What goes unmentioned in the BBFC comments, though, is just how disturbing some of the character writing gets this time out. Cheery themes like slow mental decay and moral decline were touched on in the first two films – the Ring's speedy corruption of Boromir in Fellowship, or Frodo's increasing instability in Towers. But here it's wall-to-wall paranoia, alienation and madness for a good chunk of the running time, which only makes the eventual return to nobility, friendship and sacrifice that much more of a relief.
First there's the kingdom of Gondor, which in the absence of a king is ruled over by bats**t crazy steward Denethor (John Noble). Formerly a comic relief role, Pippin (Billy Boyd) comes into his own to moving effect here, as he's first traumatised by looking into Saruman's palantir (essentially a creepy crystal ball saturated in dark magic), and later becomes servant to an increasingly off-his-rocker Denethor.
Unlike in the book there's very little subtlety to Denethor, but Noble brings a grandiose tragic heft to his arc, which culminates in a stunning sequence where he attempts to burn himself and his neglected son Faramir (David Wenham) alive. Strangely, none of this is as unsettling as the scene in which he eats some cherry tomatoes.
Meanwhile over in Mordor, Gollum exploits the Ring's corrupting influence to turn Frodo against Sam, which makes not only for a horribly sad break-up scene between the two, but also for a singularly horrifying scene in which Frodo, now alone, is stalked by enormous spider beast Shelob. The rift between Sam and Frodo was one of Peter Jackson & co's major additions – it doesn't appear at all in Tolkien's text, but was added to give the characters' relationship more weight and, yes, to make Shelob just that bit more skin-crawling and nightmare-inducing.
For much of King's running time, the only source of light or hope comes from the plotline that also inspires the title: Aragorn's long-delayed acceptance of his rightful place on the throne of Gondor. Admittedly, there's a few false steps along the way – his raising the Army of the Dead ultimately feels more like a cop-out than a satisfying climax to the film's central battle, while the sections devoted to Arwen's impending death never quite have the romantic weight you sense they should. In comparison to Miranda Otto's fiery, fiercely independent Eowyn, whose love for Aragorn only spurs her on to battle, Arwen feels inert at best as a long-term love interest.
But Mortensen is as compelling as ever, and his eventual coronation is a perfect culmination to the series, with every single character we've come to love gathered in one place. It's a triumphant, touching climax that doesn't whitewash any of what's come before – none of these characters have come out of the experience unscathed, and so as much as this is a happy ending where good triumphs over evil, there's a very human sadness underscoring it.
And setting aside any other considerations, the "My friends, you bow to no-one" moment is just plain lovely. If you didn't get something in your eye at that point, check your pulse to check you're still human.
Unlike Towers, which faltered in its attempts to juggle three narratives, The Return of the King is seamlessly cohesive despite how much is crammed into its spacious running time. The big moments – the Battle of the Pelennor Fields, the final showdown at Mount Doom, the coronation – are presented in sweeping, rapturous detail, but as in the entire trilogy it's the small stuff that really counts.