The commission's muted response to the publication of the pictures, first in the Daily Mirror and then in other tabloids, is in sharp contrast to its ex cathedra statements about this summer's other two big stories involving press ethics - reports of friction in the Prince of Wales's marriage and the liaison between David Mellor, Secretary of State for National Heritage, and Antonia de Sancha, an actress.
In the first case Lord McGregor, the commission chairman, accused journalists of 'dabbling their fingers in the stuff of other people's souls' by commenting so freely on the Princess of Wales's alleged unhappiness. In the second an emergency meeting of the commission was called, ending in an oddly ambivalent statement that distinguished between the rights to privacy enjoyed by private citizens and public figures - although Lord McGregor insisted this was not a specific comment on the Mellor case.
Last week there was no formal statement on the Duchess of York pictures, nor has there been this week about the publication of alleged transcripts of intimate telephone conversations involving the Princess of Wales. When the commission holds its regular monthly meeting today, the cases will be discussed but no public pronouncement is likely.
As the victims of the intrusion have not complained to the commission, it is not obliged to issue a formal ruling. Yet the issues involved in the use of long-lens cameras and secret recording devices are easily as important as those in the two earlier cases.
Lord McGregor's reticence this time is attributable to the tensions created within the commission by the first two cases. Unsurprisingly, there is scarcely any common ground on these matters between the two national tabloid editors who sit on the commission - Patsy Chapman of the News of the World and Brian Hitchen of the Daily Star - and the broadsheet editors and lay members. Ms Chapman and Mr Hitchen did not wholly agree with Lord McGregor's statement about the earlier Princess of Wales stories.
Mark Bolland, the newly appointed director of the PCC, plays down the significance of the differing reactions.
'We've had 59 written complaints about the Duchess of York pictures, and about 60 on the phone,' he said yesterday. 'Some say it's intrusive and others ask why they can't leave her alone. Some don't like the semi- naked pictures on the front pages of their tabloids, but the commission doesn't rule on matters of taste. A lot of the people who've phoned today and yesterday also objected to the reports on Princess Diana's taped conversation.
'But the earlier Princess of Wales story was different. That was speculative and entirely rumour- based reporting about the state of her marriage. There was greater public concern about it. We had 400 calls - a reaction we've never had before.
'There's much less sympathy for the Duchess than there was for the Princess of Wales. It wasn't anyone from the British press who took the pictures and it's difficult to stop them appearing here once they have been published elsewhere.'
Yet most people would view long- range picture-snatching as a greater invasion of privacy than retailing gossip. It is odd for a quasi- judicial body such as the PCC to decide how to proceed on the basis of the comparative popularity of the victims of intrusion.
It was noticeable how the tone of the discussion about the pictures changed rapidly when people realised just how unpopular the Duchess was. On the morning they were first published, the question being asked by radio and television interviewers was the same as that asked after the Princess of Wales and David Mellor stories: 'Has the press shot itself in the foot?'
Governments have long dangled the threat of privacy legislation over the media. Sir David Calcutt - whose 1990 report on privacy recommended a law barring the use of snatched pictures - is examining whether the PCC has 'worked' since it replaced the Press Council last year. Whenever a big new scandal breaks, the first question asked is whether it will be the final straw leading to legislation.
On this occasion the question soon disappeared from the airwaves. It is inconceivable that the Government would introduce legislation to protect the unpopular Duchess, and word was soon passed down from Whitehall that the Cabinet does not at present have such laws in mind.
This was comforting news for Lord McGregor, whose mission is to stave off legislative restrictions on the freedom of the press. Yet in the longer term the events of the past week have not augured well for the commission's role in press self- regulation.
Lord McGregor's embarrassing interview on Radio 4's Today on the morning the Mirror's pictures appeared, in which he declared himself unable to make any substantive comment, shows how hamstrung he has become by the lack of consensus among the commission's members. If the PCC cannot take a stand on the vital issues affecting press behaviour, questions are bound to be raised about its future.