"The smears were so extensive, there will be always be people who don't know me", Chris Jefferies told the Leveson Inquiry yesterday, "who will retain the impression I am some sort of very weird character who is best avoided." He added he "will never fully recover from the events" or their "incalculable" effect on him.

By 'events', Mr Jefferies, a retired teacher, was referring to the week-long persecution he suffered at the hands of our press. In seeking a culprit for Joanna Yeates' murder, they alighted on the landlord with the funny hair. His fault, I guess, for impersonating Emmett Brown, the mad doctor in Back to the Future; but front pages like The Sun's "The Strange Mr Jefferies – Kids' nickname for ex-teacher suspect" were a bit much, on reflection. Or The Daily Mirror: "Jo suspect is Peeping Tom". Or the Daily Star: "Jo landlord a creep who freaked out schoolgirls".

On my first foreign assignment as a reporter a few years back, I was sent to Portugal to cover the disappearance of Madeleine McCann. By the time I turned up in Praia da Luz, the only story in town was "Is Robert Murat guilty?". The friend of the McCann's had received the same treatment as Mr Jefferies. A Daily Mail double-page spread set the agenda: "Oddball of the Algarve". The story is still online, with a picture caption reading: "Suspect or scapegoat? Robert Murat claims he will not live unless Madeleine's true abductor is captured – is it all a pretence?" Well, is it?

In his cogent, scathing testimony to Leveson last week, Hugh Grant detailed the harassment not just of Tinglan Hong, the mother of his child, but also Ms Hong's elderly mother. Her ordeal, like that of Jefferies and Murat, show that the need for exclusives now routinely leads not just to blatant invention and deceit of readers, but unforgivable persecution of the innocent.

Tabloid journalism – a British invention – used to be one of the things that made our country great. My hero, Hugh Cudlipp, edited a Daily Mirror whose slogan was "Forward with the People". It was a tribune of the poor. Then Rupert Murdoch hijacked that slogan for The Sun, after the Mirror dropped it. With that seminal moment in Britain's post-war history, tabloids began to elevate the commercial interests of their owners above a commitment to honest reporting.

Our free press is too precious to let Sir Brian Leveson put its regulation in the hands of the state. But the bullying of Jefferies, Murat, Hong and many others risks doing just that. In more ways than one, tabloid instincts are taking our country to the gutter.