How do you define public interest journalism? One of the great conundrums of the Leveson debate is how you protect the kind of journalism that everyone agrees is the lifeblood of democracy: the fourth estate’s watchdog role. Get it right – ideally, enshrine it in statute – and much else follows. But that depends on what it means.

One approach, favoured by many tabloid editors over the years, is to follow the line first expressed in simple terms by Mark Fowler, the Reagan appointed Chairman of the Federal Communications Commission in the 1980s: “the public’s interest defines the public interest”. This is the philosophy of journalism which justifies almost any story – and of course any intrusion into the lives of others – if there’s a big enough market for it. Paul McMullan, the much reviled News of the World hack who told Lord Justice Leveson that “privacy is for paedos”, was simply taking this approach to its logical conclusion. Free speech means opening the doors on everyone’s private life, because that is what the public demands.

But do they? The classic assumption that tabloid newspaper Kiss and Tells and the minutiae of celebrity gossip are justified because people buy tabloid newspapers in large numbers is not supported by research into how the public themselves define public interest journalism. Some of us may be prurient voyeurs  who enjoy uncomfortable revelations about others (though let’s remember that even in a nation of unusually high newspaper readers, only a minority buy a national tabloid), but British citizens in fact make a very clear distinction between what can legitimately be revealed in the public interest and what should remain private.

Opinion research which I commissioned from YouGov for the British Journalism Review set out to test attitudes to the publication of stories which contained some element of intrusion into private or corporate life. To establish how attitudes to “public interest” varied across different kinds of stories, we posed eight possible story lines and asked in each case whether or not newspapers should publish the story.

Respondents were offered three possible answers: the story was “definitely in the public interest” and should be published; the story was not in the public interest “but nevertheless should be published”; the story was a private matter and “should NOT be published”. Option 2 was designed to capture precisely the kind of justification so often used by editors: that some stories may not be classic watchdog public interest journalism, but publication was justified simply because it was an interesting story.

Results demonstrate unequivocally that the British public have little appetite for the publication of stories which they regard as personal matters rather than issues which have genuine public interest consequences. A full report can be found in the original BJR article published last week, but headline responses for each of the eight stories were as follows:

Foods sold by a major supermarket have been contaminated with bacteria.

Public interest: 92%

Not public interest but should be published: 3%

Should not be published: 2%

A High Court judge has large investments in foreign companies linked to the illegal drugs trade.

Public interest: 82%

Not public interest but should be published: 12%

Should not be published: 2%

A schoolteacher has been passing on exam questions to her students to help their GCSE grades.

Public interest: 70%

Not public interest but should be published: 22%

Should not be published: 4%

A company testing medicines is suspected of cruelty towards animals

Public interest: 70%

Not public interest but should be published: 21%

Should not be published: 5%

A well-known England footballer, who is married with young children, is having an affair

Public interest: 6%

Not public interest but should be published: 30%

Should not be published: 58%

A leading politician’s daughter is found drunk in public

Public interest: 2%

Not public interest but should be published: 22%

Should not be published: 69%

A member of a leading pop group has had cosmetic surgery to change the shape of her face

Public interest: 3%

Not public interest but should be published: 25%

Should not be published: 66%

A contestant on Britain’s Got Talent who has reached the final once tried to commit suicide

Public interest: 3%;

Not public interest but should be published: 12%;

Should not be published: 80%

Thus, for stories which featured wrongdoing by those in positions of authority (either individually or corporately), there was a very clear majority in favour of publication “in the public interest”. But for those stories which were more about inappropriate behaviour or misfortune relating to people in the public eye, there was an equally clear majority against publication.

Perhaps the most surprising result is the England footballer story. Here you have two ingredients which – in the opinion of most tabloid editors, and even some judges – would make the story fair game: the footballer is an England international, and he has young children. So surely exposing an extra-marital romp which betrays his role model status as well as his wife and his children is legitimate?

Apparently not. Not only does a clear majority of the general public think it should not be published, but half of all tabloid newspaper readers feel the same. Just one in 20 regard an England footballer’s affair as a clear public interest issue deserving publication, and those figures barely change between readers of different kinds of newspaper.

So the British public understand the distinction between watchdog journalism which holds power to account and celebrity journalism which has little public value even if some of it might be “interesting” (after all, most of us like a bit of juicy gossip). The clear inference is that most of the reading public would support a law which protects investigative journalism that plays a serious democratic scrutiny role, but would accept greater restrictions on unwarranted intrusions into the private lives of public figures for nothing other than their own prurient gratification.

Of course, you won’t read about this in the mainstream press. Just as the Times is content to suppress its own opinion research showing that a clear majority believe the Leveson inquiry will lead to better press regulation, none of the newspaper have shown the slightest interest in survey data which manifestly contradict the public views of most national newspaper editors.

They will therefore continue to present commercially self-interested editorial decisions as a sacred duty to act as guardians of the public interest. In truth, they are little more than moralising gossip-mongers masquerading as the vox populi. The public clearly understand the distinction. It is time that it was recognised in law.

Steven Barnett is Professor of Communications at the University of Westminster and an editorial board member of the British Journalism Review.