It is one of the most common refrains of the lawyers who run modern Britain under the cloak of New Labour: the effect of the Human Rights Act is grotesquely exaggerated, they say, its scope misunderstood by ignorant people who attribute to it powers it does not possess.

Lord Falconer, Tony Blair’s one-time flatmate and our minister for justice, was at it again on the radio only recently: a police force which had refused to issue pictures of wanted criminals in case it breached their human rights had simply got it wrong. In this instance they may have done. But in other ways the Human Rights Act is having the most profound consequences, both for freedom of speech and for democracy.

Both of these issues are at the heart of a battle that is being fought through the English legal system, between the Mail on Sunday and the Prince of Wales. We published a story based on a leaked account he had written about one of his overseas trips, and the prince sued, claiming breach of confidence.

This is the real Human Rights Act in action. The man exploiting it is as far removed from a criminal on the run as it is possible to imagine: he is the heir to the throne itself. But the principles at stake are the same. Which takes precedence: the individual’s right to privacy or the public’s right to be informed?

To explain what is going on, we will start with Richard and Judy. Leaked documents are part of the lifeblood of any newspaper. Take just one recent Mail on Sunday front page: ‘Richard and Judy TV Quiz Scam’. A disgruntled employee hands over a bundle of emails which suggest that companies involved in the production of Channel 4’s Richard and Judy programme are making £7,000 a day by soliciting premium-rate telephone entries to the quiz section of the show after the cut-off point at which they can no longer be processed to take part.

Technically we have no right to see these emails, nor have the public: they are confidential. But viewers, it would appear, are being cheated: there is a public interest. We publish and Channel 4 takes the quiz off air pending an investigation. Textbook journalism – and a victory for tens of thousands of TV viewers who have been paying £1 a time to take part in a quiz that is already closed. But what if Channel 4 follows the path taken by the Prince of Wales and sues us for breach of confidence?

As the law of confidence has worked until now it would stand no chance. The public interest in championing the cheated viewers would always trump the embarrassment caused to Channel 4 by having its emails made public. But the Prince of Wales employs an aggressive firm of showbusiness lawyers and they have seen, as have other showbusiness lawyers, what Lord Falconer

cannot see: the Human Rights Act does have teeth.

The case of the Hong Kong journal began, like the Richard and Judy case, with a disgruntled individual who had in her possession some documents. Through an intermediary she handed them to the Mail on Sunday.

There are eight of them altogether, and they are among the most fascinating items I have ever read. Written by the prince in his own wry, lucid, Goonish style, they are accounts of official trips he has taken abroad.

They describe places he has visited, events he has witnessed and people he has met, complete with his own observations, some of them waspish. They are clearly written for an audience – the prince’s private secretary, Sir Michael Peat, later confirmed to me that the intention was to publish them at some point. They were typed up by our disgruntled former palace employee and distributed to people the prince wanted to impress – between 30 and 75 individuals. No one is quite sure how many because no one, including the prince’s own office, kept a proper list.

They contained much of interest, but one news story stood out. In the week we authenticated the journals, the Chinese president was making a state visit to Britain that included a banquet at Buckingham Palace. But the prince would not be going to the banquet, apparently because a trip of his own to America had been extended unexpectedly.

It was not the first Chinese state banquet he had missed, and on the previous occasion he had let it be known it was for political reasons: he did not approve of the Chinese communist leadership.

The Hong Kong journal made this abundantly clear. ‘Appalling waxworks’ was the phrase he used to describe China’s leaders.

As with Richard and Judy, textbook journalism you might think. Not according to the Prince of Wales, his lawyers Messrs Harbottle and Lewis, Mr Justice Blackburne, or the Court of Appeal.

Unlike Lord Falconer, who thinks it is all as warm and cuddly as he is, they see that the Human Rights Act lays the foundation stone for a law of privacy; something which, from Magna Carta onwards, has never existed in English law.

The problem is that, like all bad law, the Human Rights Act is contradictory. Article 10 guarantees freedom of speech. Article 8 guarantees the privacy of the individual. Or at least the privacy of individuals who can afford expensive lawyers – the bill for the prince’s case so far is £500,000 and it’s not finished yet.

The prince’s lawyers sued us for breach of confidence. To do so they used a procedure called ‘summary judgement’. This had the advantage for them that they did not have to produce witnesses – meaning the prince would not be obliged to give evidence in his mother’s own courts.

It had the disadvantage, for them, that they had to show that our case – that the public had a right to know what the heir to the throne thought of China’s political leadership, just as he had informed them all too clearly what he thought of carbuncular architecture, ‘grey goo’ nanotechnology and an Englishman’s right to go foxhunting – was so hopeless that it had no chance of success at all.

