The era of true power dressing makes a comeback

The mid-1970s have never looked so "now", I thought while watching the Harold Pinter play Betrayal in London's West End recently.

The YSL designer, Stefano Pilati, was the costume consultant for the play, originally written in 1978. The Four Weddings and a Funeral actress Kristin Scott Thomas takes the lead as Emma in the play that's set between 1968 and 1977. She's an art gallery owner and wears a wardrobe in the play that felt both in a time warp and startlingly new-season. Outfits such as a fuchsia silk dress (very Women's Lib), a camel cardi coat, mid-length skirts and a selection of peasant chiffon skirts decorated with Pilati's signature patterns inspired by YSL archives. I also spotted a fabulous YSL Muse bag.

This is not the first time Betrayal has received a designer's touch (in 1984, Chanel's Karl Lagerfeld did costumes) but given the period when YSL steered fashion at whim, it works particularly well. Even the male leads, Douglas Henshall and Ben Miles, in their classic YSL suede and leather "unisex" jackets, could have passed for what's just been on the menswear catwalks in Paris.

But it is the womenswear I'm most intrigued by.

My fashion journalism teacher in the 1980s had been an active pioneer in the Women's Lib movement and was very much from the make-an-effort-if-you-are-going-to-make-a-point school of dress.

A contributor to the outspoken Spare Rib magazine as well as the popular fashion magazine Nova, she loved fashion and was an advocate that fashion and feminism could and should work together. Indeed, to rip fashion out of the feminist manifesto, she argued, deprived women of something they loved.

Looking at images of women's marches in the early 1970s, it's hard not to be impressed (or become nostalgic) about the clothes worn. This could be because vintage gear is achingly hip, especially high-waisted jeans, tight "unisex" shirts and maxis.

Their clothes portray a tremendous sense of self-assurance and freedom of expression. Here were women collectively rethinking how to dress - but not as sex objects.

One of the reasons the 1970s is continually referenced is because it fell in an era with so many contradictions that all impacted on fashion.

On the one hand, this was the decade of drop-dead glamour in the form of Jerry Hall, Julie Christie in Shampoo, Studio 54 and Charlie's Angels leaping about in heels. On the other hand, there was the phenomenon of female emancipation that inspired Liza Minnelli and Jane Fonda to crop their hair and wear flares.

It all contributed to a weird fusion of boyish androgyny that seemed to exude a feminine glamour that straddled empowerment and equality.

At the last lot of designer shows back in March, there was a distinct nod to this precise moment in time - around 1974-78, when YSL was at his peak, while Vanessa Redgrave and Charlotte Rampling were "it" girls.

Marc Jacobs particularly captured this incredibly iconic fashion moment in both his own-name current collection and Louis Vuitton range, which was a tribute to Rampling in the 1974 movie The Night Porter.

Richard Nicoll, with his superficially minimalist wide trousers and flowing blouses with their trailing ties, too.

In the late 1970s, my mother, a feminist, became a university teacher and, like many women making up the workforce, used fashion as a way to forge a new image separating her from her past life as a housewife.

I can remember her going to work in psychedelic floral blouses and high-waisted trousers with red patent boots and thinking she was one heck of a strong woman.