How do we know when press regulation is good enough? The question is topical because IPSO, the self-regulator established by the big corporate newspapers, has been trying lately to persuade us it can be trusted to do its job.

IPSO has revealed changes to its rules which it says give it increased authority and independence, but as we all know there is a long history of failure in this area, and of bold claims which have proved to be false, so we can’t simply take IPSO’s word for it.

And this is not an abstract matter. When press standards slip people suffer, and they are very often vulnerable people. More than that, society suffers, because the everyday sources of information on which we rely as citizens are poisoned.

So it would be helpful if we had a yardstick to measure IPSO by, a sensible set of criteria against which we could test it to see if it really is effective enough to protect us and independent enough to be fair, while ensuring that freedom of expression is not constrained.

The good news is that such a yardstick exists. Basic standards for press regulators were set out clearly in the Leveson Report of 2012 and subsequently incorporated in the Royal Charter on press self-regulation. There is even a small, independent public body called the Press Recognition Panel whose job is to determine whether those standards are met.

Distilled to 23 criteria in the Charter, the standards cover matters such as the independence of appointments and funding, the manner in which the code of conduct to be upheld by the self-regulator should be compiled, powers to investigate code breaches, possible sanctions on news publishers and low-cost arbitration in cases of alleged libel and breach of privacy.

These criteria are not arbitrary or whimsical but were the fruit of a painstaking, year-long public inquiry established by Parliament in response to the latest widely-acknowledged collapse in press standards. The judge in charge, Sir Brian Leveson, was explicitly tasked with finding a new formula for press self-regulation that would uphold standards, protect the public and at the same time be free from political interference.

A public inquiry of this kind is the best mechanism our democracy has found for dealing with its thorniest problems, and the answers that Sir Brian Leveson came up with – including those criteria – were endorsed by every party in Parliament, by leading victims of past press abuses and by many of the most prominent people in the world of free expression in Britain. Opinion polls have also shown overwhelming public support.

In short, the Charter criteria have compelling legitimacy. They are what society wants and expects of a press self-regulator.

So, how does the new and supposedly reformed IPSO measure up? Does it meet the Charter criteria?

We don’t need to go into any detail because IPSO’s chair, Sir Alan Moses, has openly acknowledged that it doesn’t meet the standards, indeed he has made plain that it doesn’t even aim to. And the corporate newspaper groups that own and control IPSO have no intention of submitting IPSO to evaluation by the Press Recognition Panel because they know it would fail.

Their reasons could hardly be plainer. If a code of conduct in journalism is to be upheld effectively, as the Leveson Report made clear and indeed as all the world can see, a press self-regulator must have clout. It needs sufficient authority to require even the Sun and the Daily Mail to abide by the agreed ethical standards.

But the Sun and the Mail, not to mention the Mirror, the Times, the Express and the Telegraph, have no intention of keeping to a code which might prevent them distorting, intruding and bullying when they choose, and so they will not give IPSO the necessary powers.

This leaves Sir Alan Moses struggling to persuade the public to endorse something that self-evidently falls short of what the public expects.

The language he uses is revealing. Asked by the Guardian whether IPSO now satisfied the Charter criteria, Sir Alan responded: ‘I think it’s a nerd-like, tick-box way of dealing with it.’

Those are strange words, coming from a former senior judge who is presumably accustomed to reading the letter of law and trying to apply it. They are also remarkable words from a supposed regulator with a code of practice to uphold. Does he consider it nerd-like and tick-box for journalists to observe the letter of the code?

In the attempt to shore up his position, Sir Alan tells us he is about to announce an ‘independent auditor’ to check how IPSO is doing – his personal substitute for the Charter criteria. This auditor will be paid by IPSO and appointed by a panel chosen by IPSO and the press industry, and will measure IPSO against terms of reference developed by IPSO itself – in secret. (Moreover, if Sir Alan’s approach is any guide, he or she will presumably do the job without the bother of any nerd-like attention to detail.)

Sir Alan is in a corner. He can’t do what the public requires because his paymasters will not let him, so he is reduced to pretending instead, and to insinuating that the differences are insignificant when they are not.

Many thousands of people in this country have suffered as a result of press behaviour which breached the agreed industry code but which editors knew they could get away with because their regulator was a puppet. Those victims include bereaved families, people in marginalised minorities and those who simply stumbled into the crosshairs of over-aggressive reporting. The rest of us have also lost out, because important, powerful newspapers know they can get away with presenting important issues in dishonest ways.

The Leveson Inquiry laid all this bare and showed us the way to something better. IPSO, however, promises to take us in the opposite direction.