In 1937 a fairy tale about a reluctant hero with hairy feet was published by a tweedy English academic called JRR Tolkien. The Hobbit was an instant success – and its mighty sequel The Lord of the Rings followed in 1954. From the start, this was a project of scale – Tolkien specialised in ancient languages and had invented a number of new ones while still in his 20s. World-building came naturally to him: he produced maps, illustrations, songs and an entire folk lore as well as an enormous cast of characters. The Middle Earth sagas became his defining life work.

Adapting Tolkien’s oeuvre for the screen seems to have had a similarly all-consuming effect on the producers and director Peter Jackson. The success of the Lord of the Rings films spawned a sequel series after a ten-year gap, and the decade-spanning global endeavour with its starry cast and vast budget has become an epic story in itself.

Everything about the project is super-sized – the Hobbit trilogy cost more than half a billion dollars to make. This is partly because of Jackson’s decision to shoot in 3D and at 48 frames per second in order to increase the clarity of the images. (Normally films are shot at 24 frames per second.)

So here we have the final 144 minutes of a very long story indeed. This is the third Hobbit movie and the sixth in the franchise as a whole. There will be no others unless the Tolkien family release rights to The Silmarillion and other connected works, which is unlikely. But this is probably cause for celebration rather than regret.

The elusive hero.Mark Pokorny/Warner Bros. Pictures

Why? Because the final Hobbit movie feels both cumbersome and predictable. Whatever the original intentions of the production team, it is still essentially “Lord of the Rings Six”, and that shows.

I’ve used Tolkien’s The Hobbit when teaching fantasy to creative writing students – it is an excellent example of the classic hero’s journey structure, and Bilbo Baggins personifies the classic hero in that genre. Part home-loving Baggins, part thrill-seeking Took, he is in conflict with himself and susceptible therefore to the temptations that the ring presents. He’s not exactly Madame Bovary, but he has as much psychological complexity as the fantasy genre demands.

In the film adaption, Bilbo is still conflicted, but his character is overwhelmed by the scale and time-frame of epic trilogy. And so by the time we get to the The Battle of the Five Armies he is all but submerged in a welter of sub-plots.

The film opens with what looks like – and in fact is – the climax of another film. (That would be The Hobbit – The Desolation of Smaug.) The dragon is laying waste to Lake Town, producing a Dresden-like firestorm until he’s terminated by Bard the Bowman. (Here, one might assume the film is called “The Bowman”.) Meanwhile, Bilbo is holed up with the dwarves in the Lonely Mountain, reduced as he is for much of the film to the status of sensitive bystander. The ring, already in his possession, serves mainly as a slightly queasy invisibility cloak, enabling him to go incognito at crucial moments. There is nothing in this final third of the narrative to compare to his riddling match with vicious, foetal Gollum in the first film, or with the terror of this first meeting with Smaug in the second.

Bring on ‘The Bowman’.Mark Pokorny/Warner Bros. Pictures

Visually, the film looks spectacular. But there is little that is new. One scene which stands out has Legolas firing arrows while leaping across falling boulders above a giddying abyss. But even in this stunningly balletic sequence, there is no real sense of jeopardy. Likewise, the massed hordes of orcs and wargs evoke little tension – these are computer-game dramatics. Again, after starting with a climax, structurally the film has nowhere to go.

Given that the story is so confused and diffused, it is a testament to the skill of the actors that they manage to invest the story with some dramatic power. Martin Freeman, Ian McKellen, Richard Armitage and Luke Evans are particularly impressive. The same cannot be said for the Harry Potter-esque cameos phoned in by Stephen Fry and Billy Connolly.

This is event cinema, hard-wired into popular culture – and the hype, expense and global reach are all part of the package. But the narrative suffers more than is necessary. The original novel, elegant, engaging and clearly structured, was based on myths reaching back into pre-history, which may explain some of its Jungian power.

Reconstituted as a constant thrill-ride, extended over more than eight hours, the dramatic tension is fatally undermined. And the heart of the novel – Bilbo’s inner journey – is marginalised. The glittering fakery of cinematic art brings the panorama of Middle Earth vividly to the screen, but the story itself has reached vanishing point.

Sally O'Reilly does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.