If the inquiry rules that all material held in MI5 and police files about witnesses should be publicly disclosed, the vetting procedures on this secret material could take years, a lawyer warned yesterday.
Mr Philip Sales, counsel for MI5, the RUC and other security agencies, told the inquiry the agencies would have to examine all documents to decide whether they could be made public, or whether a claim of PII (Public Interest Immunity) should be entered to deny access to them.
The process would involve risk assessments, balancing tests, legal advice and ministerial reviews, in advance of special PII hearings, all of which would result in great delay to the inquiry's business.
Mr Sales said that to go this full-blown PII route would involve "a PII exercise unlike anything that has been remotely attempted in court proceedings".
However, it would be required because disclosure en masse, even of redacted or censored documents, would be likely to cause serious damage to national security by revealing "the range, direction and scale of the agencies' intelligence operations".
He said the agencies advocated the alternative approach of providing summaries of the information, if any, held on witnesses.
As much summary information as was required would be made publicly available and there would be an independent review (by tribunal lawyers) of the underlying source material.
He argued that proceeding by way of summaries setting out the gist of the underlying material was accepted practice in court proceedings. The agencies' best estimate of how long it would take to produce these summaries was at least six months.
Counsel said the agencies had assessed the scale of the task by attempting a check against the 1,200 witnesses as to whether any of them had been involved at any stage in a paramilitary organisation.
He admitted, however, that the information in the records would be suggestive only.
Arguing against the production of intelligence material, Mr Dennis Boyd, for a tribunal witness, Mr Sean Collins, said the use of such material would be in breach of the individual's right to privacy as enshrined in Article 8 of the European Convention on Human Rights. This is now adopted into UK law in the Human Rights Act.
It was also questionable to attack the credibility of a witness by using material whose reliability was itself fundamentally suspect.
Mr John Coyle, for the McGuigan family, argued that the security material could be mendacious and mistaken, and the consequences of using it could be serious. The information could be quite stale, persons might not know their accusers and might not be able to mount any "defence".
Mr Michael Lavery QC, for a number of families, said the use of such information would have profound and far-reaching implications for the safety and reputation of those against whom it would be used.
In using such material, the tribunal could unwittingly become a channel for the type of information that had, in the past, been used by loyalist paramilitaries to target individuals. Issues surrounding the right to life would inevitably arise.
During the submissions, the chairman, Lord Saville, emphasised a number of times that there was no question of the inquiry prejudicing individuals' rights, whatever route it chose to take. It would adopt a procedure to ensure those rights were protected. Further submissions on the issue will be heard next Tuesday.
Meanwhile, the hearing of evidence from witnesses will resume on Monday.