Catherine Pepinster: The lipstick guru and the convent girl

It looks, at first glance, like a girl thing. Two women together, curled up on the edge of a bed, talking about lipstick and doing their make-up. It's an image suggesting best friends, girls growing into womanhood. But the photograph published by Marie Claire last week of Cherie Blair and Carole Caplin is not a picture of innocent fun. It is about power.

The tableau presents Cherie, waiting for her lips to be painted. Then there's Carole: one hand holding the lip brush, the other imperiously waving away any disturbance. Carole, the hired help, is the one in charge. She is the mistress here. She is Dirk Bogarde in The Servant.

Cherie's relationship with Carole Caplin bemuses us because we've got used to the other Cherie - Cherie the superwoman, Cherie the high-achieving QC earning more than her husband and being mother of four at the same time. We can't understand how someone so capable could have picked as her confidante a former model and purveyor of New Age remedies, the lover of a notorious con man who embarrassed the Blairs with his financial wheeler-dealing over the purchase of a Bristol flat for their son.

But beneath the Paddy Campbell coat-dress and the Lindka Cierach suit (as we now know all picked by Caplin with meticulous planning six months in advance) is another Cherie - Cherie Booth the convent schoolgirl growing up in Sixties Liverpool. And that's the Cherie who needs Carole Caplin. Not just Carole Caplin, lifestyle guru, fitness expert and fashion adviser but Carole Caplin, indispensable nurturer to a vulnerable woman. For despite all her remarkable achievements, those who meet her can sense that here is someone who wonders about her worth.

I went to convent school with girls like Cherie. Hard-working, dutiful girls, neatly dressed in their well-ironed uniforms, who always did their homework and always went to Mass on Sundays. My three best friends were all scholarship girls who had to be top of the class. They wouldn't, couldn't fail. They all got top marks in their A-levels and went to university to read law. They are all successful, married with children, and juggling tough demands on their lives. Yet there is always the niggling doubt, and the need to be just that bit more perfect. It doesn't matter that, like Cherie, they were whizzes in English, top in maths, keen on Latin, hardworking in foreign languages. They always wonder whether they are good enough.

School left, believe me, little time for girly things - giggling with friends over make-up, and boys, and clothes. Single-sex girls schools are well-known for their hot-house atmosphere and the drive for perfection. But the convent school is not just competitive, there is also a sense that being successful is a question of duty. There are all the dreams and ambitions of your parents, but also those of these women who have invested their all in you. I can well remember the puzzlement of pupils at neighbouring schools, who couldn't understand why we, who were friendly enough, could so willingly and happily lock ourselves away with our books at exam time. Evenings out, weekends off - forget it. There was no question about it: for those who came from the poorer side of town - and Cherie, certainly did, living in her grandparents' three-up, two-down in the Liverpool docks - passing exams was the way to get on and get out. It was an escape from poverty, shame and the fate bestowed on some by feckless parents.

This background certainly served Cherie well. She went on to shine at school, at university, at bar school and in court. She became a powerful role model. She is not, thank God, like Audrey Callaghan, or Mary Wilson, or Norma Major, the old-school Downing Street wife. She has combined being a devoted mother with an incredibly successful career and she's rightly proud of it.

But for the past six years she's been in the spotlight and under constant scrutiny. Some of the gawping began even earlier than that. From the moment that she appeared wearing a hideous blue outfit more akin to a shroud than a fashion-house creation, at Tony Blair's side when he was elected leader of the Labour Party, it was obvious that Cherie was uncomfortable with her body and her image. It must have been consoling that her own professional life as a barrister provided her with a uniform of wig and gown. It seemed that neither the nuns nor the Bar Council had given her confidence in her own body, however happy she was with her mind.

All that intellectual achieving, and she ended up being judged on what she had ignored - her looks. But Carole Caplin offered a solution. She gave Cherie, that earnest, dutiful schoolgirl the chance to shine yet again. Sometimes the results have been execrable (remember the white pixie boots?) but a lot of the time Carole Caplin gets it right. She has enabled a woman who is nudging 50, with a demanding career, four children, and a very public role as a spouse, to stay trim, look good and at last find her fashion sense. Instead of hiding away in her clothes, Cherie now lets them accentuate her good points and discreetly draw attention away from the not so good ones. Ms Caplin, for instance, often picks clothes that disguise Cherie's pear shape, such as jackets and shirts that hide her wide hips. Adjectives that were once never used of Cherie - elegant, sophisticated, fashionable - now abound in the press.

Wouldn't all of us be grateful for that? But gratitude and wonder at someone else's skills can turn to dependency. And how dependent and pliant Cherie looks in the now infamous Marie Claire photo, while she has her lipstick applied by Carole Caplin. Is this really the bright, feisty QC, the top lawyer of her year at the London School of Econo-mics? The woman who can master a brief, work for charity, play trains with a toddler and attend a Downing Street function as con- sort of the Prime Minister all in the course of one day?

No wonder her relationship with Carole Caplin fascinates and appals commentators, who can't quite believe the wife of the Prime Minister submits to scrubs-down in the shower with a woman who recommends sun love as a solution to life's ills.

The past week saw another rash of "Cherie has lost her marbles" commentaries over the Marie Claire pictures and another set in Hello!, which included Carole draped over sheepskin rugs wearing tight leather trousers while she discussed her role in Cherie's life. This was taken as proof that Carole is Svengali, Rasputin and Paul Burrell rolled into one.

What she does seem to be is the person who has given Cherie belief in herself in the one area where she appeared to have none. It's as if Carole Caplin, with radar-like accuracy, has tapped into the thoughts of Cherie the convent schoolgirl - always worrying that she's not good enough, always wanting to do her best - and found her greatest fear: how she looks.

That certainly gives Carole Caplin a particular kind of power - but it is a power which is flawed. For although she might enable Mrs Blair to become chic Cherie, she also makes her more vulnerable by her dependency on a woman who has brought the Blair household all kinds of trouble.

This summer, unlike last, Cherie Blair and Carole Caplin are holidaying apart, with the Blairs in Barbados and Caplin in the Maldives, looking very fetching while she flouts the law against topless bathing in the Muslim islands. Cherie should take the time to lie back on her sun lounger, flick through Marie Claire and Hello! and consider that Carole Caplin is the worst kind of asset - the kind that doubles as a liability.