They used to say that after the Second World War people went to the cinema to learn how to kiss. Certainly the movies taught them how to dress. While men noted the drape of Cary Grant's jackets, women copied the width of Joan Crawford's shoulders and the cantilevered wonder of Jane Russell's bust. That quietly-authoritative broadcaster, Francine Stock, expanded this theme in the first instalment of her new series, Voyeurs and Visionaries (Radio 4, Sunday). In fact, this batch of four programmes runs just after Sunday's midnight news and is worthy of an earlier slot. Even so, it's still a good way for listeners to delude themselves into thinking the weekend isn't over.

The series, though, aims to probe deeper than appearance to reveal the effect on the psyche of our obsession with screen idols. But the impression left by this introductory programme was that the audience's craving for glamour in the drabness of post-war years possessed an innocent excitement lacking in the celebrity culture of today. Yet not everything was as it seemed on screen. There was, for instance, something about Judy Garland's innate loneliness that endeared her especially to gays still outlawed in the 1940s by society.

But Garland was either too tragic or too cutesy for women to emulate. Instead, they tried to cultivate Rita Hayworth's slinkiness and the bounce of her flaming hair, and in Bette Davis they found a mesmerising example of lofty insolence. Indeed one of Stock's guests recalled being reprimanded by her father with the words: ''Don't flash those Bette Davis eyes at me.''

And then along came Audrey Hepburn. As Stock explained, it wasn't until the arrival of Hepburn in Sabrina that movie studios turned to couturiers for their leading ladies' wardrobe. Hepburn was Givenchy's muse, a bewitching gazelle utterly at odds with Hollywood's fixation on pneumatic blondes. And hers were the clothes which, because of their simplicity, could be translated quickly for an improved mass market. Eleven years after her death she remains the supreme fashion icon.

Sir Christopher Frayling, omnipresent culture buff and rector of the Royal College of Art, remembered being so besotted by Hepburn when he was young that in choosing a girlfriend he went in futile search of her clone. But when he actually read Breakfast At Tiffany's, the book of the film, he discovered Truman Capote's Holly Golightly was far more hard edge, than the Hepburn model. No

wistful Moon River there.

Hepburn, said Frayling, was the kind of woman a man could take home to meet his parents, confident they'd be impressed. Taking Marlene Dietrich to meet the folks might have been trickier. Dietrich taught women how to pluck their eyebrows but she also used cross-dressing to convey a mysterious quality, something provocative, amusing and intelligent.

In his survivor's pack of Desert Island Discs (Radio 4, Sunday and Friday), Desmond Morris, zoologist and author, included a recording of her extraordinary voice as she stood onstage for the last time, keening rather than singing that bitter, little anthem, Don't Bother Me No More.

Dietrich had always regarded celebrity as a cynical game, and Morris, too, has found value in disrupting orthodoxy. Now in his late seventies, he recalled that at the time when he was demonstrating a chimpanzee's ability to paint pictures, one art critic, in the presence of Picasso, was so sniffily dismissive of the experiment that the artist went over and bit him.

But back to the movies. Actor Robert Lindsay's survey of screen greats, Putting On The Style (Radio 2, Tuesday), ended suitably with wrap-around homage to Humphrey Bogart. Everything about Bogie defied convention. Let's face it, a pin-up called Humphrey? With a lisp? But no other actor was quite so effective at converting murder into sex appeal, although by 1941 the tough manner shifted from the villain slot and into the tarnished anti-hero figure which fitted better with Bogart's own persona of hard-boiled romantic.

On screen and off he was sharp and ironic and he possessed an unsentimental integrity which none of today's Hollywood manikins can match. But the most sensational disclosure from Lindsay's studio guests came from impressionist Alistair McGowan. He likened the actor's stiff upper lip, caused in his case by a scar, to the immobile top lip of John Major. As a result McGowan can't look at the ex-prime minister without imagining him as Britain's Humphrey Bogart.

And the Tories never knew

what they had.