The media do not like complexity. The swing­ometers don't work. The newspapers' election night charts of red and blue, showing which seats fell to what swing - with a small yellow side panel for the Liberal Democrats - have to be ditched. Images of triumphant winners and despairing losers are not available. Instead, editors have to choose from a selection of apprehensive, uncertain faces and, as journalists discuss coalitions, pacts, "confidence and supply" agreements and the merits of AV+, there lurks in their minds the fear that viewers, listeners and readers haven't a clue what they're on about.

Journalism is about simple storylines, preferably ones that develop according to the rules of Greek classical drama. The 2010 campaign produced a plot where nothing was as it seemed. The televised debates produced an unprecedented surge in support for Nick Clegg. By election day, it had disappeared, almost without trace.

Gordon Brown's remark about "some bigoted woman" in Rochdale was, we were told, the defining moment of the campaign. He had insulted every northern woman, and brought out, in every northern male, the instinct to defend his beloved nan. In fact, Labour unexpectedly won Rochdale against the Lib Dems by just under 900 votes, and it generally did well in the north.

North and south

After the MPs' expenses scandal, the media confidently asserted, the voters' vengeance would be terrible to behold. Yet, with some exceptions, such as Jacqui Smith in Redditch, candidates seeking re-election did better than fresh faces. Independents such as Esther Rantzen, provoked into standing by the expenses scandal, got derisory votes, and even the good doctor in Wyre Forest was beaten, after serving as MP for two terms.

Immigration, the newspapers insisted, was the number-one issue for voters; politicians, aided and abetted by the BBC, were conspiring to keep it off the agenda. This, the story ran, would be a gift to the BNP and Ukip. BNP support, however, imploded and Ukip's performance was unspectacular.

The inescapable conclusion is that journalists - particularly newspaper journalists - do not know the public as well as they think they do. Most newspapers completely misread the campaign from the beginning. They thought that, although voters wouldn't embrace David Cameron with enthusiasm, Brown's unpopularity was a given. It was on those grounds that Rebekah Brooks, former editor of the Sun and now News International's chief executive, persuaded Rupert Murdoch that his red-top papers should declare early for Cameron - much earlier than they declared for Tony Blair in the run-up to the 1997 election - and throw their formidable weight behind the Tories. But, as Ian Jack observed in the Guardian, people in northern England speak of Brown "reasonably kindly". Visceral dislike was confined to the south. The newspapers got it wrong largely because they see the country from a southern, metropolitan standpoint, having closed nearly all their regional outposts and virtually stopped sending reporters out of the office, never mind out of Greater London. During a campaign, journalists venture into northern Britain as though it were some little-known region of the Caucasus.

No newspaper - not even the Daily Mirror, which came out not so much for Brown as against Cameron - could claim to have won the election, as the Sun did in 1992. True, the right-wing papers' offensive against Nick Clegg, which began after the first televised debate, might seem to explain the Lib Dems' surprising failure. But if the opinion polls were right, the newspapers' exercise in character assassination had no immediate effect. It's more likely that voters concluded, after watching the later debates, that Clegg wasn't as different from the other leaders as he claimed and that his promise of "change" lacked substance.

A more plausible hypothesis - but not one that the papers would want to air - is that the electorate heeded their warnings about the dangers of a hung parliament. The Mail, for example, devoted its front page and four inside pages on election day to arguing that, without "strong" government, Britain would end up like Greece. The effect, as the press intended, may have been to persuade people to return to old loyalties - but with the un-intended consequence that Labour benefited as much as the Tories.

The idea that voters can collectively decide on a conclusive result is one of many media myths about elections. Elections don't express a Rousseauian "general will" (which is why Marxists don't like them): they aggregate millions of individual decisions.

Squatter's rights

But perhaps the main lesson the media should draw from the 2010 campaign is that the 24-hour news cycle has begun to create a backlash. As the Sun discovered after its exposure of Brown's errors in a letter to a dead soldier's parents, relentless denigration can generate sympathy for the victim. If Brown did better at the polls than anybody expected six months ago, it was probably because voters thought the media were being too hard on a conscientious man with a nice wife who was just doing his best.

As soon as the campaign ended, the Mail, Sun and Telegraph accused Brown of "squatting" in Downing Street - despite the clear consensus, among experts on the mysteries of the British constitution, that he was obliged to continue until he could advise the Queen that someone else was able to form a government. A Sunday Times poll showed that 62 per cent wanted him to quit immediately. After another week of media hysteria, the public will probably say the poor man shouldn't be hounded out of his home.

Peter Wilby was editor of the New Statesman from 1998-2005.