AT the end of his Spring-Summer '93 show, hip young American designer Christian Francis Roth appeared in a pull-on hat made of old socks. ''I'm sick of fashion,'' he told the crowd. Soon after, a famous New York magazine art director was tossed out of the bar at the Ritz Hotel in Paris by a doorman who hadn't heard of grunge and took him for a tramp. Now perfectly respectable fashion writers such as Carrie Donovan of The New York Times are promoting that most prosaic of garments, the white shirt - correction, the Big White Shirt - as a must-have. Add the new season's revival of the 60s and 70s and what do you have? Emanuel Ungaro, who has never done a tacky or blatantly derivative collection in his life summed it up best: ''When fashion repeats itself, it stutters.'' To many, the latest ''trends'' are also a shallow parody made all the worse by the fact that most of the people pushing them are old enough to remember what inspired them in the first place. The Bomb, the Vietnam War, the women's movement, the Pill, the Beatles and their magical mystery tour - to the generation which grew up during that consciousness-raising era, what's happening in fashion now is an out-and-out sham. It's also a complete mess. To the love-ins of the 60s, designers have piled on the most vulgar excesses of the 70s, with the result that women are being bombarded with a truly horrible hodge-podge. Bell-bottoms (first popularised by Coco Chanel who got the idea from sailors' pants) and psychedelia; clogs and platform shoes; heavy black eye-liner and monstrous false eyelashes; the aggressively uncouth grunge look, the exhibitionist look (flashing bras and buttocks), the saccharine folksy look - talk about scraping the bottom of the barrel. A few like Christian Lacroix and Ungaro refused to be swayed and stuck to their own thing with notable success. Of those who went with the tide, Karl Lagerfeld was the classiest, Keith Varty and Alan Cleaver of Byblos the most authentic and Rifat Ozbek, who created real delight with his Indonesian batiks, the most pleasing. A tiny handful not only resisted the born-again fads, but actually came up with fresh, innovative collections. The best of them? Let's hear it for Issey Miyake who earned a standing ovation in Paris. As New York doyenne Bernadine Morris noted, it was not just for the intricacy of his cuts or the sophistication of his colours. Rather, Miyake's triumph lay in ''opening a window on the future of fashion'' through ingenious new fabrics which made magic of even the simplest designs and whose patterns ''transcended traditional printing.'' Unfortunately, most of the season's offerings are steeped in the past, so here are some guidelines for those who feel a tidal wave of nostalgia coming on: Platforms and mega high heels: elevating for short women, depressing for short men and great money-spinners for orthopaedic surgeons. Bell-bottom pants: useful for disguising bow-legs but otherwise a flapping nuisance. Also potentially lethal when worn with stiletto heels. Granny dresses and midi skirts: nice on slim, tallish girls with gamine looks. Frumpy and horribly ageing on everybody else. 70s makeup: only if you want to look like a cross between a dying raccoon and Miss Piggy. Flower-power, love beads and all that: if you've been there and done that don't make a complete fool of yourself and do it again. Grunge: be a fashionable slob and see what happens in one of Hongkong's five-star hotels. Anything else? Ah yes, the big white shirt. Actually, this falls into the category of classic and lends itself to numerous variations. Lagerfeld dictates (he never merely suggests) that the BWS should be part of a fluid-layered look, with shirt-tails protruding - tres chic if you follow the recipe exactly - Gianfranco Ferre manages to make his shirts look madly romantic, sometimes tyingthem at midriff, while just everybody else has them loose over pants or leggings, but with an emphasis on outsize double cuffs or frills. Voile, linen or silk are favoured for the BWS and the really in thing is to leave cuffs unbuttoned and dangling nonchalantly - not in your soup if you help it. A random survey in Central revealed that the BWS is already sitting pretty at the top end of the market. Claude Montana offers a crisp linen version ($4,895), Donna Karan goes rustic with vertical lace inserts ($2,550) and Dolce & Gabbana go super glam with stiffened silk and jewelled buttons ($4,350). The least pretentious and most practical? Issey Miyake's for sure. His big white shirt, done in a revolutionary fabric you've probably never heard of, isn't so big on cuffs, but boast handy pockets and is slit on both sides of the front. All yours for $2,600.