When American newspapermen mused on their profession a century ago, they would confess, usually with pride, that it was both cruel and mendacious – and had to be. H L Mencken, among the most influential writers of the early 20th century, opined that any journalist worth his salt knew that his job was “to please the crowd, to give a good show; and the way they set about giving that good show was by first selecting a deserving victim, and then putting him magnificently to the torture”. The smart journalist knows, said the “sage of Baltimore”, that “it is hard for the plain people to think about a thing, but easy for them to feel”.

Silas Bent, who fell into (as he put it) reporting in New York in the 1920s, described how he intercepted a telegram from an errant wife he was pursuing for a story, opened it, took it back to his editor who pretended shock – then ordered him to follow up the information contained in it. The New York newspaper game in which he played had been, to a large extent, formed by the crude, populist, sexy and very successful papers of the Scots immigrant W Gordon Bennett from the 1840s to the 1870s; a quarter of a century on, Joseph Pulitzer and William Randolph Hearst “fought for supremacy”, Bent wrote “through fakery and thrills”.

The Front Page is everyone’s favourite movie summation of these lives and times, and both the 1931 and the 1974 versions, together with the 1940 His Girl Friday (the same story), are all so beloved of those in the trade because, in the end, the snarling, callous, cynical beats of reporters do good, while never for a minute meaning to. It was a time, and a moral atmosphere, in which you expected policemen and politicians to be on the take, women to be the prey of the sensation seekers and truth to be wholly negotiable – though with it, there was a kind of raucous, fitful egalitarianism, a suspicion of wealth, power and social position, a love of tearing down the mighty (so long as the mighty proprietor was never in your sites).

That changed. American journalism grew up in the thirties and after the war. The corruption which yellow journalism spread so liberally in its wake began to be less acceptable, and then to be punished. New York became famed, not for the yellow papers, but for the “good, grey” New York Times. Tabloids were marginalised: the National Enquirer, outside of New York (which kept and still keeps something of a tabloid culture, with the Daily News and the New York Post) was the echo of it, though it was as interested in space invaders as adulterers.

The British tabloids kept the tradition alive. Britain had also created a yellow press culture in the 1840s – with the News of the World, like Bennett’s papers, aimed at a newly-literate lower middle and working class, much interested in court cases involving “women of the night” and “houses of ill repute”, feeding their readers what were, by today’s snappy standards, long, long stories of depravity and vice.

Rupert Murdoch clearly loved that world. His – and other – tabloids remained fixed in a turn-of-the-century attitudes, the personnel changing, the scandals the same. No longer did ministers’ wives flee with worthless lovers (or if they did, who cared?) – the subjects of Silas Bent’s $12 a week (and glad to get it) investigations; now it’s the rapid switches of lovers among various grades of celebrities, many of whom exist – it seems – in order to provide the content of tabloids, and take the big money for doing so.

Murdoch saw in Britain in the late sixties what Silvio Berlusconi saw in Italy a decade later. They saw a lower middle and working class which had long been literate, but were now becoming a little easier in their circumstances. They were living better: they were, in fact, not just living but consuming. Consuming meant they were making choices, some of them quite new – of holidays, of new foods, of homes, of televisions and refrigerators, of cars. They were learning new ways to relate to each other, to society as a whole, to the culture about them. They had time for amusement – and increasingly, that came from television. Sex, and sexual excitement, became less inhibited, more pervasive. Women became more sexually liberated. People began to have more fun, more often.

The tabloids helped create this world: Murdoch’s tabloids did it with an extra twist. They loved the new culture that they helped create: and they loved to mock the politicians, especially the politicians of the left, who might disapprove of the new hedonism, or remained attached to collective institutions – when all about them, the individual and the individual’s desires and pleasures were paramount. Like Mencken’s ideal journalist, they selected their ideal victim, and put him (or her) magnificently to the torture. Except that it usually was not magnificent. Usually, it was grubby, sniggering, through-the-keyhole stuff.

The culture of entertainment grew ever bigger: in Neil Postman’s phrase, we were amusing ourselves to death. The tabloids became more and more focused on the cult of celebrity, and of celebrity hedonism: at the same time, they ratcheted up their contempt for the politicians who scrambled for their favour and their endorsement. The politicians, increasingly, had nowhere else to go: the movements which had created their parties were failing, the parties themselves were hemorrhaging members: the tabloids had the mass audiences, and the politicians needed the masses to pay at least a little attention.

