An air of mystery surrounds the claims by The Guardian that the News of the World was involved in a huge operation involving the tapping of celebrities’ mobile phones.

Those allegedly affected included well-known figures such as the former Deputy Prime Minister John Prescott, London Mayor Boris Johnston, actress Gwyneth Paltrow, publicist Max Clifford and many others.

Throughout most of yesterday there were calls from Mr Prescott and others for more investigation of such claims which, if proved true, would be a serious breach of the personal privacy of those involved, and also a condemnation of the methods used by one of Rupert Murdoch’s most successful newspapers.

Another important dimension was the position of the Tory Director of Communications Andy Coulson, who resigned as editor of the News of the World some years ago after its correspondent Clive Goodman was jailed for hacking into the telephone messages of Royal aides. However the train of events, which was steadily gaining momentum for most of yesterday following The Guardian’s claims, was suddenly shunted into a siding — if not entirely derailed — by Metropolitan Police Assistant Commissioner John Yates.

He said that no new evidence had emerged since the original inquiry in 2007 and there would be no further police investigation of claims of a huge mobile-hacking operation.

Meanwhile, the Crown Prosecution Service indicated it would be carrying out a review of the evidence presented to it, and there will still be an inquiry by a powerful Commons Committee.

The current situation is, to say the least, extremely complex and it is difficult for the public — and media professionals themselves — to know what to make of it. At this stage, however, there are serious questions which need to be answered.

Why would such a responsible newspaper as The Guardian stake its reputation on making such claims if it did not have the evidence to back these up? What was the political significance of these claims, given that one of the major figures in the earlier story is David Cameron’s trusted Director of Communication?

Questions are also being asked why the police moved so quickly to announce no further investigations are being planned, especially as the Crown Prosecution Service and a Commons’ Committee are both continuing with their own investigations.

It is unlikely that this row will simply go away. There are too many influential people in high places who will not be content until they receive satisfactory explanations — if such are possible — about this extraordinary affair.

This is not a matter for the politicians, the police and the media only. It is also a matter of great public importance that the media should continue to investigate situations of considerable significance, but in such a way that the freedom of the Press is balanced against the private rights of the individual.

Recently the Daily Telegraph showed in its exposure of the MPs’ expenses scandal that crusading journalism can indeed be in the public interest.