Casablanca

She didn't say, "Play it again, Sam." He did say, "Of all the gin joints in all the towns in all the world, she had to walk into mine."

The script wasn't even finished when they started. Rick was going to be played by Ronald Reagan and all Ingrid Bergman wanted was to get it over with quickly so that she could make For Whom The Bell Tolls with Gary Cooper.

The plot was a nonsense, politically speaking, and in the flashback sequences, relating to Rick and Ilsa's affair in Paris, there are some of the most ludicrous back projection shots ever contrived. What is it about this film that gives it classic status? Why should a movie with a foreign-sounding name about wartime refugees, a corrupt French cop and a cynical American nightclub owner stand out above the Hollywood studios' production line? The answer lies in one word, "style".

Hungarian director Michael Curtiz, who could hardly speak English, had just finished Yankee Doodle Dandy that won Jimmy Cagney an Oscar ("The only thing Curtiz has to say is, 'Don't do it the way I showed you. Do it the way I mean'", Cagney said). He was a perfectionist, with a defined visual identity and the ability to draw strong performances from his actors.

Bergman plays Ilsa, the enigmatic wife of the Free French resistance hero Victor Lazlo (an uncharismatic performance from Paul Henreid), who arrives at Rick's Cafe Americain one evening and sees Sam (Dooley Wilson) at the piano. She is there with her husband to try and purchase exit permits, so that they can leave North Africa before the Nazis catch up with them. She remembers Sam from Paris and, if he is here, Rick (Humphrey Bogart) cannot be far away.

Essentially a love story, Casablanca is darker than a camel's eyeball. Although not an ugly drunk, Rick is certainly alcoholic. A wounded romantic, who had been stood up by Ilsa when they planned to run away together before the Germans marched into Paris, his view of life has hardened over the intervening years ("I stick my neck out for nobody"), which is why his friendship with Capt Louis Renault (an inspired Claude Rains), the police chief, fits so well. Both men recognise the fallibility of human nature and essential absurdity of honourable intent. Rick's past is a mystery. He smokes a lot and looks miserable most of the time, but deep down - and this is where Bogie's acting comes into its own - he has feelings that will not be compromised.

What makes this special? Julius and Philip Epstein's ability to write dazzling one-liners; Bergman's luminous performance ("I don't know what's right anymore"); Rains's memorable final words ("Round up the usual suspects"); Wilson singing As Time Goes By; Bogie, in his trench-coat, watching the plane take off ("We'll always have Paris").