When the photograph appeared, Buckingham Palace rushed to lodge a complaint with the PCC, accusing the Sun of "premeditated cruelty". But everyone knew that the complaint was largely a matter of putting royal disgust on record. Not that Sophie Rhys-Jones was the only person to suffer from the flouting of the PCC code last week. On Sunday, Lawrence Dallaglio was fitted up by misrepresentation (banned by clause 11) and clandestine listening devices (banned by clause 8). Lenny Henry and Ian Botham were both exposed for what the tabloids call "romps", in breach of clause 3 (privacy).
Although the code tells editors to respect private lives and to justify intrusions, in practice all that its members - eight non-media commissioners and seven newspaper editors - can do is make judgments. The PCC cannot fine a newspaper. It certainly cannot force an editor to resign.
The state of self-regulation in the British press is not a happy or a stable one. The investigation into the Sophie Rhys-Jones affair will be a largely irrelevant process given that the watchdog's toughest sanction is to force an apology - something the Sun has done anyway.
As the Liberal Democrat peer Lord McNally put it in a Lords debate on privacy issues earlier this year: "Journalists, editors and publishers throw self-regulation and codes of conduct to the wind when they think a story sensational enough.... the time has come to consider sanctions of a hefty fine - I mean seven figures - to deter breaches of the code."
In November the Sun's editor, David Yelland, indicated that he thought the PCC was already too heavy-handed in restricting coverage of the Royal Family. He told a conference of newspaper editors: "Before I decide to run a royal story, it is suggested to me that I should call Guy Black (director of the PCC), that I call Mark Bolland (Prince Charles's private secretary) at St James's Palace, that I might speak to Wakeham. There are about five or six different people I need to speak to before I make a decision."
But the extreme alternative to self-regulation - a privacy law - carries its own problems. Tory enthusiasm for the idea resulted in both the Calcutt Commission and the Heritage Select Committee trying to draft laws in the early 1990s, and failing. Both bodies came up with definitions of privacy that, in effect, were casting great nets to catch minnows.
"They suggested that anyone taking a photograph of someone on private property would need the consent of that person before the photograph could be published," says a television editor. "It sounds fair enough. But, in practice, we would never get the evening news on the air. A shot in a street including people in gardens, people browsing in shopping malls - we couldn't show them."
Normal, justifiable journalistic investigation was threatened by attempts to define private lives. "Crooks could easily shift funds from company accounts into private accounts. And the opportunities for criminals to use injunctions as blocking actions against investigations by reputable programmes would be endless," according to the editor. "France has a privacy law, which Robert Maxwell used to great effect."
In a year's time the incorporation of the European Convention on Human Rights into British law will carry with it a broad right to privacy, which will be interpreted by judges. No one knows which way the common law will go, and a statute may be needed in order to "prevent eccentric judges getting out of hand".
Many politicians think a good first step would be for the PCC to become pro-active, monitoring newspapers for offences. Now it acts only when a complaint is received.
Lord McNally agrees with the criticism. During a discussion of the hounding of the daughter of the child murderer Mary Bell last year, he said: "To allow a situation to arise where newspaper reporters are camped outside the house of a 14-year-old girl supposedly under the protection of the courts, in flagrant abuse of the PCC code, is tantamount to a fireman watching a house burn down but doing nothing because no one inside has dialled 999."