I’ve never seen Titanic and always figured, what’s the point? I’ve seen bits of it, chunks of it. I know the plot, the song, the famous lines. “Draw me like one of your French girls, Jack.” Why sacrifice three precious hours of lockdown to confirm what I already know when I could be – I don’t know – drinking vast amounts of alcohol or trying and failing to read a book? I’ve never seen Titanic but it feels as though I already have.

Except what if I’m wrong? What if James Cameron’s film is stranger, wilder or just plain different from my complacent mental image? One great thing about life is its habit of confounding expectations. For instance, I always thought I knew what Madrid was like until the moment I went there and found it considerably better than anything I’d imagined. More beautiful and fine-grained, more vivid and exciting. What if Titanic is like Madrid?

In 1997, Titanic was all but inescapable. It cleaned up at the Oscars. It earned a billion dollars at the global box office. At that time, I was writing a weekly film review column and going to screenings pretty much every night and yet still somehow conspired to avoid the biggest film of them all. Heaven knows why. I hope I wasn’t dumb enough to frame this dereliction of duty as some kind of principled stance. That would be insufferably snobbish and wilfully perverse, like a music critic bragging that they’ve never listened to the Beatles.

And so, very belatedly, I sit down and watch Titanic, in which the young Kate Winslet is swept off her feet by the young Leonardo DiCaprio and an extra in the crow’s nest shouts “Iceberg straight ahead!”, and God almighty, maybe I have seen it before because it’s pretty much exactly as I thought it would be. “To hardly know it is to know it well,” as Cary Grant nearly said in The Philadelphia Story. It’s not just the foreknowledge that the ship will sink. It’s knowing most of the beats that lead up to the sinking. Titanic moves forward as if on tramlines, helpfully indicating every twist and turn in advance. It transpires that what Rose actually says is: “Jack, I want you to draw me like one of your French girls” – but this is the film’s biggest rabbit-from-the-hat surprise.

So OK, Titanic is not the Beatles. It runs wide but not deep and has left virtually no cultural footprint. But nor is it Madrid, because there is never any danger of us becoming interestingly lost and discovering some side-street or subtext that the other tourists have missed. If anything, Titanic is Essen, a city in the industrial heartland of Germany which – inasmuch as I’d ever thought about it at all – turns out to be pretty much as one would expect it to be. It’s functional, accommodating and entirely built for purpose. In one early scene, a posh lady stands on the quay and says, “So this is the ship they say is unsinkable.” The dialogue hardly gets any less stiff and formal from there.

In the real world, people are strange and confusing. In Titanic they’re not. The good people are the poor ones who appreciate painting and dancing. The bad people are the rich ones who disapprove of Picasso and have never heard of Freud. As with many inherently conservative films, it likes to think of itself as siding with the radicals and underdogs.

Framing the story, serving as the narrator, is Gloria Stuart, who really was a radical (a pioneering environmental activist and a founding member of the Hollywood Anti-Nazi League). Here, she plays the older version of Rose, who is being interviewed on camera by a bunch of marine explorers. The woman holds her audience spellbound with a tale of forbidden love below deck. She says things like, “It was the most erotic moment of my life,” and asks with a twinkle, “You mean, did we do it?” Midway through the film, I half-hoped that old Rose would eventually be unmasked as a charlatan or a fantasist, spinning lurid tales of servant sex. But no – it turns out she’s another goodie after all.

For all that, I didn’t dislike Titanic. The director David Fincher once said that there are films and there are movies and that these should never be confused, because measuring them by the same criteria is like comparing apples with oranges. Titanic, perhaps, is the movie-est movie of the lot – a delivery system for broad emotions and enormous set-pieces and as distinct from the work of Robert Bresson as it is from an elk, a pen or a thong. Cameron’s handling is commanding and professional. He effectively grabs your head in order to direct your gaze this way and that, like a brutish schoolmaster manhandling a daydreaming pupil. But he’s also smart enough to allow just one rogue element – and it is this that makes all the difference.

Playing the role of Jack Dawson, Titanic’s emblem of youthful promise, DiCaprio looks as though he’s dropped in from a completely different movie – or more likely a different film. DiCaprio (22 years old at the time of shooting) is loose and limber where the other players are stolid. Even during the non-dancing scenes, he moves with the lightest of steps through Cameron’s world of waxwork dummies, as though recognising them all for the cheap impostors that they are. The actor is better than this material, geared for better things. But he’s exploring and experimenting; happy to stretch his muscles and find his range. He’s like a brilliant tour guide, at once respectful and irreverent, strolling back and forth around Essen and making it feel like Madrid.