Why do they hate him so much? If Ed Miliband is as useless as right-wing newspapers want us to believe, why are they so eager to pour buckets of vitriol over him at every opportunity? Not since the 1992 general election and the monstering of Neil Kinnock have I witnessed so vicious and personal a campaign against a Labour leader. It’s almost – perish the thought – as though they’re scared of something.

Every day brings a new smear, whether it’s an attack from a business leader who doesn’t even live (or pay taxes) in this country or a frankly bizarre claim that Miliband once burnt a hole in someone’s carpet. What next? He tripped over a constituent’s labrador? I keep thinking we’ve reached rock bottom but then a new absurdity heaves over the horizon. The latest is a “storm” over one of Miliband’s aides supposedly describing the row about tax avoidance as another “Milly Dowler moment”.

Milly Dowler is the murdered schoolgirl whose mobile was hacked by the News of the World, exposing the phone-hacking scandal. Keep those words “phone-hacking scandal” in mind, for Miliband’s opponents are desperate to divert attention away from the criminal and unethical practices that were habitual in some newsrooms. They accused his aide of exploiting a dead schoolgirl, a claim that fell apart when it became clear that the phrase wasn’t a direct quote from anyone in Miliband’s office. The person who actually used the girl’s name was the BBC’s political editor, Nick Robinson, who included it in a tweet, without inverted commas.

In a febrile pre-election atmosphere, when the urge to damage Miliband has gone way beyond the bounds of reason, even a non-quote is enough to produce gleeful headlines: “Storm over Labour aide who compared tax scandal to Milly Dowler’s murder”, shouted The Times. “Fury after one of Ed’s senior aides calls tax row Milly Dowler moment that could be exploited for political gain”, raged the Daily Mail. In a sentence that should have been prefaced with the words “We hope ... ”, The Daily Telegraph claimed that the aide’s comments “could badly damage Mr Miliband”.

Seldom has a politician been attacked so roundly for something neither he nor anyone close to him actually said. That speaks volumes about the corrosive atmosphere of suspicion in which the Labour leader is operating, but it’s also a very good example of wishful thinking; the papers who ran with this story wanted to link it in the public mind to a murdered girl, not to the News of the World’s abuse of power. Press regulation isn’t an issue in the election campaign, but don’t let that fool you: the papers which are attacking the Labour leader mercilessly are also the ones which have the most to fear if he becomes prime minister.

Less than a year into his leadership, Miliband decided to ignore convention and challenge the unfettered power of Rupert Murdoch. In doing so, he broke with his predecessor Tony Blair, and with the received wisdom, that holds that it’s too dangerous for a mainstream politician to criticise the press. Miliband was the first of the party leaders to call for what became the Leveson inquiry, a bold move that marked a high point in his time as leader. It was this decision that one of his aides referred to, reasonably enough, during the row over tax avoidance; standing up to a press baron and confronting tax avoidance by influential people both require guts.

It should not be forgotten that the Murdoch papers, along with the Mail, Mirror, Express and Telegraph titles, are currently defying Parliament by refusing to join an independently audited regulator. That was a key recommendation of the Leveson inquiry, which wanted to see an end to a cosy system in which newspapers were allowed to regulate themselves without independent scrutiny. Instead of complying, some newspaper groups have set up their own regulator, Ipso, which is financed and controlled by the press. (Several newspapers, including the Independent titles, have not yet joined.)

The crunch will come after the general election when, as seems likely, an independently audited regulator is set up and big newspaper groups refuse to join it. Unlike David Cameron, who seems to be taking a back seat on press regulation, Miliband gives every sign of being determined to see the Leveson process through to the end. If Labour forms the next government, on its own or in some form of coalition, there could well be another showdown.

Self-interest is a powerful motivation and I’m sure it explains the seething animosity – sometimes I would describe it as deranged – towards the Labour leader. Clearly the hope is that enough mud will stick to fix the idea in voters’ minds that Miliband is incompetent, unpopular and weird. But the experience of 1992, when the Murdoch press bragged about its supposed role in keeping Kinnock out of No 10, is instructive. Polling evidence from the period suggests that The Sun overestimated its influence; John Major had a higher approval rating than Kinnock, but researchers concluded it “was probably worth no more than one percentage point to the Tory share of the vote”.

This raises the counter-intuitive possibility (for the press, at least) that voters are more interested in policies than personalities. Whether or not that’s true, newspapers should think hard these days before giving an impression of trying to subvert the democratic process. Since the Leveson inquiry, I’m not sure the public has much appetite for editors who boast about their ability to destroy decent politicians. This time it couldn’t be more vicious or personal, dating straight back to the summer of 2011 when Ed Miliband stood up to the world’s most powerful press baron.