Rude awakening: A new Tate exhibition details the revolution fomented by visual satire (and downright smut!)

During the 1780s, the French ambassador to the Court of St James is rumoured to have written a despatch to Versailles, outlining his fears that Britain was teetering on the verge of revolution. He'd reached this disturbing conclusion because of the free availability of ribald satirical prints depicting members of the Royal Family. These prints by James Gillray, Thomas Rowlandson and many others were merciless in their lèse-majesté: if he was lucky, George III would escape with being portrayed as a bovine rustic bumpkin; his son was never lucky enough to be shown as anything but a drunken, lecherous buffoon.

As the ambassador's coach purveyed him from salon to Court to levee, he would have passed little kiosks peddling this smut, often hiring it out for the night, like a modern DVD. These booths lined the Strand and Fleet Street, stretching all the way from Charing Cross almost to St Paul's. So it's no surprise, given the evidence of this squalid trade, that the ambassador came to the conclusion he did.

After all, unlike France under the stable absolutism of the Bourbons, the British had form. One hundred and thirty years previously they had chopped off one king's head and called it a revolution; in 1688, they chased another king from his throne, and called that a "Glorious" revolution. As any civilised gentleman in Europe knew, the British were little better than beasts, and consequently highly susceptible to the destabilising effects of mucky pictures of the Prince Regent rogering his doxy. Revolution was inevitable, therefore, because apart from anything else, the British were just so... well, rude.

Of course, we know now that the ambassador was completely, and fatally, wrong. It was France that had the revolution, and then the deranged bloodletting of the Terror; and France which, before the Revolution, had been awash with bloodcurdling sexual libels about Marie Antoinette and the Court. The difference, crucially, lay in the fact that French rudeness was kept sealed inside the foetid pressure cooker of the Ancien Regime until it exploded.

Then again, we all know that the French are the rudest people on earth. Except, maybe, for the Israelis, with their tradition of the harsh egalitarianism of the kibbutzim. Unless, that is, you've ever met Russian bar staff in a London pub. As for New Yorkers...

Actually, it is we British – the shy, embarrassed, polite and reserved British – who have enjoyed a far worse reputation for savage rudeness. I long ago worked out, from bitter experience amid the hate mail and death threats I've received from around the world, that while I see my work as a cartoonist as firmly in the tradition of William Hogarth and Gillray, everyone else sees it as breathtakingly vicious. And it is this tradition that is celebrated in Tate Britain's major new exhibition, Rude Britannia: British Comic Art, examining the plaited strands of British rudeness over the past 300 years (including my own valedictory cartoon of Tony Blair as Prime Minister, telling him, through the magic of bad puns, to fuck off in three different ways).

"Rudeness", in this case, is both less and more than farting in church or mooning on the last bus home. While we all secretly enjoy a bit of smut, almost as much as we enjoy saying rude things about other people out of earshot, what the exhibition reveals is the level to which shifting standards in private behaviour have succeeded or failed to expand into being tolerated in the public arena. It also tacitly acknowledges that transgression from the private to public sphere often provides the best part of the joke.

Thus, under the theme of "Bawdy", one part of the exhibition goes from Rowlandson's semi-pornographic, under-the-counter erotica from the late 18th century, through Aubrey Beardsley's notorious priapic illustrations of Aristophanes' Lysistrata – which Beardsley ordered to be burned after his deathbed conversion to Roman Catholicism in 1898 – to Donald McGill's dirty seaside postcards, which were successfully prosecuted and ordered to be destroyed by a magistrate's court in Margate in the 1950s. These fluctuating fortunes in what is and isn't tolerable are reflected in the exhibition's examination of social and political comic art, and the extent to which visual satire has been able to get away with telling power that it's stupid, it's got a big nose and it should just bugger off.

That visual humour was ever able to get away with it is, in a way, slightly miraculous. Since the invention of printing, there had always been scurrilous images making political points, but they had usually been partisan and therefore under the protection of powerful patrons. What was new about 18th-century visual satire was that it publicly articulated the universal human emotion that the king is an idiot, but without the consequence that the print-maker would have his work burnt and his ears sheared off by the public hangman.

