Secrets, betrayals, cliques - it's not easy being mates with your female colleagues. TERRI APTER reports
I recently had dinner with the director of a publishing house. She said she was pleased that so many women worked in her firm. "However," she added, "it means I can't have any friends at work. Women friends expect too much, and get possessive. It's the schoolgirl scrum all over again."

There's nothing I would like better than to dismiss her remark without a second thought. But having spent four years studying girls' and women's friendships, I must acknowledge that however precious these relationships are, they can be difficult.

As more and more women enter business and the professions, the "feminisation" of the workplace is generally considered a positive thing for everyone. But in reality, many women have mixed feelings about working with other women. Some describe the atmosphere as having much in common with school, where subgroups form and alliances with female co-workers shift, where issues of loyalty and betrayal become the emotional centre of the working day. Our lack of understanding of these dynamics can be devastating.

A study reported recently in The Independent found that female managers in America were rated significantly higher than male managers by their bosses, by their peers and by the people who worked for them. Women managers embodied an ideal: they were both caring and dynamic. Yet before the print on this study dried, high-profile criticism of women bosses blotted this image out.

Off-the-record complaints about Tina Brown at Talk magazine include the charge that she's excessively demanding and demoralises her co-workers. The New York Times recently quoted (anonymous) criticism of Jill Barad, chief executive of the toy company Mattel, for lacking discipline and good leadership. In the political arena, the pendulum has swung against Hillary Clinton. While her dignity and loyalty were admired in her role as humiliated wife, she comes under attack as a would-be senator, because she lacks the intuition any leader needs and any woman is supposed to have: she cannot distinguish between friends and enemies, and so turns her friends into enemies.

Women are vulnerable to ridicule (jealous creatures who wreck team spirit) and self doubt (can I be both a good friend and a professional?). But if it is tempting to respond to all of this by sticking your head in the sand and refusing to talk to other women at work, remember that long-term it's the networking women, not the lone stars, who are likely to thrive.

Without question, female networks have been an enormously important factor in the advances made by women at work. It isn't just that women are more likely to know other women who might be right for a job, they can also help sift out prejudices. Natalie, a planning director in a utility company, challenges her male colleagues' assessments of other women being considered for promotion. Where her male colleagues see indecisiveness, for example, she sees reflectiveness and an ability to respond to others' input. She welcomes the opportunity to befriend other women at work, and is happy to prove her friendship by helping others up the ladder.

Many women enjoy their power to help other women, but many also feel that friendships at work carry dangers. Women tend to confide in each other, but in a work situation when does a confidence become an indiscretion? And when does withholding information spell disloyalty? Patricia is director of a software company. She is considering taking a post abroad. "Normally I would hash over the pros and cons with my friend. But I can't say anything to my best friend because I work with her and I have to be careful who knows what."

You may like to think that as you mature, you won't be as easily hurt by sudden reversals in friendships as you were at school. But even as a grown-up, there is something awful in the accusation of letting down a friend. Micki, a college lecturer, is still smarting from a falling- out with her friend and colleague Paula, who feels that Micki did not argue her case as strongly as she could have done.

"Paula's grant was up for renewal and I'm on the committee that assesses it," broods Micki. "But I can't push someone forward on personal grounds - you'd think a friend would understand that. I couldn't believe she would attack me like this."

Megan, too, was shocked when she discovered that her professional status could impair a friendship. She worked alongside Carla for six years, and remained friends when she was promoted to become Carla's boss. Then Carla got cancer - and didn't tell her until she had been through treatment and was well into remission. "She was afraid for me to know, worried she'd lose her chance for the promotion she eventually did get. I found out kind of by accident and I said, `I'm your friend, how could you go through all this and not even let me know?' I still can't believe she didn't trust me enough."

One of the hardest things in women's work friendships is accepting the inevitability of standing in opposite camps. Women friends are notoriously bad at handling direct confrontation, but conflict at work is inevitable so many women find themselves either avoiding making friends in the first place or burying their differences in order to preserve the illusion of harmony. This is where the "bitchy" tag comes in. Uneasy and confused, we tell another friend what's happened, what's been said, and take comfort in her enthusiastic condemnation of the other woman - enabling us to conclude that the fault isn't ours.

But the temptation to resort to name-calling may also spring from a misplaced sense of competition: is there room for more than one woman at the top? If another woman succeeds (even if she's a friend) does that mean the place is full and there's no room for me? There's the suspicion that once ensconced, a woman will abandon her sisterly feelings and start watching her back, acting on the assumption that she has to fall for another woman to rise.

Competition is bitter when it seems there's only one potential winner. With more women at the top, it may be that this sting can be neutralised. But it's still common for women at the top to suffer from the "I have to prove myself" syndrome. This means they constantly check up on their co-workers, and hike up their demands. It means, in short, that they behave just as Tina Brown has been said to behave.

If, on the other hand, a woman is comfortable in her high position, her presumption of status can lead to the familiar playground charge, "Who does she think she is?" Women bosses are expected to be tactful when they criticise someone or give an order and often, when women issue direct instructions or pull rank, they offend other women who see them as breaking the rules. Fifty-year-old Audrey has no time for this: "I like people at work to say what they mean and that's why I prefer working with men, because they're up-front. At least you know where you stand."

It's a lose-lose situation. So what can be done about it? First, women need to give up the idealisation of friendship as a relationship in which we always think alike and never argue; second, they must get some experience of argument - many of us need reminding that we won't be destroyed by it. But we'll only learn this if we continue to make friends with women in the workplace, and have the courage to face friendship's risks.

`Best Friends: The Pleasures and Perils of Girls' and Women's Friendships' by Terri Apter and Ruthellen Josselson is published by Crown, New York.