The desert sun burns hotter, the dunes stretch out towards the far horizon, the cast of hundreds now seem like thousands as they storm through Aqaba down to the sea.

And, at the centre of it all, Peter O'Toole's iceberg-blue eyes glitter more intensely than ever before.

It's no exaggeration to say that when Lawrence Of Arabia screens next Saturday as part of the London Film Festival, it will look better than it did at its world premiere at the Odeon Leicester Square in 1962. In technical terms, David Lean's epic has been treated to an 8K scan/4K intermediate digital restoration to mark its 50th anniversary. To the layman, this means tiny details in the costume design, which wouldn't have been visible to an audience watching celluloid copies of a print back then, now look as clear as they did through the director's viewfinder.

This is the version of the film that screened earlier this year at the Cannes Film Festival, the same one that has just been released on Blu-ray. But if ever a movie deserved to be seen on the big screen, it is Lawrence Of Arabia: only the full impact of widescreen cinema can do justice to the grandeur of Lean's art and the remarkable nature of TE Lawrence's life. And so, on November 23, this immaculate clean-up job will be re-released across the country.

I'm lucky enough to have seen Lawrence Of Arabia in a cinema before. It was 1989, when the Director's Cut was released in 70mm prints, restoring some excised scenes (notably trims to the Tafas massacre and Lawrence's subsequent crazed shooting of a Turkish soldier), re-recording decayed dialogue tracks and reinstating Maurice Jarre's overture, intermission and exit music.

I'd caught the film on television, of course, but on the cusp of my career as a film critic, I'd never seen anything like this in a cinema. To my eyes, the 1980s had been a decade of empty cinematic spectacle. For sure, certain successful Hollywood directors had tried their hand at creating a modern epic – Steven Spielberg and Francis Ford Coppola, for example – and both paid their dues by lending their weight to the 1989 restoration. But at that point in time the former was between Always and Hook, the latter between New York Stories and The Godfather Part III. Lean's work knocked them both out of the ballpark.

Having watched the Director's Cut of Lawrence Of Arabia again recently (this time in its new digital version), what strikes me now is how, in the 23 years since the film was last made widely available for the big screen, that spectacle remains undiminished. Ridley Scott can rebuild the Coliseum for Gladiator and Peter Jackson can create a massive orc army for The Lord Of The Rings, but placed beside Lean's shots of actual Bedouin horsemen streaming across actual Arabic desert, their CGI effects are reduced to animated fakery.

Not only that: when the cinematography is as precise as Freddie Young's is here and the image has a depth of focus that stretches back into the sun-baked distance or wide across the full screen ratio, the so-called "spectacle" of 3D is revealed as a superficial commercial sham.

Even those who haven't seen Lawrence Of Arabia know certain things about it. The story tells of British army officer TE Lawrence's single-handed attempt to unite Arab tribes into an army that could attack Turkish strongholds in the Middle East during the First World War. Some of David Lean's directorial flourishes have become famous – the blowing out of a burning match that cuts to the deep orange of a desert dawn; the palpable tension as a dark speck within a shimmering mirage steadily advances towards the camera to be revealed as Omar Sharif.

The film won seven Oscars including Best Picture and Best Director (although newcomer O'Toole lost out, perhaps correctly, to Gregory Peck for his turn in To Kill A Mockingbird). Robert Bolt and Michael Wilson's screenplay, although it too was beaten on the night, is one of the most literate in cinema history, balancing its memorable lines ("The trick is not minding that it hurts", "Nothing is written") with a thematic examination of the nature and peculiar psychology of heroism.

Not everyone considers the film in a positive light, however. The critic David Thomson, in his book Have You Seen ...?, notes "how little interest the film was prepared to show in Arab feelings, let alone the Arab point of view ... I lament that in this day and age the film gives very little insight as to how modern Iraq came into being."

One of Thomson's bones of contention is the casting of Alec Guinness as the wily Prince Feisal, and I have to concede that the English actor (who had worked previously with Lean on Great Expectations and Oliver Twist) looks and sounds like his distinctive self; he seems to be playing not a flesh-and-blood man but a metaphor for all Arab leaders who were willing to make compromises with the West. It is also true that the film is guilty of indulging in a certain colonial pride and arrogance, as a lone eccentric Englishman sorts out the problems of these warring tribes.

I don't, however, agree with Thomson's criticism of O'Toole ("flamboyant, staring-eyed ... a diversion from asking useful questions about Lawrence"). In fact I think the surface aspect of O'Toole's performance, with its strange physical mannerisms and meaningful pauses before sparse words of dialogue, points to the very core of Lean's film, which does nothing but ask questions about Lawrence. This is a portrait of an enigma, a film that sets out to get behind and, at the same time, reinforce the Lawrence myth. Everything Lean stages has less to do with historical document, more to do with allowing us to see the effect history has on Lawrence and his moral being.

After the opening sequence, which depicts Lawrence's death in a motorcycle accident in 1935, the film quickly moves to his memorial service in St Paul's Cathedral. There, a journalist asks several of the characters what Lawrence was like, although most claim not to have known him well. This sets the agenda for the entire film. Lawrence himself, at several points, says he doesn't really know who or what he is. When he and his young Arab companion finally reach the Suez Canal after a hazardous desert journey, an army motorcycle rider shouts "Who are you?" across the water. The fact that David Lean dubbed that bit of dialogue himself, while perhaps a matter of post-production convenience, seems strangely appropriate.

O'Toole, in an interview on the new Blu-ray, adds his tuppence worth. "He was a young man in 1916," the actor says of Lawrence. "His father died, his favourite brother was killed in France. He was emotionally wrecked - The effect it had on him was intense - He never fitted into the Oxford academia; he didn't. He never fitted into the archaeological world; he tried. He never fitted into the military world; he used to forget to put his uniform on and turn up in a jacket, hopelessly uncomfortable in an army uniform. The one thing he did do and tried to do above everything was to unite this impossible dream. So he pushed himself to extremes, amazing extremes."

Watching the film again, it's the messianic aspect of Lawrence's behaviour that I think Bolt (who wrote the classic play A Man For All Seasons) brings out best in the screenplay. We've seen Lawrence as soldier and sheriff, hero and sadist. Does he see himself as both man and god?

"My friends, who will walk on water with me?" Lawrence asks his followers before he recklessly enters the town of Daraa. A few moments later, there he is, lifting his Arab robes as he traverses a puddle on Daraa's streets. And yet this man, who was sent by a higher power (the British Army) to save a people, will now be whipped by the Turks and suffer a period of intense self-doubt; he'll have his final victory and then he'll die young. No, historical accuracy is not the goal here: this is the stuff of myth and legend.

Perhaps, however, the most accurate summation of Lawrence comes near the beginning of the film, when the US journalist played by Arthur Kennedy describes him, on the steps of St Paul's, as "a poet, a scholar and a mighty warrior" before adding "and the most shameless exhibitionist since Barnum and Bailey".

There's something of the exhibitionist about Lean and his film too. But that's what makes Lawrence Of Arabia so magnificent and why it still has a place on our screens: a smaller spectacle, a lesser work of cinematic art could not have contained the singular story of T.E. Lawrence.

Lawrence Of Arabia screens at the London Film Festival on October 20 and goes on general release in its 50th anniversary 4K restoration "roadshow" format on November 23. The digitally restored Director's Cut is available on Blu-ray now.