The first thing Taxi Driver gives you is not a man but a colour. A cab noses out of a cloud of sewer steam and the screen goes liquid — red brake lights smeared across a wet windshield, the sodium glare of a city that has forgotten how to switch off. Then two eyes find the rear-view mirror, and you understand that the camera is not looking at New York. It is looking at it the way Travis Bickle does: too closely, too long, with the wrong kind of attention.

What follows is a portrait of a man and the city that made him, painted by Martin Scorsese from a screenplay by Paul Schrader and carried by a Robert De Niro performance it is still dangerous to sit beside. Bernard Herrmann scored it — a sleazy late-night saxophone laid over a low metallic dread — and it was the last thing he ever wrote; the film is dedicated to him. You can hear the whole argument in that music: tenderness and menace breathing through the same horn.

A city that never stops sweating

Michael Chapman shot the film, and his New York is the real star — humid, festering, beautiful. He lets the neon bleed: marquees, diner signs and porno-house bulbs reflected in chrome and rain until the streets look enamelled. Scorsese slows the dissolves to a crawl, so the bodies on the sidewalk turn into a smear of heat and threat. When Travis drives, the windshield is a canvas and the wipers a metronome. By the time the famous overhead shot drifts down the carnage of the final act — Scorsese desaturated the colour to soften the red and protect his rating — the city has stopped being a place and become a state of mind.

Travis Bickle, God’s lonely man

De Niro built Travis from the inside out: the over-careful courtesy, the gym-rat discipline, the diary in which a Vietnam veteran with nowhere to put his nights calls himself “God’s lonely man.” The most quoted moment — “You talkin’ to me?”, improvised in front of a mirror — works because it is not bravado but rehearsal, a lonely man auditioning for a confrontation that exists only in his head. You watch him decide the filth outside can be scrubbed away with a gun, and the film never once lets you off the hook by telling you what to feel.

Everyone he passes

Around him Scorsese arranges a gallery of New Yorkers, each lit like a separate painting. Cybill Shepherd is Betsy, the campaign volunteer Travis idolises and then humiliates; Harvey Keitel is Sport, the pimp, all greasy charm and bad sweetness; and Jodie Foster, barely a teenager, is Iris, the child the lonely man appoints himself to save. Foster’s composure is unnerving, and the relationship at the centre of the violence is the most uncomfortable thing in the picture. Herrmann’s score threads them together, romantic and rotten at once.

Why it still idles at the curb

It took the Palme d’Or at Cannes and four Academy Award nominations, and it has never really cooled. Every alienated-loner film since — every neon-soaked study of a man coming apart in a city — pays it rent. Part of its strange power is how little it has dated: the loneliness it diagnoses, the way a wounded man can curdle into a self-appointed avenger, reads more clearly now than it did then.

That is what earns it a place near the very top of our scale: a film where every frame is composed and every silence is loaded, and where the city itself does the acting alongside De Niro.