Sienna Miller’s decision to settle with News International in her phone hacking case, though  not unexpected, certainly changes the picture in the phone hacking scandal. Not only does it set a precedent of a hacking victim accepting Rupert Murdoch’s pay-off in this phase of the affair, but the sum involved, of £100,000 (plus costs), may well prove a benchmark for other settlements.

It is worth pausing, though, to see what Miller has achieved. Have a look at her claim document, which was filed last October. It describes an extraordinary, nightmarish and all-embracing campaign of intrusion into the privacy of an actress then in her mid-20s — a campaign with no other aim but to uncover tittle-tattle about her personal relationships. Everything in that document is now admitted by the the News of the World, and possibly more.

As her barrister, Hugh Tomlinson, put it in court: “All her claims are admitted: the misuse of private information, breach of confidence, publication of articles derived from voicemail hacking and a course of conduct of harassment over a period of 12 months.” This from an organisation which for years denied all these things (having first spent seven times as much buying the silence of Gordon Taylor after he produced evidence that News International employees had been up to just this sort of thing).

We should pause, too, to ask who at executive level in this disgraced company is being held accountable for this. Certainly the police investigation is continuing, with three News of the World staff arrested and bailed. But that is a separate affair, though it may yet result in convictions. The company is institutionally liable, but no one is accepting institutional responsibility. It follows that, even after these latest admissions about Miller, nobody senior in News International really thinks any of them has done anything wrong, or has failed the company or the public in any way.

They — Rebekah Brooks, Colin Myler, James Murdoch, Tom Crone and others — might suggest that Andy Coulson took the fall, but very clearly he did not. He has insisted all along that he knew nothing, and has even claimed as a virtue the fact that he resigned as News of the World editor. That is not taking responsibility.

So we face the remarkable spectacle of a leading British company publicly admitting gross wrongdoing and then shamelessly writing cheques to make the whole thing go away — something it can do with little pain because it is very rich indeed. And in the meantime the editors and leader writers of the Times, the Sunday Times, the Sun and even the News of the World have the nerve to continue telling the rest of the world how to behave. (Compare, for example, what is alleged against Chris Huhne with what News International has admitted.)

We don’t know whether other victims of hacking will follow Miller’s example. Her claim document identified a maximum sum of £100,000 and when she was offered that in full her lawyers struggled to justify continuing. Other claimants, however, have not identified a maximum and are not vulnerable to a direct buy-off without a trial in the same way. So the civil courts may have a further role in prising open this can of worms.

The police investigation, meanwhile, continues. But what will really make a difference in this case is a full, formal and wide-ranging public inquiry. Will the decision about whether that will happen really fall in the end to David Cameron, who counts Rebekah Brooks as a personal friend, dines with her often in Oxfordshire and even, apparently, goes riding with her?

Brian Cathcart teaches journalism at Kingston University London. He Tweets at @BrianCathcart