All aboard Cowell's loveboat! Mogul's happy harem actually all hate each other, he uses mood swings to control them... and he's got a bizarre blueberry addiction, says insider By Olga Craig and Charlie Lankston She is stunningly beautiful, immaculately groomed, and plays a crucial part in Simon Cowell's life. No, she's not the latest member of the music mogul's "harem" but Slipstream, the £50 million motor yacht that has quietly played a starring role in the international drama that is Cowell's love life. And despite all her luxurious fixtures and fittings - which include everything from a bubble machine to a private "skylounge" cinema" - life aboard is anything but a holiday. As Cowell joins the woman expecting his baby, Lauren Silverman, on dry land nearby, The Mail on Sunday can reveal the most detailed account so far of life aboard "the loveboat." Centre of attention: Simon Cowell lounges with his ex-fiancee Mezhgan Hussainy, left, and pregnant lover Lauren Silverman, right on one of his many luxurious holidays Quite a view: Cowell's friend and colleague Kelly Bergantz, right and sister Jamie, left, entered the bizarre world on the Slipstream- the music mogul's 200ft yacht It's a truly bizarre world he creates. Quite mad," our insider source reveals. Cowell is currently darting between the St Tropez villa where he is officially staying with the mother of his unborn child, and the decks of Slipstream, where former girlfriend Sinitta and a bevy of other glamorous female friends are spending time. Indeed, Silverman's morning sickness won't stop Cowell continuing his customary summer break on his floating gin palace, currently moored near Lauren's villa. The deck of the 200ft vessel still resembles a photoshoot for a Pirelli calendar. Beautiful bikini-clad women, their skin tanned and oiled, are draped languidly on artfully arranged loungers. Father-to-be he may be, but Cowell, 53, still loves life on the ocean wave, if only in harbour. And, champagne flutes in hand, his coterie of female hangers-on still fawn upon the only male passenger aboard, hanging on his every word. He, by contrast, feigns an air of tolerant embarrassment, tinged with macho pride. Lauren, 36, the estranged wife of Cowell's one-time best friend Andrew Silverman, flew out to the South of France on Wednesday and this weekend she and Cowell were expected to join Sir Philip Green for his party at the new Bar D'O on St Tropez's Pampelonne Beach. Meanwhile, as ever, all is orchestrated aboard Slipstream to portray a glamorous harem, happily frolicking together. But life aboard is not the bliss Cowell would have us believe. According to one of his close friends - offering the first insider account of life on the yacht under the condition of anonymity - it is anything but. In fact, the insider says, it is a claustrophobic cauldron riven with rivalry, and ruled by the manipulative media mogul who dictates the dress code and freezes out those he decides should disembark. The chosen one: Simon Cowell's affair with Lauren Silverman, who is now expecting his baby, is said to be the 'worst kept secret on board' On dry land: 36-year-old Lauren Silverman joined Cowell in the South of France this week. Despite their relationship, Cowell invites glamorous women onto his luxury yacht, where they vie for his attention "Believe me, those women hate each other," says the insider, who has holidayed with Cowell aboard Slipstream, which costs £1.3 million a month to charter. And Simon plays them all off against each other. He loves them fighting over him. He makes a point of flirting with a different woman each night, then blanking her the next day. It all helps to explain a quite intriguing question: why so many discarded girlfriends continue dancing to attention - even in the humiliating presence of Cowell's latest conquest. He likes to cultivate this totally competitive environment and ensures that the women are at each other's throats night after night. He delights in the tension among them he causes. They are anxious all the time, desperate to be the most popular, the one to whom he pays the most attention. For Cowell it is all about control, the insider insists. And he ensures he is always calling the shots. It's a surreal experience. Simon's mood dictates the atmosphere on the boat," he says. And the women never know what to expect. One minute he is happy, the next moody and brooding. If he is in the right mood, the yacht can be a real party. Drinking, dancing, having fun. If not, they know to shut up and avoid his ire. Along with 1980s pop star Sinitta, Cowell's former fiancee Mezhgan Hussainy is due to fly out in the next few days, as is TV presenter Lizzie Cundy. Jackie St Clair, another long-standing member of the posse, is said to have turned down her invitation because she and Sinitta dislike each other intensely. With Lauren initially away dealing with her divorce, Cowell missed Jackie's presence as he likes to confide in her. "Simon was on the phone to people for up to six hours a day," the insider says. He is really upset that Jackie isn't there because she is his closest confidante. Others who have been privileged enough to step aboard the boat this summer include Kelly Bergantz, Cowell's powerful television lieutenant, her husband Ben Belldegrun and her sister Jamie. Cowell's modus operandi is to constantly wrongfoot his bevy of beauties with his mood swings. They never know what he is doing or thinking. He might say midway through dinner that he is going to the lavatory, then disappear and not return to the table Or he will stay up all night and only get up at 3pm the next day. He books tables when the yacht berths, tells the women to be dressed in their best, then doesn't turn up himself. Seat of power: The yacht's opulent lounge, where Cowell works on the X Factor at 4am and relaxes with his bevy of beauties Isolated: Cowell's unpredictable mood dictates the atmosphere on board. He often makes plans with the women and doesn't turn up Moody: If Cowell gets tired or fed up of a member of his harem, he makes sure they know they are no longer welcome on his trips For both Cowell and his coterie, the relationship is symbiotic. He revels in being surrounded by - and photographed with - his beauties and they crave the publicity. And no doubt they also enjoy the fabulous luxury, for no expense is spared when it comes to making Cowell comfortable, with a fleet of staff, including an award-winning chef, five stewardesses and two deckhands. Along with the cinema, open-air Jacuzzi, exercise bikes and running machines, the yacht is stuffed with every water plaything available, including inflatable "globes" that allow the user to "walk" on the sea, jet-skis and waverunner "waterbikes." Much of it is wasted on Cowell, whose tastes are simple. The fridges are stuffed with lobster but most of it ends up thrown overboard. Cowell is addicted to blueberries and has bowls placed all over the boat. A chain-smoker, he believes the fruit will offset his unhealthy habit. He eats only oats for breakfast and steamed fish and vegetables. Similarly, the source says, the women are obsessed with their weight and barely eat either. Although, occasionally, everyone will "pig out." Last week, Dylan Reece, the yacht's sous chef, posted a picture of croissant- flavoured ice cream he was making for Cowell on Twitter. Old friends: Simon Cowell's ex-girlfirend Sinitta often makes an appearance on his holidays No expense spared: The ship's cinema, open-air Jacuzzi and jet-skis are free to be used by Cowell's friends and acquaintances. Despite being served gourmet food by an award-winning chef, the slim women are on strict diets But, says the source: "While the girls have nothing to do, he isn't really on holiday. He is working all the time - running his empire. He will be watching episodes of X Factor on the plasma TV at 4am. Sometimes he will have the girls sprawled on the bed with him. The news that Cowell was having an affair with Lauren was, the source says, the "worst kept secret on board." "Once Simon takes a shine to a woman, that's it," says the insider. Among Cowell's bevy, there is always the worry that their host will tire of them. "The women love the status that being part of Simon's harem affords them," he says. They feel that if they aren't invited back on the boat year after year, then they are a reject. And when their time is up, Cowell makes it abundantly clear. "If he doesn't want them any more he just completely ignores them," the insider adds. That's when they know it is time to pack their bags and leave. He will just freeze them out and refuse to speak to them. It's very much Simon's world. Cowell has always joked about his inability to be "faithful," citing it as the reason he had never - so far - settled down. But if there is one elegant, classy "lady" he will never betray it is surely the ever-loyal Slipstream.