Marina Lewycka: Casual sexism was the air we breathed. Let today's women never forget that

It's easy to forget how bad things were. At the start of the 1960s, sexism wasn't just out there in the words and deeds of men. It was actually carved into our own souls. During the 1964 election, I was out canvassing for the Labour candidate, a man of course, who kindly asked me whether I had ever thought of being an MP myself. "Oh, no!" I batted my heavily mascaraed eyelashes. "I would much rather be an MP's wife!"

Four years later, I was marching down Oxford Street in London on the anti-Vietnam war demo, waving a clenched fist as I chanted "Ho! Ho! Ho Chi Minh!" and running away from charging police horses in Grosvenor Square. But I did it all in a miniskirt and calfskin sling-back high-heeled shoes.

Fast-forward another three years, and I'm now on the first International Women's Day march in London. I'm wearing jeans and a duffel coat and walking shoes (trainers for everyday wear hadn't been invented yet) and I've taken off my bra for the occasion. OK, I might still be wearing a smidgeon of mascara, but not so the sisters would notice. We're singing, "Keep young and beautiful, if you want to be loved!" What happened between 1968 and 1971? How did the deeper changes in attitude and personal culture take place?

Beneath the marches and high-profile media events, like the disruption of the Miss World Contest in 1970, a secret, largely unrecorded revolution was taking place in kitchens and sitting rooms all over the country. Under capiz-shell lampshades (remember those?), over pots of tea (Nescafé was too sophisticated; freshly brewed coffee didn't exist) and patchouli-scented joss sticks, women were meeting in informal "consciousness-raising groups" and talking about their daily lives, the slights and put-downs, at home, at work and in the streets, that we were scarcely aware of – they were part of the air we breathed – when perfectly strange men thought they were doing you a favour by sitting down beside you and saying, "Smile, love, it may never happen", and questions about marital status and pregnancy were standard at job interviews.

These were the kind of experiences with which the writer Linda Grant's Twitter stream exploded on International Women's Day this week. Grant was making a point about the achievements of feminism but she touched an extraordinary nerve, prompting responses from 2,000 women. "I told my teacher I wanted to be a lawyer. He said I should be a receptionist because I was good with people. I am a lawyer," wrote one. "My BBC boss gave me a 6 month contract & said: 'we'd give you a year, but you've just got married and might get pregnant'," recalled another.

One day in the early 1970s, fired up by the support of the women in my group, I marched into the post room of the office where I worked and ripped down the pin-up posters on the walls, scrunched them up into a ball, stamped on them and walked out. The postmen blokes looked on, a bit nonplussed, but nobody said a thing, and the posters never reappeared. I imagine scenes like that must have happened up and down the country. Nowadays, the pin-ups have disappeared even from my local garage.

Other women walked out of their homes, secure relationships, office jobs, marriages. Walked into communes, squats, lesbian relationships, a diet of beans and lentils, politics, high-level jobs in academia, journalism and the public sector. We campaigned for the family allowance, which previously went straight into the husband's wage packet, to be replaced by universal child benefit, to be paid to the parent who actually looked after the children. We picketed with the night office cleaners. We used speculums and mirrors, and became acquainted with our vaginas. We demanded to be called Ms rather than Mrs or Miss. For a while, it was like the world turned upside down; then we had children and settled down.

From the 1980s onwards, there was a gradual parting of the ways in the women's movement, between women who really couldn't be bothered with men, and were now free to come out and live as lesbians, and those of us who basically still liked men, but wanted them to be different. It wasn't a bitter or angry parting; we're still friends. But for many heterosexual women, the long, sometimes funny, sometimes heartbreaking slog of the past three decades has been re-educating the men in our lives (and allowing ourselves to lighten up and be re-educated ourselves).

Young women nowadays seem to think the battles have all been won, or there was never any need for a battle at all. They don't have to choose between high heels and feminism; they want them both, and in a way I'm glad they can take for granted the things we struggled for. But I wonder whether they realise just how hard it was for us, and how vigilant they still need to be. The tweets sent to Linda Grant should shock them into consciousness. My 33-year-old daughter, applying for an academic job in 2007, was told that other female academics were worried about the effects of maternity leave on the department should she become pregnant. There are still websites offering women from Eastern Europe as brides "untouched by feminism". And, of course, many of the cuts of this new age of austerity will fall disproportionately on women.

Although we were pilloried in the press in the 1970s as lesbian man-haters and spoilt navel-gazing children of the middle classes, we achieved much of what we were asking for: the petition we handed in on that first International Women's Day march demanded equal pay for equal work, equal opportunities in education and jobs, free contraception and abortion on demand, and free 24-hour childcare.

It seems strange now that the first two should ever have been considered contentious. Technology has made the demands about reproductive rights both more accessible and more contentious. And we've thought again about asking the state to provide free 24-hour childcare, and come up with a better solution: we've taught men to do the childcare, and to love doing it.

Marina Lewycka's latest novel, 'Various Pets Alive and Dead', has just been published