FOR 15 months a courtroom in North Wales has heard some of the most shocking evidence ever recounted in this country of the way in which vulnerable children were submitted to terrible, systematic abuse.

Moving accounts of violence, of assault, of fear and of basic cruelty have emerged from the secret, closed world of the care system. The tribunal, under Sir Ronald Waterhouse QC, was ordered by the former Secretary of State for Wales, William Hague, following the convictions of seven men for assaulting youngsters in the care of the former Clwyd and Gwynedd county councils in the early 1990s. It ended years of speculation surrounding allegations of child abuse of almost epidemic proportions.

There have been 200 full days of hearings and evidence from more than 300 people - from the managers responsible for the homes, the men convicted of abuse, care workers and those accused of abuse but never prosecuted, and, of course, from the alleged young victims. Many of the allegations centred on the notorious Bryn Estyn children's home in Wrexham, which is now closed, although 40 other North Wales homes have been implicated.

Day after day, for more than two months, the tribunal heard detailed accounts from young men about how their lives had been ruined by their time in care. And it also heard how officialdom - from social services to the police - let them down.

Yesterday, the tribunal heard the closing speech by its senior counsel, Gerard Elias QC, who had begun it all 15 months ago with a simple pledge: "No civilised society may tolerate abuse of its children, and no civilised society will consider those who find themselves in care to be in any different position to those who enjoy the benefit of living at home."

For years, allegations of abuse in North Wales homes had been rife. One of the first to question whether systematic abuse was going on was Alison Taylor, a care manager, who went first to her superiors and then to the police with information. All she got for her pains was the sack. Eventually, her actions did lead to a police inquiry in 1991, from which it emerged that two homes in particular, Bryn Estyn, a council home, and Bryn Alyn, privately run, had been centres of paedophile activity. Six perpetrators were convicted, but others were alleged to have been involved and never punished. An investigation commissioned by Clwyd County Council, chaired by John Jillings, urged that only a full public judicial inquiry could get to the truth.

The eventual tribunal had some difficult questions to answer: How many people were abused? Why it was not prevented or detected? But, as well as these terms of reference, there was a sub-plot to the hearings. Might there have been an organised paedophile ring operating? Were well-known people really involved in the abuse of children?

While evidence was heard from the homes' managers, the men convicted of abuse, care workers and those accused of abuse but never prosecuted, it was the testimony of the 150 young people who said they were victims that brought silence to the court. They were quietly determined, but uncomfortable and in some cases wretchedly nervous, a stark contract to the ranks of lawyers.

In many cases, as Mr Elias pointed out, it took great bravery to relive those painful events. The sheer volume of the statements was impressive: "If they are accepted by the tribunal, then it may be that they will compel the conclusion that children in care in Clwyd and Gwynedd were abused physically and sexually on a scale which bordered on wholesale exploitation," he said.

These young witnesses were all, in one sense or another, victims even before they came into public care. They had come from broken homes, or homes where the parents could not cope. Some were rowdy children, officially declared beyond parental control, and some had already been abused.

The allegations grew in recent years, rather than at the time in the 1970s and 1980s when residential children's homes - and the abuse - were at their height, for a clear, understandable reason. When a child is being abused, he or she is often both threatened and made to feel guilty by the perpetrator. The guilt later turns into shame and a reluctance to discuss what happened. Many victims feel that their failure to speak out at the time made them accomplices. Their complaints aired at the inquiry have come at a time when many had settled down in life. But they remained deeply troubled - and their sense of injustice at what had happened to them grew.

Many of the indicators of abuse had been there for some time, and it is to many people's shame that allegations were not taken seriously before: there had been children running away from home; there were complaints about staff and their lack of care; there was the lack of regulation and the entry of highly unsuitable and unmonitored people into the staff of the homes. In some cases, children's homes were run at arm's length from the local authority, while in others they were run as private operations. They were out of sight, and out of control. The children were an invisible underclass.

In stark contrast were the convicted abusers. There was John Allen, a man who had not only abused the children placed in his care, but who had made a considerable amount of money along the way. Allen, who owned the Bryn Alyn home, had threatened to refuse to give evidence to the tribunal, but in the event, he turned up to protest his innocence.

Allen had been paid more than pounds 28m by local authorities to look after children, and he was at one time drawing an income of more than pounds 200,000 from the operation. "You ran Bryn Alyn to exploit children for your own gratification and to be paid substantial funds," Mr Elias told him.

Throughout the tribunal, abusers and alleged abusers have been named - one man has had 60 individual allegations of abuse made against him - but Sir Ronald has banned publication of the names of all but those who have been convicted, although he has intimated that he may use some names in his final report.

But it was not just abusers and alleged abusers who came in for criticism. The Welsh Office, the North Wales Police, councils, managers, and insurers were all summoned to give evidence and all interrogated over alleged failings.

In his opening speech 15 months ago, Mr Elias said the issue of an organised paedophile network was one of the most important questions to be answered: "Was such abuse the product of a series of chance, unrelated occurrences or does it bear the hallmarks, in part or in whole, of greater organisation or infiltration by those with a determination to exploit vulnerable children in care?" he asked.

"If there was such an infiltration, this raises the question of the existence of a so-called paedophile ring. If such a ring did exist, was it organised, or simply an informal arrangement between abusers to share information and opportunities?"

Just what the final inquiry report will say remains unknown. Not only is the report as yet unwritten, but Sir Ronald has forbidden any speculation about what may be in it under pain of contempt proceedings.

Childcare specialists would like the final Waterhouse report to tackle a number of issues. Apart from its verdict on the allegation of past abuse and what went wrong, they hope it will give guidance on how to stop such mistakes ever being repeated.

As the inquiry comes to an end, one thing more than ever overshadows it: the number of additional young men who should have given evidence - at least 12, maybe 20. They are dead: from drug overdoses or by their own hand. Their tragic stories will never be told.