Maybe Detective Sergeant Paul Hughes knew he was handling dynamite. Then again, maybe he didn't. In 1991 the policeman, from the child protection unit at Bannockburn, wrote a report detailing the disturbing behaviour of a man called Thomas Hamilton. It recommended Hamilton be prosecuted for his conduct at a children's residential holiday camp, and recommended his firearms licence be revoked. Neither recommendation was acted upon.

Parts of Mr Hughes's heartbreakingly prescient report were published in June 1996 after the Dunblane

massacre. ''I would contend that Mr Hamilton will be a risk to children whenever he has access to them, and that he appears to me to be an unsuitable person to possess a firearms certificate in view of the number of occasions he has come to adverse attention of the police and his apparent

instability,'' he wrote. Hamilton was ''scheming, devious, and deceitful''.

But these were only extracts. The actual details of Mr Hughes's report - a ''voluminous'' work relating to Hamilton's activities and listing large numbers of children's names - were not released. And in 1996, after Hamilton killed 16 pupils and a teacher at Dunblane Primary School, Lord Cullen met the staff of the Scottish Records Office and recommended that the report be placed under 100-year closure.

The huge question now waiting to be answered, following allegations at the weekend, is whether the report did more than list abused children. Did it, as alleged, also contain damning evidence that Hamilton had friends in high places? That he was being protected by a former cabinet minister and a high-ranking lawyer? Is this the real reason why Paul Hughes's report is suppressed for so long?

Rightly or wrongly, within a culture of institutionalised secrecy it is hard to avoid the conclusion there is something to hide. A ban like this gives the conspiracy theorists validity. A century's wait invites accusations of a high-level cover-up. Hence the veiled suggestions one of these high-ranking individuals was also a child sex abuser, and the implication that freemasonry encouraged an evil network to flourish, protected by the establishment. Hamilton's masonic links, the conspiracy theorists point out, have been long rumoured but never investigated.

Now all this may be overheated nonsense, hot-housed by a society which sees paedophilia lurking in every shadow, but it is very hard to defend when the source is inaccessible: not for 30 years, or even 75, but for 100, by which time we will all be dead. The only way to silence such accusations is to lift the ban. If the allegations are true, justice must be done. Such a move is clearly in the public interest.

Yesterday the Records Office, now called the National Archive, confirmed that the 100-year rule was enforced because the report relates to young children. Dr Peter Anderson, a deputy keeper who was involved in Lord Cullen's decision, confirmed that while most 100-year cases were reduced to 75-year closure in the late 1980s, documents still under a 100-year ban include anything involving children; plus rape victims (for instance, the identity of Carol X); sectarian politics in Northern Ireland; and the royal family.

He said his office had been asked a few years ago to see if it was possible to ''anonymise'' the Hughes report by blotting out all the names of the children, and had re-examined the report carefully. In its expert opinion, it was not possible. ''It would be very hard to dis-aggregate bits,'' he said. He pointed out that anything heavily amended and blotted out would only fuel the conspiracy theorists, and expressed his belief that the Freedom of Information Act, presently being implemented, would not make any difference as material given in confidence or which would endanger life, or cause substantial distress, would still be exempt.

Dr Anderson is not unsympathetic, nor is he trying to be difficult. He is trapped by a system which provokes more questions than it does answers. The fact is that there is no law or legislation relating to Scottish cases, only custom and practice. The Public Records Act of 1958 specifically excluded any body within or concerned with Scotland, but the Scottish Office effectively implemented the act by administration. In practice, the Crown Office holds the power to release information, although, just to add to the ambiguity, it seems the first minister could request release.

Which leaves us no closer to the solving the mystery of the Hughes report. The longer this nastiness brews, the more sensational the conspiracy theories will become and the more damage will be done to individuals. It is an embarrassment to a modern, open society. It is an additional cause of pain for the Dunblane families, who have already suffered too much.

Michael Matheson MSP, the SNP justice spokesman, said yesterday that two of the bereaved families seek the removal of the 100-year closure. He has pertinent questions. He wants to establish under what jurisdiction in Scots law the closure was made, and who is responsible for enforcing it. He also wants to know what provisions there are for it to be revised and revoked. He believes a device called a Chancellor's Instrument exists to release secret documents in England, but does not know if it applies in Scotland. Nor, it seems, does anyone.

Matheson believes the names of

the children could be blanked out

and the Hughes report released. He does not accept it is impossible to make the report anonymous. ''It's

the other names we are interested

in. I somehow don't think that is sufficient justification for a 100-year rule to be applied.''

Likewise, the existence of a judicial grey area does not bar the application of common sense. A system operates in the Scottish courts which daily protects the identity of children. Newspapers live by Section 45 of the Criminal Procedure (Scotland) Act 1995. There seems no reason why the

Hughes report could not be released under similar restrictions.

The Scottish Executive must display courage, muscle, and initiative and ask the Crown Office to lift the ban. Not to do so invites the inevitable conclusion that there is something to hide. They would also do themselves much good if they investigated the legal anomalies surrounding public records, especially with the arrival of the Freedom of Information Act. There may - just may - be justification in 100-year protection for children who may live to a great age. But it is hard to see any other circumstances where such excessive secrecy is necessary. The danger is always that the establishment will use the rules to protect itself.

After Hughes's evidence came to light, the deputy chief constable of Central Scotland Police, Douglas McMurdo, resigned. He was the man who, aware of Paul Hughes's advice to the contrary, signed Hamilton's last firearms certificate. Was he fall-guy for others who have never been named? It would be terrible to think so. It would be the ultimate betrayal if the 100-year rule, while purporting to protect children, was used instead to protect adults whose bad judgments may have facilitated Hamilton's evil. Only full transparency over Hughes's report can reassure us.