I’ve watched the hackgate/NewsCorp/Leveson circus with a fascinated mixture of horror, revulsion and amusement. It’s been something of a car crash spectacle, only onlookers didn’t hack the phones belonging to the relatives of those expiring in the inferno, stick a camera into the faces of dying people or hound the relatives of the dead afterwards.

Seeing the likes of Brooks and the Murdochs get some measure of comeuppance has been vaguely satisfying, but I don’t think a lot will change. One lot of dodgy newsroom execs will get the boot; another load, steeped in the dubious cultures of modern national newsrooms, will take their place.

The new I'm A Celebrity cast lines up at the Leveson Inquiry

What may happen is that the ridiculous Press Complaints Commission might finally shuffle off to a Soho restaurant for good, in that it should be clear to even the most swivel-eyed hack that it’s permanently fucked; rather like a semi-senile octogenarian business type constantly befuddled by what his avaricious minions are up to behind his back.

The revelations over what families such as the Dowlers and McCanns were put through should cause everyone who calls himself a journalist to cringe with the awfulness of it all. The press has been out of control for much of the last decade; each jaw-dropping anecdote about hacking, blagging or other criminal behaviour another black mark against an industry capable of so much good.

Yesterday at the Leveson inquiry absolutely blew that away though, with the testimony of Paul McMullan, a man who has only existed previously in cartoonish representations of the most archetypally amoral journalist going. McMullan virtually admitted, without shame, that he had broken the law in many and varied ways more times than he could remember – and went on to explain that absolutely anything that sold newspapers was justified.

I’d suggest that the combination of massive, extra-legal power, backed up by lorry-loads of available cash – essentially the tools of tabloid journalists over the last ten years – coupled with the belief that virtually any behaviour, and any story, is justifiable is a pretty worrying proposition.

McMullan didn’t seem to think so. “Privacy is for paedos,” he averred, tucking his press card into a hatband, scowling at a Muslim and knocking one out to a page three picture of Lucy Pinder’s tits. `

“Circulation defines what is the public interest,” he continued, lighting up a fag, breaking wind and slurping on a pint of warm beer. “I don’t see it’s the job of anyone else to force the public to read this or that.”

The public interest. Have three words ever been so misused to justify such scandalous behaviour? To a new generation of hacks and hackettes, this new definition of “the public interest” happens to dovetail with “what newspapers want to publish”. Jon Venables’ new identity; Kate McCann’s private diaries; Charlotte Church’s norks – public interest.

These things cannot possibly be in any recognised definition of “the public interest”; the only “interest” involved here is self-interest. Over the last 40 years journalists have started to fantasise a bizarre superhero role for themselves, where they bring down druglords, bent politicans and have become crusaders for free speech and the Great British Public.

In some ways they have – and the right of the press to muddy what constitutes legal and illegal conduct in the pursuit of uncovering corruption, mass illegality and behaviour inimical to civil society has been, unofficially, enshrined.

McMullan just about stopped short of admitting to – but happily defended – a wide spectrum of illegal activities, such as cultivating contacts with police, being involved in high-speed car chases, entering private buildings under false pretences, theft, telephone hacking and using private detectives to ‘blag’ information.

Many of these activities fall into a kind of grey area in the PCC’s codes of practice – and statutory law. The Guardian only managed to bring down Jonathan Aitken – one of the greatest instances of investigative journalism in our country’s history – by faking a letter from the House of Commons. Illegal? Unethical? Perhaps – but there’s a peculiar ‘ends justify the means’ aspect to journalism in this country.

In some instances they do. Most of the great political scoops of the tabloid era will have been broken with some assistance from legally dubious methods. If that work exposes corruption, illegality or double standards of those in public life then I can see a justification.

But somehow “the public interest” has been extended to actors, sportspeople, musicians, reality TV types – even the families of those in the public eye; basically anyone famous enough to arguably be of interest to people who buy newspapers. Tabloids tell us they’re the guardians of truth and honesty and give us tawdry sex-and-drugs splashes concerning people like Joe Calzaghe and Kate Middleton’s uncle; the News of the World wasn’t known as the News of the Screws for nothing.

McMullan’s only apparent regret was that he once discovered Denholm Elliot’s daughter – homeless, drug-addicted and working as a prostitute – took her to his flat, reeled of some grimy topless photos of her and splashed her sad wreck of a life all over the weekend papers. A couple of years later she killed herself. Public interest, right?

Some journos and editors cannot tell the difference any more between who’s a legitimate target and who isn’t. And their behaviour risks legislation, in response, that will make it harder for journalists to investigate legitimate targets.

In taking advantage of the grey areas of what’s excusable as part of political and economic journalism – by exporting those cloak-and-dagger methods to tittle-tattle – they’ve probably made it easier for governments to muzzle the kind of journalists who exposed Jonathan Aitken, Robert Maxwell, Jeffrey Archer, Conrad Black and expenses-fiddling politicians.

That they can’t see it themselves, apart from a few notable exceptions, is worrying. They genuinely believe they have the right to do what they want in the pursuit of a story. That extends to deleting messages on Milly Dowler’s phone, causing her family to believe she was still alive when she was dead; and printing Kate McCann’s grief-filled private diaries, before going on to suggest the McCanns had sold their daughter for cash without a shred of evidence.

The hacking and the dubious provenance of the diaries – almost certainly both illegal – sold papers, runs the McMullan defence, therefore they were fair game. His testimony, while amusing, should do little to convince the general population that tabloid hacks aren’t the absolute scum of the Earth.

How did any of it support his view that the PCC does a good job, the press should remain free and that journos are sympathetic characters who are working in the “the public interest”? Not one jot; in fact his testimony was so batshit that there was apparently some discussion that it should be ignored completely.

Justice Leveson, currently overseeing what amounts to the most fascinating chat show ever broadcast, says that a free press represents “an essential check on all aspects of public life”. Certainly it does, but it’s become clear from the parade of celebs, tits, paedos, grief-mongering, jingoism and shrill hyperbole in many of the tabloids that it’s simply not fulfilling that role any more.

Nick Davies – whose horribly depressing book Flat Earth News is a must for any journos and has been circulated among every journo, by every journo, I know – says that it’s “incredibly difficult” to know where the public interest lies. That difficulty has become a cloak to protect dodgy journalists and covers a multitude of sins.

“[A]ny failure within the media affects all of us,” says Leveson. “At the heart of this inquiry, therefore, may be one simple question — who guards the guardians?”

That should send shock waves rippling through the media – and particularly the PCC. But they only have themselves to blame. For too long the cowboy journalists have bent rules designed to help the press expose wrongdoing in order to shaft anyone who enters into the same definition of “public interest” to which Paul McMullan subcribes.

“A balance must be struck between the freedom of the press and the rights of individuals to be treated fairly,” said Leveson. That the balance is hopelessly skewed is fairly clear from the first few days of the inquiry; that Leveson will feel compelled to act, given some of his statements thus far, seems equally clear.

How has this been allowed to happen? Because successive governments enter a Faustian pact with media moguls and their lackeys such as Murdoch, Brooks, Lord Rothermere, the Barclay Brothers, Paul Dacre and Richard Desmond – bestowing favours and turning blind eyes to the worst excesses.

The end result is a situation where the Prime Minister is best chums with two people described at the Leveson inquiry as “the scum of journalism”, complicit in a system that has the power to bring down politicians – or destroy any public figure – almost at a whim.

I wonder if Leveson has changed his mobile passcode.