Lord of the Rings: The Return of the King, The Odeon, Leicester Square, London

From the start, director Peter Jackson said the finalinstalment would be the best. Hundreds turned up in the wee hours of yesterday morning, despite the rain, so they would have a good view ofcast members such as Liv Tyler, Orlando Bloom and Sir Ian McKellen walking into thepremiere at London's Odeon Leicester Square.

Tolkien's The Lord of the Rings trilogy has morphed from being a quirky gamble ­ a fantasy adventure too frightening for kids and possibly too silly for adults ­ into the surest thing in town. Harry Potter 3 didn't dare take it on this Christmas. The battle for the West has been fought and Jackson, the hairy, humble New Zealander who met his wife while working on the BBC's Worzel Gummidge, would seem to have won.

Expectations for The Return of the King have peaked somewhere around the Himalayas. The opening sequence leaves us giddier still. Gollum ­ the hissing, bubble-eyed, two-timing maniac who stole the show in The Two Towers ­ is here seen as a harmless hobbit, Smeagol, before the precious ring came into his life, and as he raspingly puts it, "Cursed us!"

Andy Serkis, the British actor formerly invisible "beneath" the computer animation, undergoes an electrifying transformation ­ sinking, like the most desperate of junkies, into the squalid ecstasy of self-annihilation. Jackson has taken a risk, but it pays off.

After that, Jackson gets on with the more conventional business of setting up the various plot-strands (for those unfamiliar with Tolkien, or the previous two films, I apologise for the confusion that's about to ensue). Frodo Baggins and Sam are led off by Gollum (the world's least reliable tourist guide) to Mordor; Gandalf goes with Pippin to the aid of a besieged castle in Gondor; Theoden and his niece and Merry prepare to meet him there later; Arwen persuades her father that she really, really, really is prepared to die for Aragorn; and the latter (with Legolas and Gimli in tow) tries to whip up an army amongst the undead. I've missed one or two people out, but you get the gist. Everyone's busy and there's not a minute to lose.

The New Zealand landscape, as ever, shovels its way into your psyche and the huge battle scenes feel as personal and fraught with tension as domestic dramas. Meanwhile, the actors say their lines with such fierce commitment that you daren't miss a word. Aragorn (Viggo Mortenson) and Gandalf (Ian McKellen) are the crucial authority figures, but the little hobbits, this time, play a much bigger (ahem) part.

Every now and again we may get a little restless, but mostly we're right in there, weeping softly when a certain person passes away; laughing madly at the carefully paced jokes; keeping an eye on the increasingly agitated and Byronic Frodo.

And then ­ disaster! Having stroked and stimulated us into submission, Jackson just can't think how to wrap things up. At one of the film's many climaxes, Sam implores Frodo to let go of the ring. Jackson's fingers show a similar unwillingness to unfurl. The magic has time to wear off. Who are this portentous lot? You suddenly find yourself wondering, and why have they stolen so much of my time (three and a half hours, and that's before all the DVDs)?

Reverence is crucial to this project. But, as our heroes say soppy farewells to each other for the umpteenth time, all sorts of blasphemous thoughts come to mind. Such as that the real battle here is between two sorts of men's hairdo: the wet-look perm and the samurai pony-tail.

I came out of The Two Towers feeling like I'd been converted to the Church of Tolkien; I emerged from The Return of the King on the side of the gargoyles. Those orcs may have bad teeth and kill you without thinking. On the up-side, they probably wouldn't chew your ears off with long goodbyes.