Swift's aim, as he wrote to his friend Alexander Pope, was "to vex the world, rather than divert it... When you think of the world," he added, "give it one lash the more at my request." And, diverting as it is, his spoof-travelogue certainly gave it some wonderful lashes. His portrait of organised religion and politics - where preferment literally depends upon leaping and creeping - anticipated Dickens in its avenging savagery. What is the purpose of lawyers? To get rich at the expense of their clients, replies the ever-topical Swift. What is a soldier? "A Yahoo hired to kill in cold blood as many of his own species, who have never offended him, as possibly he can."
In Swift's satirical world, opening your egg at the wrong end, or wearing heels of the wrong height, is an outrage sufficient to brand you as an outcast, or start a civil war. After politely listening to Gulliver's description of his native land, the giant-king delivers his verdict: "I cannot but conclude the bulk of your natives to be the most pernicious race of little odious vermin that nature ever suffered to crawl upon the surface of the earth."
On its appearance in 1726, the book was a runaway best-seller. As John Gay wrote to the author, "From the lowest to the highest it is universally read, from the Cabinet-council to the Nursery." The Houyhnhnms in particular caught people's fancy: it became the fashion to talk in their manner, and one opera went topical with a "neighing duetto".The book was an equal success in France, with Voltaire hailing Swift as the English Rabelais.
But the extremity of the satire, coupled with its author's fame as a Tory pamphleteer, provoked extreme reactions. "There must be some Witchery in it," wrote one of Swift's ecclesiastical enemies, "for People, who do not seem to be downright Fools, to waste so many Hours on a Book made up of Folly and Extravagance." The voyage to the Houyhnhnms, said another, was "a real insult upon mankind".
"A man grows sick at the shocking things inserted here," wrote a cleric, on reading of Gulliver's encounters with the shit-daubed Yahoos. "His gorge rises; he closes the book with detestation and disappointment."
Dr Johnson, whose moral fable Rasselas can be seen as a decorous riposte to Gulliver, was unimpressed. "Swift is clear, but he is shallow. When once you have thought of big men and little men, it is very easy to do all the rest." William Hazlitt, leaping to Swift's defence, neatly saw off this argument: "You might as well take away the merit in the invention of the telescope, by saying that, after its uses were explained and understood, any ordinary eyesight could look through it." Swift, he added, had "tried an experiment upon human life, sifted its pretensions from the alloy of circumstances, and found it, for the most part, wanting and worthless."
The Victorians didn't join the fan-club. Thackeray accused Swift of writing in "Yahoo language... A monster gibbering shrieks, and gnashing imprecations against mankind - tearing down all shreds of modesty, past all sense of manliness and shame; filthy in word, filthy in thought, furious, raging, obscene." What fever was boiling in Swift, he asked, "that he should see all the world bloodshot"?
Aldous Huxley concluded that Swift "hated bowels with such a passionate abhorrence that he felt a perverse compulsion to bathe continually in the squelchy imagination of them". Orwell regarded him as an evil-minded snob, a ridiculer of all intellectual effort. Michael Foot, however, has declared that "everyone standing for political office in Dublin, the United States, or London, should have a compulsory examination in Gulliver's Travels." So the Swifteans can rest their case.
What tends to get lost in all this argument is the sheer fun Swift had along the way. Gulliver's well-meaning extinction of the palace fire in Lilliput, and the tiny queen's outrage at being pissed on, is high comedy. Each country Gulliver visits has its own language, elaborated with zealous mock-pedantry. The "flappers" of Laputa, employed to belabour their master out of his intellectual trances, are wonderfully bizarre, while Swift's rumination on the idea of size - "nothing is great or little otherwise than by comparison" - anticipates not only 20th-century science, but also the games played by our "Martian" poets.
But the book is at the same time an emotional odyssey, swinging wildly between bliss and horror, delight and disgust. Gulliver may be revolted at the sight of the Brobdingnagian servant-girls' breasts - 6ft high and covered with pits and freckles - and he may be affronted by their use of him as a sexual toy, but he enjoys a sweet romance with his nine-year- old keeper, an amiable giantess named Glumdalclitch. Finally cast out by the disdainful Houyhnhnms, the hero ends up in a state of revulsion at the thought of any contact with his own kind. Whether he meant to or not, Swift has left us with a chilling case-study of a crack-up.
That is not the sort of thing which appeals to Hollywood. Two films have been made of Gulliver - one in 1939, the other in 1976 - but both are wacky cartoons focusing on high jinks in Lilliput. The extraordinary two- part film which Channel 4 are screening over Easter, however, is a very different kettle of fish. Gulliver, aka Ted Danson, is magnified and shrunk with the aid of the highest of hi-technology, and his adventures are shot against the palaces and beaches of Portugal. His emotional disturbance is the pivot of the plot.
"We wanted to reclaim the story for its adult audience. We wanted to do it in its entirety, and do justice to its satire," says producer Duncan Kenworthy (of Four Weddings fame). He's certainly done it in style, with Charles (Brideshead Revisited) Sturridge directing a cast that includes John Gielgud, Omar Sharif, Peter O'Toole, Geraldine Chaplin and Mary Steenburgen. And screenwriter Simon Moore has not been afraid to take liberties with the text.
The biggest of these is Moore's notion of framing the voyages with a melodramatic sub-plot in which Gulliver, diagnosed as suffering from delusions, is banged up in Bedlam. The justification for this is two-fold: economic, in that they had to offset the expensive visual effects with scenes which were cheaper to film; and dramatic, in that to have the story narrated by Gulliver at his fireside (as in the original) would have felt a bit limp.
Swift's fun is here in spades - Gielgud, for example, playing the mad scientist who extracts sunbeams from cucumbers - but the blackness of his ultimate vision is missing. One of the most horrifying passages in the book concerns the Struldbrugs, who are condemned to live for ever like shambling Alzheimer wrecks. Sturridge decreed that the chief Struldbrug should be played by the radiantly beautiful Kristin Scott Thomas, and that we should be told merely that she is blind, thus harmlessly diluting Swift's pungent brew.
But the biggest departure comes at the end, where Danson is joyfully reunited with his family. Here we enter the politics of showbiz. Moore's original ending was faithful to Swift's, with Gulliver shunning humanity. If Channel 4 had been the sole producer, this ending could have stood. But the co-producer was the American NBC, whose executives were appalled at the idea of their hero ending up talking to horses in a field. That wasn't "life-affirming" enough. So we climax with a Hollywood-style cliff- top kiss. No matter. As Moore points out, the film is going to make a lot of people read the book. And (pace Dr Johnson) that can't be bad.
n `Gulliver's Travels' will be shown at 6pm, 7 and 8 April, on Channel 4Reuse content