The hepatitis C tribunal is expected to furnish its report in about four weeks time. It is already clear from the extensive media accounts of its hearings that its final report will alter irrevocably what were once reassuring certainties in Irish society. Two of those certainties were the absolute reliability of Irish blood transfusion services and the efficacy of the surveillance and control of medicinal supplies. The evidence coming before Mr Justice Finlay already demonstrates that the reliability of the blood supply went out the window two decades ago, and that surveillance and control mechanisms have been substantially fictional, with webs of confusion and collusion binding the Blood Transfusion Service Board with the Department of Health and the Department with the National Drugs Advisory Board (now replaced by the Medicines Board).

Such a state of affairs would have been unthinkable even a few years ago. But, as much of the evidence to the tribunal is showing, people confronted by the unthinkable may fail to think. "It cannot happen, so it did not happen" is a common response, leading to attitudes of denial and defensiveness. This is the most charitable explanation of the appalling series of events that have been revealed to the tribunal by people involved at all levels of the hepatitis C scandal. Given the human devastation that has resulted from those events, Mr Justice Finlay may well find himself unable to put so charitable an interpretation into his final report. If that report is to provide any satisfaction to the victims of the anti D debacle, it will need to allocate blame. And, if it is to prescribe safer and surer systems, it will need to be precise in its determinations.

The unthinkable must now be thought through, and great efforts must be made to restore earlier certainties. But the tribunal has not only made clear the collapse of those certainties within the blood service and its various over seeing State agencies, it has also strikingly altered some political perceptions. The Minister for Health, Mr Noonan, was widely perceived as a man of great political competence prior to his taking over the health portfolio. That perception has been blurred by a succession of political errors made as some of the facts in this scandal began to emerge. And Mr Brendan Howlin, his predecessor, was generally perceived as an excellent Minister for Health - a perception that has been severely dented by his own evidence of how he dealt with what has been described as one of worst public health scandals since the foundation of the State.

From the failure to observe the most basic procedures in the blood bank and its laboratories, which were put in place to protect the blood supply from contamination, through the collective failure of the external controls to ensure that the rules and the laws were applied, to the political failure to recognise and respond rapidly to the emerging crisis, the saga of antiD has proved a deeply sorrowful affair. Still to be addressed are the separate but related issues of HIV contamination and the transmission of hepatitis C in blood products other than anti D. Mr Noonan was probably right to decide not to add these issues to the work of the current tribunal - at least not until after it has reported its findings on anti D. But the examination and resolution of those issues is no less vital and has been given added urgency with the deteriorating condition of the Kilkenny victim of HIV contamination. Alas, a sense of urgency has developed only very late in this catalogue of disasters and denial.