She's raw, she's rough, she's our new icon

For five years it has been business as usual among the boys' club at Westminster. There may have been the odd fracas about women's quotas, the occasional argument about Virginia Bottomley's true qualities, but the levers of power have been firmly in men's hands. That's why Margaret Thatcher's return to the scene this week was not just a stark reminder of her extraordinary political potency but also of how much she transformed the prevailing view of the relationship between women and power; how much she upset the natural order of things.

The fact that she got to the top was clearly crucial. But perhaps even more important was how she did it and the style with which she does everything, whether governing a country or marketing a book. After all, a central tenet of feminist belief is the idea that if women were to come into power, their values would civilise society. Co-operation would replace competition. Sweet reason would gradually prevail over strutting egos, and men would gradually discover their inner, feminine selves. Instead, Thatcher showed that what equality really meant was an equal right to be hard, tough and even nasty.

As so often, popular culture has been far ahead of politics in thinking through women's relationship to power and understanding the profound inversions of gender roles that are taking place. For, while Thatcher has been languishing in the House of Lords, Hollywood has provided a string of new macho female role models, such as Nikita and Jamie Lee Curtis in Blue Steel, and women who enjoy using sex as a tool of power, such as Sharon Stone in Basic Instinct. Just as in the real world women are becoming engineers and managers of organised crime syndicates, or chief constables, on celluloid they're playing professional assassins, spies or cowboys in ever greater numbers.

Now the movies are going a step further with Tank Girl, which opens next week. Tank Girl the movie has its roots in the cult British comic strip invented by two twenty-something males in the late Eighties. The character they created - a hard-drinking, homicidal and stroppy young woman - is now being brought to life on the big screen, overtly bidding for the ground occupied by Schwarzenegger and Stallone. The lead character isn't just another brawny bimbo: she farts, picks her nose, cuts herself shaving, lives in a rubbish tip and is generally as unfeminine as you could imagine.

On one level Tank Girl is a straightforward metaphor for women's liberation: the film is set in the not-too-distant future, 2033, in a world of water deprivation after an eco-catastrophe. Like the tough heroine who prepares humanity for survival after the apocalypse in the Terminator films, she is cast as a liberator. But the important difference is that we see her getting off on power and violence just as much as men.

And that's why Tank Girl fits so well with a post-literate Generation X - men as well as women - who are media-wise, fed on a diet of videos and violence, and like women to be assertive. It is no accident that 60 per cent of Tank Girl's fans are girls, many of them the kind of girls who are aspiring and determined to have careers. Her attitude and ambition, her cocksure behaviour, chimes well with a generation that is beating the boys at exams, beating them in the jobs market and may soon be beating them in the race for the top jobs. For them it is appropriate that men don't have much of a role in the future - even her lover is half man, half kangaroo.

For some strands of feminist thinking Tank Girl won't be an easy watch. After all, who would have thought that one of the legacies of feminism to a younger generation would be the enjoyment of unadulterated violence, Stallone-style, and the right to be as uncivilised as men? But anyone who believes Tank Girl is just the product of a feverish Hollywood imagination should think again. She appeals because she goes with the grain of change in society. Girl gangs are roaming the streets of many inner cities, attacking and mugging women at random - including, famously, that other image of modern womanhood, Elizabeth Hurley. Part of the reason is that male and female values are converging, and while feminised new man is still a rare breed, masculinised new woman is ever present. Across the board there are signs that young women are seeking risk and excitement, and taking greater pleasure in overt displays of sexuality. They're also suffering from illnesses that were once seen as predominantly male: heart disease among women is rising dramatically, as is alcoholism.

Indeed it's not just on the streets that woman are learning to enjoy power - it's increasingly in the workplace. And history has a way of coming full circle:women are fast learning that power can and does indeed corrupt, whether you're female or not. Female sexual harassment - the great feminist taboo - is becoming more commonplace as women move into top jobs. In the US, it is estimated that even now the proportion of sexual harassment cases in which a woman is the perpetrator is 5 per cent and rising, because, as Michael Crichton's Disclosure pointed out, harassment is really about power, not sex.

These are disorienting symptoms. A long queue of critics (predominantly male) have been lining up to attack Tank Girl on grounds of taste: it's too violent, they say, exploitative and unrealistic. Nice girls don't do that sort of thing. Others will argue that Tank Girl is an appalling role model for impressionable teenagers. Behind the clamour of criticism is the rather simple fact that many men are genuinely threatened by the assertive young women that feminism has spawned.

Yet little of Tank Girl's symbolism should really surprise us. For we lived for more than a decade under the ultimate tank girl of them all. Margaret Thatcher didn't just cultivate a Churchillian air. She didn't just visibly enjoy power. She revelled in her reputation as the Iron Lady and even enjoyed being driven around in tanks in ways that it would be hard to imagine either John Major or Tony Blair doing. She did, of course, mix power and respect with a careful use of sexuality to seduce and manipulate any number of her male colleagues. But it was crucial to her image that she was - as many put it - more of a man than the men she had to fight to get to the top.

Most of the female politicians who've come after her have chosen a more traditional image. They want to be the caring sex, loved rather than feared. They want to bring more feminine values to bear in the public sphere. But Tank Girl is a metaphor for the new terrain of gender politics, catching the mood of a younger generation of women who have been the beneficiaries of feminism: women who have grasped what it was that made Madonna, Sigourney Weaver and Sharon Stone such icons, women who welcome the breaking down of gender stereotypes and who want the opportunity to develop their masculine attributes; girls who are saying that it shouldn't just be the men who get to be bad.