and constantly calls me “Stephen”.

We meet on the day before ITV records its second Simon Cowell This Is Your Life – the first was four years ago. Cowell is also conducting the first-round auditions of his new series, Britain’s Got Talent. This is a talent show in the postwar Butlins tradition. Anyone can enter, which means that boys with squeaky ears, men who play frying pans with a pen and truly atrocious comedy magicians all get their 15 minutes in front of Cowell, Piers Morgan and Amanda Holden, in effect expanding the best part of The X Factor: the insanity of the early stages. The show seems curiously old-fashioned,and when he says he wants it to revive variety, it feels as if he’s promoting an end-of-the-pier entertainment. “Well, I’ve always been a big fan of entertainment in the 1950s and 1960s,” he nods. “To me, that was the absolute pinnacle. There was a kind of naivety in those days that I enjoy. We went through a phase in the 1990s when we became incredibly cynical, and I didn’t like that. Now we’re back on track, because I don’t think tastes change.”

He says his hero was Mickie Most, the acerbic judge of the 1970s talent competition New Faces: “He was a smart guy, knew what the public wanted and wasn’t interested in the art of it all. He was just interested in being successful.” And when Most was on air, success was important to the young Cowell, sitting on the floor in front of the variety show on the screen, caught between worlds in Elstree. He knew he wanted to be successful – he just had to be – but he wasn’t sure how he was going to make it.

His parents were an unusual couple for their time. His dad was an estate agent who wooed his dancer mother on a train journey from Birmingham. The woman he won was a socialite with Celia Johnson vowels – “a creature of the 1960s. She absolutely typified that whole Jackie Onassis glamorous look. Very energetic, very vivacious, very camp. During that time, she was in her element”. Perhaps to sprinkle some fairy dust in front of his new wife, Cowell Sr took a job at EMI, running its property division, and moved the family into Elstree’s equivalent of Beverly Hills. Cowell loves to tell the story of their neighbour, Gerry Blatner, head of Warner Bros films in the UK, who threw fabulous garden parties. “As a kid, I would look over the fence at this great house and see everyone – Robert Mitchum, Elizabeth Taylor, all these great actors – having the time of their lives. I remember thinking from a very, very early age, ‘God, I hope I grow up and have a nice house so I can have parties like that.’”

But there were problems. For one thing, he hated school. He hated the lack of control – being told what to do, being forced to do things he didn’t like. He was expelled from three of them, and says it was only nicotine that got him through: “Because everything revolved around getting out of the classroom, meeting your friends, getting the cigarette and then looking forward to the next one. All of my school was about cigarettes.” After leaving with no qualifications, he tried a few odd jobs until his dad bagged him a place in EMI’s post room, and, finally, he could try to make it as Mickie Most.

He rose into A&R and found his 1960s tastes ideally suited to the multicoloured world of 1980s pop. He signed Curiosity Killed the Cat as well as the Stock, Aitken and Waterman moppets Sinitta and Sonia. Anything fun and silly – a single from the Power Rangers, or Robson & Jerome doing Unchained Melody, perhaps – he leapt at. He loved getting what he wanted. When he chased Robson Green to get him to record Unchained Melody, Green’s lawyer threatened him with a court order. Cowell simply switched his attentions to Green’s mum, and two months later the deal was signed.

It was only rebel music he didn’t understand – “I hated punk, and in the early 1990s, when house was big, I had a very bad time with my career” – and he narrowly avoided bankruptcy when his borrowing spiralled out of control. His tastes may be constant, but sometimes we, his public, can be fickle. He spent five years living with his parents, getting his career going again. By the late 1990s, he had just got Five and Westlife off the ground, and was preparing to launch Girl Thing, when television, a medium he had seen just as a tool, slipped him a low blow. He had turned down the chance to appear on Popstars, the first hit-maker show, in 2001, and he was furious to discover it was not only successful, but had stolen Pure and Simple, a song from his group Girl Thing’s flop album. “I was so mad, I thought, ‘I’ve got to do something to retaliate. I want Popstars off the market. I want to be on a show that’s going to kick it off the air.’ That was Idol.”

