On the 25th anniversary of her death, the National Film Theatre this month pays tribute to one of cinema's most famous blondes. No, not that plump Playgirl Norma Jean, but slinky, sophisticated screen icon, Veronica Lake.

Born with the slightly less glamorous moniker of Constance Ockleman, Lake epitomises the ephemeral starlets thrown up then mown down by Hollywood's studio system of the 1940s. Unlike other stars of the period, such as Bette Davis and Joan Crawford, who clawed their way to the top through sheer determination, Lake was a natural. "She's nothing much in real life," director Preston Sturges said once, "a quiet, rather timid little thing. But the screen transforms her and brings her to life."

If the camera loved Lake, then so did America, for a while at least. After a tentative entry into film in 1939, as "Constance Keane", with a string of feminine roles in movies such as Forty Little Mothers, Lake changed her name and her fortunes. Her first leading role came with I Wanted Wings (Mon 1 Jun NFT2), an aviation drama which established her glamorous persona and had women rushing to their hairdressers to copy her long platinum locks and distinctive peek-a-boo fringe.

"You could have put all the talent I had into your left eye and still not suffer from impaired vision," Lake confessed once, so that blonde curtain obviously did little to hinder her performance. Still, the star's next film, Sullivan's Travels (Tue 2 Jun NFT1) proved a great showcase for her modest abilities. A classic comedy, the film shows a remarkably svelte Lake on sparkling form opposite Joel McCrea, sporting a baggy suit to disguise the fact that she was six months' pregnant.

By the end of the year, more photographs appeared of Lake in magazines and newspapers than of any other star. She was courted by such magnates as Aristotle Onassis and Howard Hughes. With the release of 1942's This Gun For Hire (Wed 3 Jun NFT2), Lake's star shone even brighter. The first pairing of Lake with the similarly cool and self-possessed Alan Ladd, This Gun for Hire was a hard-boiled thriller that captured the spirit of the times. Ladd's role was modelled on the psychopathic killer of Graham Greene's novel, Lake's nightclub siren was one of many temptresses that would establish her, as she later put it, as "Everyman's mistress".

Another noir classic with Ladd, The Glass Key (Thur 4 Jun NFT 1) followed, along with a starring role in Rene Clair's wicked fantasy, I Married a Witch (Fri 5 Jun, NFT1), which saw Lake giving a wonderfully sharp performance as the mischievous witch, reincarnated to get revenge on the descendant of the man who burned her at the stake. Although Clair was initially reluctant to hire Lake for the role, he later admitted she was "one hell of a good comedienne".

Such was Lake's influence by this time that in 1943, she was forced by the War Production Board to unveil a new "factory safe" swept-back hairstyle, to prevent her female fan club from snarling up their long hair in war- plant machinery. Meanwhile, the star won the Army Poll as most popular actress and was voted top female box-office attraction by Life magazine.

When Lake married director Andre de Toth in 1945, her success seemed complete, but as the Forties wore on, her career began to wane. Lake cropped up in cameo roles in Paramount celebrity galas such as Star Spangled Rhythm (Tue 9 Jun NFT2) and Duffy's Tavern (Tue 16 Jun NFT2) alongside such luminaries as Bing Crosby and Bob Hope, but studio cut-backs and a reputation for being "difficult" meant that A-list leads were hard to come by.

Reunited with Ladd for the Chandler-based noir, The Blue Dahlia (Thur 18 Jun NFT1), Lake was as luminous as ever, but by the early 1950s, both she and De Toth were filing for bankruptcy. Nothing fades quicker than yesterday's face, and Lake dropped from public view as quickly as she had risen, her appearances in newspapers now limited to reports of her arrest for public drunkenness.

In the 1960s, she was famously "re-discovered" working as a barmaid in New York, and staged a muted comeback in schlocky horrors such as 1970's Flesh Feast. She died three years later, a symbol of the glamour and caprice of the Hollywood star machine, but her iconic influence lives on in movies such as Dead Men Don't Wear Plaid (Mon 1 Jun, NFT1) and LA Confidential (Fri 26 Jun NFT2).

'Blonde Icon: Veronica Lake' runs 1-29 Jun at the NFT, South Bank, SE1 (0171-928 3232)