On seven of the eight journals the judge ruled that the issue should go to full trial. But in the case of the Hong Kong journal he ruled otherwise. This despite that fact that the journal contained nothing of an intimate, medical or sexual nature, indeed nothing that any normal person would regard as private, beyond the revelation that he had had to fly to China club class, whereas the prime minister and various other politicians had flown first. (Even then, he omitted to tell his coterie of correspondents that he and his entourage had been given the whole of the club class cabin to themselves.) And also despite the fact that the prince’s lawyers had happily made the entire journal a court document (we had only published a news story quoting brief key passages).

When other newspapers argued that, as a court document, it was publishable, Mr Justice Blackburne quite bizarrely allowed reporters to read it for an hour and make notes, but not to photocopy it. Perhaps he thought that if he let newspapers publish as many interesting bits as they could copy out in 60 minutes he could preserve the privacy of the uninteresting bits.

His judgment makes interesting reading and reflects the unconscious prejudices of one who is a member of what was once called the Establishment. He pays almost no attention to our constitutional argument, developed elsewhere by the historian Tristram Hunt and others, that the journal illustrates and supports the case that the prince, notorious for writing to cabinet

ministers and memorably described during the trial as a ‘dissident’, has been assiduously developing a political role for himself, in defiance of his constitutional position.

He accepts most of the prince’s evidence as fact, and dismisses ours as hearsay, despite the fact that our main witness, Mark Bolland, worked for the prince as his deputy private secretary at the time the journal was circulated, whereas his main witness, Sir Michael Peat, was working elsewhere.

He seems much perturbed that the source who handed the journals to our intermediary was a secretary. One wonders if he would have taken a different view if the source had been one of the journal’s intended recipients, Sir Nicholas Soames perhaps.

The Court of Appeal took a different tack, ruling that while there was a public interest, it was not enough of a public interest. We had argued, in part, that as the Prince of Wales had authorised the leaking of his views of the Chinese leadership in the past, he could hardly claim that our amplification of those views was private.

They turned that on its head, saying that because his views were already partly in the public domain we could not claim a public interest that overrode his right to confidentiality.

As I write, we are preparing to take the case to the House of Lords, where David Pannick QC will argue forcefully that, even under the Human Rights Act, privacy is relative; that because of the public position he occupies, and because of the effect that his beliefs and actions have on the lives of others, a politician or a prince must be more open to scrutiny than a private citizen.

If we win, we will be able to write about some fascinating and historic documents. If we lose, the consequences for a free press are deeply disturbing.

First, it will establish that it is for a judge to decide what is or is not newsworthy for a newspaper to publish. Simply throwing light on what important people think and do will not be enough. Even criminality may not be enough, as recent cases are beginning to show.

Second, it will suggest that the social status of the whistleblower will determine whether a story can be published. Any political editor will tell you that the greatest leakers of stories, apart from ‘friends’ of the royals, are cabinet ministers. I have yet to see a privacy action over documents leaked by a government minister. Why should a secretary be prevented from doing the same?

Third, it will endorse a remedy only open to the rich. The law firm Schillings, whose boss describes himself as the ‘Prince of Darkness’ and which has done most to develop the use of Article 8, has been thwarted by Mr Justice Eady in an attempt to recover £450 an hour for its services.

This is by no means the only case where the Human Rights Act has been deployed against freedom of expression. It stands alone only in that our story has already been published, and the arguments are being heard in open court. Much more worrying are the increasing number of instances in which rich and powerful people use Article 8 to suppress news before publication.

One notorious case involves a leading figure in the world of sport who had an affair with a woman. When the woman’s husband found out, he tried to go public with his story. Mr Justice Eady, sympathetic to the feelings of the adulterous football figure, who claimed he had patched up his marriage, ruled that the wronged husband must not talk about the affair to anyone. Thus not only has he been cuckolded, but the man who cuckolded him now has the protection of the law.

It is an not an edifying case, but the principle that has been breached, that the law should not protect wrongdoing, is a very important one. At least in this instance Mr Justice Eady, who hears the majority of these cases, gave his judgment in public, albeit with the identities of the individuals involved kept secret.

The Mail on Sunday is nowadays threatened with injunctions nearly every Saturday afternoon. Many of these cases concern issues much more serious than

adultery in the world of sport; in some, criminal acts are involved. But if the individual about whom we plan to run a story can convince a duty judge, sitting alone and hearing the arguments by conference call, that the allegation impinge on his private life, the court will generally play safe and impose an injunction. Routinely the terms of the injunction prohibit the newspaper from

reporting the fact that an injunction has been granted, or the arguments that were presented for and against.

One of the fundamental principles of English law is that justice should be public: it must be seen to be done. There is a very good reason for this: if judges know they are not open to scrutiny, they are tempted to take shortcuts and allow themselves to be swayed by their prejudices.

That is what is happening with Article 8 of the Human Rights Act. Not only are important news stories being suppressed, and wrongdoing protected, but a law of privacy is being created, not by our elected representatives in open debate, but by lone judges, sitting in secret.

And that is why it is so important, in cases like that of the Prince of Wales, where the arguments are heard in public, that someone stands up for free speech.

Peter Wright is the editor of the Mail on Sunday