This summer, Rihanna had the longest-running British No 1 single by a female artist since Whitney Houston’s I Will Always Love You: her song Umbrella spent 10 weeks at the top, transforming the 19-year-old Barbadian from fluffy, frothy popster into international R&B superstar. So, presumably, she could, if she chose to, make outrageous demands, be accompanied by an army of sycophants, demand things just so or refuse to play ball. But the cramped and freezing backstage area of the Berlin concert hall where she’s about to appear witnesses no hissy fits. Her entourage is tiny, her dressing room curtained off with improvised, gaffer-taped cloth.

Later on, she will drive through the night to Bratislava in a convoy of coaches. A year of pretty much nonstop promotion finally winds up this Friday in Moscow. From there, it’s back, for the first time in ages, to her family in Barbados for Christmas.

The story of her career to date – spotted by a holidaying record producer when she was just 15, whisked to New York to sign for Jay-Z’s record label, straight into the Top 10 all around the world with her first single, 2005’s Pon De Replay – is the stuff of dreams. But what about the reality? “Oh, it’s lonely,” the singer says, her green eyes filling with tears. “At first, I was on an adrenaline high: this is my dream, I’m actually doing it. It didn’t phase me that I was alone, that I wasn’t with the people I love. But after a while it gets repetitive, and that’s when you kind of go, ‘Oh, wow, I’m sitting in a hotel room once again, me and the television.’ When you’re in the spotlight, people are like, ‘What do you have to worry about?’ They forget that the success is one great aspect of your life, but behind that there are problems, there are dark sides, there’s loneliness, unhappiness.”

Her childhood was not an easy one, and there seems to have been an element of eagerness, even urgency, in her embrace of a new life aboard the celebrity rollercoaster. The eldest of three children, she did well at school, hung around the clubs and the beaches, sang loudly in the shower until the neighbours complained. But her father was addicted to crack cocaine and, when her mother kicked him out, Rihanna took on a quasi-maternal role towards her brothers, and began to have problems with trust, personal space and control.

“I have always had a thing for reading people,” she says. “When I come into contact with a situation or a person, the first thing I do is, I’m just quiet for a little while. I sit, I watch you, I observe you. And being able to read people helps me to know how easy it is to be read. I know the key things that show people who you are. In this business, people are shallow, they’re dishonest. You can’t trust them. It really helps me understand how to play the game, and sometimes you have to play it. And it’s a game that sucks.”

On the one hand, she reached for the stars, and the daydreams she had had as a tomboy school pupil in Barbados came thrillingly true. On the other, she hopped out of the frying pan and into the fire. Yes, a degree of independence has come her way: she has a home in California, and platinum discs to hang on its walls; she is fêted, idolised, envied. Yet Rihanna conveys a real sense of someone weighing the cost of the decisions she took – of, as she puts it, “being ahead” of the limitations and the values of the business she’s in. Later that evening, on stage in front of an adoring crowd, she sings a song while reclining on a chaise longue, dressed in lingerie. The bullet points of her career trajectory attest to ambitions fulfilled, to empowering success, to records broken and targets reached. Yet, up there amid the dry ice, auto-emoting through a limp, platitudinous ballad, she looks ominously detached. If she’s staying on message, she seems to be hanging onto it by her fingernails.

One particular event sticks in her mind as a turning point in how she perceived the music industry and her part in it. When she was promoting her second album, last year’s A Girl Like Me, Rihanna found herself in Paris, and fancied a haircut. Off came the long locks, and she returned to her hotel delighted with the bob she’d reduced them to. “The minute I got back,” she recalls, “someone in authority, they were like, ‘Yeah, your hair looks good.’ But somebody else went, ‘You need to put your hair back in – soon.’ ” (How chilling is that “someone in authority”?) In went the extensions, as instructed. “It just crushed me,” she continues. “When you’re growing up, 17, 18, that’s when you’re really trying to figure out who you are, and at that point I just wanted to try something outside of the box. But as soon as you come out of your shell, like, ‘This is who I am’, they just shove you back in with, ‘No, because this is what we want the box to look like.’ You just feel like a tool after a while.”

Reinforcing this sense of her being a puppet, the web was soon awash with spite about how she got a record deal thanks only to the casting couch, and how Jay-Z’s jealous girlfriend, Beyoncé, supposedly pushed her downstairs in a rage. Rihanna, instead of ignoring the rumours, logged on and read them all. “I wouldn’t know what was being said,” she says, explaining this decision, “then I’d get asked about them, and I’m like, ‘What?’ I have to know what’s being said about me, so I know what to expect. So me and my friends will go on an internet gossip site and look this stuff up. But it’s kind of sick how people read it and think this is their way to knowledge, that they know all about you.”

Barbados, far from being a refuge from the tittle-tattle, was as bad as anywhere. “It’s a silly way of Barbadians,” Rihanna sighs. “They always have to find fault, they’re waiting for you to fall. As much as they enjoy your success, and are like, ‘Keep it up’, they have so much pride, it’s easier for them to say, ‘Little whore, you slept with Jay-Z to get signed.’ Even when I go back there now, I’ll see girls in the street, walking and snubbing and saying stuff about me.”

None of this is said self-pityingly. She fights back tears and seems completely exhausted, but she talks levelly, never moaning, in an accented voice so mellifluous and caressing, you want to bottle it and take it home. She laughs, too, remembering the neighbours whining about her singing, and how stardom’s sharpest shock was the self-consciousness she suddenly felt about what had been the most natural thing in the world. As for the benefits of success, the greatest, she insists, is the distance it allows her from her upbringing. “A child shouldn’t have to go through that,” she says, referring to her father’s addiction and the chaos it created (he is now clean). “Being in the whirlwind, it frustrates you, it angers you, because you’re being tortured and you don’t know why. But now there isn’t resentment but relief, because I understand it. I’m like, ‘Thank God I’m not in that any more.’”

She describes the early days of stardom as utterly baffling. “I did what I thought I was supposed to do, because I’d seen other people do it. I knew that on the red carpet, you stop and you shake and you smile. But you don’t really know. Everybody’s calling your name – that was weird to me. And I thought I wasn’t pleasing them. They all sounded so angry: ‘Rihanna, look here’; ‘No, look here, Rihanna’.”

The huge success of Umbrella, and Good Girl Gone Bad, the album from which it came, has given her the kind of clout she’s never had before. It hasn’t, by the looks of it, yet provided her with meaningful, as opposed to superficial, affirmation of her real worth. Behind her, she has guiding hands on her shoulders; in front, exploding flashbulbs and inquisitive fans. Neither seems especially comforting.

“I did a show two days ago in Belgrade,” she says. “We were expecting 6,000 people and 24,000 showed up. And I couldn’t understand why. I . .. ” She trails off, suddenly in floods of tears. “I look at them and I still think, ‘Why are you screaming for me?’ I still think of myself as a normal girl.” Rihanna got what she wanted, and it was more than she bargained for. She exchanged a chaotic environment for a controlled one in which haircuts are policed and achievements called into question. Enviable? Think about it.

Rihanna’s British tour continues today in London

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