IT IS common cause among those nations which deem themselves civilised that state complicity in, or tolerance of murder by the agents of the state is in violation of international norms on basic human rights.

The United Nations Special Rapporteur on Summary or Arbitrary Executions defines summary or arbitrary executions as (in part):

"The deprivation of life as a result of killings carried out by the order of a government or with its complicity, tolerance or acquiescence, without any judicial or legal process" and:

"The deprivation of life of civilians by members of the armed or security forces in violation of law governing the state of war or armed conflict."

There is no statute of limitations on the prosecution of such crimes, and the argument in some quarters that the Bloody Sunday killings should be forgotten and the case dropped simply because so much time has elapsed is simply an argument that the guilty should go scot free - and the truth untold - if they can evade detection for long enough.

Immediately after Bloody Sunday, the International Commission of Jurists proposed that an international inquiry should be set up, with neither British nor Irish participation in any of the key roles.

Britain chose instead, on the day following Bloody Sunday, to announce the establishment of its own tribunal of inquiry. One crucial effect of this early announcement was to inhibit all other formal investigations of the evidence surrounding the events.

In the days following Bloody Sunday, members of the Insight team with the Sunday Times - then a formidable investigative journalistic force - had appeared on the streets of the Bogside, actively gathering eyewitness and physical evidence. It had every intention of publishing a detailed investigative account of events the following Sunday.

With the establishment of Lord Widgery's tribunal, this project was shelved and the tribunal became the sole focus of official investigation. The Insight team did compile a three page report on the incidents, but only after Lord Widgery had done his work. That account concluded that the actions of the troops had been totally disproportionate to any resistance they met when they entered the Bogside.

It documented what everybody in the Bogside knew but nobody told Lord Widgery, that the IRA's Bogside units had been up in the Creggan several miles from the scene when the shooting began. When IRA members drove down to the Bogside Inn, they opened fire briefly, with a motley assortment of weapons, on the departing paratroopers. By that stage the main action was over.

Many salient questions remain unresolved and have become more significant as fresh evidence, highlighted by Don Mullan's book, Eyewitness Bloody Sunday, has been uncovered and new insights have developed into the significance of aspects of Bloody Sunday which were not considered by Lord Widgery.

For example, anyone who was present on the day must testify to incredulity at the British army's ammunition count, accepted by Lord Widgery, which asserted that only 108 rounds had been fired by the paratroopers.

The new questions also concern the strong evidence of heavy firing from the city walls and from the British army observation post on top of the Embassy Ballroom in the city centre.

Solicitors for the relatives have already petitioned the European Court which, at that stage, was not persuaded that sufficient new evidence had been presented to justify accepting the case.

But in the past few weeks the new perspective on events has become more focused, and the shortcomings of the Widgery Tribunal are more sharply evident. While the calls to Britain for a new inquiry are unlikely to be heeded, the international options have not yet been exhausted.

There have already been suggestions that a Truth Commission may yet be an essential element if there is to be any healing of the psychological wounds and divisions deepened during the Northern Troubles.

Those who pursue this issue would argue that it is no business of Britain to impede the uncovering of the truth and neither is it any business of Sinn Fein or the IRA to exploit the exercise for propaganda purposes. The enormity of Bloody Sunday transcends the political interests of those on either side of the Northern conflict.

The Rev Terence McCaughey, in a foreword to Eyewitness Bloody Sunday, quotes a commentator from El Salvador: "Unless a society exposes itself to the truth it can harbour no possibility of reconciliation, reunification and trust. For a peace settlement to be solid and durable it must be based on truth."