From then on, it became about control – revenge and control. He wanted to create the environment in which his acts would be showcased. He wanted to own the formats, not appear in them. He wanted every step of the process to be in his hands. He tells stories about meetings in America at which lowly office juniors would kick him out of the building. “I’ve still got an e-mail from three years ago, when I was launching my opera boyband, Il Divo,” he says. “I trusted this TV producer and got him in, saying, ‘I’d like you to listen to them before anyone else. You’re doing a big show, and I’d like them to be on it.’ The following day, my promotions girl got a mail from him, tearing the band apart and saying why they’d never be successful. I thought, ‘I’m never going to put my life in the hands of an idiot like that again.’”

When I ask him what bothers him about all of this, his face darkens for a second. “I don’t like being patronised.” Surely people don’t patronise a multimillionaire with global media properties. He gives a grim laugh. “All the time. All the time. It’s this weird, icy politeness you see a lot of in this business. People pretending to be happy about your success. I mean, I’m never happy about a competitor’s success. I despise it when somebody who isn’t working with me is successful on their own – it really upsets me. And I wish for their demise. And I’m very open about it, because I know they’re wishing for mine.” As a result, Syco now makes about 1,500 hours of television a year, much of it focused on promoting acts that are signed to his label.

Given that he’s now in a position to spread his tastes around the world, I ask him what they are. “If you look in my kitchen, you’ll find jellybeans and baked beans, nothing fancy,” he shrugs. “I like Jaws and Star Wars, rather than some Polish film with subtitles. A lot of the so-called great music of the world has bypassed me as well. I’ve just stuck to my guns. If I like it, there’s a very good chance other people will like it as well.”

So, what would we watch if you switched on the telly now? He smiles. “Stuff from 40 or 50 years ago. Black-and-white British films. I like St Trinian’s films, Cary Grant in Arsenic and Old Lace.” And what would we eat? “Roast chicken and roast potatoes the way my mum makes.” What about music? “It’s hard to relax with music – it’s work.” But isn’t there a fantasy band that you would have loved to sign? “The Beatles. Because they’re still worth a lot today.” Not because of the music? “No.” And then he laughs, and shrugs. “It’s true.”

I tell him I’ll be at the studio for the recording of This Is Your Life, and he grins with delight at the show. “I remember thinking the first one I did wasn’t great. It felt too early. I never watched it or read the book. Ally Ross wrote that it was hilarious watching Simon Cowell with no friends. So I made bloody sure this time that there are more friends. I’m updating it with the best four years

The following night, This Is Your Life’s studio is filled with Ricky Gervais, Sharon Osbourne and Ant and Dec, who parade on, deliver a few affectionate jokes and give the beaming Cowell a hug. Grateful X-Factor winners offer thanks for their break. Ben Elton says he wrote a novel lampooning Cowell having never met the bloke, but got a phone call from his office saying how much he loved it, and they’ve been mates ever since. The finale sees Il Divo singing Bernstein and Sondheim’s Somewhere, joined halfway through by his latest X-Factor protégée, Leona. The fivesome hit the high notes as fire cascades down the wall behind.

Then the show ends and the celebrities mill around on stage shaking hands and swapping kisses. Out front, the audience are on their feet applauding, when something strange happens. At his moment of utmost triumph, Cowell takes the red book and steps down from the podium, walking forwards until he’s standing, alone, between the backslapping on the podium and wild cheering from the crowd. He holds the book out towards us and it’s hard to tell if this is a tribute or a sacrifice. Why has he stepped away from the glamour and the pop stars to face us like this – with his feet apart and the book thrust forward in both hands? Perhaps because we are the public, the people whose moods and whims have tossed him around and down, then up far higher than he could have possibly dreamed when peering over Gerry Blatner’s fence. I read his name picked out in gold on the book’s crimson cover, then glance up and catch the set of his jaw and glint in his eyes. I realise that, for the first time tonight, he isn’t smiling.

Britain’s Got Talent starts on ITV1 on Saturday

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