Although "tolerance" was central to the Whig philosophy underpinning the Glorious Revolution of 1688, when the Censorship Laws lapsed in 1695, the failure to renew them was more down to oversight than principle. Nonetheless, that act of neglect left Britain unique in the world. There was a sudden mushrooming of satire of all kinds, which governments were largely unable to control. Robert Walpole was subjected to a sustained, personalised onslaught, and even his title, as first "Prime Minister", was a term, like the words "Christian" and "Tory", first coined as an insult to mock, in this case, Walpole's propensity for accruing offices, money and power for himself.

Indeed, the satirical mood of the times has coloured the way we think we see the whole century: mucky, rumbustious, earthy, humorous and, definingly, Hogarthian. The art critic Robert Hughes summed it up thus: "Modern squalor is squalid but Georgian squalor is 'Hogarthian', an art form in itself." Even at his most polemical and preachy – in Gin Lane, for instance, or in A Rake's Progress – you feel that Hogarth can't stop himself laughing while he's lecturing.

And taking the piss was, quite literally, the point. In the 18th and 19th centuries, London was the largest and richest city the world had seen, and for most of that time existed without flush toilets or adequate sewers. Visual satirists such as Philip Dawe could outstrip their merely textual counterparts in depicting the absurdity of the elite's finery being dragged through the gutter, while at the same time he and his peers were, through mockery, stripping away the robes of power to show the pissing, shitting, sweating human being underneath, no less stinky than you and me. A generation after Hogarth, Gillray was still exercising Swift's scatalogical vision in satirical prints of Prime Minister Pitt defecating paper money into the Bank of England or, during the Napoleonic Wars, George III transformed into a map of Britain and showering shit out of the Solent over the French invasion fleet.

Now that's rude by anyone's standards, and its purpose satirically is primal: it's voodoo, doing damage to an enemy at a distance with a sharp object, although in this case it's an etching tool or a nib rather than a needle. That's why visual satire works, in its capacity to insult and therefore belittle men who think themselves great; that's why the cartoonist David Low was placed on the Gestapo's death list, because he'd dared to draw Hitler as a bloody fool in a stupid uniform and with a Charlie Chaplin moustache.

Between Gillray and Low, however, rudeness did not prosper, in public at least. Creeping respectability and the middle class's increasing insistence on deference meant Gladstone and Disraeli never suffered the indignities of Pitt, although hypocrisy did allow for innuendo to come fully into its own, even if only among the masses in the music halls. A century on, the moral actions of the burghers of Margate in burning McGill's immoral postcards were probably an unconscious stabilising response to a recent war which had been set in course by other moralists burning books, then burning people.

But that was almost respectability's last hurrah. A decade-and-a-half later, the Lord Chamberlain – brought in to impose political censorship on the theatre by Walpole after the success of The Beggar's Opera, but dedicated to extirpating the sauce and the foul language for most of the next 200 years – was gone, and soon afterwards most of the prevalent taboos had gone too. So you rather wonder, when you get to the YBAs represented in the exhibition, such as Sarah Lucas, who exactly they're being rude to, and how iconoclastic you can be when your patrons specialise in putting on displays of smashed icons in their respectable galleries.

But although firebombing the Saatchi Collection remains terribly attractive as an exercise in all sorts of rudeness, maybe the new doesn't shock any more. And anyway, perhaps the point of rudeness isn't to shock the "rudee" at all, but just make the rude and their mates snigger, thereby evening up all sorts of different social and political equations for those who are in on the joke. After all, from 1849 until the 1920s, Punch, the embodiment of stifling Victorian respectability, ran the same Richard Doyle cover every week, with just the issue number and date changed, brazening its frieze of Mr Punch on a mule, fondling his huge erect cock. Either no one noticed, or they were smirking fit to bust.

Rude Britannia is at Tate Britain, London SW1 (tate.org.uk), from Wednesday