Thus Rupert Murdoch, the greatest newspaperman in the world, became the most eagerly sought guest at top politicians’ dinner table. Thus did Tony Blair, when leader of the opposition, go half way round the world to Australia to address his executives. Thus did David Cameron hire Andy Coulson, his former editor, even after the latter had resigned when phone hacking was discovered in his paper, the News of the World. Alastair Campbell, Blair’s director of communications, wrote in the FT on Monday that “I accept that, for all of us, at times media support was something we courted at the expense of opinions of principle on media issues”. There it is: a little grudging, but an admission from one whose motto could have been: never apologise, never explain. Murdoch wielded raw power; the political class of Britain had to bow to it.

Then, suddenly this summer, the smouldering issue of phone hacking – which had ignited, feebly, four years before – burst into light. We owe much of that to the dogged reporting of the Guardian, especially to Nick Davies. Revelations and allegations began to swirl about the News of the World, still the most popular newspaper in the UK – resulting in its closure. The country –the world – was treated to a barrage of stories which pointed in one direction: that the News of the World had systemically hacked into the phones of politicians, celebrities and people in the news – including murder victims and their relatives – in order to produce exclusives. They also bribed policemen, both with petty cash and – allegedly – with large payments. And they found out about the private sins of people in public life – and where they did not print details, they held the results of the investigations over their heads.

Many political figures have felt bound to confess they had wooed Rupert Murdoch, to catch the favour of his papers - The Times and the Sunday Times, The Sun and the News of the World. The honest among them, having expressed dismay at the scale of the criminality, turn the question back: what would you have us do? Politics requires power; to keep it requires some measure of public support; our main competitor for public attention are the news media. Here was a news media company with vast power over public opinion, with a proven record of diminishing politicians. To scorn it and its owner, was to invite the treatment meted out to Neil Kinnock, leader of the Labour Party, who never won an election; or John Major, Conservative Prime Minister, who had News International (and most other newspapers’) support in 1992 when he won, and had their contempt in 1997, when he lost. Wooing, as dignified as possible, seemed the best tactic.

The revelations are grotesque: and one of their grotesqueries is that, it now seems, we “knew” that these things happened. We – really, the political and media people – “knew” that phones were hacked, policemen were paid off and politicians were exposed, or threatened with exposure if they felt like attacking News International. We “knew” all this – and yet the revelations burst like a bomb – as if on a wholly unaware society.

The British tabloids live by the disclosure of private details, however obtained, and may die for the lack of it (if matters really do change): and their kind of disclosure takes some space below. Second, disclosure of what we “know” changes the way in which we know: it supplies details rather than rumours, and replaces the pseudo-sophisticated cynicism with which most insiders dealt with what they “knew” with a context in which outrage could – indeed must – be expressed, a reaction which only a few had possessed before.

Another grotesquerie: the News International titles, in common with all newspapers and especially tabloid newspapers, have huge reservoirs of indignation ready to be poured over governments (especially), corporations and other institutions which lie, cover up, disguise, obfuscate and spin. Yet here is another thing we “knew”: that, though the news media relentlessly promoted transparency and accountability, they are of all institutions the least likely to live by their rules – indeed, reject their rules in the name of freedom. The classic critique was that of the philosopher Onora O’Neill who argued that

_“the media, in particular the print media - while deeply preoccupied with others’ untrustworthiness - have escaped demands for accountability (that is, apart from the financial disciplines set by company law and accounting practices).…Newspaper editors and journalists are not held accountable in these ways. Outstanding reporting and accurate writing mingle with editing and reporting that smears, sneers and jeers, names, shames and blames. Some reporting ‘covers’ (or should I say ‘uncovers’?) dementing amounts of trivia, some misrepresents, some denigrates, some teeters on the brink of defamation… Above all there is no requirement to make evidence accessible to readers” _(Onora O’Neill, Reith Lecture 5, 2002)

O’Neill “knew” that by observation: but she, and we, did not know how right she was – or rather, how only partially right she was, since to add to the smears, sneers and jeers, the names, shames and blames, have to be added the driven, ruthless hacking into the private lives of the powerful and the powerless; the contempt the senior levels of news international expressed for those politicians who sought to call them to account; and the ways in which they lied, again and again, about what they knew, when they knew it, what they had done and what they had allowed to be done. A final grotesquerie (for now): journalism has been at the heart of a generally optimistic narrative of freedom and openness over the past three decades, one which the British news media have been among the leaders in celebrating abroad - and which simultaneously some of them were busily undermining at home.